mcs/mcs/expression.cs

   1 //
   2 // expression.cs: Expression representation for the IL tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 // Copyright 2011 Xamarin Inc.
  11 //
  12
  13 using System;
  14 using System.Collections.Generic;
  15 using System.Linq;
  16 using SLE = System.Linq.Expressions;
  17
  18 #if STATIC
  19 using MetaType = IKVM.Reflection.Type;
  20 using IKVM.Reflection;
  21 using IKVM.Reflection.Emit;
  22 #else
  23 using MetaType = System.Type;
  24 using System.Reflection;
  25 using System.Reflection.Emit;
  26 #endif
  27
  28 namespace Mono.CSharp
  29 {
  30         //
  31         // This is an user operator expression, automatically created during
  32         // resolve phase
  33         //
  34         public class UserOperatorCall : Expression {
  35                 protected readonly Arguments arguments;
  36                 protected readonly MethodSpec oper;
  37                 readonly Func<ResolveContext, Expression, Expression> expr_tree;
  38
  39                 public UserOperatorCall (MethodSpec oper, Arguments args, Func<ResolveContext, Expression, Expression> expr_tree, Location loc)
  40                 {
  41                         this.oper = oper;
  42                         this.arguments = args;
  43                         this.expr_tree = expr_tree;
  44
  45                         type = oper.ReturnType;
  46                         eclass = ExprClass.Value;
  47                         this.loc = loc;
  48                 }
  49
  50                 public override bool ContainsEmitWithAwait ()
  51                 {
  52                         return arguments.ContainsEmitWithAwait ();
  53                 }
  54
  55                 public override Expression CreateExpressionTree (ResolveContext ec)
  56                 {
  57                         if (expr_tree != null)
  58                                 return expr_tree (ec, new TypeOfMethod (oper, loc));
  59
  60                         Arguments args = Arguments.CreateForExpressionTree (ec, arguments,
  61                                 new NullLiteral (loc),
  62                                 new TypeOfMethod (oper, loc));
  63
  64                         return CreateExpressionFactoryCall (ec, "Call", args);
  65                 }
  66
  67                 protected override void CloneTo (CloneContext context, Expression target)
  68                 {
  69                         // Nothing to clone
  70                 }
  71
  72                 protected override Expression DoResolve (ResolveContext ec)
  73                 {
  74                         //
  75                         // We are born fully resolved
  76                         //
  77                         return this;
  78                 }
  79
  80                 public override void Emit (EmitContext ec)
  81                 {
  82                         var call = new CallEmitter ();
  83                         call.EmitPredefined (ec, oper, arguments, loc);
  84                 }
  85
  86                 public override void FlowAnalysis (FlowAnalysisContext fc)
  87                 {
  88                         arguments.FlowAnalysis (fc);
  89                 }
  90
  91                 public override SLE.Expression MakeExpression (BuilderContext ctx)
  92                 {
  93 #if STATIC
  94                         return base.MakeExpression (ctx);
  95 #else
  96                         return SLE.Expression.Call ((MethodInfo) oper.GetMetaInfo (), Arguments.MakeExpression (arguments, ctx));
  97 #endif
  98                 }
  99         }
 100
 101         public class ParenthesizedExpression : ShimExpression
 102         {
 103                 public ParenthesizedExpression (Expression expr, Location loc)
 104                         : base (expr)
 105                 {
 106                         this.loc = loc;
 107                 }
 108
 109                 protected override Expression DoResolve (ResolveContext ec)
 110                 {
 111                         var res = expr.Resolve (ec);
 112                         var constant = res as Constant;
 113                         if (constant != null && constant.IsLiteral)
 114                                 return Constant.CreateConstantFromValue (res.Type, constant.GetValue (), expr.Location);
 115
 116                         return res;
 117                 }
 118
 119                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 120                 {
 121                         return expr.DoResolveLValue (ec, right_side);
 122                 }
 123
 124                 public override object Accept (StructuralVisitor visitor)
 125                 {
 126                         return visitor.Visit (this);
 127                 }
 128         }
 129
 130         //
 131         //   Unary implements unary expressions.
 132         //
 133         public class Unary : Expression
 134         {
 135                 public enum Operator : byte {
 136                         UnaryPlus, UnaryNegation, LogicalNot, OnesComplement,
 137                         AddressOf,  TOP
 138                 }
 139
 140                 public readonly Operator Oper;
 141                 public Expression Expr;
 142                 Expression enum_conversion;
 143
 144                 public Unary (Operator op, Expression expr, Location loc)
 145                 {
 146                         Oper = op;
 147                         Expr = expr;
 148                         this.loc = loc;
 149                 }
 150
 151                 // <summary>
 152                 //   This routine will attempt to simplify the unary expression when the
 153                 //   argument is a constant.
 154                 // </summary>
 155                 Constant TryReduceConstant (ResolveContext ec, Constant constant)
 156                 {
 157                         var e = constant;
 158
 159                         while (e is EmptyConstantCast)
 160                                 e = ((EmptyConstantCast) e).child;
 161
 162                         if (e is SideEffectConstant) {
 163                                 Constant r = TryReduceConstant (ec, ((SideEffectConstant) e).value);
 164                                 return r == null ? null : new SideEffectConstant (r, e, r.Location);
 165                         }
 166
 167                         TypeSpec expr_type = e.Type;
 168
 169                         switch (Oper){
 170                         case Operator.UnaryPlus:
 171                                 // Unary numeric promotions
 172                                 switch (expr_type.BuiltinType) {
 173                                 case BuiltinTypeSpec.Type.Byte:
 174                                         return new IntConstant (ec.BuiltinTypes, ((ByteConstant) e).Value, e.Location);
 175                                 case BuiltinTypeSpec.Type.SByte:
 176                                         return new IntConstant (ec.BuiltinTypes, ((SByteConstant) e).Value, e.Location);
 177                                 case BuiltinTypeSpec.Type.Short:
 178                                         return new IntConstant (ec.BuiltinTypes, ((ShortConstant) e).Value, e.Location);
 179                                 case BuiltinTypeSpec.Type.UShort:
 180                                         return new IntConstant (ec.BuiltinTypes, ((UShortConstant) e).Value, e.Location);
 181                                 case BuiltinTypeSpec.Type.Char:
 182                                         return new IntConstant (ec.BuiltinTypes, ((CharConstant) e).Value, e.Location);
 183
 184                                 // Predefined operators
 185                                 case BuiltinTypeSpec.Type.Int:
 186                                 case BuiltinTypeSpec.Type.UInt:
 187                                 case BuiltinTypeSpec.Type.Long:
 188                                 case BuiltinTypeSpec.Type.ULong:
 189                                 case BuiltinTypeSpec.Type.Float:
 190                                 case BuiltinTypeSpec.Type.Double:
 191                                 case BuiltinTypeSpec.Type.Decimal:
 192                                         return e;
 193                                 }
 194
 195                                 return null;
 196
 197                         case Operator.UnaryNegation:
 198                                 // Unary numeric promotions
 199                                 switch (expr_type.BuiltinType) {
 200                                 case BuiltinTypeSpec.Type.Byte:
 201                                         return new IntConstant (ec.BuiltinTypes, -((ByteConstant) e).Value, e.Location);
 202                                 case BuiltinTypeSpec.Type.SByte:
 203                                         return new IntConstant (ec.BuiltinTypes, -((SByteConstant) e).Value, e.Location);
 204                                 case BuiltinTypeSpec.Type.Short:
 205                                         return new IntConstant (ec.BuiltinTypes, -((ShortConstant) e).Value, e.Location);
 206                                 case BuiltinTypeSpec.Type.UShort:
 207                                         return new IntConstant (ec.BuiltinTypes, -((UShortConstant) e).Value, e.Location);
 208                                 case BuiltinTypeSpec.Type.Char:
 209                                         return new IntConstant (ec.BuiltinTypes, -((CharConstant) e).Value, e.Location);
 210
 211                                 // Predefined operators
 212                                 case BuiltinTypeSpec.Type.Int:
 213                                         int ivalue = ((IntConstant) e).Value;
 214                                         if (ivalue == int.MinValue) {
 215                                                 if (ec.ConstantCheckState) {
 216                                                         ConstantFold.Error_CompileTimeOverflow (ec, loc);
 217                                                         return null;
 218                                                 }
 219                                                 return e;
 220                                         }
 221                                         return new IntConstant (ec.BuiltinTypes, -ivalue, e.Location);
 222
 223                                 case BuiltinTypeSpec.Type.Long:
 224                                         long lvalue = ((LongConstant) e).Value;
 225                                         if (lvalue == long.MinValue) {
 226                                                 if (ec.ConstantCheckState) {
 227                                                         ConstantFold.Error_CompileTimeOverflow (ec, loc);
 228                                                         return null;
 229                                                 }
 230                                                 return e;
 231                                         }
 232                                         return new LongConstant (ec.BuiltinTypes, -lvalue, e.Location);
 233
 234                                 case BuiltinTypeSpec.Type.UInt:
 235                                         UIntLiteral uil = constant as UIntLiteral;
 236                                         if (uil != null) {
 237                                                 if (uil.Value == int.MaxValue + (uint) 1)
 238                                                         return new IntLiteral (ec.BuiltinTypes, int.MinValue, e.Location);
 239                                                 return new LongLiteral (ec.BuiltinTypes, -uil.Value, e.Location);
 240                                         }
 241                                         return new LongConstant (ec.BuiltinTypes, -((UIntConstant) e).Value, e.Location);
 242
 243
 244                                 case BuiltinTypeSpec.Type.ULong:
 245                                         ULongLiteral ull = constant as ULongLiteral;
 246                                         if (ull != null && ull.Value == 9223372036854775808)
 247                                                 return new LongLiteral (ec.BuiltinTypes, long.MinValue, e.Location);
 248                                         return null;
 249
 250                                 case BuiltinTypeSpec.Type.Float:
 251                                         FloatLiteral fl = constant as FloatLiteral;
 252                                         // For better error reporting
 253                                         if (fl != null)
 254                                                 return new FloatLiteral (ec.BuiltinTypes, -fl.Value, e.Location);
 255
 256                                         return new FloatConstant (ec.BuiltinTypes, -((FloatConstant) e).Value, e.Location);
 257
 258                                 case BuiltinTypeSpec.Type.Double:
 259                                         DoubleLiteral dl = constant as DoubleLiteral;
 260                                         // For better error reporting
 261                                         if (dl != null)
 262                                                 return new DoubleLiteral (ec.BuiltinTypes, -dl.Value, e.Location);
 263
 264                                         return new DoubleConstant (ec.BuiltinTypes, -((DoubleConstant) e).Value, e.Location);
 265
 266                                 case BuiltinTypeSpec.Type.Decimal:
 267                                         return new DecimalConstant (ec.BuiltinTypes, -((DecimalConstant) e).Value, e.Location);
 268                                 }
 269
 270                                 return null;
 271
 272                         case Operator.LogicalNot:
 273                                 if (expr_type.BuiltinType != BuiltinTypeSpec.Type.Bool)
 274                                         return null;
 275
 276                                 bool b = (bool)e.GetValue ();
 277                                 return new BoolConstant (ec.BuiltinTypes, !b, e.Location);
 278
 279                         case Operator.OnesComplement:
 280                                 // Unary numeric promotions
 281                                 switch (expr_type.BuiltinType) {
 282                                 case BuiltinTypeSpec.Type.Byte:
 283                                         return new IntConstant (ec.BuiltinTypes, ~((ByteConstant) e).Value, e.Location);
 284                                 case BuiltinTypeSpec.Type.SByte:
 285                                         return new IntConstant (ec.BuiltinTypes, ~((SByteConstant) e).Value, e.Location);
 286                                 case BuiltinTypeSpec.Type.Short:
 287                                         return new IntConstant (ec.BuiltinTypes, ~((ShortConstant) e).Value, e.Location);
 288                                 case BuiltinTypeSpec.Type.UShort:
 289                                         return new IntConstant (ec.BuiltinTypes, ~((UShortConstant) e).Value, e.Location);
 290                                 case BuiltinTypeSpec.Type.Char:
 291                                         return new IntConstant (ec.BuiltinTypes, ~((CharConstant) e).Value, e.Location);
 292
 293                                 // Predefined operators
 294                                 case BuiltinTypeSpec.Type.Int:
 295                                         return new IntConstant (ec.BuiltinTypes, ~((IntConstant)e).Value, e.Location);
 296                                 case BuiltinTypeSpec.Type.UInt:
 297                                         return new UIntConstant (ec.BuiltinTypes, ~((UIntConstant) e).Value, e.Location);
 298                                 case BuiltinTypeSpec.Type.Long:
 299                                         return new LongConstant (ec.BuiltinTypes, ~((LongConstant) e).Value, e.Location);
 300                                 case BuiltinTypeSpec.Type.ULong:
 301                                         return new ULongConstant (ec.BuiltinTypes, ~((ULongConstant) e).Value, e.Location);
 302                                 }
 303                                 if (e is EnumConstant) {
 304                                         var res = TryReduceConstant (ec, ((EnumConstant)e).Child);
 305                                         if (res != null) {
 306                                                 //
 307                                                 // Numeric promotion upgraded types to int but for enum constant
 308                                                 // original underlying constant type is needed
 309                                                 //
 310                                                 if (res.Type.BuiltinType == BuiltinTypeSpec.Type.Int) {
 311                                                         int v = ((IntConstant) res).Value;
 312                                                         switch (((EnumConstant) e).Child.Type.BuiltinType) {
 313                                                                 case BuiltinTypeSpec.Type.UShort:
 314                                                                 res = new UShortConstant (ec.BuiltinTypes, (ushort) v, e.Location);
 315                                                                 break;
 316                                                                 case BuiltinTypeSpec.Type.Short:
 317                                                                 res = new ShortConstant (ec.BuiltinTypes, (short) v, e.Location);
 318                                                                 break;
 319                                                                 case BuiltinTypeSpec.Type.Byte:
 320                                                                 res = new ByteConstant (ec.BuiltinTypes, (byte) v, e.Location);
 321                                                                 break;
 322                                                                 case BuiltinTypeSpec.Type.SByte:
 323                                                                 res = new SByteConstant (ec.BuiltinTypes, (sbyte) v, e.Location);
 324                                                                 break;
 325                                                         }
 326                                                 }
 327
 328                                                 res = new EnumConstant (res, expr_type);
 329                                         }
 330                                         return res;
 331                                 }
 332                                 return null;
 333                         }
 334                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 335                 }
 336
 337                 protected virtual Expression ResolveOperator (ResolveContext ec, Expression expr)
 338                 {
 339                         eclass = ExprClass.Value;
 340
 341                         TypeSpec expr_type = expr.Type;
 342                         Expression best_expr;
 343
 344                         TypeSpec[] predefined = ec.BuiltinTypes.OperatorsUnary [(int) Oper];
 345
 346                         //
 347                         // Primitive types first
 348                         //
 349                         if (BuiltinTypeSpec.IsPrimitiveType (expr_type)) {
 350                                 best_expr = ResolvePrimitivePredefinedType (ec, expr, predefined);
 351                                 if (best_expr == null)
 352                                         return null;
 353
 354                                 type = best_expr.Type;
 355                                 Expr = best_expr;
 356                                 return this;
 357                         }
 358
 359                         //
 360                         // E operator ~(E x);
 361                         //
 362                         if (Oper == Operator.OnesComplement && expr_type.IsEnum)
 363                                 return ResolveEnumOperator (ec, expr, predefined);
 364
 365                         return ResolveUserType (ec, expr, predefined);
 366                 }
 367
 368                 protected virtual Expression ResolveEnumOperator (ResolveContext ec, Expression expr, TypeSpec[] predefined)
 369                 {
 370                         TypeSpec underlying_type = EnumSpec.GetUnderlyingType (expr.Type);
 371                         Expression best_expr = ResolvePrimitivePredefinedType (ec, EmptyCast.Create (expr, underlying_type), predefined);
 372                         if (best_expr == null)
 373                                 return null;
 374
 375                         Expr = best_expr;
 376                         enum_conversion = Convert.ExplicitNumericConversion (ec, new EmptyExpression (best_expr.Type), underlying_type);
 377                         type = expr.Type;
 378                         return EmptyCast.Create (this, type);
 379                 }
 380
 381                 public override bool ContainsEmitWithAwait ()
 382                 {
 383                         return Expr.ContainsEmitWithAwait ();
 384                 }
 385
 386                 public override Expression CreateExpressionTree (ResolveContext ec)
 387                 {
 388                         return CreateExpressionTree (ec, null);
 389                 }
 390
 391                 Expression CreateExpressionTree (ResolveContext ec, Expression user_op)
 392                 {
 393                         string method_name;
 394                         switch (Oper) {
 395                         case Operator.AddressOf:
 396                                 Error_PointerInsideExpressionTree (ec);
 397                                 return null;
 398                         case Operator.UnaryNegation:
 399                                 if (ec.HasSet (ResolveContext.Options.CheckedScope) && user_op == null && !IsFloat (type))
 400                                         method_name = "NegateChecked";
 401                                 else
 402                                         method_name = "Negate";
 403                                 break;
 404                         case Operator.OnesComplement:
 405                         case Operator.LogicalNot:
 406                                 method_name = "Not";
 407                                 break;
 408                         case Operator.UnaryPlus:
 409                                 method_name = "UnaryPlus";
 410                                 break;
 411                         default:
 412                                 throw new InternalErrorException ("Unknown unary operator " + Oper.ToString ());
 413                         }
 414
 415                         Arguments args = new Arguments (2);
 416                         args.Add (new Argument (Expr.CreateExpressionTree (ec)));
 417                         if (user_op != null)
 418                                 args.Add (new Argument (user_op));
 419
 420                         return CreateExpressionFactoryCall (ec, method_name, args);
 421                 }
 422
 423                 public static TypeSpec[][] CreatePredefinedOperatorsTable (BuiltinTypes types)
 424                 {
 425                         var predefined_operators = new TypeSpec[(int) Operator.TOP][];
 426
 427                         //
 428                         // 7.6.1 Unary plus operator
 429                         //
 430                         predefined_operators [(int) Operator.UnaryPlus] = new TypeSpec [] {
 431                                 types.Int, types.UInt,
 432                                 types.Long, types.ULong,
 433                                 types.Float, types.Double,
 434                                 types.Decimal
 435                         };
 436
 437                         //
 438                         // 7.6.2 Unary minus operator
 439                         //
 440                         predefined_operators [(int) Operator.UnaryNegation] = new TypeSpec [] {
 441                                 types.Int,  types.Long,
 442                                 types.Float, types.Double,
 443                                 types.Decimal
 444                         };
 445
 446                         //
 447                         // 7.6.3 Logical negation operator
 448                         //
 449                         predefined_operators [(int) Operator.LogicalNot] = new TypeSpec [] {
 450                                 types.Bool
 451                         };
 452
 453                         //
 454                         // 7.6.4 Bitwise complement operator
 455                         //
 456                         predefined_operators [(int) Operator.OnesComplement] = new TypeSpec [] {
 457                                 types.Int, types.UInt,
 458                                 types.Long, types.ULong
 459                         };
 460
 461                         return predefined_operators;
 462                 }
 463
 464                 //
 465                 // Unary numeric promotions
 466                 //
 467                 static Expression DoNumericPromotion (ResolveContext rc, Operator op, Expression expr)
 468                 {
 469                         TypeSpec expr_type = expr.Type;
 470                         if (op == Operator.UnaryPlus || op == Operator.UnaryNegation || op == Operator.OnesComplement) {
 471                                 switch (expr_type.BuiltinType) {
 472                                 case BuiltinTypeSpec.Type.Byte:
 473                                 case BuiltinTypeSpec.Type.SByte:
 474                                 case BuiltinTypeSpec.Type.Short:
 475                                 case BuiltinTypeSpec.Type.UShort:
 476                                 case BuiltinTypeSpec.Type.Char:
 477                                         return Convert.ImplicitNumericConversion (expr, rc.BuiltinTypes.Int);
 478                                 }
 479                         }
 480
 481                         if (op == Operator.UnaryNegation && expr_type.BuiltinType == BuiltinTypeSpec.Type.UInt)
 482                                 return Convert.ImplicitNumericConversion (expr, rc.BuiltinTypes.Long);
 483
 484                         return expr;
 485                 }
 486
 487                 protected override Expression DoResolve (ResolveContext ec)
 488                 {
 489                         if (Oper == Operator.AddressOf) {
 490                                 return ResolveAddressOf (ec);
 491                         }
 492
 493                         Expr = Expr.Resolve (ec);
 494                         if (Expr == null)
 495                                 return null;
 496
 497                         if (Expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
 498                                 Arguments args = new Arguments (1);
 499                                 args.Add (new Argument (Expr));
 500                                 return new DynamicUnaryConversion (GetOperatorExpressionTypeName (), args, loc).Resolve (ec);
 501                         }
 502
 503                         if (Expr.Type.IsNullableType)
 504                                 return new Nullable.LiftedUnaryOperator (Oper, Expr, loc).Resolve (ec);
 505
 506                         //
 507                         // Attempt to use a constant folding operation.
 508                         //
 509                         Constant cexpr = Expr as Constant;
 510                         if (cexpr != null) {
 511                                 cexpr = TryReduceConstant (ec, cexpr);
 512                                 if (cexpr != null)
 513                                         return cexpr;
 514                         }
 515
 516                         Expression expr = ResolveOperator (ec, Expr);
 517                         if (expr == null)
 518                                 Error_OperatorCannotBeApplied (ec, loc, OperName (Oper), Expr.Type);
 519
 520                         //
 521                         // Reduce unary operator on predefined types
 522                         //
 523                         if (expr == this && Oper == Operator.UnaryPlus)
 524                                 return Expr;
 525
 526                         return expr;
 527                 }
 528
 529                 public override Expression DoResolveLValue (ResolveContext ec, Expression right)
 530                 {
 531                         return null;
 532                 }
 533
 534                 public override void Emit (EmitContext ec)
 535                 {
 536                         EmitOperator (ec, type);
 537                 }
 538
 539                 protected void EmitOperator (EmitContext ec, TypeSpec type)
 540                 {
 541                         switch (Oper) {
 542                         case Operator.UnaryPlus:
 543                                 Expr.Emit (ec);
 544                                 break;
 545
 546                         case Operator.UnaryNegation:
 547                                 if (ec.HasSet (EmitContext.Options.CheckedScope) && !IsFloat (type)) {
 548                                         if (ec.HasSet (BuilderContext.Options.AsyncBody) && Expr.ContainsEmitWithAwait ())
 549                                                 Expr = Expr.EmitToField (ec);
 550
 551                                         ec.EmitInt (0);
 552                                         if (type.BuiltinType == BuiltinTypeSpec.Type.Long)
 553                                                 ec.Emit (OpCodes.Conv_U8);
 554                                         Expr.Emit (ec);
 555                                         ec.Emit (OpCodes.Sub_Ovf);
 556                                 } else {
 557                                         Expr.Emit (ec);
 558                                         ec.Emit (OpCodes.Neg);
 559                                 }
 560
 561                                 break;
 562
 563                         case Operator.LogicalNot:
 564                                 Expr.Emit (ec);
 565                                 ec.EmitInt (0);
 566                                 ec.Emit (OpCodes.Ceq);
 567                                 break;
 568
 569                         case Operator.OnesComplement:
 570                                 Expr.Emit (ec);
 571                                 ec.Emit (OpCodes.Not);
 572                                 break;
 573
 574                         case Operator.AddressOf:
 575                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 576                                 break;
 577
 578                         default:
 579                                 throw new Exception ("This should not happen: Operator = "
 580                                                      + Oper.ToString ());
 581                         }
 582
 583                         //
 584                         // Same trick as in Binary expression
 585                         //
 586                         if (enum_conversion != null)
 587                                 enum_conversion.Emit (ec);
 588                 }
 589
 590                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
 591                 {
 592                         if (Oper == Operator.LogicalNot)
 593                                 Expr.EmitBranchable (ec, target, !on_true);
 594                         else
 595                                 base.EmitBranchable (ec, target, on_true);
 596                 }
 597
 598                 public override void EmitSideEffect (EmitContext ec)
 599                 {
 600                         Expr.EmitSideEffect (ec);
 601                 }
 602
 603                 public static void Error_Ambiguous (ResolveContext rc, string oper, TypeSpec type, Location loc)
 604                 {
 605                         rc.Report.Error (35, loc, "Operator `{0}' is ambiguous on an operand of type `{1}'",
 606                                 oper, type.GetSignatureForError ());
 607                 }
 608
 609                 public override void FlowAnalysis (FlowAnalysisContext fc)
 610                 {
 611                         if (Oper == Operator.AddressOf) {
 612                                 var vr = Expr as VariableReference;
 613                                 if (vr != null && vr.VariableInfo != null)
 614                                         fc.SetVariableAssigned (vr.VariableInfo);
 615
 616                                 return;
 617                         }
 618
 619                         Expr.FlowAnalysis (fc);
 620
 621                         if (Oper == Operator.LogicalNot) {
 622                                 var temp = fc.DefiniteAssignmentOnTrue;
 623                                 fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignmentOnFalse;
 624                                 fc.DefiniteAssignmentOnFalse = temp;
 625                         }
 626                 }
 627
 628                 //
 629                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
 630                 //
 631                 string GetOperatorExpressionTypeName ()
 632                 {
 633                         switch (Oper) {
 634                         case Operator.OnesComplement:
 635                                 return "OnesComplement";
 636                         case Operator.LogicalNot:
 637                                 return "Not";
 638                         case Operator.UnaryNegation:
 639                                 return "Negate";
 640                         case Operator.UnaryPlus:
 641                                 return "UnaryPlus";
 642                         default:
 643                                 throw new NotImplementedException ("Unknown express type operator " + Oper.ToString ());
 644                         }
 645                 }
 646
 647                 static bool IsFloat (TypeSpec t)
 648                 {
 649                         return t.BuiltinType == BuiltinTypeSpec.Type.Double || t.BuiltinType == BuiltinTypeSpec.Type.Float;
 650                 }
 651
 652                 //
 653                 // Returns a stringified representation of the Operator
 654                 //
 655                 public static string OperName (Operator oper)
 656                 {
 657                         switch (oper) {
 658                         case Operator.UnaryPlus:
 659                                 return "+";
 660                         case Operator.UnaryNegation:
 661                                 return "-";
 662                         case Operator.LogicalNot:
 663                                 return "!";
 664                         case Operator.OnesComplement:
 665                                 return "~";
 666                         case Operator.AddressOf:
 667                                 return "&";
 668                         }
 669
 670                         throw new NotImplementedException (oper.ToString ());
 671                 }
 672
 673                 public override SLE.Expression MakeExpression (BuilderContext ctx)
 674                 {
 675                         var expr = Expr.MakeExpression (ctx);
 676                         bool is_checked = ctx.HasSet (BuilderContext.Options.CheckedScope);
 677
 678                         switch (Oper) {
 679                         case Operator.UnaryNegation:
 680                                 return is_checked ? SLE.Expression.NegateChecked (expr) : SLE.Expression.Negate (expr);
 681                         case Operator.LogicalNot:
 682                                 return SLE.Expression.Not (expr);
 683 #if NET_4_0 || MOBILE_DYNAMIC
 684                         case Operator.OnesComplement:
 685                                 return SLE.Expression.OnesComplement (expr);
 686 #endif
 687                         default:
 688                                 throw new NotImplementedException (Oper.ToString ());
 689                         }
 690                 }
 691
 692                 Expression ResolveAddressOf (ResolveContext ec)
 693                 {
 694                         if (!ec.IsUnsafe)
 695                                 UnsafeError (ec, loc);
 696
 697                         Expr = Expr.DoResolveLValue (ec, EmptyExpression.UnaryAddress);
 698                         if (Expr == null || Expr.eclass != ExprClass.Variable) {
 699                                 ec.Report.Error (211, loc, "Cannot take the address of the given expression");
 700                                 return null;
 701                         }
 702
 703                         if (!TypeManager.VerifyUnmanaged (ec.Module, Expr.Type, loc)) {
 704                                 return null;
 705                         }
 706
 707                         IVariableReference vr = Expr as IVariableReference;
 708                         bool is_fixed;
 709                         if (vr != null) {
 710                                 is_fixed = vr.IsFixed;
 711                                 vr.SetHasAddressTaken ();
 712
 713                                 if (vr.IsHoisted) {
 714                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, vr, loc);
 715                                 }
 716                         } else {
 717                                 IFixedExpression fe = Expr as IFixedExpression;
 718                                 is_fixed = fe != null && fe.IsFixed;
 719                         }
 720
 721                         if (!is_fixed && !ec.HasSet (ResolveContext.Options.FixedInitializerScope)) {
 722                                 ec.Report.Error (212, loc, "You can only take the address of unfixed expression inside of a fixed statement initializer");
 723                         }
 724
 725                         type = PointerContainer.MakeType (ec.Module, Expr.Type);
 726                         eclass = ExprClass.Value;
 727                         return this;
 728                 }
 729
 730                 Expression ResolvePrimitivePredefinedType (ResolveContext rc, Expression expr, TypeSpec[] predefined)
 731                 {
 732                         expr = DoNumericPromotion (rc, Oper, expr);
 733                         TypeSpec expr_type = expr.Type;
 734                         foreach (TypeSpec t in predefined) {
 735                                 if (t == expr_type)
 736                                         return expr;
 737                         }
 738                         return null;
 739                 }
 740
 741                 //
 742                 // Perform user-operator overload resolution
 743                 //
 744                 protected virtual Expression ResolveUserOperator (ResolveContext ec, Expression expr)
 745                 {
 746                         CSharp.Operator.OpType op_type;
 747                         switch (Oper) {
 748                         case Operator.LogicalNot:
 749                                 op_type = CSharp.Operator.OpType.LogicalNot; break;
 750                         case Operator.OnesComplement:
 751                                 op_type = CSharp.Operator.OpType.OnesComplement; break;
 752                         case Operator.UnaryNegation:
 753                                 op_type = CSharp.Operator.OpType.UnaryNegation; break;
 754                         case Operator.UnaryPlus:
 755                                 op_type = CSharp.Operator.OpType.UnaryPlus; break;
 756                         default:
 757                                 throw new InternalErrorException (Oper.ToString ());
 758                         }
 759
 760                         var methods = MemberCache.GetUserOperator (expr.Type, op_type, false);
 761                         if (methods == null)
 762                                 return null;
 763
 764                         Arguments args = new Arguments (1);
 765                         args.Add (new Argument (expr));
 766
 767                         var res = new OverloadResolver (methods, OverloadResolver.Restrictions.BaseMembersIncluded | OverloadResolver.Restrictions.NoBaseMembers, loc);
 768                         var oper = res.ResolveOperator (ec, ref args);
 769
 770                         if (oper == null)
 771                                 return null;
 772
 773                         Expr = args [0].Expr;
 774                         return new UserOperatorCall (oper, args, CreateExpressionTree, expr.Location);
 775                 }
 776
 777                 //
 778                 // Unary user type overload resolution
 779                 //
 780                 Expression ResolveUserType (ResolveContext ec, Expression expr, TypeSpec[] predefined)
 781                 {
 782                         Expression best_expr = ResolveUserOperator (ec, expr);
 783                         if (best_expr != null)
 784                                 return best_expr;
 785
 786                         foreach (TypeSpec t in predefined) {
 787                                 Expression oper_expr = Convert.ImplicitUserConversion (ec, expr, t, expr.Location);
 788                                 if (oper_expr == null)
 789                                         continue;
 790
 791                                 if (oper_expr == ErrorExpression.Instance)
 792                                         return oper_expr;
 793
 794                                 //
 795                                 // decimal type is predefined but has user-operators
 796                                 //
 797                                 if (oper_expr.Type.BuiltinType == BuiltinTypeSpec.Type.Decimal)
 798                                         oper_expr = ResolveUserType (ec, oper_expr, predefined);
 799                                 else
 800                                         oper_expr = ResolvePrimitivePredefinedType (ec, oper_expr, predefined);
 801
 802                                 if (oper_expr == null)
 803                                         continue;
 804
 805                                 if (best_expr == null) {
 806                                         best_expr = oper_expr;
 807                                         continue;
 808                                 }
 809
 810                                 int result = OverloadResolver.BetterTypeConversion (ec, best_expr.Type, t);
 811                                 if (result == 0) {
 812                                         if ((oper_expr is UserOperatorCall || oper_expr is UserCast) && (best_expr is UserOperatorCall || best_expr is UserCast)) {
 813                                                 Error_Ambiguous (ec, OperName (Oper), expr.Type, loc);
 814                                         } else {
 815                                                 Error_OperatorCannotBeApplied (ec, loc, OperName (Oper), expr.Type);
 816                                         }
 817
 818                                         break;
 819                                 }
 820
 821                                 if (result == 2)
 822                                         best_expr = oper_expr;
 823                         }
 824
 825                         if (best_expr == null)
 826                                 return null;
 827
 828                         //
 829                         // HACK: Decimal user-operator is included in standard operators
 830                         //
 831                         if (best_expr.Type.BuiltinType == BuiltinTypeSpec.Type.Decimal)
 832                                 return best_expr;
 833
 834                         Expr = best_expr;
 835                         type = best_expr.Type;
 836                         return this;
 837                 }
 838
 839                 protected override void CloneTo (CloneContext clonectx, Expression t)
 840                 {
 841                         Unary target = (Unary) t;
 842
 843                         target.Expr = Expr.Clone (clonectx);
 844                 }
 845
 846                 public override object Accept (StructuralVisitor visitor)
 847                 {
 848                         return visitor.Visit (this);
 849                 }
 850
 851         }
 852
 853         //
 854         // Unary operators are turned into Indirection expressions
 855         // after semantic analysis (this is so we can take the address
 856         // of an indirection).
 857         //
 858         public class Indirection : Expression, IMemoryLocation, IAssignMethod, IFixedExpression {
 859                 Expression expr;
 860                 LocalTemporary temporary;
 861                 bool prepared;
 862
 863                 public Indirection (Expression expr, Location l)
 864                 {
 865                         this.expr = expr;
 866                         loc = l;
 867                 }
 868
 869                 public Expression Expr {
 870                         get {
 871                                 return expr;
 872                         }
 873                 }
 874
 875                 public bool IsFixed {
 876                         get { return true; }
 877                 }
 878
 879                 public override Location StartLocation {
 880                         get {
 881                                 return expr.StartLocation;
 882                         }
 883                 }
 884
 885                 protected override void CloneTo (CloneContext clonectx, Expression t)
 886                 {
 887                         Indirection target = (Indirection) t;
 888                         target.expr = expr.Clone (clonectx);
 889                 }
 890
 891                 public override bool ContainsEmitWithAwait ()
 892                 {
 893                         throw new NotImplementedException ();
 894                 }
 895
 896                 public override Expression CreateExpressionTree (ResolveContext ec)
 897                 {
 898                         Error_PointerInsideExpressionTree (ec);
 899                         return null;
 900                 }
 901
 902                 public override void Emit (EmitContext ec)
 903                 {
 904                         if (!prepared)
 905                                 expr.Emit (ec);
 906
 907                         ec.EmitLoadFromPtr (Type);
 908                 }
 909
 910                 public void Emit (EmitContext ec, bool leave_copy)
 911                 {
 912                         Emit (ec);
 913                         if (leave_copy) {
 914                                 ec.Emit (OpCodes.Dup);
 915                                 temporary = new LocalTemporary (expr.Type);
 916                                 temporary.Store (ec);
 917                         }
 918                 }
 919
 920                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
 921                 {
 922                         prepared = isCompound;
 923
 924                         expr.Emit (ec);
 925
 926                         if (isCompound)
 927                                 ec.Emit (OpCodes.Dup);
 928
 929                         source.Emit (ec);
 930                         if (leave_copy) {
 931                                 ec.Emit (OpCodes.Dup);
 932                                 temporary = new LocalTemporary (source.Type);
 933                                 temporary.Store (ec);
 934                         }
 935
 936                         ec.EmitStoreFromPtr (type);
 937
 938                         if (temporary != null) {
 939                                 temporary.Emit (ec);
 940                                 temporary.Release (ec);
 941                         }
 942                 }
 943
 944                 public void AddressOf (EmitContext ec, AddressOp Mode)
 945                 {
 946                         expr.Emit (ec);
 947                 }
 948
 949                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 950                 {
 951                         return DoResolve (ec);
 952                 }
 953
 954                 protected override Expression DoResolve (ResolveContext ec)
 955                 {
 956                         expr = expr.Resolve (ec);
 957                         if (expr == null)
 958                                 return null;
 959
 960                         if (!ec.IsUnsafe)
 961                                 UnsafeError (ec, loc);
 962
 963                         var pc = expr.Type as PointerContainer;
 964
 965                         if (pc == null) {
 966                                 ec.Report.Error (193, loc, "The * or -> operator must be applied to a pointer");
 967                                 return null;
 968                         }
 969
 970                         type = pc.Element;
 971
 972                         if (type.Kind == MemberKind.Void) {
 973                                 Error_VoidPointerOperation (ec);
 974                                 return null;
 975                         }
 976
 977                         eclass = ExprClass.Variable;
 978                         return this;
 979                 }
 980
 981                 public override object Accept (StructuralVisitor visitor)
 982                 {
 983                         return visitor.Visit (this);
 984                 }
 985         }
 986
 987         /// <summary>
 988         ///   Unary Mutator expressions (pre and post ++ and --)
 989         /// </summary>
 990         ///
 991         /// <remarks>
 992         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 993         ///   ExpressionStatement becuase the pre/post increment/decrement
 994         ///   operators can be used in a statement context.
 995         ///
 996         /// FIXME: Idea, we could split this up in two classes, one simpler
 997         /// for the common case, and one with the extra fields for more complex
 998         /// classes (indexers require temporary access;  overloaded require method)
 999         ///
1000         /// </remarks>
1001         public class UnaryMutator : ExpressionStatement
1002         {
1003                 class DynamicPostMutator : Expression, IAssignMethod
1004                 {
1005                         LocalTemporary temp;
1006                         Expression expr;
1007
1008                         public DynamicPostMutator (Expression expr)
1009                         {
1010                                 this.expr = expr;
1011                                 this.type = expr.Type;
1012                                 this.loc = expr.Location;
1013                         }
1014
1015                         public override Expression CreateExpressionTree (ResolveContext ec)
1016                         {
1017                                 throw new NotImplementedException ("ET");
1018                         }
1019
1020                         protected override Expression DoResolve (ResolveContext rc)
1021                         {
1022                                 eclass = expr.eclass;
1023                                 return this;
1024                         }
1025
1026                         public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1027                         {
1028                                 expr.DoResolveLValue (ec, right_side);
1029                                 return DoResolve (ec);
1030                         }
1031
1032                         public override void Emit (EmitContext ec)
1033                         {
1034                                 temp.Emit (ec);
1035                         }
1036
1037                         public void Emit (EmitContext ec, bool leave_copy)
1038                         {
1039                                 throw new NotImplementedException ();
1040                         }
1041
1042                         //
1043                         // Emits target assignment using unmodified source value
1044                         //
1045                         public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
1046                         {
1047                                 //
1048                                 // Allocate temporary variable to keep original value before it's modified
1049                                 //
1050                                 temp = new LocalTemporary (type);
1051                                 expr.Emit (ec);
1052                                 temp.Store (ec);
1053
1054                                 ((IAssignMethod) expr).EmitAssign (ec, source, false, isCompound);
1055
1056                                 if (leave_copy)
1057                                         Emit (ec);
1058
1059                                 temp.Release (ec);
1060                                 temp = null;
1061                         }
1062                 }
1063
1064                 [Flags]
1065                 public enum Mode : byte {
1066                         IsIncrement    = 0,
1067                         IsDecrement    = 1,
1068                         IsPre          = 0,
1069                         IsPost         = 2,
1070
1071                         PreIncrement   = 0,
1072                         PreDecrement   = IsDecrement,
1073                         PostIncrement  = IsPost,
1074                         PostDecrement  = IsPost | IsDecrement
1075                 }
1076
1077                 Mode mode;
1078                 bool is_expr, recurse;
1079
1080                 protected Expression expr;
1081
1082                 // Holds the real operation
1083                 Expression operation;
1084
1085                 public UnaryMutator (Mode m, Expression e, Location loc)
1086                 {
1087                         mode = m;
1088                         this.loc = loc;
1089                         expr = e;
1090                 }
1091
1092                 public Mode UnaryMutatorMode {
1093                         get {
1094                                 return mode;
1095                         }
1096                 }
1097
1098                 public Expression Expr {
1099                         get {
1100                                 return expr;
1101                         }
1102                 }
1103
1104                 public override Location StartLocation {
1105                         get {
1106                                 return (mode & Mode.IsPost) != 0 ? expr.Location : loc;
1107                         }
1108                 }
1109
1110                 public override bool ContainsEmitWithAwait ()
1111                 {
1112                         return expr.ContainsEmitWithAwait ();
1113                 }
1114
1115                 public override Expression CreateExpressionTree (ResolveContext ec)
1116                 {
1117                         return new SimpleAssign (this, this).CreateExpressionTree (ec);
1118                 }
1119
1120                 public static TypeSpec[] CreatePredefinedOperatorsTable (BuiltinTypes types)
1121                 {
1122                         //
1123                         // Predefined ++ and -- operators exist for the following types:
1124                         // sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal
1125                         //
1126                         return new TypeSpec[] {
1127                                 types.Int,
1128                                 types.Long,
1129
1130                                 types.SByte,
1131                                 types.Byte,
1132                                 types.Short,
1133                                 types.UInt,
1134                                 types.ULong,
1135                                 types.Char,
1136                                 types.Float,
1137                                 types.Double,
1138                                 types.Decimal
1139                         };
1140                 }
1141
1142                 protected override Expression DoResolve (ResolveContext ec)
1143                 {
1144                         expr = expr.Resolve (ec);
1145
1146                         if (expr == null)
1147                                 return null;
1148
1149                         if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1150                                 //
1151                                 // Handle postfix unary operators using local
1152                                 // temporary variable
1153                                 //
1154                                 if ((mode & Mode.IsPost) != 0)
1155                                         expr = new DynamicPostMutator (expr);
1156
1157                                 Arguments args = new Arguments (1);
1158                                 args.Add (new Argument (expr));
1159                                 return new SimpleAssign (expr, new DynamicUnaryConversion (GetOperatorExpressionTypeName (), args, loc)).Resolve (ec);
1160                         }
1161
1162                         if (expr.Type.IsNullableType)
1163                                 return new Nullable.LiftedUnaryMutator (mode, expr, loc).Resolve (ec);
1164
1165                         return DoResolveOperation (ec);
1166                 }
1167
1168                 protected Expression DoResolveOperation (ResolveContext ec)
1169                 {
1170                         eclass = ExprClass.Value;
1171                         type = expr.Type;
1172
1173                         if (expr is RuntimeValueExpression) {
1174                                 operation = expr;
1175                         } else {
1176                                 // Use itself at the top of the stack
1177                                 operation = new EmptyExpression (type);
1178                         }
1179
1180                         //
1181                         // The operand of the prefix/postfix increment decrement operators
1182                         // should be an expression that is classified as a variable,
1183                         // a property access or an indexer access
1184                         //
1185                         // TODO: Move to parser, expr is ATypeNameExpression
1186                         if (expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.IndexerAccess || expr.eclass == ExprClass.PropertyAccess) {
1187                                 expr = expr.ResolveLValue (ec, expr);
1188                         } else {
1189                                 ec.Report.Error (1059, loc, "The operand of an increment or decrement operator must be a variable, property or indexer");
1190                         }
1191
1192                         //
1193                         // Step 1: Try to find a user operator, it has priority over predefined ones
1194                         //
1195                         var user_op = IsDecrement ? Operator.OpType.Decrement : Operator.OpType.Increment;
1196                         var methods = MemberCache.GetUserOperator (type, user_op, false);
1197
1198                         if (methods != null) {
1199                                 Arguments args = new Arguments (1);
1200                                 args.Add (new Argument (expr));
1201
1202                                 var res = new OverloadResolver (methods, OverloadResolver.Restrictions.BaseMembersIncluded | OverloadResolver.Restrictions.NoBaseMembers, loc);
1203                                 var method = res.ResolveOperator (ec, ref args);
1204                                 if (method == null)
1205                                         return null;
1206
1207                                 args[0].Expr = operation;
1208                                 operation = new UserOperatorCall (method, args, null, loc);
1209                                 operation = Convert.ImplicitConversionRequired (ec, operation, type, loc);
1210                                 return this;
1211                         }
1212
1213                         //
1214                         // Step 2: Try predefined types
1215                         //
1216
1217                         Expression source = null;
1218                         bool primitive_type;
1219
1220                         //
1221                         // Predefined without user conversion first for speed-up
1222                         //
1223                         // Predefined ++ and -- operators exist for the following types:
1224                         // sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal
1225                         //
1226                         switch (type.BuiltinType) {
1227                         case BuiltinTypeSpec.Type.Byte:
1228                         case BuiltinTypeSpec.Type.SByte:
1229                         case BuiltinTypeSpec.Type.Short:
1230                         case BuiltinTypeSpec.Type.UShort:
1231                         case BuiltinTypeSpec.Type.Int:
1232                         case BuiltinTypeSpec.Type.UInt:
1233                         case BuiltinTypeSpec.Type.Long:
1234                         case BuiltinTypeSpec.Type.ULong:
1235                         case BuiltinTypeSpec.Type.Char:
1236                         case BuiltinTypeSpec.Type.Float:
1237                         case BuiltinTypeSpec.Type.Double:
1238                         case BuiltinTypeSpec.Type.Decimal:
1239                                 source = operation;
1240                                 primitive_type = true;
1241                                 break;
1242                         default:
1243                                 primitive_type = false;
1244
1245                                 // ++/-- on pointer variables of all types except void*
1246                                 if (type.IsPointer) {
1247                                         if (((PointerContainer) type).Element.Kind == MemberKind.Void) {
1248                                                 Error_VoidPointerOperation (ec);
1249                                                 return null;
1250                                         }
1251
1252                                         source = operation;
1253                                 } else {
1254                                         Expression best_source = null;
1255                                         foreach (var t in ec.BuiltinTypes.OperatorsUnaryMutator) {
1256                                                 source = Convert.ImplicitUserConversion (ec, operation, t, loc);
1257
1258                                                 // LAMESPEC: It should error on ambiguous operators but that would make us incompatible
1259                                                 if (source == null)
1260                                                         continue;
1261
1262                                                 if (best_source == null) {
1263                                                         best_source = source;
1264                                                         continue;
1265                                                 }
1266
1267                                                 var better = OverloadResolver.BetterTypeConversion (ec, best_source.Type, source.Type);
1268                                                 if (better == 1)
1269                                                         continue;
1270
1271                                                 if (better == 2) {
1272                                                         best_source = source;
1273                                                         continue;
1274                                                 }
1275
1276                                                 Unary.Error_Ambiguous (ec, OperName (mode), type, loc);
1277                                                 break;
1278                                         }
1279
1280                                         source = best_source;
1281                                 }
1282
1283                                 // ++/-- on enum types
1284                                 if (source == null && type.IsEnum)
1285                                         source = operation;
1286
1287                                 if (source == null) {
1288                                         expr.Error_OperatorCannotBeApplied (ec, loc, Operator.GetName (user_op), type);
1289                                         return null;
1290                                 }
1291
1292                                 break;
1293                         }
1294
1295                         var one = new IntConstant (ec.BuiltinTypes, 1, loc);
1296                         var op = IsDecrement ? Binary.Operator.Subtraction : Binary.Operator.Addition;
1297                         operation = new Binary (op, source, one);
1298                         operation = operation.Resolve (ec);
1299                         if (operation == null)
1300                                 throw new NotImplementedException ("should not be reached");
1301
1302                         if (operation.Type != type) {
1303                                 if (primitive_type)
1304                                         operation = Convert.ExplicitNumericConversion (ec, operation, type);
1305                                 else
1306                                         operation = Convert.ImplicitConversionRequired (ec, operation, type, loc);
1307                         }
1308
1309                         return this;
1310                 }
1311
1312                 void EmitCode (EmitContext ec, bool is_expr)
1313                 {
1314                         recurse = true;
1315                         this.is_expr = is_expr;
1316                         ((IAssignMethod) expr).EmitAssign (ec, this, is_expr && (mode == Mode.PreIncrement || mode == Mode.PreDecrement), true);
1317                 }
1318
1319                 public override void Emit (EmitContext ec)
1320                 {
1321                         //
1322                         // We use recurse to allow ourselfs to be the source
1323                         // of an assignment. This little hack prevents us from
1324                         // having to allocate another expression
1325                         //
1326                         if (recurse) {
1327                                 ((IAssignMethod) expr).Emit (ec, is_expr && (mode == Mode.PostIncrement || mode == Mode.PostDecrement));
1328
1329                                 EmitOperation (ec);
1330
1331                                 recurse = false;
1332                                 return;
1333                         }
1334
1335                         EmitCode (ec, true);
1336                 }
1337
1338                 protected virtual void EmitOperation (EmitContext ec)
1339                 {
1340                         operation.Emit (ec);
1341                 }
1342
1343                 public override void EmitStatement (EmitContext ec)
1344                 {
1345                         EmitCode (ec, false);
1346                 }
1347
1348                 public override void FlowAnalysis (FlowAnalysisContext fc)
1349                 {
1350                         expr.FlowAnalysis (fc);
1351                 }
1352
1353                 //
1354                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
1355                 //
1356                 string GetOperatorExpressionTypeName ()
1357                 {
1358                         return IsDecrement ? "Decrement" : "Increment";
1359                 }
1360
1361                 bool IsDecrement {
1362                         get { return (mode & Mode.IsDecrement) != 0; }
1363                 }
1364
1365
1366 #if NET_4_0 || MOBILE_DYNAMIC
1367                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1368                 {
1369                         var target = ((RuntimeValueExpression) expr).MetaObject.Expression;
1370                         var source = SLE.Expression.Convert (operation.MakeExpression (ctx), target.Type);
1371                         return SLE.Expression.Assign (target, source);
1372                 }
1373 #endif
1374
1375                 public static string OperName (Mode oper)
1376                 {
1377                         return (oper & Mode.IsDecrement) != 0 ? "--" : "++";
1378                 }
1379
1380                 protected override void CloneTo (CloneContext clonectx, Expression t)
1381                 {
1382                         UnaryMutator target = (UnaryMutator) t;
1383
1384                         target.expr = expr.Clone (clonectx);
1385                 }
1386
1387                 public override object Accept (StructuralVisitor visitor)
1388                 {
1389                         return visitor.Visit (this);
1390                 }
1391
1392         }
1393
1394         //
1395         // Base class for the `is' and `as' operators
1396         //
1397         public abstract class Probe : Expression
1398         {
1399                 public Expression ProbeType;
1400                 protected Expression expr;
1401                 protected TypeSpec probe_type_expr;
1402
1403                 protected Probe (Expression expr, Expression probe_type, Location l)
1404                 {
1405                         ProbeType = probe_type;
1406                         loc = l;
1407                         this.expr = expr;
1408                 }
1409
1410                 public Expression Expr {
1411                         get {
1412                                 return expr;
1413                         }
1414                 }
1415
1416                 public override bool ContainsEmitWithAwait ()
1417                 {
1418                         return expr.ContainsEmitWithAwait ();
1419                 }
1420
1421                 protected override Expression DoResolve (ResolveContext ec)
1422                 {
1423                         probe_type_expr = ProbeType.ResolveAsType (ec);
1424                         if (probe_type_expr == null)
1425                                 return null;
1426
1427                         expr = expr.Resolve (ec);
1428                         if (expr == null)
1429                                 return null;
1430
1431                         if (probe_type_expr.IsStatic) {
1432                                 ec.Report.Error (-244, loc, "The `{0}' operator cannot be applied to an operand of a static type",
1433                                         OperatorName);
1434                         }
1435
1436                         if (expr.Type.IsPointer || probe_type_expr.IsPointer) {
1437                                 ec.Report.Error (244, loc, "The `{0}' operator cannot be applied to an operand of pointer type",
1438                                         OperatorName);
1439                                 return null;
1440                         }
1441
1442                         if (expr.Type == InternalType.AnonymousMethod) {
1443                                 ec.Report.Error (837, loc, "The `{0}' operator cannot be applied to a lambda expression or anonymous method",
1444                                         OperatorName);
1445                                 return null;
1446                         }
1447
1448                         return this;
1449                 }
1450
1451                 public override void FlowAnalysis (FlowAnalysisContext fc)
1452                 {
1453                         expr.FlowAnalysis (fc);
1454                 }
1455
1456                 protected abstract string OperatorName { get; }
1457
1458                 protected override void CloneTo (CloneContext clonectx, Expression t)
1459                 {
1460                         Probe target = (Probe) t;
1461
1462                         target.expr = expr.Clone (clonectx);
1463                         target.ProbeType = ProbeType.Clone (clonectx);
1464                 }
1465
1466         }
1467
1468         /// <summary>
1469         ///   Implementation of the `is' operator.
1470         /// </summary>
1471         public class Is : Probe
1472         {
1473                 Nullable.Unwrap expr_unwrap;
1474
1475                 public Is (Expression expr, Expression probe_type, Location l)
1476                         : base (expr, probe_type, l)
1477                 {
1478                 }
1479
1480                 protected override string OperatorName {
1481                         get { return "is"; }
1482                 }
1483
1484                 public override Expression CreateExpressionTree (ResolveContext ec)
1485                 {
1486                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1487                                 expr.CreateExpressionTree (ec),
1488                                 new TypeOf (probe_type_expr, loc));
1489
1490                         return CreateExpressionFactoryCall (ec, "TypeIs", args);
1491                 }
1492
1493                 public override void Emit (EmitContext ec)
1494                 {
1495                         if (expr_unwrap != null) {
1496                                 expr_unwrap.EmitCheck (ec);
1497                                 return;
1498                         }
1499
1500                         expr.Emit (ec);
1501
1502                         // Only to make verifier happy
1503                         if (probe_type_expr.IsGenericParameter && TypeSpec.IsValueType (expr.Type))
1504                                 ec.Emit (OpCodes.Box, expr.Type);
1505
1506                         ec.Emit (OpCodes.Isinst, probe_type_expr);
1507                         ec.EmitNull ();
1508                         ec.Emit (OpCodes.Cgt_Un);
1509                 }
1510
1511                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
1512                 {
1513                         if (expr_unwrap != null) {
1514                                 expr_unwrap.EmitCheck (ec);
1515                         } else {
1516                                 expr.Emit (ec);
1517                                 ec.Emit (OpCodes.Isinst, probe_type_expr);
1518                         }
1519                         ec.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1520                 }
1521
1522                 Expression CreateConstantResult (ResolveContext ec, bool result)
1523                 {
1524                         if (result)
1525                                 ec.Report.Warning (183, 1, loc, "The given expression is always of the provided (`{0}') type",
1526                                         probe_type_expr.GetSignatureForError ());
1527                         else
1528                                 ec.Report.Warning (184, 1, loc, "The given expression is never of the provided (`{0}') type",
1529                                         probe_type_expr.GetSignatureForError ());
1530
1531                         return ReducedExpression.Create (new BoolConstant (ec.BuiltinTypes, result, loc), this);
1532                 }
1533
1534                 protected override Expression DoResolve (ResolveContext ec)
1535                 {
1536                         if (base.DoResolve (ec) == null)
1537                                 return null;
1538
1539                         TypeSpec d = expr.Type;
1540                         bool d_is_nullable = false;
1541
1542                         //
1543                         // If E is a method group or the null literal, or if the type of E is a reference
1544                         // type or a nullable type and the value of E is null, the result is false
1545                         //
1546                         if (expr.IsNull || expr.eclass == ExprClass.MethodGroup)
1547                                 return CreateConstantResult (ec, false);
1548
1549                         if (d.IsNullableType) {
1550                                 var ut = Nullable.NullableInfo.GetUnderlyingType (d);
1551                                 if (!ut.IsGenericParameter) {
1552                                         d = ut;
1553                                         d_is_nullable = true;
1554                                 }
1555                         }
1556
1557                         type = ec.BuiltinTypes.Bool;
1558                         eclass = ExprClass.Value;
1559                         TypeSpec t = probe_type_expr;
1560                         bool t_is_nullable = false;
1561                         if (t.IsNullableType) {
1562                                 var ut = Nullable.NullableInfo.GetUnderlyingType (t);
1563                                 if (!ut.IsGenericParameter) {
1564                                         t = ut;
1565                                         t_is_nullable = true;
1566                                 }
1567                         }
1568
1569                         if (t.IsStruct) {
1570                                 if (d == t) {
1571                                         //
1572                                         // D and T are the same value types but D can be null
1573                                         //
1574                                         if (d_is_nullable && !t_is_nullable) {
1575                                                 expr_unwrap = Nullable.Unwrap.Create (expr, false);
1576                                                 return this;
1577                                         }
1578
1579                                         //
1580                                         // The result is true if D and T are the same value types
1581                                         //
1582                                         return CreateConstantResult (ec, true);
1583                                 }
1584
1585                                 var tp = d as TypeParameterSpec;
1586                                 if (tp != null)
1587                                         return ResolveGenericParameter (ec, t, tp);
1588
1589                                 //
1590                                 // An unboxing conversion exists
1591                                 //
1592                                 if (Convert.ExplicitReferenceConversionExists (d, t))
1593                                         return this;
1594
1595                                 //
1596                                 // open generic type
1597                                 //
1598                                 if (d is InflatedTypeSpec && InflatedTypeSpec.ContainsTypeParameter (d))
1599                                         return this;
1600                         } else {
1601                                 var tps = t as TypeParameterSpec;
1602                                 if (tps != null)
1603                                         return ResolveGenericParameter (ec, d, tps);
1604
1605                                 if (t.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1606                                         ec.Report.Warning (1981, 3, loc,
1607                                                 "Using `{0}' to test compatibility with `{1}' is identical to testing compatibility with `object'",
1608                                                 OperatorName, t.GetSignatureForError ());
1609                                 }
1610
1611                                 if (TypeManager.IsGenericParameter (d))
1612                                         return ResolveGenericParameter (ec, t, (TypeParameterSpec) d);
1613
1614                                 if (TypeSpec.IsValueType (d)) {
1615                                         if (Convert.ImplicitBoxingConversion (null, d, t) != null) {
1616                                                 if (d_is_nullable && !t_is_nullable) {
1617                                                         expr_unwrap = Nullable.Unwrap.Create (expr, false);
1618                                                         return this;
1619                                                 }
1620
1621                                                 return CreateConstantResult (ec, true);
1622                                         }
1623                                 } else {
1624                                         if (Convert.ImplicitReferenceConversionExists (d, t)) {
1625                                                 var c = expr as Constant;
1626                                                 if (c != null)
1627                                                         return CreateConstantResult (ec, !c.IsNull);
1628
1629                                                 //
1630                                                 // Do not optimize for imported type or dynamic type
1631                                                 //
1632                                                 if (d.MemberDefinition.IsImported && d.BuiltinType != BuiltinTypeSpec.Type.None &&
1633                                                         d.MemberDefinition.DeclaringAssembly != t.MemberDefinition.DeclaringAssembly) {
1634                                                         return this;
1635                                                 }
1636
1637                                                 if (d.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
1638                                                         return this;
1639
1640                                                 //
1641                                                 // Turn is check into simple null check for implicitly convertible reference types
1642                                                 //
1643                                                 return ReducedExpression.Create (
1644                                                         new Binary (Binary.Operator.Inequality, expr, new NullLiteral (loc)).Resolve (ec),
1645                                                         this).Resolve (ec);
1646                                         }
1647
1648                                         if (Convert.ExplicitReferenceConversionExists (d, t))
1649                                                 return this;
1650
1651                                         //
1652                                         // open generic type
1653                                         //
1654                                         if ((d is InflatedTypeSpec || d.IsArray) && InflatedTypeSpec.ContainsTypeParameter (d))
1655                                                 return this;
1656                                 }
1657                         }
1658
1659                         return CreateConstantResult (ec, false);
1660                 }
1661
1662                 Expression ResolveGenericParameter (ResolveContext ec, TypeSpec d, TypeParameterSpec t)
1663                 {
1664                         if (t.IsReferenceType) {
1665                                 if (d.IsStruct)
1666                                         return CreateConstantResult (ec, false);
1667                         }
1668
1669                         if (expr.Type.IsGenericParameter) {
1670                                 if (expr.Type == d && TypeSpec.IsValueType (t) && TypeSpec.IsValueType (d))
1671                                         return CreateConstantResult (ec, true);
1672
1673                                 expr = new BoxedCast (expr, d);
1674                         }
1675
1676                         return this;
1677                 }
1678
1679                 public override object Accept (StructuralVisitor visitor)
1680                 {
1681                         return visitor.Visit (this);
1682                 }
1683         }
1684
1685         /// <summary>
1686         ///   Implementation of the `as' operator.
1687         /// </summary>
1688         public class As : Probe {
1689                 Expression resolved_type;
1690
1691                 public As (Expression expr, Expression probe_type, Location l)
1692                         : base (expr, probe_type, l)
1693                 {
1694                 }
1695
1696                 protected override string OperatorName {
1697                         get { return "as"; }
1698                 }
1699
1700                 public override Expression CreateExpressionTree (ResolveContext ec)
1701                 {
1702                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1703                                 expr.CreateExpressionTree (ec),
1704                                 new TypeOf (probe_type_expr, loc));
1705
1706                         return CreateExpressionFactoryCall (ec, "TypeAs", args);
1707                 }
1708
1709                 public override void Emit (EmitContext ec)
1710                 {
1711                         expr.Emit (ec);
1712
1713                         ec.Emit (OpCodes.Isinst, type);
1714
1715                         if (TypeManager.IsGenericParameter (type) || type.IsNullableType)
1716                                 ec.Emit (OpCodes.Unbox_Any, type);
1717                 }
1718
1719                 protected override Expression DoResolve (ResolveContext ec)
1720                 {
1721                         if (resolved_type == null) {
1722                                 resolved_type = base.DoResolve (ec);
1723
1724                                 if (resolved_type == null)
1725                                         return null;
1726                         }
1727
1728                         type = probe_type_expr;
1729                         eclass = ExprClass.Value;
1730                         TypeSpec etype = expr.Type;
1731
1732                         if (!TypeSpec.IsReferenceType (type) && !type.IsNullableType) {
1733                                 if (TypeManager.IsGenericParameter (type)) {
1734                                         ec.Report.Error (413, loc,
1735                                                 "The `as' operator cannot be used with a non-reference type parameter `{0}'. Consider adding `class' or a reference type constraint",
1736                                                 probe_type_expr.GetSignatureForError ());
1737                                 } else {
1738                                         ec.Report.Error (77, loc,
1739                                                 "The `as' operator cannot be used with a non-nullable value type `{0}'",
1740                                                 type.GetSignatureForError ());
1741                                 }
1742                                 return null;
1743                         }
1744
1745                         if (expr.IsNull && type.IsNullableType) {
1746                                 return Nullable.LiftedNull.CreateFromExpression (ec, this);
1747                         }
1748
1749                         // If the compile-time type of E is dynamic, unlike the cast operator the as operator is not dynamically bound
1750                         if (etype.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
1751                                 return this;
1752                         }
1753
1754                         Expression e = Convert.ImplicitConversionStandard (ec, expr, type, loc);
1755                         if (e != null) {
1756                                 e = EmptyCast.Create (e, type);
1757                                 return ReducedExpression.Create (e, this).Resolve (ec);
1758                         }
1759
1760                         if (Convert.ExplicitReferenceConversionExists (etype, type)){
1761                                 if (TypeManager.IsGenericParameter (etype))
1762                                         expr = new BoxedCast (expr, etype);
1763
1764                                 return this;
1765                         }
1766
1767                         if (InflatedTypeSpec.ContainsTypeParameter (etype) || InflatedTypeSpec.ContainsTypeParameter (type)) {
1768                                 expr = new BoxedCast (expr, etype);
1769                                 return this;
1770                         }
1771
1772                         if (etype != InternalType.ErrorType) {
1773                                 ec.Report.Error (39, loc, "Cannot convert type `{0}' to `{1}' via a built-in conversion",
1774                                         etype.GetSignatureForError (), type.GetSignatureForError ());
1775                         }
1776
1777                         return null;
1778                 }
1779
1780                 public override object Accept (StructuralVisitor visitor)
1781                 {
1782                         return visitor.Visit (this);
1783                 }
1784         }
1785
1786         //
1787         // This represents a typecast in the source language.
1788         //
1789         public class Cast : ShimExpression {
1790                 Expression target_type;
1791
1792                 public Cast (Expression cast_type, Expression expr, Location loc)
1793                         : base (expr)
1794                 {
1795                         this.target_type = cast_type;
1796                         this.loc = loc;
1797                 }
1798
1799                 public Expression TargetType {
1800                         get { return target_type; }
1801                 }
1802
1803                 protected override Expression DoResolve (ResolveContext ec)
1804                 {
1805                         expr = expr.Resolve (ec);
1806                         if (expr == null)
1807                                 return null;
1808
1809                         type = target_type.ResolveAsType (ec);
1810                         if (type == null)
1811                                 return null;
1812
1813                         if (type.IsStatic) {
1814                                 ec.Report.Error (716, loc, "Cannot convert to static type `{0}'", type.GetSignatureForError ());
1815                                 return null;
1816                         }
1817
1818                         if (type.IsPointer && !ec.IsUnsafe) {
1819                                 UnsafeError (ec, loc);
1820                         }
1821
1822                         eclass = ExprClass.Value;
1823
1824                         Constant c = expr as Constant;
1825                         if (c != null) {
1826                                 c = c.Reduce (ec, type);
1827                                 if (c != null)
1828                                         return c;
1829                         }
1830
1831                         var res = Convert.ExplicitConversion (ec, expr, type, loc);
1832                         if (res == expr)
1833                                 return EmptyCast.Create (res, type);
1834
1835                         return res;
1836                 }
1837
1838                 protected override void CloneTo (CloneContext clonectx, Expression t)
1839                 {
1840                         Cast target = (Cast) t;
1841
1842                         target.target_type = target_type.Clone (clonectx);
1843                         target.expr = expr.Clone (clonectx);
1844                 }
1845
1846                 public override object Accept (StructuralVisitor visitor)
1847                 {
1848                         return visitor.Visit (this);
1849                 }
1850         }
1851
1852         public class ImplicitCast : ShimExpression
1853         {
1854                 bool arrayAccess;
1855
1856                 public ImplicitCast (Expression expr, TypeSpec target, bool arrayAccess)
1857                         : base (expr)
1858                 {
1859                         this.loc = expr.Location;
1860                         this.type = target;
1861                         this.arrayAccess = arrayAccess;
1862                 }
1863
1864                 protected override Expression DoResolve (ResolveContext ec)
1865                 {
1866                         expr = expr.Resolve (ec);
1867                         if (expr == null)
1868                                 return null;
1869
1870                         if (arrayAccess)
1871                                 expr = ConvertExpressionToArrayIndex (ec, expr);
1872                         else
1873                                 expr = Convert.ImplicitConversionRequired (ec, expr, type, loc);
1874
1875                         return expr;
1876                 }
1877         }
1878
1879         //
1880         // C# 2.0 Default value expression
1881         //
1882         public class DefaultValueExpression : Expression
1883         {
1884                 Expression expr;
1885
1886                 public DefaultValueExpression (Expression expr, Location loc)
1887                 {
1888                         this.expr = expr;
1889                         this.loc = loc;
1890                 }
1891
1892                 public Expression Expr {
1893                         get {
1894                                 return this.expr;
1895                         }
1896                 }
1897
1898                 public override bool IsSideEffectFree {
1899                         get {
1900                                 return true;
1901                         }
1902                 }
1903
1904                 public override bool ContainsEmitWithAwait ()
1905                 {
1906                         return false;
1907                 }
1908
1909                 public override Expression CreateExpressionTree (ResolveContext ec)
1910                 {
1911                         Arguments args = new Arguments (2);
1912                         args.Add (new Argument (this));
1913                         args.Add (new Argument (new TypeOf (type, loc)));
1914                         return CreateExpressionFactoryCall (ec, "Constant", args);
1915                 }
1916
1917                 protected override Expression DoResolve (ResolveContext ec)
1918                 {
1919                         type = expr.ResolveAsType (ec);
1920                         if (type == null)
1921                                 return null;
1922
1923                         if (type.IsStatic) {
1924                                 ec.Report.Error (-244, loc, "The `default value' operator cannot be applied to an operand of a static type");
1925                         }
1926
1927                         if (type.IsPointer)
1928                                 return new NullLiteral (Location).ConvertImplicitly (type);
1929
1930                         if (TypeSpec.IsReferenceType (type))
1931                                 return new NullConstant (type, loc);
1932
1933                         Constant c = New.Constantify (type, expr.Location);
1934                         if (c != null)
1935                                 return c;
1936
1937                         eclass = ExprClass.Variable;
1938                         return this;
1939                 }
1940
1941                 public override void Emit (EmitContext ec)
1942                 {
1943                         LocalTemporary temp_storage = new LocalTemporary(type);
1944
1945                         temp_storage.AddressOf(ec, AddressOp.LoadStore);
1946                         ec.Emit(OpCodes.Initobj, type);
1947                         temp_storage.Emit(ec);
1948                         temp_storage.Release (ec);
1949                 }
1950
1951 #if (NET_4_0 || MOBILE_DYNAMIC) && !STATIC
1952                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1953                 {
1954                         return SLE.Expression.Default (type.GetMetaInfo ());
1955                 }
1956 #endif
1957
1958                 protected override void CloneTo (CloneContext clonectx, Expression t)
1959                 {
1960                         DefaultValueExpression target = (DefaultValueExpression) t;
1961
1962                         target.expr = expr.Clone (clonectx);
1963                 }
1964
1965                 public override object Accept (StructuralVisitor visitor)
1966                 {
1967                         return visitor.Visit (this);
1968                 }
1969         }
1970
1971         /// <summary>
1972         ///   Binary operators
1973         /// </summary>
1974         public class Binary : Expression, IDynamicBinder
1975         {
1976                 public class PredefinedOperator
1977                 {
1978                         protected readonly TypeSpec left;
1979                         protected readonly TypeSpec right;
1980                         protected readonly TypeSpec left_unwrap;
1981                         protected readonly TypeSpec right_unwrap;
1982                         public readonly Operator OperatorsMask;
1983                         public TypeSpec ReturnType;
1984
1985                         public PredefinedOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask)
1986                                 : this (ltype, rtype, op_mask, ltype)
1987                         {
1988                         }
1989
1990                         public PredefinedOperator (TypeSpec type, Operator op_mask, TypeSpec return_type)
1991                                 : this (type, type, op_mask, return_type)
1992                         {
1993                         }
1994
1995                         public PredefinedOperator (TypeSpec type, Operator op_mask)
1996                                 : this (type, type, op_mask, type)
1997                         {
1998                         }
1999
2000                         public PredefinedOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask, TypeSpec return_type)
2001                         {
2002                                 if ((op_mask & Operator.ValuesOnlyMask) != 0)
2003                                         throw new InternalErrorException ("Only masked values can be used");
2004
2005                                 if ((op_mask & Operator.NullableMask) != 0) {
2006                                         left_unwrap = Nullable.NullableInfo.GetUnderlyingType (ltype);
2007                                         right_unwrap = Nullable.NullableInfo.GetUnderlyingType (rtype);
2008                                 } else {
2009                                         left_unwrap = ltype;
2010                                         right_unwrap = rtype;
2011                                 }
2012
2013                                 this.left = ltype;
2014                                 this.right = rtype;
2015                                 this.OperatorsMask = op_mask;
2016                                 this.ReturnType = return_type;
2017                         }
2018
2019                         public bool IsLifted {
2020                                 get {
2021                                         return (OperatorsMask & Operator.NullableMask) != 0;
2022                                 }
2023                         }
2024
2025                         public virtual Expression ConvertResult (ResolveContext rc, Binary b)
2026                         {
2027                                 Constant c;
2028
2029                                 var left_expr = b.left;
2030                                 var right_expr = b.right;
2031
2032                                 b.type = ReturnType;
2033
2034                                 if (IsLifted) {
2035                                         if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
2036                                                 b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2037                                                 b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2038                                         }
2039
2040                                         if (right_expr.IsNull) {
2041                                                 if ((b.oper & Operator.EqualityMask) != 0) {
2042                                                         if (!left_expr.Type.IsNullableType && BuiltinTypeSpec.IsPrimitiveType (left_expr.Type))
2043                                                                 return b.CreateLiftedValueTypeResult (rc, left_expr.Type);
2044                                                 } else if ((b.oper & Operator.BitwiseMask) != 0) {
2045                                                         if (left_unwrap.BuiltinType != BuiltinTypeSpec.Type.Bool)
2046                                                                 return Nullable.LiftedNull.CreateFromExpression (rc, b);
2047                                                 } else {
2048                                                         b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2049                                                         b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2050
2051                                                         if ((b.Oper & (Operator.ArithmeticMask | Operator.ShiftMask)) != 0)
2052                                                                 return Nullable.LiftedNull.CreateFromExpression (rc, b);
2053
2054                                                         return b.CreateLiftedValueTypeResult (rc, left);
2055                                                 }
2056                                         } else if (left_expr.IsNull) {
2057                                                 if ((b.oper & Operator.EqualityMask) != 0) {
2058                                                         if (!right_expr.Type.IsNullableType && BuiltinTypeSpec.IsPrimitiveType (right_expr.Type))
2059                                                                 return b.CreateLiftedValueTypeResult (rc, right_expr.Type);
2060                                                 } else if ((b.oper & Operator.BitwiseMask) != 0) {
2061                                                         if (right_unwrap.BuiltinType != BuiltinTypeSpec.Type.Bool)
2062                                                                 return Nullable.LiftedNull.CreateFromExpression (rc, b);
2063                                                 } else {
2064                                                         b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2065                                                         b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2066
2067                                                         if ((b.Oper & (Operator.ArithmeticMask | Operator.ShiftMask)) != 0)
2068                                                                 return Nullable.LiftedNull.CreateFromExpression (rc, b);
2069
2070                                                         return b.CreateLiftedValueTypeResult (rc, right);
2071                                                 }
2072                                         }
2073                                 }
2074
2075                                 //
2076                                 // A user operators does not support multiple user conversions, but decimal type
2077                                 // is considered to be predefined type therefore we apply predefined operators rules
2078                                 // and then look for decimal user-operator implementation
2079                                 //
2080                                 if (left.BuiltinType == BuiltinTypeSpec.Type.Decimal) {
2081                                         b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2082                                         b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2083
2084                                         return b.ResolveUserOperator (rc, b.left, b.right);
2085                                 }
2086
2087                                 c = right_expr as Constant;
2088                                 if (c != null) {
2089                                         if (c.IsDefaultValue) {
2090                                                 //
2091                                                 // Optimizes
2092                                                 //
2093                                                 // (expr + 0) to expr
2094                                                 // (expr - 0) to expr
2095                                                 // (bool? | false) to bool?
2096                                                 //
2097                                                 if (b.oper == Operator.Addition || b.oper == Operator.Subtraction ||
2098                                                         (b.oper == Operator.BitwiseOr && left_unwrap.BuiltinType == BuiltinTypeSpec.Type.Bool && c is BoolConstant)) {
2099                                                         b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2100                                                         return ReducedExpression.Create (b.left, b).Resolve (rc);
2101                                                 }
2102
2103                                                 //
2104                                                 // Optimizes (value &/&& 0) to 0
2105                                                 //
2106                                                 if ((b.oper == Operator.BitwiseAnd || b.oper == Operator.LogicalAnd) && !IsLifted) {
2107                                                         Constant side_effect = new SideEffectConstant (c, b.left, c.Location);
2108                                                         return ReducedExpression.Create (side_effect, b);
2109                                                 }
2110                                         } else {
2111                                                 //
2112                                                 // Optimizes (bool? & true) to bool?
2113                                                 //
2114                                                 if (IsLifted && left_unwrap.BuiltinType == BuiltinTypeSpec.Type.Bool && b.oper == Operator.BitwiseAnd) {
2115                                                         return ReducedExpression.Create (b.left, b).Resolve (rc);
2116                                                 }
2117                                         }
2118
2119                                         if ((b.oper == Operator.Multiply || b.oper == Operator.Division) && c.IsOneInteger)
2120                                                 return ReducedExpression.Create (b.left, b).Resolve (rc);
2121
2122                                         if ((b.oper & Operator.ShiftMask) != 0 && c is IntConstant) {
2123                                                 b.right = new IntConstant (rc.BuiltinTypes, ((IntConstant) c).Value & GetShiftMask (left_unwrap), b.right.Location);
2124                                         }
2125                                 }
2126
2127                                 c = b.left as Constant;
2128                                 if (c != null) {
2129                                         if (c.IsDefaultValue) {
2130                                                 //
2131                                                 // Optimizes
2132                                                 //
2133                                                 // (0 + expr) to expr
2134                                                 // (false | bool?) to bool?
2135                                                 //
2136                                                 if (b.oper == Operator.Addition ||
2137                                                         (b.oper == Operator.BitwiseOr && right_unwrap.BuiltinType == BuiltinTypeSpec.Type.Bool && c is BoolConstant)) {
2138                                                         b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2139                                                         return ReducedExpression.Create (b.right, b).Resolve (rc);
2140                                                 }
2141
2142                                                 //
2143                                                 // Optimizes (false && expr) to false
2144                                                 //
2145                                                 if (b.oper == Operator.LogicalAnd && c.Type.BuiltinType == BuiltinTypeSpec.Type.Bool) {
2146                                                         // No rhs side-effects
2147                                                         Expression.Warning_UnreachableExpression (rc, b.right.StartLocation);
2148                                                         return ReducedExpression.Create (c, b);
2149                                                 }
2150
2151                                                 //
2152                                                 // Optimizes (0 & value) to 0
2153                                                 //
2154                                                 if (b.oper == Operator.BitwiseAnd && !IsLifted) {
2155                                                         Constant side_effect = new SideEffectConstant (c, b.right, c.Location);
2156                                                         return ReducedExpression.Create (side_effect, b);
2157                                                 }
2158                                         } else {
2159                                                 //
2160                                                 // Optimizes (true & bool?) to bool?
2161                                                 //
2162                                                 if (IsLifted && left_unwrap.BuiltinType == BuiltinTypeSpec.Type.Bool && b.oper == Operator.BitwiseAnd) {
2163                                                         return ReducedExpression.Create (b.right, b).Resolve (rc);
2164                                                 }
2165
2166                                                 //
2167                                                 // Optimizes (true || expr) to true
2168                                                 //
2169                                                 if (b.oper == Operator.LogicalOr && c.Type.BuiltinType == BuiltinTypeSpec.Type.Bool) {
2170                                                         // No rhs side-effects
2171                                                         Expression.Warning_UnreachableExpression (rc, b.right.StartLocation);
2172                                                         return ReducedExpression.Create (c, b);
2173                                                 }
2174                                         }
2175
2176                                         if (b.oper == Operator.Multiply && c.IsOneInteger)
2177                                                 return ReducedExpression.Create (b.right, b).Resolve (rc);
2178                                 }
2179
2180                                 if (IsLifted) {
2181                                         var lifted = new Nullable.LiftedBinaryOperator (b);
2182
2183                                         TypeSpec ltype, rtype;
2184                                         if (b.left.Type.IsNullableType) {
2185                                                 lifted.UnwrapLeft = new Nullable.Unwrap (b.left);
2186                                                 ltype = left_unwrap;
2187                                         } else {
2188                                                 ltype = left;
2189                                         }
2190
2191                                         if (b.right.Type.IsNullableType) {
2192                                                 lifted.UnwrapRight = new Nullable.Unwrap (b.right);
2193                                                 rtype = right_unwrap;
2194                                         } else {
2195                                                 rtype = right;
2196                                         }
2197
2198                                         lifted.Left = b.left.IsNull ?
2199                                                 b.left :
2200                                                 Convert.ImplicitConversion (rc, lifted.UnwrapLeft ?? b.left, ltype, b.left.Location);
2201
2202                                         lifted.Right = b.right.IsNull ?
2203                                                 b.right :
2204                                                 Convert.ImplicitConversion (rc, lifted.UnwrapRight ?? b.right, rtype, b.right.Location);
2205
2206                                         return lifted.Resolve (rc);
2207                                 }
2208
2209                                 b.left = Convert.ImplicitConversion (rc, b.left, left, b.left.Location);
2210                                 b.right = Convert.ImplicitConversion (rc, b.right, right, b.right.Location);
2211
2212                                 return b;
2213                         }
2214
2215                         public bool IsPrimitiveApplicable (TypeSpec ltype, TypeSpec rtype)
2216                         {
2217                                 //
2218                                 // We are dealing with primitive types only
2219                                 //
2220                                 return left == ltype && ltype == rtype;
2221                         }
2222
2223                         public virtual bool IsApplicable (ResolveContext ec, Expression lexpr, Expression rexpr)
2224                         {
2225                                 // Quick path
2226                                 if (left == lexpr.Type && right == rexpr.Type)
2227                                         return true;
2228
2229                                 return Convert.ImplicitConversionExists (ec, lexpr, left) &&
2230                                         Convert.ImplicitConversionExists (ec, rexpr, right);
2231                         }
2232
2233                         public PredefinedOperator ResolveBetterOperator (ResolveContext ec, PredefinedOperator best_operator)
2234                         {
2235                                 if ((OperatorsMask & Operator.DecomposedMask) != 0)
2236                                         return best_operator;
2237
2238                                 if ((best_operator.OperatorsMask & Operator.DecomposedMask) != 0)
2239                                         return this;
2240
2241                                 int result = 0;
2242                                 if (left != null && best_operator.left != null) {
2243                                         result = OverloadResolver.BetterTypeConversion (ec, best_operator.left_unwrap, left_unwrap);
2244                                 }
2245
2246                                 //
2247                                 // When second argument is same as the first one, the result is same
2248                                 //
2249                                 if (right != null && (left != right || best_operator.left != best_operator.right)) {
2250                                         result |= OverloadResolver.BetterTypeConversion (ec, best_operator.right_unwrap, right_unwrap);
2251                                 }
2252
2253                                 if (result == 0 || result > 2)
2254                                         return null;
2255
2256                                 return result == 1 ? best_operator : this;
2257                         }
2258                 }
2259
2260                 sealed class PredefinedStringOperator : PredefinedOperator
2261                 {
2262                         public PredefinedStringOperator (TypeSpec type, Operator op_mask, TypeSpec retType)
2263                                 : base (type, type, op_mask, retType)
2264                         {
2265                         }
2266
2267                         public PredefinedStringOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask, TypeSpec retType)
2268                                 : base (ltype, rtype, op_mask, retType)
2269                         {
2270                         }
2271
2272                         public override Expression ConvertResult (ResolveContext ec, Binary b)
2273                         {
2274                                 //
2275                                 // Use original expression for nullable arguments
2276                                 //
2277                                 Nullable.Unwrap unwrap = b.left as Nullable.Unwrap;
2278                                 if (unwrap != null)
2279                                         b.left = unwrap.Original;
2280
2281                                 unwrap = b.right as Nullable.Unwrap;
2282                                 if (unwrap != null)
2283                                         b.right = unwrap.Original;
2284
2285                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
2286                                 b.right = Convert.ImplicitConversion (ec, b.right, right, b.right.Location);
2287
2288                                 //
2289                                 // Start a new concat expression using converted expression
2290                                 //
2291                                 return StringConcat.Create (ec, b.left, b.right, b.loc);
2292                         }
2293                 }
2294
2295                 sealed class PredefinedEqualityOperator : PredefinedOperator
2296                 {
2297                         MethodSpec equal_method, inequal_method;
2298
2299                         public PredefinedEqualityOperator (TypeSpec arg, TypeSpec retType)
2300                                 : base (arg, arg, Operator.EqualityMask, retType)
2301                         {
2302                         }
2303
2304                         public override Expression ConvertResult (ResolveContext ec, Binary b)
2305                         {
2306                                 b.type = ReturnType;
2307
2308                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
2309                                 b.right = Convert.ImplicitConversion (ec, b.right, right, b.right.Location);
2310
2311                                 Arguments args = new Arguments (2);
2312                                 args.Add (new Argument (b.left));
2313                                 args.Add (new Argument (b.right));
2314
2315                                 MethodSpec method;
2316                                 if (b.oper == Operator.Equality) {
2317                                         if (equal_method == null) {
2318                                                 if (left.BuiltinType == BuiltinTypeSpec.Type.String)
2319                                                         equal_method = ec.Module.PredefinedMembers.StringEqual.Resolve (b.loc);
2320                                                 else if (left.BuiltinType == BuiltinTypeSpec.Type.Delegate)
2321                                                         equal_method = ec.Module.PredefinedMembers.DelegateEqual.Resolve (b.loc);
2322                                                 else
2323                                                         throw new NotImplementedException (left.GetSignatureForError ());
2324                                         }
2325
2326                                         method = equal_method;
2327                                 } else {
2328                                         if (inequal_method == null) {
2329                                                 if (left.BuiltinType == BuiltinTypeSpec.Type.String)
2330                                                         inequal_method = ec.Module.PredefinedMembers.StringInequal.Resolve (b.loc);
2331                                                 else if (left.BuiltinType == BuiltinTypeSpec.Type.Delegate)
2332                                                         inequal_method = ec.Module.PredefinedMembers.DelegateInequal.Resolve (b.loc);
2333                                                 else
2334                                                         throw new NotImplementedException (left.GetSignatureForError ());
2335                                         }
2336
2337                                         method = inequal_method;
2338                                 }
2339
2340                                 return new UserOperatorCall (method, args, b.CreateExpressionTree, b.loc);
2341                         }
2342                 }
2343
2344                 class PredefinedPointerOperator : PredefinedOperator
2345                 {
2346                         public PredefinedPointerOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask)
2347                                 : base (ltype, rtype, op_mask)
2348                         {
2349                         }
2350
2351                         public PredefinedPointerOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask, TypeSpec retType)
2352                                 : base (ltype, rtype, op_mask, retType)
2353                         {
2354                         }
2355
2356                         public PredefinedPointerOperator (TypeSpec type, Operator op_mask, TypeSpec return_type)
2357                                 : base (type, op_mask, return_type)
2358                         {
2359                         }
2360
2361                         public override bool IsApplicable (ResolveContext ec, Expression lexpr, Expression rexpr)
2362                         {
2363                                 if (left == null) {
2364                                         if (!lexpr.Type.IsPointer)
2365                                                 return false;
2366                                 } else {
2367                                         if (!Convert.ImplicitConversionExists (ec, lexpr, left))
2368                                                 return false;
2369                                 }
2370
2371                                 if (right == null) {
2372                                         if (!rexpr.Type.IsPointer)
2373                                                 return false;
2374                                 } else {
2375                                         if (!Convert.ImplicitConversionExists (ec, rexpr, right))
2376                                                 return false;
2377                                 }
2378
2379                                 return true;
2380                         }
2381
2382                         public override Expression ConvertResult (ResolveContext ec, Binary b)
2383                         {
2384                                 if (left != null) {
2385                                         b.left = EmptyCast.Create (b.left, left);
2386                                 } else if (right != null) {
2387                                         b.right = EmptyCast.Create (b.right, right);
2388                                 }
2389
2390                                 TypeSpec r_type = ReturnType;
2391                                 Expression left_arg, right_arg;
2392                                 if (r_type == null) {
2393                                         if (left == null) {
2394                                                 left_arg = b.left;
2395                                                 right_arg = b.right;
2396                                                 r_type = b.left.Type;
2397                                         } else {
2398                                                 left_arg = b.right;
2399                                                 right_arg = b.left;
2400                                                 r_type = b.right.Type;
2401                                         }
2402                                 } else {
2403                                         left_arg = b.left;
2404                                         right_arg = b.right;
2405                                 }
2406
2407                                 return new PointerArithmetic (b.oper, left_arg, right_arg, r_type, b.loc).Resolve (ec);
2408                         }
2409                 }
2410
2411                 [Flags]
2412                 public enum Operator {
2413                         Multiply        = 0 | ArithmeticMask,
2414                         Division        = 1 | ArithmeticMask,
2415                         Modulus         = 2 | ArithmeticMask,
2416                         Addition        = 3 | ArithmeticMask | AdditionMask,
2417                         Subtraction = 4 | ArithmeticMask | SubtractionMask,
2418
2419                         LeftShift       = 5 | ShiftMask,
2420                         RightShift      = 6 | ShiftMask,
2421
2422                         LessThan        = 7 | ComparisonMask | RelationalMask,
2423                         GreaterThan     = 8 | ComparisonMask | RelationalMask,
2424                         LessThanOrEqual         = 9 | ComparisonMask | RelationalMask,
2425                         GreaterThanOrEqual      = 10 | ComparisonMask | RelationalMask,
2426                         Equality        = 11 | ComparisonMask | EqualityMask,
2427                         Inequality      = 12 | ComparisonMask | EqualityMask,
2428
2429                         BitwiseAnd      = 13 | BitwiseMask,
2430                         ExclusiveOr     = 14 | BitwiseMask,
2431                         BitwiseOr       = 15 | BitwiseMask,
2432
2433                         LogicalAnd      = 16 | LogicalMask,
2434                         LogicalOr       = 17 | LogicalMask,
2435
2436                         //
2437                         // Operator masks
2438                         //
2439                         ValuesOnlyMask  = ArithmeticMask - 1,
2440                         ArithmeticMask  = 1 << 5,
2441                         ShiftMask               = 1 << 6,
2442                         ComparisonMask  = 1 << 7,
2443                         EqualityMask    = 1 << 8,
2444                         BitwiseMask             = 1 << 9,
2445                         LogicalMask             = 1 << 10,
2446                         AdditionMask    = 1 << 11,
2447                         SubtractionMask = 1 << 12,
2448                         RelationalMask  = 1 << 13,
2449
2450                         DecomposedMask  = 1 << 19,
2451                         NullableMask    = 1 << 20,
2452                 }
2453
2454                 [Flags]
2455                 enum State : byte
2456                 {
2457                         None = 0,
2458                         Compound = 1 << 1,
2459                 }
2460
2461                 readonly Operator oper;
2462                 Expression left, right;
2463                 State state;
2464                 ConvCast.Mode enum_conversion;
2465
2466                 public Binary (Operator oper, Expression left, Expression right, bool isCompound)
2467                         : this (oper, left, right)
2468                 {
2469                         if (isCompound)
2470                                 state |= State.Compound;
2471                 }
2472
2473                 public Binary (Operator oper, Expression left, Expression right)
2474                 {
2475                         this.oper = oper;
2476                         this.left = left;
2477                         this.right = right;
2478                         this.loc = left.Location;
2479                 }
2480
2481                 #region Properties
2482
2483                 public bool IsCompound {
2484                         get {
2485                                 return (state & State.Compound) != 0;
2486                         }
2487                 }
2488
2489                 public Operator Oper {
2490                         get {
2491                                 return oper;
2492                         }
2493                 }
2494
2495                 public Expression Left {
2496                         get {
2497                                 return this.left;
2498                         }
2499                 }
2500
2501                 public Expression Right {
2502                         get {
2503                                 return this.right;
2504                         }
2505                 }
2506
2507                 public override Location StartLocation {
2508                         get {
2509                                 return left.StartLocation;
2510                         }
2511                 }
2512
2513                 #endregion
2514
2515                 /// <summary>
2516                 ///   Returns a stringified representation of the Operator
2517                 /// </summary>
2518                 string OperName (Operator oper)
2519                 {
2520                         string s;
2521                         switch (oper){
2522                         case Operator.Multiply:
2523                                 s = "*";
2524                                 break;
2525                         case Operator.Division:
2526                                 s = "/";
2527                                 break;
2528                         case Operator.Modulus:
2529                                 s = "%";
2530                                 break;
2531                         case Operator.Addition:
2532                                 s = "+";
2533                                 break;
2534                         case Operator.Subtraction:
2535                                 s = "-";
2536                                 break;
2537                         case Operator.LeftShift:
2538                                 s = "<<";
2539                                 break;
2540                         case Operator.RightShift:
2541                                 s = ">>";
2542                                 break;
2543                         case Operator.LessThan:
2544                                 s = "<";
2545                                 break;
2546                         case Operator.GreaterThan:
2547                                 s = ">";
2548                                 break;
2549                         case Operator.LessThanOrEqual:
2550                                 s = "<=";
2551                                 break;
2552                         case Operator.GreaterThanOrEqual:
2553                                 s = ">=";
2554                                 break;
2555                         case Operator.Equality:
2556                                 s = "==";
2557                                 break;
2558                         case Operator.Inequality:
2559                                 s = "!=";
2560                                 break;
2561                         case Operator.BitwiseAnd:
2562                                 s = "&";
2563                                 break;
2564                         case Operator.BitwiseOr:
2565                                 s = "|";
2566                                 break;
2567                         case Operator.ExclusiveOr:
2568                                 s = "^";
2569                                 break;
2570                         case Operator.LogicalOr:
2571                                 s = "||";
2572                                 break;
2573                         case Operator.LogicalAnd:
2574                                 s = "&&";
2575                                 break;
2576                         default:
2577                                 s = oper.ToString ();
2578                                 break;
2579                         }
2580
2581                         if (IsCompound)
2582                                 return s + "=";
2583
2584                         return s;
2585                 }
2586
2587                 public static void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right, Operator oper, Location loc)
2588                 {
2589                         new Binary (oper, left, right).Error_OperatorCannotBeApplied (ec, left, right);
2590                 }
2591
2592                 public static void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right, string oper, Location loc)
2593                 {
2594                         if (left.Type == InternalType.ErrorType || right.Type == InternalType.ErrorType)
2595                                 return;
2596
2597                         string l, r;
2598                         l = left.Type.GetSignatureForError ();
2599                         r = right.Type.GetSignatureForError ();
2600
2601                         ec.Report.Error (19, loc, "Operator `{0}' cannot be applied to operands of type `{1}' and `{2}'",
2602                                 oper, l, r);
2603                 }
2604
2605                 void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right)
2606                 {
2607                         Error_OperatorCannotBeApplied (ec, left, right, OperName (oper), loc);
2608                 }
2609
2610                 public override void FlowAnalysis (FlowAnalysisContext fc)
2611                 {
2612                         if ((oper & Operator.LogicalMask) == 0) {
2613                                 left.FlowAnalysis (fc);
2614                                 right.FlowAnalysis (fc);
2615                                 return;
2616                         }
2617
2618                         //
2619                         // Optimized version when on-true/on-false data are not needed
2620                         //
2621                         bool set_on_true_false;
2622                         if (fc.DefiniteAssignmentOnTrue == null && fc.DefiniteAssignmentOnFalse == null) {
2623                                 fc.DefiniteAssignmentOnFalse = fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignment;
2624                                 set_on_true_false = false;
2625                         } else {
2626                                 set_on_true_false = true;
2627                         }
2628
2629                         left.FlowAnalysis (fc);
2630                         var left_fc = fc.DefiniteAssignment;
2631                         var left_fc_ontrue = fc.DefiniteAssignmentOnTrue;
2632                         var left_fc_onfalse = fc.DefiniteAssignmentOnFalse;
2633
2634                         fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignmentOnFalse = fc.DefiniteAssignment = new DefiniteAssignmentBitSet (
2635                                 oper == Operator.LogicalOr ? left_fc_onfalse : left_fc_ontrue);
2636                         right.FlowAnalysis (fc);
2637                         fc.DefiniteAssignment = left_fc;
2638
2639                         if (!set_on_true_false) {
2640                                 fc.DefiniteAssignmentOnFalse = fc.DefiniteAssignmentOnTrue = null;
2641                                 return;
2642                         }
2643
2644                         if (oper == Operator.LogicalOr) {
2645                                 fc.DefiniteAssignmentOnTrue = new DefiniteAssignmentBitSet (left_fc_ontrue);
2646                                 fc.DefiniteAssignmentOnFalse = left_fc_onfalse | fc.DefiniteAssignmentOnFalse;
2647                         } else {
2648                                 fc.DefiniteAssignmentOnTrue = left_fc_ontrue | fc.DefiniteAssignmentOnTrue;
2649                                 fc.DefiniteAssignmentOnFalse = new DefiniteAssignmentBitSet (left_fc_onfalse);
2650                         }
2651                 }
2652
2653                 //
2654                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
2655                 //
2656                 string GetOperatorExpressionTypeName ()
2657                 {
2658                         switch (oper) {
2659                         case Operator.Addition:
2660                                 return IsCompound ? "AddAssign" : "Add";
2661                         case Operator.BitwiseAnd:
2662                                 return IsCompound ? "AndAssign" : "And";
2663                         case Operator.BitwiseOr:
2664                                 return IsCompound ? "OrAssign" : "Or";
2665                         case Operator.Division:
2666                                 return IsCompound ? "DivideAssign" : "Divide";
2667                         case Operator.ExclusiveOr:
2668                                 return IsCompound ? "ExclusiveOrAssign" : "ExclusiveOr";
2669                         case Operator.Equality:
2670                                 return "Equal";
2671                         case Operator.GreaterThan:
2672                                 return "GreaterThan";
2673                         case Operator.GreaterThanOrEqual:
2674                                 return "GreaterThanOrEqual";
2675                         case Operator.Inequality:
2676                                 return "NotEqual";
2677                         case Operator.LeftShift:
2678                                 return IsCompound ? "LeftShiftAssign" : "LeftShift";
2679                         case Operator.LessThan:
2680                                 return "LessThan";
2681                         case Operator.LessThanOrEqual:
2682                                 return "LessThanOrEqual";
2683                         case Operator.LogicalAnd:
2684                                 return "And";
2685                         case Operator.LogicalOr:
2686                                 return "Or";
2687                         case Operator.Modulus:
2688                                 return IsCompound ? "ModuloAssign" : "Modulo";
2689                         case Operator.Multiply:
2690                                 return IsCompound ? "MultiplyAssign" : "Multiply";
2691                         case Operator.RightShift:
2692                                 return IsCompound ? "RightShiftAssign" : "RightShift";
2693                         case Operator.Subtraction:
2694                                 return IsCompound ? "SubtractAssign" : "Subtract";
2695                         default:
2696                                 throw new NotImplementedException ("Unknown expression type operator " + oper.ToString ());
2697                         }
2698                 }
2699
2700                 static CSharp.Operator.OpType ConvertBinaryToUserOperator (Operator op)
2701                 {
2702                         switch (op) {
2703                         case Operator.Addition:
2704                                 return CSharp.Operator.OpType.Addition;
2705                         case Operator.BitwiseAnd:
2706                         case Operator.LogicalAnd:
2707                                 return CSharp.Operator.OpType.BitwiseAnd;
2708                         case Operator.BitwiseOr:
2709                         case Operator.LogicalOr:
2710                                 return CSharp.Operator.OpType.BitwiseOr;
2711                         case Operator.Division:
2712                                 return CSharp.Operator.OpType.Division;
2713                         case Operator.Equality:
2714                                 return CSharp.Operator.OpType.Equality;
2715                         case Operator.ExclusiveOr:
2716                                 return CSharp.Operator.OpType.ExclusiveOr;
2717                         case Operator.GreaterThan:
2718                                 return CSharp.Operator.OpType.GreaterThan;
2719                         case Operator.GreaterThanOrEqual:
2720                                 return CSharp.Operator.OpType.GreaterThanOrEqual;
2721                         case Operator.Inequality:
2722                                 return CSharp.Operator.OpType.Inequality;
2723                         case Operator.LeftShift:
2724                                 return CSharp.Operator.OpType.LeftShift;
2725                         case Operator.LessThan:
2726                                 return CSharp.Operator.OpType.LessThan;
2727                         case Operator.LessThanOrEqual:
2728                                 return CSharp.Operator.OpType.LessThanOrEqual;
2729                         case Operator.Modulus:
2730                                 return CSharp.Operator.OpType.Modulus;
2731                         case Operator.Multiply:
2732                                 return CSharp.Operator.OpType.Multiply;
2733                         case Operator.RightShift:
2734                                 return CSharp.Operator.OpType.RightShift;
2735                         case Operator.Subtraction:
2736                                 return CSharp.Operator.OpType.Subtraction;
2737                         default:
2738                                 throw new InternalErrorException (op.ToString ());
2739                         }
2740                 }
2741
2742                 public override bool ContainsEmitWithAwait ()
2743                 {
2744                         return left.ContainsEmitWithAwait () || right.ContainsEmitWithAwait ();
2745                 }
2746
2747                 public static void EmitOperatorOpcode (EmitContext ec, Operator oper, TypeSpec l, Expression right)
2748                 {
2749                         OpCode opcode;
2750
2751                         switch (oper){
2752                         case Operator.Multiply:
2753                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2754                                         if (l.BuiltinType == BuiltinTypeSpec.Type.Int || l.BuiltinType == BuiltinTypeSpec.Type.Long)
2755                                                 opcode = OpCodes.Mul_Ovf;
2756                                         else if (!IsFloat (l))
2757                                                 opcode = OpCodes.Mul_Ovf_Un;
2758                                         else
2759                                                 opcode = OpCodes.Mul;
2760                                 } else
2761                                         opcode = OpCodes.Mul;
2762
2763                                 break;
2764
2765                         case Operator.Division:
2766                                 if (IsUnsigned (l))
2767                                         opcode = OpCodes.Div_Un;
2768                                 else
2769                                         opcode = OpCodes.Div;
2770                                 break;
2771
2772                         case Operator.Modulus:
2773                                 if (IsUnsigned (l))
2774                                         opcode = OpCodes.Rem_Un;
2775                                 else
2776                                         opcode = OpCodes.Rem;
2777                                 break;
2778
2779                         case Operator.Addition:
2780                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2781                                         if (l.BuiltinType == BuiltinTypeSpec.Type.Int || l.BuiltinType == BuiltinTypeSpec.Type.Long)
2782                                                 opcode = OpCodes.Add_Ovf;
2783                                         else if (!IsFloat (l))
2784                                                 opcode = OpCodes.Add_Ovf_Un;
2785                                         else
2786                                                 opcode = OpCodes.Add;
2787                                 } else
2788                                         opcode = OpCodes.Add;
2789                                 break;
2790
2791                         case Operator.Subtraction:
2792                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2793                                         if (l.BuiltinType == BuiltinTypeSpec.Type.Int || l.BuiltinType == BuiltinTypeSpec.Type.Long)
2794                                                 opcode = OpCodes.Sub_Ovf;
2795                                         else if (!IsFloat (l))
2796                                                 opcode = OpCodes.Sub_Ovf_Un;
2797                                         else
2798                                                 opcode = OpCodes.Sub;
2799                                 } else
2800                                         opcode = OpCodes.Sub;
2801                                 break;
2802
2803                         case Operator.RightShift:
2804                                 if (!(right is IntConstant)) {
2805                                         ec.EmitInt (GetShiftMask (l));
2806                                         ec.Emit (OpCodes.And);
2807                                 }
2808
2809                                 if (IsUnsigned (l))
2810                                         opcode = OpCodes.Shr_Un;
2811                                 else
2812                                         opcode = OpCodes.Shr;
2813                                 break;
2814
2815                         case Operator.LeftShift:
2816                                 if (!(right is IntConstant)) {
2817                                         ec.EmitInt (GetShiftMask (l));
2818                                         ec.Emit (OpCodes.And);
2819                                 }
2820
2821                                 opcode = OpCodes.Shl;
2822                                 break;
2823
2824                         case Operator.Equality:
2825                                 opcode = OpCodes.Ceq;
2826                                 break;
2827
2828                         case Operator.Inequality:
2829                                 ec.Emit (OpCodes.Ceq);
2830                                 ec.EmitInt (0);
2831
2832                                 opcode = OpCodes.Ceq;
2833                                 break;
2834
2835                         case Operator.LessThan:
2836                                 if (IsUnsigned (l))
2837                                         opcode = OpCodes.Clt_Un;
2838                                 else
2839                                         opcode = OpCodes.Clt;
2840                                 break;
2841
2842                         case Operator.GreaterThan:
2843                                 if (IsUnsigned (l))
2844                                         opcode = OpCodes.Cgt_Un;
2845                                 else
2846                                         opcode = OpCodes.Cgt;
2847                                 break;
2848
2849                         case Operator.LessThanOrEqual:
2850                                 if (IsUnsigned (l) || IsFloat (l))
2851                                         ec.Emit (OpCodes.Cgt_Un);
2852                                 else
2853                                         ec.Emit (OpCodes.Cgt);
2854                                 ec.EmitInt (0);
2855
2856                                 opcode = OpCodes.Ceq;
2857                                 break;
2858
2859                         case Operator.GreaterThanOrEqual:
2860                                 if (IsUnsigned (l) || IsFloat (l))
2861                                         ec.Emit (OpCodes.Clt_Un);
2862                                 else
2863                                         ec.Emit (OpCodes.Clt);
2864
2865                                 ec.EmitInt (0);
2866
2867                                 opcode = OpCodes.Ceq;
2868                                 break;
2869
2870                         case Operator.BitwiseOr:
2871                                 opcode = OpCodes.Or;
2872                                 break;
2873
2874                         case Operator.BitwiseAnd:
2875                                 opcode = OpCodes.And;
2876                                 break;
2877
2878                         case Operator.ExclusiveOr:
2879                                 opcode = OpCodes.Xor;
2880                                 break;
2881
2882                         default:
2883                                 throw new InternalErrorException (oper.ToString ());
2884                         }
2885
2886                         ec.Emit (opcode);
2887                 }
2888
2889                 static int GetShiftMask (TypeSpec type)
2890                 {
2891                         return type.BuiltinType == BuiltinTypeSpec.Type.Int || type.BuiltinType == BuiltinTypeSpec.Type.UInt ? 0x1f : 0x3f;
2892                 }
2893
2894                 static bool IsUnsigned (TypeSpec t)
2895                 {
2896                         switch (t.BuiltinType) {
2897                         case BuiltinTypeSpec.Type.Char:
2898                         case BuiltinTypeSpec.Type.UInt:
2899                         case BuiltinTypeSpec.Type.ULong:
2900                         case BuiltinTypeSpec.Type.UShort:
2901                         case BuiltinTypeSpec.Type.Byte:
2902                                 return true;
2903                         }
2904
2905                         return t.IsPointer;
2906                 }
2907
2908                 static bool IsFloat (TypeSpec t)
2909                 {
2910                         return t.BuiltinType == BuiltinTypeSpec.Type.Float || t.BuiltinType == BuiltinTypeSpec.Type.Double;
2911                 }
2912
2913                 public Expression ResolveOperator (ResolveContext rc)
2914                 {
2915                         eclass = ExprClass.Value;
2916
2917                         TypeSpec l = left.Type;
2918                         TypeSpec r = right.Type;
2919                         Expression expr;
2920                         bool primitives_only = false;
2921
2922                         //
2923                         // Handles predefined primitive types
2924                         //
2925                         if ((BuiltinTypeSpec.IsPrimitiveType (l) || (l.IsNullableType && BuiltinTypeSpec.IsPrimitiveType (Nullable.NullableInfo.GetUnderlyingType (l)))) &&
2926                                 (BuiltinTypeSpec.IsPrimitiveType (r) || (r.IsNullableType && BuiltinTypeSpec.IsPrimitiveType (Nullable.NullableInfo.GetUnderlyingType (r))))) {
2927                                 if ((oper & Operator.ShiftMask) == 0) {
2928                                         if (!DoBinaryOperatorPromotion (rc))
2929                                                 return null;
2930
2931                                         primitives_only = BuiltinTypeSpec.IsPrimitiveType (l) && BuiltinTypeSpec.IsPrimitiveType (r);
2932                                 }
2933                         } else {
2934                                 // Pointers
2935                                 if (l.IsPointer || r.IsPointer)
2936                                         return ResolveOperatorPointer (rc, l, r);
2937
2938                                 // User operators
2939                                 expr = ResolveUserOperator (rc, left, right);
2940                                 if (expr != null)
2941                                         return expr;
2942
2943
2944                                 bool lenum = l.IsEnum;
2945                                 bool renum = r.IsEnum;
2946                                 if ((oper & (Operator.ComparisonMask | Operator.BitwiseMask)) != 0) {
2947                                         //
2948                                         // Enumerations
2949                                         //
2950                                         if (IsEnumOrNullableEnum (l) || IsEnumOrNullableEnum (r)) {
2951                                                 expr = ResolveSingleEnumOperators (rc, lenum, renum, l, r);
2952
2953                                                 if (expr == null)
2954                                                         return null;
2955
2956                                                 if ((oper & Operator.BitwiseMask) != 0) {
2957                                                         expr = EmptyCast.Create (expr, type);
2958                                                         AddEnumResultCast (type);
2959
2960                                                         if (oper == Operator.BitwiseAnd && left.Type.IsEnum && right.Type.IsEnum) {
2961                                                                 expr = OptimizeAndOperation (expr);
2962                                                         }
2963                                                 }
2964
2965                                                 left = ConvertEnumOperandToUnderlyingType (rc, left);
2966                                                 right = ConvertEnumOperandToUnderlyingType (rc, right);
2967                                                 return expr;
2968                                         }
2969                                 } else if ((oper == Operator.Addition || oper == Operator.Subtraction)) {
2970                                         if (IsEnumOrNullableEnum (l) || IsEnumOrNullableEnum (r)) {
2971                                                 //
2972                                                 // Enumerations
2973                                                 //
2974                                                 expr = ResolveEnumOperators (rc, lenum, renum, l, r);
2975
2976                                                 //
2977                                                 // We cannot break here there is also Enum + String possible match
2978                                                 // which is not ambiguous with predefined enum operators
2979                                                 //
2980                                                 if (expr != null) {
2981                                                         left = ConvertEnumOperandToUnderlyingType (rc, left);
2982                                                         right = ConvertEnumOperandToUnderlyingType (rc, right);
2983
2984                                                         return expr;
2985                                                 }
2986                                         } else if (l.IsDelegate || r.IsDelegate) {
2987                                                 //
2988                                                 // Delegates
2989                                                 //
2990                                                 expr = ResolveOperatorDelegate (rc, l, r);
2991
2992                                                 // TODO: Can this be ambiguous
2993                                                 if (expr != null)
2994                                                         return expr;
2995                                         }
2996                                 }
2997                         }
2998
2999                         //
3000                         // Equality operators are more complicated
3001                         //
3002                         if ((oper & Operator.EqualityMask) != 0) {
3003                                 return ResolveEquality (rc, l, r, primitives_only);
3004                         }
3005
3006                         expr = ResolveOperatorPredefined (rc, rc.BuiltinTypes.OperatorsBinaryStandard, primitives_only);
3007                         if (expr != null)
3008                                 return expr;
3009
3010                         if (primitives_only)
3011                                 return null;
3012
3013                         //
3014                         // Lifted operators have lower priority
3015                         //
3016                         return ResolveOperatorPredefined (rc, rc.Module.OperatorsBinaryLifted, false);
3017                 }
3018
3019                 static bool IsEnumOrNullableEnum (TypeSpec type)
3020                 {
3021                         return type.IsEnum || (type.IsNullableType && Nullable.NullableInfo.GetUnderlyingType (type).IsEnum);
3022                 }
3023
3024
3025                 // at least one of 'left' or 'right' is an enumeration constant (EnumConstant or SideEffectConstant or ...)
3026                 // if 'left' is not an enumeration constant, create one from the type of 'right'
3027                 Constant EnumLiftUp (ResolveContext ec, Constant left, Constant right)
3028                 {
3029                         switch (oper) {
3030                         case Operator.BitwiseOr:
3031                         case Operator.BitwiseAnd:
3032                         case Operator.ExclusiveOr:
3033                         case Operator.Equality:
3034                         case Operator.Inequality:
3035                         case Operator.LessThan:
3036                         case Operator.LessThanOrEqual:
3037                         case Operator.GreaterThan:
3038                         case Operator.GreaterThanOrEqual:
3039                                 if (left.Type.IsEnum)
3040                                         return left;
3041
3042                                 if (left.IsZeroInteger)
3043                                         return left.Reduce (ec, right.Type);
3044
3045                                 break;
3046
3047                         case Operator.Addition:
3048                         case Operator.Subtraction:
3049                                 return left;
3050
3051                         case Operator.Multiply:
3052                         case Operator.Division:
3053                         case Operator.Modulus:
3054                         case Operator.LeftShift:
3055                         case Operator.RightShift:
3056                                 if (right.Type.IsEnum || left.Type.IsEnum)
3057                                         break;
3058                                 return left;
3059                         }
3060
3061                         return null;
3062                 }
3063
3064                 //
3065                 // The `|' operator used on types which were extended is dangerous
3066                 //
3067                 void CheckBitwiseOrOnSignExtended (ResolveContext ec)
3068                 {
3069                         OpcodeCast lcast = left as OpcodeCast;
3070                         if (lcast != null) {
3071                                 if (IsUnsigned (lcast.UnderlyingType))
3072                                         lcast = null;
3073                         }
3074
3075                         OpcodeCast rcast = right as OpcodeCast;
3076                         if (rcast != null) {
3077                                 if (IsUnsigned (rcast.UnderlyingType))
3078                                         rcast = null;
3079                         }
3080
3081                         if (lcast == null && rcast == null)
3082                                 return;
3083
3084                         // FIXME: consider constants
3085
3086                         var ltype = lcast != null ? lcast.UnderlyingType : rcast.UnderlyingType;
3087                         ec.Report.Warning (675, 3, loc,
3088                                 "The operator `|' used on the sign-extended type `{0}'. Consider casting to a smaller unsigned type first",
3089                                 ltype.GetSignatureForError ());
3090                 }
3091
3092                 public static PredefinedOperator[] CreatePointerOperatorsTable (BuiltinTypes types)
3093                 {
3094                         return new PredefinedOperator[] {
3095                                 //
3096                                 // Pointer arithmetic:
3097                                 //
3098                                 // T* operator + (T* x, int y);         T* operator - (T* x, int y);
3099                                 // T* operator + (T* x, uint y);        T* operator - (T* x, uint y);
3100                                 // T* operator + (T* x, long y);        T* operator - (T* x, long y);
3101                                 // T* operator + (T* x, ulong y);       T* operator - (T* x, ulong y);
3102                                 //
3103                                 new PredefinedPointerOperator (null, types.Int, Operator.AdditionMask | Operator.SubtractionMask),
3104                                 new PredefinedPointerOperator (null, types.UInt, Operator.AdditionMask | Operator.SubtractionMask),
3105                                 new PredefinedPointerOperator (null, types.Long, Operator.AdditionMask | Operator.SubtractionMask),
3106                                 new PredefinedPointerOperator (null, types.ULong, Operator.AdditionMask | Operator.SubtractionMask),
3107
3108                                 //
3109                                 // T* operator + (int y,   T* x);
3110                                 // T* operator + (uint y,  T *x);
3111                                 // T* operator + (long y,  T *x);
3112                                 // T* operator + (ulong y, T *x);
3113                                 //
3114                                 new PredefinedPointerOperator (types.Int, null, Operator.AdditionMask, null),
3115                                 new PredefinedPointerOperator (types.UInt, null, Operator.AdditionMask, null),
3116                                 new PredefinedPointerOperator (types.Long, null, Operator.AdditionMask, null),
3117                                 new PredefinedPointerOperator (types.ULong, null, Operator.AdditionMask, null),
3118
3119                                 //
3120                                 // long operator - (T* x, T *y)
3121                                 //
3122                                 new PredefinedPointerOperator (null, Operator.SubtractionMask, types.Long)
3123                         };
3124                 }
3125
3126                 public static PredefinedOperator[] CreateStandardOperatorsTable (BuiltinTypes types)
3127                 {
3128                         TypeSpec bool_type = types.Bool;
3129
3130                         return new [] {
3131                                 new PredefinedOperator (types.Int, Operator.ArithmeticMask | Operator.BitwiseMask | Operator.ShiftMask),
3132                                 new PredefinedOperator (types.UInt, Operator.ArithmeticMask | Operator.BitwiseMask),
3133                                 new PredefinedOperator (types.Long, Operator.ArithmeticMask | Operator.BitwiseMask),
3134                                 new PredefinedOperator (types.ULong, Operator.ArithmeticMask | Operator.BitwiseMask),
3135                                 new PredefinedOperator (types.Float, Operator.ArithmeticMask),
3136                                 new PredefinedOperator (types.Double, Operator.ArithmeticMask),
3137                                 new PredefinedOperator (types.Decimal, Operator.ArithmeticMask),
3138
3139                                 new PredefinedOperator (types.Int, Operator.ComparisonMask, bool_type),
3140                                 new PredefinedOperator (types.UInt, Operator.ComparisonMask, bool_type),
3141                                 new PredefinedOperator (types.Long, Operator.ComparisonMask, bool_type),
3142                                 new PredefinedOperator (types.ULong, Operator.ComparisonMask, bool_type),
3143                                 new PredefinedOperator (types.Float, Operator.ComparisonMask, bool_type),
3144                                 new PredefinedOperator (types.Double, Operator.ComparisonMask, bool_type),
3145                                 new PredefinedOperator (types.Decimal, Operator.ComparisonMask, bool_type),
3146
3147                                 new PredefinedStringOperator (types.String, Operator.AdditionMask, types.String),
3148                                 // Remaining string operators are in lifted tables
3149
3150                                 new PredefinedOperator (bool_type, Operator.BitwiseMask | Operator.LogicalMask | Operator.EqualityMask, bool_type),
3151
3152                                 new PredefinedOperator (types.UInt, types.Int, Operator.ShiftMask),
3153                                 new PredefinedOperator (types.Long, types.Int, Operator.ShiftMask),
3154                                 new PredefinedOperator (types.ULong, types.Int, Operator.ShiftMask)
3155                         };
3156
3157                 }
3158                 public static PredefinedOperator[] CreateStandardLiftedOperatorsTable (ModuleContainer module)
3159                 {
3160                         var nullable = module.PredefinedTypes.Nullable.TypeSpec;
3161                         if (nullable == null)
3162                                 return new PredefinedOperator [0];
3163
3164                         var types = module.Compiler.BuiltinTypes;
3165                         var bool_type = types.Bool;
3166
3167                         var nullable_bool = nullable.MakeGenericType (module, new[] { bool_type });
3168                         var nullable_int = nullable.MakeGenericType (module, new[] { types.Int });
3169                         var nullable_uint = nullable.MakeGenericType (module, new[] { types.UInt });
3170                         var nullable_long = nullable.MakeGenericType (module, new[] { types.Long });
3171                         var nullable_ulong = nullable.MakeGenericType (module, new[] { types.ULong });
3172                         var nullable_float = nullable.MakeGenericType (module, new[] { types.Float });
3173                         var nullable_double = nullable.MakeGenericType (module, new[] { types.Double });
3174                         var nullable_decimal = nullable.MakeGenericType (module, new[] { types.Decimal });
3175
3176                         return new[] {
3177                                 new PredefinedOperator (nullable_int, Operator.NullableMask | Operator.ArithmeticMask | Operator.BitwiseMask | Operator.ShiftMask),
3178                                 new PredefinedOperator (nullable_uint, Operator.NullableMask | Operator.ArithmeticMask | Operator.BitwiseMask),
3179                                 new PredefinedOperator (nullable_long, Operator.NullableMask | Operator.ArithmeticMask | Operator.BitwiseMask),
3180                                 new PredefinedOperator (nullable_ulong, Operator.NullableMask | Operator.ArithmeticMask | Operator.BitwiseMask),
3181                                 new PredefinedOperator (nullable_float, Operator.NullableMask | Operator.ArithmeticMask),
3182                                 new PredefinedOperator (nullable_double, Operator.NullableMask | Operator.ArithmeticMask),
3183                                 new PredefinedOperator (nullable_decimal, Operator.NullableMask | Operator.ArithmeticMask),
3184
3185                                 new PredefinedOperator (nullable_int, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3186                                 new PredefinedOperator (nullable_uint, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3187                                 new PredefinedOperator (nullable_long, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3188                                 new PredefinedOperator (nullable_ulong, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3189                                 new PredefinedOperator (nullable_float, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3190                                 new PredefinedOperator (nullable_double, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3191                                 new PredefinedOperator (nullable_decimal, Operator.NullableMask | Operator.ComparisonMask, bool_type),
3192
3193                                 new PredefinedOperator (nullable_bool, Operator.NullableMask | Operator.BitwiseMask, nullable_bool),
3194
3195                                 new PredefinedOperator (nullable_uint, nullable_int, Operator.NullableMask | Operator.ShiftMask),
3196                                 new PredefinedOperator (nullable_long, nullable_int, Operator.NullableMask | Operator.ShiftMask),
3197                                 new PredefinedOperator (nullable_ulong, nullable_int, Operator.NullableMask | Operator.ShiftMask),
3198
3199                                 //
3200                                 // Not strictly lifted but need to be in second group otherwise expressions like
3201                                 // int + null would resolve to +(object, string) instead of +(int?, int?)
3202                                 //
3203                                 new PredefinedStringOperator (types.String, types.Object, Operator.AdditionMask, types.String),
3204                                 new PredefinedStringOperator (types.Object, types.String, Operator.AdditionMask, types.String),
3205
3206                         };
3207                 }
3208
3209                 public static PredefinedOperator[] CreateEqualityOperatorsTable (BuiltinTypes types)
3210                 {
3211                         TypeSpec bool_type = types.Bool;
3212
3213                         return new[] {
3214                                 new PredefinedEqualityOperator (types.String, bool_type),
3215                                 new PredefinedEqualityOperator (types.Delegate, bool_type),
3216                                 new PredefinedOperator (bool_type, Operator.EqualityMask, bool_type),
3217                                 new PredefinedOperator (types.Int, Operator.EqualityMask, bool_type),
3218                                 new PredefinedOperator (types.UInt, Operator.EqualityMask, bool_type),
3219                                 new PredefinedOperator (types.Long, Operator.EqualityMask, bool_type),
3220                                 new PredefinedOperator (types.ULong, Operator.EqualityMask, bool_type),
3221                                 new PredefinedOperator (types.Float, Operator.EqualityMask, bool_type),
3222                                 new PredefinedOperator (types.Double, Operator.EqualityMask, bool_type),
3223                                 new PredefinedOperator (types.Decimal, Operator.EqualityMask, bool_type),
3224                         };
3225                 }
3226
3227                 public static PredefinedOperator[] CreateEqualityLiftedOperatorsTable (ModuleContainer module)
3228                 {
3229                         var nullable = module.PredefinedTypes.Nullable.TypeSpec;
3230
3231                         if (nullable == null)
3232                                 return new PredefinedOperator [0];
3233
3234                         var types = module.Compiler.BuiltinTypes;
3235                         var bool_type = types.Bool;
3236                         var nullable_bool = nullable.MakeGenericType (module, new [] { bool_type });
3237                         var nullable_int = nullable.MakeGenericType (module, new[] { types.Int });
3238                         var nullable_uint = nullable.MakeGenericType (module, new[] { types.UInt });
3239                         var nullable_long = nullable.MakeGenericType (module, new[] { types.Long });
3240                         var nullable_ulong = nullable.MakeGenericType (module, new[] { types.ULong });
3241                         var nullable_float = nullable.MakeGenericType (module, new[] { types.Float });
3242                         var nullable_double = nullable.MakeGenericType (module, new[] { types.Double });
3243                         var nullable_decimal = nullable.MakeGenericType (module, new[] { types.Decimal });
3244
3245                         return new [] {
3246                                 new PredefinedOperator (nullable_bool, Operator.NullableMask | Operator.EqualityMask, bool_type),
3247                                 new PredefinedOperator (nullable_int, Operator.NullableMask | Operator.EqualityMask, bool_type),
3248                                 new PredefinedOperator (nullable_uint, Operator.NullableMask | Operator.EqualityMask, bool_type),
3249                                 new PredefinedOperator (nullable_long, Operator.NullableMask | Operator.EqualityMask, bool_type),
3250                                 new PredefinedOperator (nullable_ulong, Operator.NullableMask | Operator.EqualityMask, bool_type),
3251                                 new PredefinedOperator (nullable_float, Operator.NullableMask | Operator.EqualityMask, bool_type),
3252                                 new PredefinedOperator (nullable_double, Operator.NullableMask | Operator.EqualityMask, bool_type),
3253                                 new PredefinedOperator (nullable_decimal, Operator.NullableMask | Operator.EqualityMask, bool_type)
3254                         };
3255                 }
3256
3257                 //
3258                 // 7.2.6.2 Binary numeric promotions
3259                 //
3260                 bool DoBinaryOperatorPromotion (ResolveContext rc)
3261                 {
3262                         TypeSpec ltype = left.Type;
3263                         if (ltype.IsNullableType) {
3264                                 ltype = Nullable.NullableInfo.GetUnderlyingType (ltype);
3265                         }
3266
3267                         //
3268                         // This is numeric promotion code only
3269                         //
3270                         if (ltype.BuiltinType == BuiltinTypeSpec.Type.Bool)
3271                                 return true;
3272
3273                         TypeSpec rtype = right.Type;
3274                         if (rtype.IsNullableType) {
3275                                 rtype = Nullable.NullableInfo.GetUnderlyingType (rtype);
3276                         }
3277
3278                         var lb = ltype.BuiltinType;
3279                         var rb = rtype.BuiltinType;
3280                         TypeSpec type;
3281                         Expression expr;
3282
3283                         if (lb == BuiltinTypeSpec.Type.Decimal || rb == BuiltinTypeSpec.Type.Decimal) {
3284                                 type = rc.BuiltinTypes.Decimal;
3285                         } else if (lb == BuiltinTypeSpec.Type.Double || rb == BuiltinTypeSpec.Type.Double) {
3286                                 type = rc.BuiltinTypes.Double;
3287                         } else if (lb == BuiltinTypeSpec.Type.Float || rb == BuiltinTypeSpec.Type.Float) {
3288                                 type = rc.BuiltinTypes.Float;
3289                         } else if (lb == BuiltinTypeSpec.Type.ULong || rb == BuiltinTypeSpec.Type.ULong) {
3290                                 type = rc.BuiltinTypes.ULong;
3291
3292                                 if (IsSignedType (lb)) {
3293                                         expr = ConvertSignedConstant (left, type);
3294                                         if (expr == null)
3295                                                 return false;
3296                                         left = expr;
3297                                 } else if (IsSignedType (rb)) {
3298                                         expr = ConvertSignedConstant (right, type);
3299                                         if (expr == null)
3300                                                 return false;
3301                                         right = expr;
3302                                 }
3303
3304                         } else if (lb == BuiltinTypeSpec.Type.Long || rb == BuiltinTypeSpec.Type.Long) {
3305                                 type = rc.BuiltinTypes.Long;
3306                         } else if (lb == BuiltinTypeSpec.Type.UInt || rb == BuiltinTypeSpec.Type.UInt) {
3307                                 type = rc.BuiltinTypes.UInt;
3308
3309                                 if (IsSignedType (lb)) {
3310                                         expr = ConvertSignedConstant (left, type);
3311                                         if (expr == null)
3312                                                 type = rc.BuiltinTypes.Long;
3313                                 } else if (IsSignedType (rb)) {
3314                                         expr = ConvertSignedConstant (right, type);
3315                                         if (expr == null)
3316                                                 type = rc.BuiltinTypes.Long;
3317                                 }
3318                         } else {
3319                                 type = rc.BuiltinTypes.Int;
3320                         }
3321
3322                         if (ltype != type) {
3323                                 expr = PromoteExpression (rc, left, type);
3324                                 if (expr == null)
3325                                         return false;
3326
3327                                 left = expr;
3328                         }
3329
3330                         if (rtype != type) {
3331                                 expr = PromoteExpression (rc, right, type);
3332                                 if (expr == null)
3333                                         return false;
3334
3335                                 right = expr;
3336                         }
3337
3338                         return true;
3339                 }
3340
3341                 static bool IsSignedType (BuiltinTypeSpec.Type type)
3342                 {
3343                         switch (type) {
3344                         case BuiltinTypeSpec.Type.Int:
3345                         case BuiltinTypeSpec.Type.Short:
3346                         case BuiltinTypeSpec.Type.SByte:
3347                         case BuiltinTypeSpec.Type.Long:
3348                                 return true;
3349                         default:
3350                                 return false;
3351                         }
3352                 }
3353
3354                 static Expression ConvertSignedConstant (Expression expr, TypeSpec type)
3355                 {
3356                         var c = expr as Constant;
3357                         if (c == null)
3358                                 return null;
3359
3360                         return c.ConvertImplicitly (type);
3361                 }
3362
3363                 static Expression PromoteExpression (ResolveContext rc, Expression expr, TypeSpec type)
3364                 {
3365                         if (expr.Type.IsNullableType) {
3366                                 return Convert.ImplicitConversionStandard (rc, expr,
3367                                         rc.Module.PredefinedTypes.Nullable.TypeSpec.MakeGenericType (rc, new[] { type }), expr.Location);
3368                         }
3369
3370                         var c = expr as Constant;
3371                         if (c != null)
3372                                 return c.ConvertImplicitly (type);
3373
3374                         return Convert.ImplicitNumericConversion (expr, type);
3375                 }
3376
3377                 protected override Expression DoResolve (ResolveContext ec)
3378                 {
3379                         if (left == null)
3380                                 return null;
3381
3382                         if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
3383                                 left = ((ParenthesizedExpression) left).Expr;
3384                                 left = left.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.Type);
3385                                 if (left == null)
3386                                         return null;
3387
3388                                 if (left.eclass == ExprClass.Type) {
3389                                         ec.Report.Error (75, loc, "To cast a negative value, you must enclose the value in parentheses");
3390                                         return null;
3391                                 }
3392                         } else
3393                                 left = left.Resolve (ec);
3394
3395                         if (left == null)
3396                                 return null;
3397
3398                         right = right.Resolve (ec);
3399                         if (right == null)
3400                                 return null;
3401
3402                         Constant lc = left as Constant;
3403                         Constant rc = right as Constant;
3404
3405                         // The conversion rules are ignored in enum context but why
3406                         if (!ec.HasSet (ResolveContext.Options.EnumScope) && lc != null && rc != null && (left.Type.IsEnum || right.Type.IsEnum)) {
3407                                 lc = EnumLiftUp (ec, lc, rc);
3408                                 if (lc != null)
3409                                         rc = EnumLiftUp (ec, rc, lc);
3410                         }
3411
3412                         if (rc != null && lc != null) {
3413                                 int prev_e = ec.Report.Errors;
3414                                 Expression e = ConstantFold.BinaryFold (ec, oper, lc, rc, loc);
3415                                 if (e != null || ec.Report.Errors != prev_e)
3416                                         return e;
3417                         }
3418
3419                         // Comparison warnings
3420                         if ((oper & Operator.ComparisonMask) != 0) {
3421                                 if (left.Equals (right)) {
3422                                         ec.Report.Warning (1718, 3, loc, "A comparison made to same variable. Did you mean to compare something else?");
3423                                 }
3424                                 CheckOutOfRangeComparison (ec, lc, right.Type);
3425                                 CheckOutOfRangeComparison (ec, rc, left.Type);
3426                         }
3427
3428                         if (left.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic || right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
3429                                 return DoResolveDynamic (ec);
3430
3431                         return DoResolveCore (ec, left, right);
3432                 }
3433
3434                 Expression DoResolveDynamic (ResolveContext rc)
3435                 {
3436                         var lt = left.Type;
3437                         var rt = right.Type;
3438                         if (lt.Kind == MemberKind.Void || lt == InternalType.MethodGroup || lt == InternalType.AnonymousMethod ||
3439                                 rt.Kind == MemberKind.Void || rt == InternalType.MethodGroup || rt == InternalType.AnonymousMethod) {
3440                                 Error_OperatorCannotBeApplied (rc, left, right);
3441                                 return null;
3442                         }
3443
3444                         Arguments args;
3445
3446                         //
3447                         // Special handling for logical boolean operators which require rhs not to be
3448                         // evaluated based on lhs value
3449                         //
3450                         if ((oper & Operator.LogicalMask) != 0) {
3451                                 Expression cond_left, cond_right, expr;
3452
3453                                 args = new Arguments (2);
3454
3455                                 if (lt.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
3456                                         LocalVariable temp = LocalVariable.CreateCompilerGenerated (lt, rc.CurrentBlock, loc);
3457
3458                                         var cond_args = new Arguments (1);
3459                                         cond_args.Add (new Argument (new SimpleAssign (temp.CreateReferenceExpression (rc, loc), left).Resolve (rc)));
3460
3461                                         //
3462                                         // dynamic && bool => IsFalse (temp = left) ? temp : temp && right;
3463                                         // dynamic || bool => IsTrue (temp = left) ? temp : temp || right;
3464                                         //
3465                                         left = temp.CreateReferenceExpression (rc, loc);
3466                                         if (oper == Operator.LogicalAnd) {
3467                                                 expr = DynamicUnaryConversion.CreateIsFalse (rc, cond_args, loc);
3468                                                 cond_left = left;
3469                                         } else {
3470                                                 expr = DynamicUnaryConversion.CreateIsTrue (rc, cond_args, loc);
3471                                                 cond_left = left;
3472                                         }
3473
3474                                         args.Add (new Argument (left));
3475                                         args.Add (new Argument (right));
3476                                         cond_right = new DynamicExpressionStatement (this, args, loc);
3477                                 } else {
3478                                         LocalVariable temp = LocalVariable.CreateCompilerGenerated (rc.BuiltinTypes.Bool, rc.CurrentBlock, loc);
3479
3480                                         args.Add (new Argument (temp.CreateReferenceExpression (rc, loc).Resolve (rc)));
3481                                         args.Add (new Argument (right));
3482                                         right = new DynamicExpressionStatement (this, args, loc);
3483
3484                                         //
3485                                         // bool && dynamic => (temp = left) ? temp && right : temp;
3486                                         // bool || dynamic => (temp = left) ? temp : temp || right;
3487                                         //
3488                                         if (oper == Operator.LogicalAnd) {
3489                                                 cond_left = right;
3490                                                 cond_right = temp.CreateReferenceExpression (rc, loc);
3491                                         } else {
3492                                                 cond_left = temp.CreateReferenceExpression (rc, loc);
3493                                                 cond_right = right;
3494                                         }
3495
3496                                         expr = new BooleanExpression (new SimpleAssign (temp.CreateReferenceExpression (rc, loc), left));
3497                                 }
3498
3499                                 return new Conditional (expr, cond_left, cond_right, loc).Resolve (rc);
3500                         }
3501
3502                         args = new Arguments (2);
3503                         args.Add (new Argument (left));
3504                         args.Add (new Argument (right));
3505                         return new DynamicExpressionStatement (this, args, loc).Resolve (rc);
3506                 }
3507
3508                 Expression DoResolveCore (ResolveContext ec, Expression left_orig, Expression right_orig)
3509                 {
3510                         Expression expr = ResolveOperator (ec);
3511                         if (expr == null)
3512                                 Error_OperatorCannotBeApplied (ec, left_orig, right_orig);
3513
3514                         if (left == null || right == null)
3515                                 throw new InternalErrorException ("Invalid conversion");
3516
3517                         if (oper == Operator.BitwiseOr)
3518                                 CheckBitwiseOrOnSignExtended (ec);
3519
3520                         return expr;
3521                 }
3522
3523                 public override SLE.Expression MakeExpression (BuilderContext ctx)
3524                 {
3525                         return MakeExpression (ctx, left, right);
3526                 }
3527
3528                 public SLE.Expression MakeExpression (BuilderContext ctx, Expression left, Expression right)
3529                 {
3530                         var le = left.MakeExpression (ctx);
3531                         var re = right.MakeExpression (ctx);
3532                         bool is_checked = ctx.HasSet (BuilderContext.Options.CheckedScope);
3533
3534                         switch (oper) {
3535                         case Operator.Addition:
3536                                 return is_checked ? SLE.Expression.AddChecked (le, re) : SLE.Expression.Add (le, re);
3537                         case Operator.BitwiseAnd:
3538                                 return SLE.Expression.And (le, re);
3539                         case Operator.BitwiseOr:
3540                                 return SLE.Expression.Or (le, re);
3541                         case Operator.Division:
3542                                 return SLE.Expression.Divide (le, re);
3543                         case Operator.Equality:
3544                                 return SLE.Expression.Equal (le, re);
3545                         case Operator.ExclusiveOr:
3546                                 return SLE.Expression.ExclusiveOr (le, re);
3547                         case Operator.GreaterThan:
3548                                 return SLE.Expression.GreaterThan (le, re);
3549                         case Operator.GreaterThanOrEqual:
3550                                 return SLE.Expression.GreaterThanOrEqual (le, re);
3551                         case Operator.Inequality:
3552                                 return SLE.Expression.NotEqual (le, re);
3553                         case Operator.LeftShift:
3554                                 return SLE.Expression.LeftShift (le, re);
3555                         case Operator.LessThan:
3556                                 return SLE.Expression.LessThan (le, re);
3557                         case Operator.LessThanOrEqual:
3558                                 return SLE.Expression.LessThanOrEqual (le, re);
3559                         case Operator.LogicalAnd:
3560                                 return SLE.Expression.AndAlso (le, re);
3561                         case Operator.LogicalOr:
3562                                 return SLE.Expression.OrElse (le, re);
3563                         case Operator.Modulus:
3564                                 return SLE.Expression.Modulo (le, re);
3565                         case Operator.Multiply:
3566                                 return is_checked ? SLE.Expression.MultiplyChecked (le, re) : SLE.Expression.Multiply (le, re);
3567                         case Operator.RightShift:
3568                                 return SLE.Expression.RightShift (le, re);
3569                         case Operator.Subtraction:
3570                                 return is_checked ? SLE.Expression.SubtractChecked (le, re) : SLE.Expression.Subtract (le, re);
3571                         default:
3572                                 throw new NotImplementedException (oper.ToString ());
3573                         }
3574                 }
3575
3576                 //
3577                 // D operator + (D x, D y)
3578                 // D operator - (D x, D y)
3579                 //
3580                 Expression ResolveOperatorDelegate (ResolveContext ec, TypeSpec l, TypeSpec r)
3581                 {
3582                         if (l != r && !TypeSpecComparer.Variant.IsEqual (r, l)) {
3583                                 Expression tmp;
3584                                 if (right.eclass == ExprClass.MethodGroup || r == InternalType.AnonymousMethod || r == InternalType.NullLiteral) {
3585                                         tmp = Convert.ImplicitConversionRequired (ec, right, l, loc);
3586                                         if (tmp == null)
3587                                                 return null;
3588                                         right = tmp;
3589                                         r = right.Type;
3590                                 } else if (left.eclass == ExprClass.MethodGroup || (l == InternalType.AnonymousMethod || l == InternalType.NullLiteral)) {
3591                                         tmp = Convert.ImplicitConversionRequired (ec, left, r, loc);
3592                                         if (tmp == null)
3593                                                 return null;
3594                                         left = tmp;
3595                                         l = left.Type;
3596                                 } else {
3597                                         return null;
3598                                 }
3599                         }
3600
3601                         MethodSpec method = null;
3602                         Arguments args = new Arguments (2);
3603                         args.Add (new Argument (left));
3604                         args.Add (new Argument (right));
3605
3606                         if (oper == Operator.Addition) {
3607                                 method = ec.Module.PredefinedMembers.DelegateCombine.Resolve (loc);
3608                         } else if (oper == Operator.Subtraction) {
3609                                 method = ec.Module.PredefinedMembers.DelegateRemove.Resolve (loc);
3610                         }
3611
3612                         if (method == null)
3613                                 return new EmptyExpression (ec.BuiltinTypes.Decimal);
3614
3615                         Expression expr = new UserOperatorCall (method, args, CreateExpressionTree, loc);
3616                         return new ClassCast (expr, l);
3617                 }
3618
3619                 //
3620                 // Resolves enumeration operators where only single predefined overload exists, handles lifted versions too
3621                 //
3622                 Expression ResolveSingleEnumOperators (ResolveContext rc, bool lenum, bool renum, TypeSpec ltype, TypeSpec rtype)
3623                 {
3624                         //
3625                         // bool operator == (E x, E y);
3626                         // bool operator != (E x, E y);
3627                         // bool operator < (E x, E y);
3628                         // bool operator > (E x, E y);
3629                         // bool operator <= (E x, E y);
3630                         // bool operator >= (E x, E y);
3631                         //
3632                         // E operator & (E x, E y);
3633                         // E operator | (E x, E y);
3634                         // E operator ^ (E x, E y);
3635                         //
3636                         Expression expr;
3637                         if ((oper & Operator.ComparisonMask) != 0) {
3638                                 type = rc.BuiltinTypes.Bool;
3639                         } else {
3640                                 if (lenum)
3641                                         type = ltype;
3642                                 else if (renum)
3643                                         type = rtype;
3644                                 else if (ltype.IsNullableType && Nullable.NullableInfo.GetUnderlyingType (ltype).IsEnum)
3645                                         type = ltype;
3646                                 else
3647                                         type = rtype;
3648                         }
3649
3650                         if (ltype == rtype) {
3651                                 if (lenum || renum)
3652                                         return this;
3653
3654                                 var lifted = new Nullable.LiftedBinaryOperator (this);
3655                                 lifted.Left = left;
3656                                 lifted.Right = right;
3657                                 return lifted.Resolve (rc);
3658                         }
3659
3660                         if (renum && !ltype.IsNullableType) {
3661                                 expr = Convert.ImplicitConversion (rc, left, rtype, loc);
3662                                 if (expr != null) {
3663                                         left = expr;
3664                                         return this;
3665                                 }
3666                         } else if (lenum && !rtype.IsNullableType) {
3667                                 expr = Convert.ImplicitConversion (rc, right, ltype, loc);
3668                                 if (expr != null) {
3669                                         right = expr;
3670                                         return this;
3671                                 }
3672                         }
3673
3674                         //
3675                         // Now try lifted version of predefined operator
3676                         //
3677                         var nullable_type = rc.Module.PredefinedTypes.Nullable.TypeSpec;
3678                         if (nullable_type != null) {
3679                                 if (renum && !ltype.IsNullableType) {
3680                                         var lifted_type = nullable_type.MakeGenericType (rc.Module, new[] { rtype });
3681
3682                                         expr = Convert.ImplicitConversion (rc, left, lifted_type, loc);
3683                                         if (expr != null) {
3684                                                 left = expr;
3685                                                 right = Convert.ImplicitConversion (rc, right, lifted_type, loc);
3686                                         }
3687
3688                                         if ((oper & Operator.BitwiseMask) != 0)
3689                                                 type = lifted_type;
3690
3691                                         if (left.IsNull) {
3692                                                 if ((oper & Operator.BitwiseMask) != 0)
3693                                                         return Nullable.LiftedNull.CreateFromExpression (rc, this);
3694
3695                                                 return CreateLiftedValueTypeResult (rc, rtype);
3696                                         }
3697
3698                                         if (expr != null) {
3699                                                 var lifted = new Nullable.LiftedBinaryOperator (this);
3700                                                 lifted.Left = expr;
3701                                                 lifted.Right = right;
3702                                                 return lifted.Resolve (rc);
3703                                         }
3704                                 } else if (lenum && !rtype.IsNullableType) {
3705                                         var lifted_type = nullable_type.MakeGenericType (rc.Module, new[] { ltype });
3706
3707                                         expr = Convert.ImplicitConversion (rc, right, lifted_type, loc);
3708                                         if (expr != null) {
3709                                                 right = expr;
3710                                                 left = Convert.ImplicitConversion (rc, left, lifted_type, loc);
3711                                         }
3712
3713                                         if ((oper & Operator.BitwiseMask) != 0)
3714                                                 type = lifted_type;
3715
3716                                         if (right.IsNull) {
3717                                                 if ((oper & Operator.BitwiseMask) != 0)
3718                                                         return Nullable.LiftedNull.CreateFromExpression (rc, this);
3719
3720                                                 return CreateLiftedValueTypeResult (rc, ltype);
3721                                         }
3722
3723                                         if (expr != null) {
3724                                                 var lifted = new Nullable.LiftedBinaryOperator (this);
3725                                                 lifted.Left = left;
3726                                                 lifted.Right = expr;
3727                                                 return lifted.Resolve (rc);
3728                                         }
3729                                 } else if (rtype.IsNullableType && Nullable.NullableInfo.GetUnderlyingType (rtype).IsEnum) {
3730                                         if (left.IsNull) {
3731                                                 if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
3732                                                         left = Convert.ImplicitConversion (rc, left, rtype, left.Location);
3733
3734                                                 if ((oper & Operator.RelationalMask) != 0)
3735                                                         return CreateLiftedValueTypeResult (rc, rtype);
3736
3737                                                 if ((oper & Operator.BitwiseMask) != 0)
3738                                                         return Nullable.LiftedNull.CreateFromExpression (rc, this);
3739
3740                                                 // Equality operators are valid between E? and null
3741                                                 expr = left;
3742                                         } else {
3743                                                 expr = Convert.ImplicitConversion (rc, left, Nullable.NullableInfo.GetUnderlyingType (rtype), loc);
3744                                                 if (expr == null)
3745                                                         return null;
3746                                         }
3747
3748                                         if (expr != null) {
3749                                                 var lifted = new Nullable.LiftedBinaryOperator (this);
3750                                                 lifted.Left = expr;
3751                                                 lifted.Right = right;
3752                                                 return lifted.Resolve (rc);
3753                                         }
3754                                 } else if (ltype.IsNullableType && Nullable.NullableInfo.GetUnderlyingType (ltype).IsEnum) {
3755                                         if (right.IsNull) {
3756                                                 if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
3757                                                         right = Convert.ImplicitConversion (rc, right, ltype, right.Location);
3758
3759                                                 if ((oper & Operator.RelationalMask) != 0)
3760                                                         return CreateLiftedValueTypeResult (rc, ltype);
3761
3762                                                 if ((oper & Operator.BitwiseMask) != 0)
3763                                                         return Nullable.LiftedNull.CreateFromExpression (rc, this);
3764
3765                                                 // Equality operators are valid between E? and null
3766                                                 expr = right;
3767                                         } else {
3768                                                 expr = Convert.ImplicitConversion (rc, right, Nullable.NullableInfo.GetUnderlyingType (ltype), loc);
3769                                                 if (expr == null)
3770                                                         return null;
3771                                         }
3772
3773                                         if (expr != null) {
3774                                                 var lifted = new Nullable.LiftedBinaryOperator (this);
3775                                                 lifted.Left = left;
3776                                                 lifted.Right = expr;
3777                                                 return lifted.Resolve (rc);
3778                                         }
3779                                 }
3780                         }
3781
3782                         return null;
3783                 }
3784
3785                 static Expression ConvertEnumOperandToUnderlyingType (ResolveContext rc, Expression expr)
3786                 {
3787                         TypeSpec underlying_type;
3788                         if (expr.Type.IsNullableType) {
3789                                 var nt = Nullable.NullableInfo.GetUnderlyingType (expr.Type);
3790                                 if (nt.IsEnum)
3791                                         underlying_type = EnumSpec.GetUnderlyingType (nt);
3792                                 else
3793                                         underlying_type = nt;
3794                         } else if (expr.Type.IsEnum) {
3795                                 underlying_type = EnumSpec.GetUnderlyingType (expr.Type);
3796                         } else {
3797                                 underlying_type = expr.Type;
3798                         }
3799
3800                         switch (underlying_type.BuiltinType) {
3801                         case BuiltinTypeSpec.Type.SByte:
3802                         case BuiltinTypeSpec.Type.Byte:
3803                         case BuiltinTypeSpec.Type.Short:
3804                         case BuiltinTypeSpec.Type.UShort:
3805                                 underlying_type = rc.BuiltinTypes.Int;
3806                                 break;
3807                         }
3808
3809                         if (expr.Type.IsNullableType)
3810                                 underlying_type = rc.Module.PredefinedTypes.Nullable.TypeSpec.MakeGenericType (rc.Module, new[] { underlying_type });
3811
3812                         if (expr.Type == underlying_type)
3813                                 return expr;
3814
3815                         return EmptyCast.Create (expr, underlying_type);
3816                 }
3817
3818                 Expression ResolveEnumOperators (ResolveContext rc, bool lenum, bool renum, TypeSpec ltype, TypeSpec rtype)
3819                 {
3820                         //
3821                         // U operator - (E e, E f)
3822                         // E operator - (E e, U x)  // Internal decomposition operator
3823                         // E operator - (U x, E e)      // Internal decomposition operator
3824                         //
3825                         // E operator + (E e, U x)
3826                         // E operator + (U x, E e)
3827                         //
3828
3829                         TypeSpec enum_type;
3830
3831                         if (lenum)
3832                                 enum_type = ltype;
3833                         else if (renum)
3834                                 enum_type = rtype;
3835                         else if (ltype.IsNullableType && Nullable.NullableInfo.GetUnderlyingType (ltype).IsEnum)
3836                                 enum_type = ltype;
3837                         else
3838                                 enum_type = rtype;
3839
3840                         Expression expr;
3841                         if (!enum_type.IsNullableType) {
3842                                 expr = ResolveOperatorPredefined (rc, rc.Module.GetPredefinedEnumAritmeticOperators (enum_type, false), false);
3843                                 if (expr != null) {
3844                                         if (oper == Operator.Subtraction)
3845                                                 expr = ConvertEnumSubtractionResult (rc, expr);
3846                                         else
3847                                                 expr = ConvertEnumAdditionalResult (expr, enum_type);
3848
3849                                         AddEnumResultCast (expr.Type);
3850
3851                                         return expr;
3852                                 }
3853
3854                                 enum_type = rc.Module.PredefinedTypes.Nullable.TypeSpec.MakeGenericType (rc.Module, new[] { enum_type });
3855                         }
3856
3857                         expr = ResolveOperatorPredefined (rc, rc.Module.GetPredefinedEnumAritmeticOperators (enum_type, true), false);
3858                         if (expr != null) {
3859                                 if (oper == Operator.Subtraction)
3860                                         expr = ConvertEnumSubtractionResult (rc, expr);
3861                                 else
3862                                         expr = ConvertEnumAdditionalResult (expr, enum_type);
3863
3864                                 AddEnumResultCast (expr.Type);
3865                         }
3866
3867                         return expr;
3868                 }
3869
3870                 static Expression ConvertEnumAdditionalResult (Expression expr, TypeSpec enumType)
3871                 {
3872                         return EmptyCast.Create (expr, enumType);
3873                 }
3874
3875                 Expression ConvertEnumSubtractionResult (ResolveContext rc, Expression expr)
3876                 {
3877                         //
3878                         // Enumeration subtraction has different result type based on
3879                         // best overload
3880                         //
3881                         TypeSpec result_type;
3882                         if (left.Type == right.Type) {
3883                                 var c = right as EnumConstant;
3884                                 if (c != null && c.IsZeroInteger && !right.Type.IsEnum) {
3885                                         //
3886                                         // LAMESPEC: This is quite unexpected for expression E - 0 the return type is
3887                                         // E which is not what expressions E - 1 or 0 - E return
3888                                         //
3889                                         result_type = left.Type;
3890                                 } else {
3891                                         result_type = left.Type.IsNullableType ?
3892                                                 Nullable.NullableInfo.GetEnumUnderlyingType (rc.Module, left.Type) :
3893                                                 EnumSpec.GetUnderlyingType (left.Type);
3894                                 }
3895                         } else {
3896                                 if (IsEnumOrNullableEnum (left.Type)) {
3897                                         result_type = left.Type;
3898                                 } else {
3899                                         result_type = right.Type;
3900                                 }
3901
3902                                 if (expr is Nullable.LiftedBinaryOperator && !result_type.IsNullableType)
3903                                         result_type = rc.Module.PredefinedTypes.Nullable.TypeSpec.MakeGenericType (rc.Module, new[] { result_type });
3904                         }
3905
3906                         return EmptyCast.Create (expr, result_type);
3907                 }
3908
3909                 void AddEnumResultCast (TypeSpec type)
3910                 {
3911                         if (type.IsNullableType)
3912                                 type = Nullable.NullableInfo.GetUnderlyingType (type);
3913
3914                         if (type.IsEnum)
3915                                 type = EnumSpec.GetUnderlyingType (type);
3916
3917                         switch (type.BuiltinType) {
3918                         case BuiltinTypeSpec.Type.SByte:
3919                                 enum_conversion = ConvCast.Mode.I4_I1;
3920                                 break;
3921                         case BuiltinTypeSpec.Type.Byte:
3922                                 enum_conversion = ConvCast.Mode.I4_U1;
3923                                 break;
3924                         case BuiltinTypeSpec.Type.Short:
3925                                 enum_conversion = ConvCast.Mode.I4_I2;
3926                                 break;
3927                         case BuiltinTypeSpec.Type.UShort:
3928                                 enum_conversion = ConvCast.Mode.I4_U2;
3929                                 break;
3930                         }
3931                 }
3932
3933                 //
3934                 // Equality operators rules
3935                 //
3936                 Expression ResolveEquality (ResolveContext ec, TypeSpec l, TypeSpec r, bool primitives_only)
3937                 {
3938                         Expression result;
3939                         type = ec.BuiltinTypes.Bool;
3940                         bool no_arg_conv = false;
3941
3942                         if (!primitives_only) {
3943
3944                                 //
3945                                 // a, Both operands are reference-type values or the value null
3946                                 // b, One operand is a value of type T where T is a type-parameter and
3947                                 // the other operand is the value null. Furthermore T does not have the
3948                                 // value type constraint
3949                                 //
3950                                 // LAMESPEC: Very confusing details in the specification, basically any
3951                                 // reference like type-parameter is allowed
3952                                 //
3953                                 var tparam_l = l as TypeParameterSpec;
3954                                 var tparam_r = r as TypeParameterSpec;
3955                                 if (tparam_l != null) {
3956                                         if (right is NullLiteral) {
3957                                                 if (tparam_l.GetEffectiveBase ().BuiltinType == BuiltinTypeSpec.Type.ValueType)
3958                                                         return null;
3959
3960                                                 left = new BoxedCast (left, ec.BuiltinTypes.Object);
3961                                                 return this;
3962                                         }
3963
3964                                         if (!tparam_l.IsReferenceType)
3965                                                 return null;
3966
3967                                         l = tparam_l.GetEffectiveBase ();
3968                                         left = new BoxedCast (left, l);
3969                                 } else if (left is NullLiteral && tparam_r == null) {
3970                                         if (TypeSpec.IsReferenceType (r))
3971                                                 return this;
3972
3973                                         if (r.Kind == MemberKind.InternalCompilerType)
3974                                                 return null;
3975                                 }
3976
3977                                 if (tparam_r != null) {
3978                                         if (left is NullLiteral) {
3979                                                 if (tparam_r.GetEffectiveBase ().BuiltinType == BuiltinTypeSpec.Type.ValueType)
3980                                                         return null;
3981
3982                                                 right = new BoxedCast (right, ec.BuiltinTypes.Object);
3983                                                 return this;
3984                                         }
3985
3986                                         if (!tparam_r.IsReferenceType)
3987                                                 return null;
3988
3989                                         r = tparam_r.GetEffectiveBase ();
3990                                         right = new BoxedCast (right, r);
3991                                 } else if (right is NullLiteral) {
3992                                         if (TypeSpec.IsReferenceType (l))
3993                                                 return this;
3994
3995                                         if (l.Kind == MemberKind.InternalCompilerType)
3996                                                 return null;
3997                                 }
3998
3999                                 //
4000                                 // LAMESPEC: method groups can be compared when they convert to other side delegate
4001                                 //
4002                                 if (l.IsDelegate) {
4003                                         if (right.eclass == ExprClass.MethodGroup) {
4004                                                 result = Convert.ImplicitConversion (ec, right, l, loc);
4005                                                 if (result == null)
4006                                                         return null;
4007
4008                                                 right = result;
4009                                                 r = l;
4010                                         } else if (r.IsDelegate && l != r) {
4011                                                 return null;
4012                                         }
4013                                 } else if (left.eclass == ExprClass.MethodGroup && r.IsDelegate) {
4014                                         result = Convert.ImplicitConversionRequired (ec, left, r, loc);
4015                                         if (result == null)
4016                                                 return null;
4017
4018                                         left = result;
4019                                         l = r;
4020                                 } else {
4021                                         no_arg_conv = l == r && !l.IsStruct;
4022                                 }
4023                         }
4024
4025                         //
4026                         // bool operator != (string a, string b)
4027                         // bool operator == (string a, string b)
4028                         //
4029                         // bool operator != (Delegate a, Delegate b)
4030                         // bool operator == (Delegate a, Delegate b)
4031                         //
4032                         // bool operator != (bool a, bool b)
4033                         // bool operator == (bool a, bool b)
4034                         //
4035                         // LAMESPEC: Reference equality comparison can apply to value/reference types when
4036                         // they implement an implicit conversion to any of types above. This does
4037                         // not apply when both operands are of same reference type
4038                         //
4039                         if (r.BuiltinType != BuiltinTypeSpec.Type.Object && l.BuiltinType != BuiltinTypeSpec.Type.Object) {
4040                                 result = ResolveOperatorPredefined (ec, ec.BuiltinTypes.OperatorsBinaryEquality, no_arg_conv);
4041                                 if (result != null)
4042                                         return result;
4043
4044                                 //
4045                                 // Now try lifted version of predefined operators
4046                                 //
4047                                 if (no_arg_conv && !l.IsNullableType) {
4048                                         //
4049                                         // Optimizes cases which won't match
4050                                         //
4051                                 } else {
4052                                         result = ResolveOperatorPredefined (ec, ec.Module.OperatorsBinaryEqualityLifted, no_arg_conv);
4053                                         if (result != null)
4054                                                 return result;
4055                                 }
4056
4057                                 //
4058                                 // The == and != operators permit one operand to be a value of a nullable
4059                                 // type and the other to be the null literal, even if no predefined or user-defined
4060                                 // operator (in unlifted or lifted form) exists for the operation.
4061                                 //
4062                                 if ((l.IsNullableType && right.IsNull) || (r.IsNullableType && left.IsNull)) {
4063                                         var lifted = new Nullable.LiftedBinaryOperator (this);
4064                                         lifted.Left = left;
4065                                         lifted.Right = right;
4066                                         return lifted.Resolve (ec);
4067                                 }
4068                         }
4069
4070                         //
4071                         // bool operator != (object a, object b)
4072                         // bool operator == (object a, object b)
4073                         //
4074                         // An explicit reference conversion exists from the
4075                         // type of either operand to the type of the other operand.
4076                         //
4077
4078                         // Optimize common path
4079                         if (l == r) {
4080                                 return l.Kind == MemberKind.InternalCompilerType || l.Kind == MemberKind.Struct ? null : this;
4081                         }
4082
4083                         if (!Convert.ExplicitReferenceConversionExists (l, r) &&
4084                                 !Convert.ExplicitReferenceConversionExists (r, l))
4085                                 return null;
4086
4087                         // Reject allowed explicit conversions like int->object
4088                         if (!TypeSpec.IsReferenceType (l) || !TypeSpec.IsReferenceType (r))
4089                                 return null;
4090
4091                         if (l.BuiltinType == BuiltinTypeSpec.Type.String || l.BuiltinType == BuiltinTypeSpec.Type.Delegate || MemberCache.GetUserOperator (l, CSharp.Operator.OpType.Equality, false) != null)
4092                                 ec.Report.Warning (253, 2, loc,
4093                                         "Possible unintended reference comparison. Consider casting the right side expression to type `{0}' to get value comparison",
4094                                         l.GetSignatureForError ());
4095
4096                         if (r.BuiltinType == BuiltinTypeSpec.Type.String || r.BuiltinType == BuiltinTypeSpec.Type.Delegate || MemberCache.GetUserOperator (r, CSharp.Operator.OpType.Equality, false) != null)
4097                                 ec.Report.Warning (252, 2, loc,
4098                                         "Possible unintended reference comparison. Consider casting the left side expression to type `{0}' to get value comparison",
4099                                         r.GetSignatureForError ());
4100
4101                         return this;
4102                 }
4103
4104
4105                 Expression ResolveOperatorPointer (ResolveContext ec, TypeSpec l, TypeSpec r)
4106                 {
4107                         //
4108                         // bool operator == (void* x, void* y);
4109                         // bool operator != (void* x, void* y);
4110                         // bool operator < (void* x, void* y);
4111                         // bool operator > (void* x, void* y);
4112                         // bool operator <= (void* x, void* y);
4113                         // bool operator >= (void* x, void* y);
4114                         //
4115                         if ((oper & Operator.ComparisonMask) != 0) {
4116                                 Expression temp;
4117                                 if (!l.IsPointer) {
4118                                         temp = Convert.ImplicitConversion (ec, left, r, left.Location);
4119                                         if (temp == null)
4120                                                 return null;
4121                                         left = temp;
4122                                 }
4123
4124                                 if (!r.IsPointer) {
4125                                         temp = Convert.ImplicitConversion (ec, right, l, right.Location);
4126                                         if (temp == null)
4127                                                 return null;
4128                                         right = temp;
4129                                 }
4130
4131                                 type = ec.BuiltinTypes.Bool;
4132                                 return this;
4133                         }
4134
4135                         return ResolveOperatorPredefined (ec, ec.BuiltinTypes.OperatorsBinaryUnsafe, false);
4136                 }
4137
4138                 //
4139                 // Build-in operators method overloading
4140                 //
4141                 Expression ResolveOperatorPredefined (ResolveContext ec, PredefinedOperator [] operators, bool primitives_only)
4142                 {
4143                         PredefinedOperator best_operator = null;
4144                         TypeSpec l = left.Type;
4145                         TypeSpec r = right.Type;
4146                         Operator oper_mask = oper & ~Operator.ValuesOnlyMask;
4147
4148                         foreach (PredefinedOperator po in operators) {
4149                                 if ((po.OperatorsMask & oper_mask) == 0)
4150                                         continue;
4151
4152                                 if (primitives_only) {
4153                                         if (!po.IsPrimitiveApplicable (l, r))
4154                                                 continue;
4155                                 } else {
4156                                         if (!po.IsApplicable (ec, left, right))
4157                                                 continue;
4158                                 }
4159
4160                                 if (best_operator == null) {
4161                                         best_operator = po;
4162                                         if (primitives_only)
4163                                                 break;
4164
4165                                         continue;
4166                                 }
4167
4168                                 best_operator = po.ResolveBetterOperator (ec, best_operator);
4169
4170                                 if (best_operator == null) {
4171                                         ec.Report.Error (34, loc, "Operator `{0}' is ambiguous on operands of type `{1}' and `{2}'",
4172                                                 OperName (oper), l.GetSignatureForError (), r.GetSignatureForError ());
4173
4174                                         best_operator = po;
4175                                         break;
4176                                 }
4177                         }
4178
4179                         if (best_operator == null)
4180                                 return null;
4181
4182                         return best_operator.ConvertResult (ec, this);
4183                 }
4184
4185                 //
4186                 // Optimize & constant expressions with 0 value
4187                 //
4188                 Expression OptimizeAndOperation (Expression expr)
4189                 {
4190                         Constant rc = right as Constant;
4191                         Constant lc = left as Constant;
4192                         if ((lc != null && lc.IsDefaultValue) || (rc != null && rc.IsDefaultValue)) {
4193                                 //
4194                                 // The result is a constant with side-effect
4195                                 //
4196                                 Constant side_effect = rc == null ?
4197                                         new SideEffectConstant (lc, right, loc) :
4198                                         new SideEffectConstant (rc, left, loc);
4199
4200                                 return ReducedExpression.Create (side_effect, expr);
4201                         }
4202
4203                         return expr;
4204                 }
4205
4206                 //
4207                 // Value types can be compared with the null literal because of the lifting
4208                 // language rules. However the result is always true or false.
4209                 //
4210                 public Expression CreateLiftedValueTypeResult (ResolveContext rc, TypeSpec valueType)
4211                 {
4212                         if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
4213                                 type = rc.BuiltinTypes.Bool;
4214                                 return this;
4215                         }
4216
4217                         // FIXME: Handle side effect constants
4218                         Constant c = new BoolConstant (rc.BuiltinTypes, Oper == Operator.Inequality, loc);
4219
4220                         if ((Oper & Operator.EqualityMask) != 0) {
4221                                 rc.Report.Warning (472, 2, loc, "The result of comparing value type `{0}' with null is always `{1}'",
4222                                         valueType.GetSignatureForError (), c.GetValueAsLiteral ());
4223                         } else {
4224                                 rc.Report.Warning (464, 2, loc, "The result of comparing type `{0}' with null is always `{1}'",
4225                                         valueType.GetSignatureForError (), c.GetValueAsLiteral ());
4226                         }
4227
4228                         return c;
4229                 }
4230
4231                 //
4232                 // Performs user-operator overloading
4233                 //
4234                 Expression ResolveUserOperator (ResolveContext rc, Expression left, Expression right)
4235                 {
4236                         Expression oper_expr;
4237
4238                         var op = ConvertBinaryToUserOperator (oper);
4239                         var l = left.Type;
4240                         if (l.IsNullableType)
4241                                 l = Nullable.NullableInfo.GetUnderlyingType (l);
4242                         var r = right.Type;
4243                         if (r.IsNullableType)
4244                                 r = Nullable.NullableInfo.GetUnderlyingType (r);
4245
4246                         IList<MemberSpec> left_operators = MemberCache.GetUserOperator (l, op, false);
4247                         IList<MemberSpec> right_operators = null;
4248
4249                         if (l != r) {
4250                                 right_operators = MemberCache.GetUserOperator (r, op, false);
4251                                 if (right_operators == null && left_operators == null)
4252                                         return null;
4253                         } else if (left_operators == null) {
4254                                 return null;
4255                         }
4256
4257                         Arguments args = new Arguments (2);
4258                         Argument larg = new Argument (left);
4259                         args.Add (larg);
4260                         Argument rarg = new Argument (right);
4261                         args.Add (rarg);
4262
4263                         //
4264                         // User-defined operator implementations always take precedence
4265                         // over predefined operator implementations
4266                         //
4267                         if (left_operators != null && right_operators != null) {
4268                                 left_operators = CombineUserOperators (left_operators, right_operators);
4269                         } else if (right_operators != null) {
4270                                 left_operators = right_operators;
4271                         }
4272
4273                         const OverloadResolver.Restrictions restr = OverloadResolver.Restrictions.ProbingOnly |
4274                                 OverloadResolver.Restrictions.NoBaseMembers | OverloadResolver.Restrictions.BaseMembersIncluded;
4275
4276                         var res = new OverloadResolver (left_operators, restr, loc);
4277
4278                         var oper_method = res.ResolveOperator (rc, ref args);
4279                         if (oper_method == null) {
4280                                 //
4281                                 // Logical && and || cannot be lifted
4282                                 //
4283                                 if ((oper & Operator.LogicalMask) != 0)
4284                                         return null;
4285
4286                                 //
4287                                 // Apply lifted user operators only for liftable types. Implicit conversion
4288                                 // to nullable types is not allowed
4289                                 //
4290                                 if (!IsLiftedOperatorApplicable ())
4291                                         return null;
4292
4293                                 // TODO: Cache the result in module container
4294                                 var lifted_methods = CreateLiftedOperators (rc, left_operators);
4295                                 if (lifted_methods == null)
4296                                         return null;
4297
4298                                 res = new OverloadResolver (lifted_methods, restr | OverloadResolver.Restrictions.ProbingOnly, loc);
4299
4300                                 oper_method = res.ResolveOperator (rc, ref args);
4301                                 if (oper_method == null)
4302                                         return null;
4303
4304                                 MethodSpec best_original = null;
4305                                 foreach (MethodSpec ms in left_operators) {
4306                                         if (ms.MemberDefinition == oper_method.MemberDefinition) {
4307                                                 best_original = ms;
4308                                                 break;
4309                                         }
4310                                 }
4311
4312                                 if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
4313                                         //
4314                                         // Expression trees use lifted notation in this case
4315                                         //
4316                                         this.left = Convert.ImplicitConversion (rc, left, oper_method.Parameters.Types[0], left.Location);
4317                                         this.right = Convert.ImplicitConversion (rc, right, oper_method.Parameters.Types[1], left.Location);
4318                                 }
4319
4320                                 var ptypes = best_original.Parameters.Types;
4321
4322                                 if (left.IsNull || right.IsNull) {
4323                                         //
4324                                         // The lifted operator produces the value false if one or both operands are null for
4325                                         // relational operators.
4326                                         //
4327                                         if ((oper & Operator.ComparisonMask) != 0) {
4328                                                 //
4329                                                 // CSC BUG: This should be different warning, csc reports CS0458 with bool? which is wrong
4330                                                 // because return type is actually bool
4331                                                 //
4332                                                 // For some reason CSC does not report this warning for equality operators
4333                                                 //
4334                                                 return CreateLiftedValueTypeResult (rc, left.IsNull ? ptypes [1] : ptypes [0]);
4335                                         }
4336
4337                                         // The lifted operator produces a null value if one or both operands are null
4338                                         //
4339                                         if ((oper & (Operator.ArithmeticMask | Operator.ShiftMask | Operator.BitwiseMask)) != 0) {
4340                                                 type = oper_method.ReturnType;
4341                                                 return Nullable.LiftedNull.CreateFromExpression (rc, this);
4342                                         }
4343                                 }
4344
4345                                 type = oper_method.ReturnType;
4346                                 var lifted = new Nullable.LiftedBinaryOperator (this);
4347                                 lifted.UserOperator = best_original;
4348
4349                                 if (left.Type.IsNullableType && !ptypes[0].IsNullableType) {
4350                                         lifted.UnwrapLeft = new Nullable.Unwrap (left);
4351                                 }
4352
4353                                 if (right.Type.IsNullableType && !ptypes[1].IsNullableType) {
4354                                         lifted.UnwrapRight = new Nullable.Unwrap (right);
4355                                 }
4356
4357                                 lifted.Left = Convert.ImplicitConversion (rc, lifted.UnwrapLeft ?? left, ptypes[0], left.Location);
4358                                 lifted.Right = Convert.ImplicitConversion (rc, lifted.UnwrapRight ?? right, ptypes[1], right.Location);
4359
4360                                 return lifted.Resolve (rc);
4361                         }
4362
4363                         if ((oper & Operator.LogicalMask) != 0) {
4364                                 // TODO: CreateExpressionTree is allocated every time
4365                                 oper_expr = new ConditionalLogicalOperator (oper_method, args, CreateExpressionTree,
4366                                         oper == Operator.LogicalAnd, loc).Resolve (rc);
4367                         } else {
4368                                 oper_expr = new UserOperatorCall (oper_method, args, CreateExpressionTree, loc);
4369                         }
4370
4371                         this.left = larg.Expr;
4372                         this.right = rarg.Expr;
4373
4374                         return oper_expr;
4375                 }
4376
4377                 bool IsLiftedOperatorApplicable ()
4378                 {
4379                         if (left.Type.IsNullableType) {
4380                                 if ((oper & Operator.EqualityMask) != 0)
4381                                         return !right.IsNull;
4382
4383                                 return true;
4384                         }
4385
4386                         if (right.Type.IsNullableType) {
4387                                 if ((oper & Operator.EqualityMask) != 0)
4388                                         return !left.IsNull;
4389
4390                                 return true;
4391                         }
4392
4393                         if (TypeSpec.IsValueType (left.Type))
4394                                 return right.IsNull;
4395
4396                         if (TypeSpec.IsValueType (right.Type))
4397                                 return left.IsNull;
4398
4399                         return false;
4400                 }
4401
4402                 List<MemberSpec> CreateLiftedOperators (ResolveContext rc, IList<MemberSpec> operators)
4403                 {
4404                         var nullable_type = rc.Module.PredefinedTypes.Nullable.TypeSpec;
4405                         if (nullable_type == null)
4406                                 return null;
4407
4408                         //
4409                         // Lifted operators permit predefined and user-defined operators that operate
4410                         // on non-nullable value types to also be used with nullable forms of those types.
4411                         // Lifted operators are constructed from predefined and user-defined operators
4412                         // that meet certain requirements
4413                         //
4414                         List<MemberSpec> lifted = null;
4415                         foreach (MethodSpec oper in operators) {
4416                                 TypeSpec rt;
4417                                 if ((Oper & Operator.ComparisonMask) != 0) {
4418                                         //
4419                                         // Result type must be of type bool for lifted comparison operators
4420                                         //
4421                                         rt = oper.ReturnType;
4422                                         if (rt.BuiltinType != BuiltinTypeSpec.Type.Bool)
4423                                                 continue;
4424                                 } else {
4425                                         if (!TypeSpec.IsNonNullableValueType (oper.ReturnType))
4426                                                 continue;
4427
4428                                         rt = null;
4429                                 }
4430
4431                                 var ptypes = oper.Parameters.Types;
4432                                 if (!TypeSpec.IsNonNullableValueType (ptypes [0]) || !TypeSpec.IsNonNullableValueType (ptypes [1]))
4433                                         continue;
4434
4435                                 //
4436                                 // LAMESPEC: I am not sure why but for equality operators to be lifted
4437                                 // both types have to match
4438                                 //
4439                                 if ((Oper & Operator.EqualityMask) != 0 && ptypes [0] != ptypes [1])
4440                                         continue;
4441
4442                                 if (lifted == null)
4443                                         lifted = new List<MemberSpec> ();
4444
4445                                 //
4446                                 // The lifted form is constructed by adding a single ? modifier to each operand and
4447                                 // result type except for comparison operators where return type is bool
4448                                 //
4449                                 if (rt == null)
4450                                         rt = nullable_type.MakeGenericType (rc.Module, new[] { oper.ReturnType });
4451
4452                                 var parameters = ParametersCompiled.CreateFullyResolved (
4453                                         nullable_type.MakeGenericType (rc.Module, new [] { ptypes[0] }),
4454                                         nullable_type.MakeGenericType (rc.Module, new [] { ptypes[1] }));
4455
4456                                 var lifted_op = new MethodSpec (oper.Kind, oper.DeclaringType, oper.MemberDefinition,
4457                                         rt, parameters, oper.Modifiers);
4458
4459                                 lifted.Add (lifted_op);
4460                         }
4461
4462                         return lifted;
4463                 }
4464
4465                 //
4466                 // Merge two sets of user operators into one, they are mostly distinguish
4467                 // except when they share base type and it contains an operator
4468                 //
4469                 static IList<MemberSpec> CombineUserOperators (IList<MemberSpec> left, IList<MemberSpec> right)
4470                 {
4471                         var combined = new List<MemberSpec> (left.Count + right.Count);
4472                         combined.AddRange (left);
4473                         foreach (var r in right) {
4474                                 bool same = false;
4475                                 foreach (var l in left) {
4476                                         if (l.DeclaringType == r.DeclaringType) {
4477                                                 same = true;
4478                                                 break;
4479                                         }
4480                                 }
4481
4482                                 if (!same)
4483                                         combined.Add (r);
4484                         }
4485
4486                         return combined;
4487                 }
4488
4489                 void CheckOutOfRangeComparison (ResolveContext ec, Constant c, TypeSpec type)
4490                 {
4491                         if (c is IntegralConstant || c is CharConstant) {
4492                                 try {
4493                                         c.ConvertExplicitly (true, type);
4494                                 } catch (OverflowException) {
4495                                         ec.Report.Warning (652, 2, loc,
4496                                                 "A comparison between a constant and a variable is useless. The constant is out of the range of the variable type `{0}'",
4497                                                 type.GetSignatureForError ());
4498                                 }
4499                         }
4500                 }
4501
4502                 /// <remarks>
4503                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
4504                 ///   context of a conditional bool expression.  This function will return
4505                 ///   false if it is was possible to use EmitBranchable, or true if it was.
4506                 ///
4507                 ///   The expression's code is generated, and we will generate a branch to `target'
4508                 ///   if the resulting expression value is equal to isTrue
4509                 /// </remarks>
4510                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
4511                 {
4512                         if (ec.HasSet (BuilderContext.Options.AsyncBody) && right.ContainsEmitWithAwait ()) {
4513                                 left = left.EmitToField (ec);
4514
4515                                 if ((oper & Operator.LogicalMask) == 0) {
4516                                         right = right.EmitToField (ec);
4517                                 }
4518                         }
4519
4520                         //
4521                         // This is more complicated than it looks, but its just to avoid
4522                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
4523                         // but on top of that we want for == and != to use a special path
4524                         // if we are comparing against null
4525                         //
4526                         if ((oper & Operator.EqualityMask) != 0 && (left is Constant || right is Constant)) {
4527                                 bool my_on_true = oper == Operator.Inequality ? on_true : !on_true;
4528
4529                                 //
4530                                 // put the constant on the rhs, for simplicity
4531                                 //
4532                                 if (left is Constant) {
4533                                         Expression swap = right;
4534                                         right = left;
4535                                         left = swap;
4536                                 }
4537
4538                                 //
4539                                 // brtrue/brfalse works with native int only
4540                                 //
4541                                 if (((Constant) right).IsZeroInteger && right.Type.BuiltinType != BuiltinTypeSpec.Type.Long && right.Type.BuiltinType != BuiltinTypeSpec.Type.ULong) {
4542                                         left.EmitBranchable (ec, target, my_on_true);
4543                                         return;
4544                                 }
4545                                 if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Bool) {
4546                                         // right is a boolean, and it's not 'false' => it is 'true'
4547                                         left.EmitBranchable (ec, target, !my_on_true);
4548                                         return;
4549                                 }
4550
4551                         } else if (oper == Operator.LogicalAnd) {
4552
4553                                 if (on_true) {
4554                                         Label tests_end = ec.DefineLabel ();
4555
4556                                         left.EmitBranchable (ec, tests_end, false);
4557                                         right.EmitBranchable (ec, target, true);
4558                                         ec.MarkLabel (tests_end);
4559                                 } else {
4560                                         //
4561                                         // This optimizes code like this
4562                                         // if (true && i > 4)
4563                                         //
4564                                         if (!(left is Constant))
4565                                                 left.EmitBranchable (ec, target, false);
4566
4567                                         if (!(right is Constant))
4568                                                 right.EmitBranchable (ec, target, false);
4569                                 }
4570
4571                                 return;
4572
4573                         } else if (oper == Operator.LogicalOr){
4574                                 if (on_true) {
4575                                         left.EmitBranchable (ec, target, true);
4576                                         right.EmitBranchable (ec, target, true);
4577
4578                                 } else {
4579                                         Label tests_end = ec.DefineLabel ();
4580                                         left.EmitBranchable (ec, tests_end, true);
4581                                         right.EmitBranchable (ec, target, false);
4582                                         ec.MarkLabel (tests_end);
4583                                 }
4584
4585                                 return;
4586
4587                         } else if ((oper & Operator.ComparisonMask) == 0) {
4588                                 base.EmitBranchable (ec, target, on_true);
4589                                 return;
4590                         }
4591
4592                         left.Emit (ec);
4593                         right.Emit (ec);
4594
4595                         TypeSpec t = left.Type;
4596                         bool is_float = IsFloat (t);
4597                         bool is_unsigned = is_float || IsUnsigned (t);
4598
4599                         switch (oper){
4600                         case Operator.Equality:
4601                                 if (on_true)
4602                                         ec.Emit (OpCodes.Beq, target);
4603                                 else
4604                                         ec.Emit (OpCodes.Bne_Un, target);
4605                                 break;
4606
4607                         case Operator.Inequality:
4608                                 if (on_true)
4609                                         ec.Emit (OpCodes.Bne_Un, target);
4610                                 else
4611                                         ec.Emit (OpCodes.Beq, target);
4612                                 break;
4613
4614                         case Operator.LessThan:
4615                                 if (on_true)
4616                                         if (is_unsigned && !is_float)
4617                                                 ec.Emit (OpCodes.Blt_Un, target);
4618                                         else
4619                                                 ec.Emit (OpCodes.Blt, target);
4620                                 else
4621                                         if (is_unsigned)
4622                                                 ec.Emit (OpCodes.Bge_Un, target);
4623                                         else
4624                                                 ec.Emit (OpCodes.Bge, target);
4625                                 break;
4626
4627                         case Operator.GreaterThan:
4628                                 if (on_true)
4629                                         if (is_unsigned && !is_float)
4630                                                 ec.Emit (OpCodes.Bgt_Un, target);
4631                                         else
4632                                                 ec.Emit (OpCodes.Bgt, target);
4633                                 else
4634                                         if (is_unsigned)
4635                                                 ec.Emit (OpCodes.Ble_Un, target);
4636                                         else
4637                                                 ec.Emit (OpCodes.Ble, target);
4638                                 break;
4639
4640                         case Operator.LessThanOrEqual:
4641                                 if (on_true)
4642                                         if (is_unsigned && !is_float)
4643                                                 ec.Emit (OpCodes.Ble_Un, target);
4644                                         else
4645                                                 ec.Emit (OpCodes.Ble, target);
4646                                 else
4647                                         if (is_unsigned)
4648                                                 ec.Emit (OpCodes.Bgt_Un, target);
4649                                         else
4650                                                 ec.Emit (OpCodes.Bgt, target);
4651                                 break;
4652
4653
4654                         case Operator.GreaterThanOrEqual:
4655                                 if (on_true)
4656                                         if (is_unsigned && !is_float)
4657                                                 ec.Emit (OpCodes.Bge_Un, target);
4658                                         else
4659                                                 ec.Emit (OpCodes.Bge, target);
4660                                 else
4661                                         if (is_unsigned)
4662                                                 ec.Emit (OpCodes.Blt_Un, target);
4663                                         else
4664                                                 ec.Emit (OpCodes.Blt, target);
4665                                 break;
4666                         default:
4667                                 throw new InternalErrorException (oper.ToString ());
4668                         }
4669                 }
4670
4671                 public override void Emit (EmitContext ec)
4672                 {
4673                         if (ec.HasSet (BuilderContext.Options.AsyncBody) && right.ContainsEmitWithAwait ()) {
4674                                 left = left.EmitToField (ec);
4675
4676                                 if ((oper & Operator.LogicalMask) == 0) {
4677                                         right = right.EmitToField (ec);
4678                                 }
4679                         }
4680
4681                         //
4682                         // Handle short-circuit operators differently
4683                         // than the rest
4684                         //
4685                         if ((oper & Operator.LogicalMask) != 0) {
4686                                 Label load_result = ec.DefineLabel ();
4687                                 Label end = ec.DefineLabel ();
4688
4689                                 bool is_or = oper == Operator.LogicalOr;
4690                                 left.EmitBranchable (ec, load_result, is_or);
4691                                 right.Emit (ec);
4692                                 ec.Emit (OpCodes.Br_S, end);
4693
4694                                 ec.MarkLabel (load_result);
4695                                 ec.EmitInt (is_or ? 1 : 0);
4696                                 ec.MarkLabel (end);
4697                                 return;
4698                         }
4699
4700                         //
4701                         // Optimize zero-based operations which cannot be optimized at expression level
4702                         //
4703                         if (oper == Operator.Subtraction) {
4704                                 var lc = left as IntegralConstant;
4705                                 if (lc != null && lc.IsDefaultValue) {
4706                                         right.Emit (ec);
4707                                         ec.Emit (OpCodes.Neg);
4708                                         return;
4709                                 }
4710                         }
4711
4712                         EmitOperator (ec, left, right);
4713                 }
4714
4715                 public void EmitOperator (EmitContext ec, Expression left, Expression right)
4716                 {
4717                         left.Emit (ec);
4718                         right.Emit (ec);
4719
4720                         EmitOperatorOpcode (ec, oper, left.Type, right);
4721
4722                         //
4723                         // Emit result enumerable conversion this way because it's quite complicated get it
4724                         // to resolved tree because expression tree cannot see it.
4725                         //
4726                         if (enum_conversion != 0)
4727                                 ConvCast.Emit (ec, enum_conversion);
4728                 }
4729
4730                 public override void EmitSideEffect (EmitContext ec)
4731                 {
4732                         if ((oper & Operator.LogicalMask) != 0 ||
4733                                 (ec.HasSet (EmitContext.Options.CheckedScope) && (oper == Operator.Multiply || oper == Operator.Addition || oper == Operator.Subtraction))) {
4734                                 base.EmitSideEffect (ec);
4735                         } else {
4736                                 left.EmitSideEffect (ec);
4737                                 right.EmitSideEffect (ec);
4738                         }
4739                 }
4740
4741                 public override Expression EmitToField (EmitContext ec)
4742                 {
4743                         if ((oper & Operator.LogicalMask) == 0) {
4744                                 var await_expr = left as Await;
4745                                 if (await_expr != null && right.IsSideEffectFree) {
4746                                         await_expr.Statement.EmitPrologue (ec);
4747                                         left = await_expr.Statement.GetResultExpression (ec);
4748                                         return this;
4749                                 }
4750
4751                                 await_expr = right as Await;
4752                                 if (await_expr != null && left.IsSideEffectFree) {
4753                                         await_expr.Statement.EmitPrologue (ec);
4754                                         right = await_expr.Statement.GetResultExpression (ec);
4755                                         return this;
4756                                 }
4757                         }
4758
4759                         return base.EmitToField (ec);
4760                 }
4761
4762                 protected override void CloneTo (CloneContext clonectx, Expression t)
4763                 {
4764                         Binary target = (Binary) t;
4765
4766                         target.left = left.Clone (clonectx);
4767                         target.right = right.Clone (clonectx);
4768                 }
4769
4770                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
4771                 {
4772                         Arguments binder_args = new Arguments (4);
4773
4774                         MemberAccess sle = new MemberAccess (new MemberAccess (
4775                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
4776
4777                         CSharpBinderFlags flags = 0;
4778                         if (ec.HasSet (ResolveContext.Options.CheckedScope))
4779                                 flags = CSharpBinderFlags.CheckedContext;
4780
4781                         if ((oper & Operator.LogicalMask) != 0)
4782                                 flags |= CSharpBinderFlags.BinaryOperationLogical;
4783
4784                         binder_args.Add (new Argument (new EnumConstant (new IntLiteral (ec.BuiltinTypes, (int) flags, loc), ec.Module.PredefinedTypes.BinderFlags.Resolve ())));
4785                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), GetOperatorExpressionTypeName (), loc)));
4786                         binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
4787                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
4788
4789                         return new Invocation (new MemberAccess (new TypeExpression (ec.Module.PredefinedTypes.Binder.TypeSpec, loc), "BinaryOperation", loc), binder_args);
4790                 }
4791
4792                 public override Expression CreateExpressionTree (ResolveContext ec)
4793                 {
4794                         return CreateExpressionTree (ec, null);
4795                 }
4796
4797                 public Expression CreateExpressionTree (ResolveContext ec, Expression method)
4798                 {
4799                         string method_name;
4800                         bool lift_arg = false;
4801
4802                         switch (oper) {
4803                         case Operator.Addition:
4804                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
4805                                         method_name = "AddChecked";
4806                                 else
4807                                         method_name = "Add";
4808                                 break;
4809                         case Operator.BitwiseAnd:
4810                                 method_name = "And";
4811                                 break;
4812                         case Operator.BitwiseOr:
4813                                 method_name = "Or";
4814                                 break;
4815                         case Operator.Division:
4816                                 method_name = "Divide";
4817                                 break;
4818                         case Operator.Equality:
4819                                 method_name = "Equal";
4820                                 lift_arg = true;
4821                                 break;
4822                         case Operator.ExclusiveOr:
4823                                 method_name = "ExclusiveOr";
4824                                 break;
4825                         case Operator.GreaterThan:
4826                                 method_name = "GreaterThan";
4827                                 lift_arg = true;
4828                                 break;
4829                         case Operator.GreaterThanOrEqual:
4830                                 method_name = "GreaterThanOrEqual";
4831                                 lift_arg = true;
4832                                 break;
4833                         case Operator.Inequality:
4834                                 method_name = "NotEqual";
4835                                 lift_arg = true;
4836                                 break;
4837                         case Operator.LeftShift:
4838                                 method_name = "LeftShift";
4839                                 break;
4840                         case Operator.LessThan:
4841                                 method_name = "LessThan";
4842                                 lift_arg = true;
4843                                 break;
4844                         case Operator.LessThanOrEqual:
4845                                 method_name = "LessThanOrEqual";
4846                                 lift_arg = true;
4847                                 break;
4848                         case Operator.LogicalAnd:
4849                                 method_name = "AndAlso";
4850                                 break;
4851                         case Operator.LogicalOr:
4852                                 method_name = "OrElse";
4853                                 break;
4854                         case Operator.Modulus:
4855                                 method_name = "Modulo";
4856                                 break;
4857                         case Operator.Multiply:
4858                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
4859                                         method_name = "MultiplyChecked";
4860                                 else
4861                                         method_name = "Multiply";
4862                                 break;
4863                         case Operator.RightShift:
4864                                 method_name = "RightShift";
4865                                 break;
4866                         case Operator.Subtraction:
4867                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
4868                                         method_name = "SubtractChecked";
4869                                 else
4870                                         method_name = "Subtract";
4871                                 break;
4872
4873                         default:
4874                                 throw new InternalErrorException ("Unknown expression tree binary operator " + oper);
4875                         }
4876
4877                         Arguments args = new Arguments (2);
4878                         args.Add (new Argument (left.CreateExpressionTree (ec)));
4879                         args.Add (new Argument (right.CreateExpressionTree (ec)));
4880                         if (method != null) {
4881                                 if (lift_arg)
4882                                         args.Add (new Argument (new BoolLiteral (ec.BuiltinTypes, false, loc)));
4883
4884                                 args.Add (new Argument (method));
4885                         }
4886
4887                         return CreateExpressionFactoryCall (ec, method_name, args);
4888                 }
4889
4890                 public override object Accept (StructuralVisitor visitor)
4891                 {
4892                         return visitor.Visit (this);
4893                 }
4894
4895         }
4896
4897         //
4898         // Represents the operation a + b [+ c [+ d [+ ...]]], where a is a string
4899         // b, c, d... may be strings or objects.
4900         //
4901         public class StringConcat : Expression
4902         {
4903                 Arguments arguments;
4904
4905                 StringConcat (Location loc)
4906                 {
4907                         this.loc = loc;
4908                         arguments = new Arguments (2);
4909                 }
4910
4911                 public override bool ContainsEmitWithAwait ()
4912                 {
4913                         return arguments.ContainsEmitWithAwait ();
4914                 }
4915
4916                 public static StringConcat Create (ResolveContext rc, Expression left, Expression right, Location loc)
4917                 {
4918                         if (left.eclass == ExprClass.Unresolved || right.eclass == ExprClass.Unresolved)
4919                                 throw new ArgumentException ();
4920
4921                         var s = new StringConcat (loc);
4922                         s.type = rc.BuiltinTypes.String;
4923                         s.eclass = ExprClass.Value;
4924
4925                         s.Append (rc, left);
4926                         s.Append (rc, right);
4927                         return s;
4928                 }
4929
4930                 public override Expression CreateExpressionTree (ResolveContext ec)
4931                 {
4932                         Argument arg = arguments [0];
4933                         return CreateExpressionAddCall (ec, arg, arg.CreateExpressionTree (ec), 1);
4934                 }
4935
4936                 //
4937                 // Creates nested calls tree from an array of arguments used for IL emit
4938                 //
4939                 Expression CreateExpressionAddCall (ResolveContext ec, Argument left, Expression left_etree, int pos)
4940                 {
4941                         Arguments concat_args = new Arguments (2);
4942                         Arguments add_args = new Arguments (3);
4943
4944                         concat_args.Add (left);
4945                         add_args.Add (new Argument (left_etree));
4946
4947                         concat_args.Add (arguments [pos]);
4948                         add_args.Add (new Argument (arguments [pos].CreateExpressionTree (ec)));
4949
4950                         var methods = GetConcatMethodCandidates ();
4951                         if (methods == null)
4952                                 return null;
4953
4954                         var res = new OverloadResolver (methods, OverloadResolver.Restrictions.NoBaseMembers, loc);
4955                         var method = res.ResolveMember<MethodSpec> (ec, ref concat_args);
4956                         if (method == null)
4957                                 return null;
4958
4959                         add_args.Add (new Argument (new TypeOfMethod (method, loc)));
4960
4961                         Expression expr = CreateExpressionFactoryCall (ec, "Add", add_args);
4962                         if (++pos == arguments.Count)
4963                                 return expr;
4964
4965                         left = new Argument (new EmptyExpression (method.ReturnType));
4966                         return CreateExpressionAddCall (ec, left, expr, pos);
4967                 }
4968
4969                 protected override Expression DoResolve (ResolveContext ec)
4970                 {
4971                         return this;
4972                 }
4973
4974                 void Append (ResolveContext rc, Expression operand)
4975                 {
4976                         //
4977                         // Constant folding
4978                         //
4979                         StringConstant sc = operand as StringConstant;
4980                         if (sc != null) {
4981                                 if (arguments.Count != 0) {
4982                                         Argument last_argument = arguments [arguments.Count - 1];
4983                                         StringConstant last_expr_constant = last_argument.Expr as StringConstant;
4984                                         if (last_expr_constant != null) {
4985                                                 last_argument.Expr = new StringConstant (rc.BuiltinTypes, last_expr_constant.Value + sc.Value, sc.Location);
4986                                                 return;
4987                                         }
4988                                 }
4989                         } else {
4990                                 //
4991                                 // Multiple (3+) concatenation are resolved as multiple StringConcat instances
4992                                 //
4993                                 StringConcat concat_oper = operand as StringConcat;
4994                                 if (concat_oper != null) {
4995                                         arguments.AddRange (concat_oper.arguments);
4996                                         return;
4997                                 }
4998                         }
4999
5000                         arguments.Add (new Argument (operand));
5001                 }
5002
5003                 IList<MemberSpec> GetConcatMethodCandidates ()
5004                 {
5005                         return MemberCache.FindMembers (type, "Concat", true);
5006                 }
5007
5008                 public override void Emit (EmitContext ec)
5009                 {
5010                         // Optimize by removing any extra null arguments, they are no-op
5011                         for (int i = 0; i < arguments.Count; ++i) {
5012                                 if (arguments[i].Expr is NullConstant)
5013                                         arguments.RemoveAt (i--);
5014                         }
5015
5016                         var members = GetConcatMethodCandidates ();
5017                         var res = new OverloadResolver (members, OverloadResolver.Restrictions.NoBaseMembers, loc);
5018                         var method = res.ResolveMember<MethodSpec> (new ResolveContext (ec.MemberContext), ref arguments);
5019                         if (method != null) {
5020                                 var call = new CallEmitter ();
5021                                 call.EmitPredefined (ec, method, arguments);
5022                         }
5023                 }
5024
5025                 public override void FlowAnalysis (FlowAnalysisContext fc)
5026                 {
5027                         arguments.FlowAnalysis (fc);
5028                 }
5029
5030                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5031                 {
5032                         if (arguments.Count != 2)
5033                                 throw new NotImplementedException ("arguments.Count != 2");
5034
5035                         var concat = typeof (string).GetMethod ("Concat", new[] { typeof (object), typeof (object) });
5036                         return SLE.Expression.Add (arguments[0].Expr.MakeExpression (ctx), arguments[1].Expr.MakeExpression (ctx), concat);
5037                 }
5038         }
5039
5040         //
5041         // User-defined conditional logical operator
5042         //
5043         public class ConditionalLogicalOperator : UserOperatorCall
5044         {
5045                 readonly bool is_and;
5046                 Expression oper_expr;
5047
5048                 public ConditionalLogicalOperator (MethodSpec oper, Arguments arguments, Func<ResolveContext, Expression, Expression> expr_tree, bool is_and, Location loc)
5049                         : base (oper, arguments, expr_tree, loc)
5050                 {
5051                         this.is_and = is_and;
5052                         eclass = ExprClass.Unresolved;
5053                 }
5054
5055                 protected override Expression DoResolve (ResolveContext ec)
5056                 {
5057                         AParametersCollection pd = oper.Parameters;
5058                         if (!TypeSpecComparer.IsEqual (type, pd.Types[0]) || !TypeSpecComparer.IsEqual (type, pd.Types[1])) {
5059                                 ec.Report.Error (217, loc,
5060                                         "A user-defined operator `{0}' must have each parameter type and return type of the same type in order to be applicable as a short circuit operator",
5061                                         oper.GetSignatureForError ());
5062                                 return null;
5063                         }
5064
5065                         Expression left_dup = new EmptyExpression (type);
5066                         Expression op_true = GetOperatorTrue (ec, left_dup, loc);
5067                         Expression op_false = GetOperatorFalse (ec, left_dup, loc);
5068                         if (op_true == null || op_false == null) {
5069                                 ec.Report.Error (218, loc,
5070                                         "The type `{0}' must have operator `true' and operator `false' defined when `{1}' is used as a short circuit operator",
5071                                         type.GetSignatureForError (), oper.GetSignatureForError ());
5072                                 return null;
5073                         }
5074
5075                         oper_expr = is_and ? op_false : op_true;
5076                         eclass = ExprClass.Value;
5077                         return this;
5078                 }
5079
5080                 public override void Emit (EmitContext ec)
5081                 {
5082                         Label end_target = ec.DefineLabel ();
5083
5084                         //
5085                         // Emit and duplicate left argument
5086                         //
5087                         bool right_contains_await = ec.HasSet (BuilderContext.Options.AsyncBody) && arguments[1].Expr.ContainsEmitWithAwait ();
5088                         if (right_contains_await) {
5089                                 arguments[0] = arguments[0].EmitToField (ec, false);
5090                                 arguments[0].Expr.Emit (ec);
5091                         } else {
5092                                 arguments[0].Expr.Emit (ec);
5093                                 ec.Emit (OpCodes.Dup);
5094                                 arguments.RemoveAt (0);
5095                         }
5096
5097                         oper_expr.EmitBranchable (ec, end_target, true);
5098
5099                         base.Emit (ec);
5100
5101                         if (right_contains_await) {
5102                                 //
5103                                 // Special handling when right expression contains await and left argument
5104                                 // could not be left on stack before logical branch
5105                                 //
5106                                 Label skip_left_load = ec.DefineLabel ();
5107                                 ec.Emit (OpCodes.Br_S, skip_left_load);
5108                                 ec.MarkLabel (end_target);
5109                                 arguments[0].Expr.Emit (ec);
5110                                 ec.MarkLabel (skip_left_load);
5111                         } else {
5112                                 ec.MarkLabel (end_target);
5113                         }
5114                 }
5115         }
5116
5117         public class PointerArithmetic : Expression {
5118                 Expression left, right;
5119                 readonly Binary.Operator op;
5120
5121                 //
5122                 // We assume that `l' is always a pointer
5123                 //
5124                 public PointerArithmetic (Binary.Operator op, Expression l, Expression r, TypeSpec t, Location loc)
5125                 {
5126                         type = t;
5127                         this.loc = loc;
5128                         left = l;
5129                         right = r;
5130                         this.op = op;
5131                 }
5132
5133                 public override bool ContainsEmitWithAwait ()
5134                 {
5135                         throw new NotImplementedException ();
5136                 }
5137
5138                 public override Expression CreateExpressionTree (ResolveContext ec)
5139                 {
5140                         Error_PointerInsideExpressionTree (ec);
5141                         return null;
5142                 }
5143
5144                 protected override Expression DoResolve (ResolveContext ec)
5145                 {
5146                         eclass = ExprClass.Variable;
5147
5148                         var pc = left.Type as PointerContainer;
5149                         if (pc != null && pc.Element.Kind == MemberKind.Void) {
5150                                 Error_VoidPointerOperation (ec);
5151                                 return null;
5152                         }
5153
5154                         return this;
5155                 }
5156
5157                 public override void Emit (EmitContext ec)
5158                 {
5159                         TypeSpec op_type = left.Type;
5160
5161                         // It must be either array or fixed buffer
5162                         TypeSpec element;
5163                         if (TypeManager.HasElementType (op_type)) {
5164                                 element = TypeManager.GetElementType (op_type);
5165                         } else {
5166                                 FieldExpr fe = left as FieldExpr;
5167                                 if (fe != null)
5168                                         element = ((FixedFieldSpec) (fe.Spec)).ElementType;
5169                                 else
5170                                         element = op_type;
5171                         }
5172
5173                         int size = BuiltinTypeSpec.GetSize(element);
5174                         TypeSpec rtype = right.Type;
5175
5176                         if ((op & Binary.Operator.SubtractionMask) != 0 && rtype.IsPointer){
5177                                 //
5178                                 // handle (pointer - pointer)
5179                                 //
5180                                 left.Emit (ec);
5181                                 right.Emit (ec);
5182                                 ec.Emit (OpCodes.Sub);
5183
5184                                 if (size != 1){
5185                                         if (size == 0)
5186                                                 ec.Emit (OpCodes.Sizeof, element);
5187                                         else
5188                                                 ec.EmitInt (size);
5189                                         ec.Emit (OpCodes.Div);
5190                                 }
5191                                 ec.Emit (OpCodes.Conv_I8);
5192                         } else {
5193                                 //
5194                                 // handle + and - on (pointer op int)
5195                                 //
5196                                 Constant left_const = left as Constant;
5197                                 if (left_const != null) {
5198                                         //
5199                                         // Optimize ((T*)null) pointer operations
5200                                         //
5201                                         if (left_const.IsDefaultValue) {
5202                                                 left = EmptyExpression.Null;
5203                                         } else {
5204                                                 left_const = null;
5205                                         }
5206                                 }
5207
5208                                 left.Emit (ec);
5209
5210                                 var right_const = right as Constant;
5211                                 if (right_const != null) {
5212                                         //
5213                                         // Optimize 0-based arithmetic
5214                                         //
5215                                         if (right_const.IsDefaultValue)
5216                                                 return;
5217
5218                                         if (size != 0)
5219                                                 right = new IntConstant (ec.BuiltinTypes, size, right.Location);
5220                                         else
5221                                                 right = new SizeOf (new TypeExpression (element, right.Location), right.Location);
5222
5223                                         // TODO: Should be the checks resolve context sensitive?
5224                                         ResolveContext rc = new ResolveContext (ec.MemberContext, ResolveContext.Options.UnsafeScope);
5225                                         right = new Binary (Binary.Operator.Multiply, right, right_const).Resolve (rc);
5226                                         if (right == null)
5227                                                 return;
5228                                 }
5229
5230                                 right.Emit (ec);
5231                                 switch (rtype.BuiltinType) {
5232                                 case BuiltinTypeSpec.Type.SByte:
5233                                 case BuiltinTypeSpec.Type.Byte:
5234                                 case BuiltinTypeSpec.Type.Short:
5235                                 case BuiltinTypeSpec.Type.UShort:
5236                                         ec.Emit (OpCodes.Conv_I);
5237                                         break;
5238                                 case BuiltinTypeSpec.Type.UInt:
5239                                         ec.Emit (OpCodes.Conv_U);
5240                                         break;
5241                                 }
5242
5243                                 if (right_const == null && size != 1){
5244                                         if (size == 0)
5245                                                 ec.Emit (OpCodes.Sizeof, element);
5246                                         else
5247                                                 ec.EmitInt (size);
5248                                         if (rtype.BuiltinType == BuiltinTypeSpec.Type.Long || rtype.BuiltinType == BuiltinTypeSpec.Type.ULong)
5249                                                 ec.Emit (OpCodes.Conv_I8);
5250
5251                                         Binary.EmitOperatorOpcode (ec, Binary.Operator.Multiply, rtype, right);
5252                                 }
5253
5254                                 if (left_const == null) {
5255                                         if (rtype.BuiltinType == BuiltinTypeSpec.Type.Long)
5256                                                 ec.Emit (OpCodes.Conv_I);
5257                                         else if (rtype.BuiltinType == BuiltinTypeSpec.Type.ULong)
5258                                                 ec.Emit (OpCodes.Conv_U);
5259
5260                                         Binary.EmitOperatorOpcode (ec, op, op_type, right);
5261                                 }
5262                         }
5263                 }
5264         }
5265
5266         //
5267         // A boolean-expression is an expression that yields a result
5268         // of type bool
5269         //
5270         public class BooleanExpression : ShimExpression
5271         {
5272                 public BooleanExpression (Expression expr)
5273                         : base (expr)
5274                 {
5275                         this.loc = expr.Location;
5276                 }
5277
5278                 public override Expression CreateExpressionTree (ResolveContext ec)
5279                 {
5280                         // TODO: We should emit IsTrue (v4) instead of direct user operator
5281                         // call but that would break csc compatibility
5282                         return base.CreateExpressionTree (ec);
5283                 }
5284
5285                 protected override Expression DoResolve (ResolveContext ec)
5286                 {
5287                         // A boolean-expression is required to be of a type
5288                         // that can be implicitly converted to bool or of
5289                         // a type that implements operator true
5290
5291                         expr = expr.Resolve (ec);
5292                         if (expr == null)
5293                                 return null;
5294
5295                         Assign ass = expr as Assign;
5296                         if (ass != null && ass.Source is Constant) {
5297                                 ec.Report.Warning (665, 3, loc,
5298                                         "Assignment in conditional expression is always constant. Did you mean to use `==' instead ?");
5299                         }
5300
5301                         if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.Bool)
5302                                 return expr;
5303
5304                         if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
5305                                 Arguments args = new Arguments (1);
5306                                 args.Add (new Argument (expr));
5307                                 return DynamicUnaryConversion.CreateIsTrue (ec, args, loc).Resolve (ec);
5308                         }
5309
5310                         type = ec.BuiltinTypes.Bool;
5311                         Expression converted = Convert.ImplicitConversion (ec, expr, type, loc);
5312                         if (converted != null)
5313                                 return converted;
5314
5315                         //
5316                         // If no implicit conversion to bool exists, try using `operator true'
5317                         //
5318                         converted = GetOperatorTrue (ec, expr, loc);
5319                         if (converted == null) {
5320                                 expr.Error_ValueCannotBeConverted (ec, type, false);
5321                                 return null;
5322                         }
5323
5324                         return converted;
5325                 }
5326
5327                 public override object Accept (StructuralVisitor visitor)
5328                 {
5329                         return visitor.Visit (this);
5330                 }
5331         }
5332
5333         public class BooleanExpressionFalse : Unary
5334         {
5335                 public BooleanExpressionFalse (Expression expr)
5336                         : base (Operator.LogicalNot, expr, expr.Location)
5337                 {
5338                 }
5339
5340                 protected override Expression ResolveOperator (ResolveContext ec, Expression expr)
5341                 {
5342                         return GetOperatorFalse (ec, expr, loc) ?? base.ResolveOperator (ec, expr);
5343                 }
5344         }
5345
5346         /// <summary>
5347         ///   Implements the ternary conditional operator (?:)
5348         /// </summary>
5349         public class Conditional : Expression {
5350                 Expression expr, true_expr, false_expr;
5351
5352                 public Conditional (Expression expr, Expression true_expr, Expression false_expr, Location loc)
5353                 {
5354                         this.expr = expr;
5355                         this.true_expr = true_expr;
5356                         this.false_expr = false_expr;
5357                         this.loc = loc;
5358                 }
5359
5360                 #region Properties
5361
5362                 public Expression Expr {
5363                         get {
5364                                 return expr;
5365                         }
5366                 }
5367
5368                 public Expression TrueExpr {
5369                         get {
5370                                 return true_expr;
5371                         }
5372                 }
5373
5374                 public Expression FalseExpr {
5375                         get {
5376                                 return false_expr;
5377                         }
5378                 }
5379
5380                 #endregion
5381
5382                 public override bool ContainsEmitWithAwait ()
5383                 {
5384                         return Expr.ContainsEmitWithAwait () || true_expr.ContainsEmitWithAwait () || false_expr.ContainsEmitWithAwait ();
5385                 }
5386
5387                 public override Expression CreateExpressionTree (ResolveContext ec)
5388                 {
5389                         Arguments args = new Arguments (3);
5390                         args.Add (new Argument (expr.CreateExpressionTree (ec)));
5391                         args.Add (new Argument (true_expr.CreateExpressionTree (ec)));
5392                         args.Add (new Argument (false_expr.CreateExpressionTree (ec)));
5393                         return CreateExpressionFactoryCall (ec, "Condition", args);
5394                 }
5395
5396                 protected override Expression DoResolve (ResolveContext ec)
5397                 {
5398                         expr = expr.Resolve (ec);
5399                         true_expr = true_expr.Resolve (ec);
5400                         false_expr = false_expr.Resolve (ec);
5401
5402                         if (true_expr == null || false_expr == null || expr == null)
5403                                 return null;
5404
5405                         eclass = ExprClass.Value;
5406                         TypeSpec true_type = true_expr.Type;
5407                         TypeSpec false_type = false_expr.Type;
5408                         type = true_type;
5409
5410                         //
5411                         // First, if an implicit conversion exists from true_expr
5412                         // to false_expr, then the result type is of type false_expr.Type
5413                         //
5414                         if (!TypeSpecComparer.IsEqual (true_type, false_type)) {
5415                                 Expression conv = Convert.ImplicitConversion (ec, true_expr, false_type, loc);
5416                                 if (conv != null && true_type.BuiltinType != BuiltinTypeSpec.Type.Dynamic) {
5417                                         //
5418                                         // Check if both can convert implicitly to each other's type
5419                                         //
5420                                         type = false_type;
5421
5422                                         if (false_type.BuiltinType != BuiltinTypeSpec.Type.Dynamic) {
5423                                                 var conv_false_expr = Convert.ImplicitConversion (ec, false_expr, true_type, loc);
5424                                                 //
5425                                                 // LAMESPEC: There seems to be hardcoded promotition to int type when
5426                                                 // both sides are numeric constants and one side is int constant and
5427                                                 // other side is numeric constant convertible to int.
5428                                                 //
5429                                                 // var res = condition ? (short)1 : 1;
5430                                                 //
5431                                                 // Type of res is int even if according to the spec the conversion is
5432                                                 // ambiguous because 1 literal can be converted to short.
5433                                                 //
5434                                                 if (conv_false_expr != null) {
5435                                                         if (conv_false_expr.Type.BuiltinType == BuiltinTypeSpec.Type.Int && conv is Constant) {
5436                                                                 type = true_type;
5437                                                                 conv_false_expr = null;
5438                                                         } else if (type.BuiltinType == BuiltinTypeSpec.Type.Int && conv_false_expr is Constant) {
5439                                                                 conv_false_expr = null;
5440                                                         }
5441                                                 }
5442
5443                                                 if (conv_false_expr != null) {
5444                                                         ec.Report.Error (172, true_expr.Location,
5445                                                                 "Type of conditional expression cannot be determined as `{0}' and `{1}' convert implicitly to each other",
5446                                                                         true_type.GetSignatureForError (), false_type.GetSignatureForError ());
5447                                                 }
5448                                         }
5449
5450                                         true_expr = conv;
5451                                         if (true_expr.Type != type)
5452                                                 true_expr = EmptyCast.Create (true_expr, type);
5453                                 } else if ((conv = Convert.ImplicitConversion (ec, false_expr, true_type, loc)) != null) {
5454                                         false_expr = conv;
5455                                 } else {
5456                                         ec.Report.Error (173, true_expr.Location,
5457                                                 "Type of conditional expression cannot be determined because there is no implicit conversion between `{0}' and `{1}'",
5458                                                 true_type.GetSignatureForError (), false_type.GetSignatureForError ());
5459                                         return null;
5460                                 }
5461                         }
5462
5463                         Constant c = expr as Constant;
5464                         if (c != null) {
5465                                 bool is_false = c.IsDefaultValue;
5466
5467                                 //
5468                                 // Don't issue the warning for constant expressions
5469                                 //
5470                                 if (!(is_false ? true_expr is Constant : false_expr is Constant)) {
5471                                         // CSC: Missing warning
5472                                         Warning_UnreachableExpression (ec, is_false ? true_expr.Location : false_expr.Location);
5473                                 }
5474
5475                                 return ReducedExpression.Create (
5476                                         is_false ? false_expr : true_expr, this,
5477                                         false_expr is Constant && true_expr is Constant).Resolve (ec);
5478                         }
5479
5480                         return this;
5481                 }
5482
5483                 public override void Emit (EmitContext ec)
5484                 {
5485                         Label false_target = ec.DefineLabel ();
5486                         Label end_target = ec.DefineLabel ();
5487
5488                         expr.EmitBranchable (ec, false_target, false);
5489                         true_expr.Emit (ec);
5490
5491                         //
5492                         // Verifier doesn't support interface merging. When there are two types on
5493                         // the stack without common type hint and the common type is an interface.
5494                         // Use temporary local to give verifier hint on what type to unify the stack
5495                         //
5496                         if (type.IsInterface && true_expr is EmptyCast && false_expr is EmptyCast) {
5497                                 var temp = ec.GetTemporaryLocal (type);
5498                                 ec.Emit (OpCodes.Stloc, temp);
5499                                 ec.Emit (OpCodes.Ldloc, temp);
5500                                 ec.FreeTemporaryLocal (temp, type);
5501                         }
5502
5503                         ec.Emit (OpCodes.Br, end_target);
5504                         ec.MarkLabel (false_target);
5505                         false_expr.Emit (ec);
5506                         ec.MarkLabel (end_target);
5507                 }
5508
5509                 public override void FlowAnalysis (FlowAnalysisContext fc)
5510                 {
5511                         fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignmentOnFalse = fc.DefiniteAssignment;
5512
5513                         expr.FlowAnalysis (fc);
5514                         var da_true = fc.DefiniteAssignmentOnTrue;
5515                         var da_false = fc.DefiniteAssignmentOnFalse;
5516
5517                         fc.DefiniteAssignment = new DefiniteAssignmentBitSet (da_true);
5518                         true_expr.FlowAnalysis (fc);
5519                         var true_fc = fc.DefiniteAssignment;
5520
5521                         fc.DefiniteAssignment = new DefiniteAssignmentBitSet (da_false);
5522                         false_expr.FlowAnalysis (fc);
5523
5524                         fc.DefiniteAssignment &= true_fc;
5525                         if (fc.DefiniteAssignmentOnTrue != null)
5526                                 fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignment;
5527                         if (fc.DefiniteAssignmentOnFalse != null)
5528                                 fc.DefiniteAssignmentOnFalse = fc.DefiniteAssignment;
5529                 }
5530
5531                 protected override void CloneTo (CloneContext clonectx, Expression t)
5532                 {
5533                         Conditional target = (Conditional) t;
5534
5535                         target.expr = expr.Clone (clonectx);
5536                         target.true_expr = true_expr.Clone (clonectx);
5537                         target.false_expr = false_expr.Clone (clonectx);
5538                 }
5539         }
5540
5541         public abstract class VariableReference : Expression, IAssignMethod, IMemoryLocation, IVariableReference
5542         {
5543                 LocalTemporary temp;
5544
5545                 #region Abstract
5546                 public abstract HoistedVariable GetHoistedVariable (AnonymousExpression ae);
5547                 public abstract void SetHasAddressTaken ();
5548
5549                 public abstract bool IsLockedByStatement { get; set; }
5550
5551                 public abstract bool IsFixed { get; }
5552                 public abstract bool IsRef { get; }
5553                 public abstract string Name { get; }
5554
5555                 //
5556                 // Variable IL data, it has to be protected to encapsulate hoisted variables
5557                 //
5558                 protected abstract ILocalVariable Variable { get; }
5559
5560                 //
5561                 // Variable flow-analysis data
5562                 //
5563                 public abstract VariableInfo VariableInfo { get; }
5564                 #endregion
5565
5566                 public virtual void AddressOf (EmitContext ec, AddressOp mode)
5567                 {
5568                         HoistedVariable hv = GetHoistedVariable (ec);
5569                         if (hv != null) {
5570                                 hv.AddressOf (ec, mode);
5571                                 return;
5572                         }
5573
5574                         Variable.EmitAddressOf (ec);
5575                 }
5576
5577                 public override bool ContainsEmitWithAwait ()
5578                 {
5579                         return false;
5580                 }
5581
5582                 public override Expression CreateExpressionTree (ResolveContext ec)
5583                 {
5584                         HoistedVariable hv = GetHoistedVariable (ec);
5585                         if (hv != null)
5586                                 return hv.CreateExpressionTree ();
5587
5588                         Arguments arg = new Arguments (1);
5589                         arg.Add (new Argument (this));
5590                         return CreateExpressionFactoryCall (ec, "Constant", arg);
5591                 }
5592
5593                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
5594                 {
5595                         if (IsLockedByStatement) {
5596                                 rc.Report.Warning (728, 2, loc,
5597                                         "Possibly incorrect assignment to `{0}' which is the argument to a using or lock statement",
5598                                         Name);
5599                         }
5600
5601                         return this;
5602                 }
5603
5604                 public override void Emit (EmitContext ec)
5605                 {
5606                         Emit (ec, false);
5607                 }
5608
5609                 public override void EmitSideEffect (EmitContext ec)
5610                 {
5611                         // do nothing
5612                 }
5613
5614                 //
5615                 // This method is used by parameters that are references, that are
5616                 // being passed as references:  we only want to pass the pointer (that
5617                 // is already stored in the parameter, not the address of the pointer,
5618                 // and not the value of the variable).
5619                 //
5620                 public void EmitLoad (EmitContext ec)
5621                 {
5622                         Variable.Emit (ec);
5623                 }
5624
5625                 public void Emit (EmitContext ec, bool leave_copy)
5626                 {
5627                         HoistedVariable hv = GetHoistedVariable (ec);
5628                         if (hv != null) {
5629                                 hv.Emit (ec, leave_copy);
5630                                 return;
5631                         }
5632
5633                         EmitLoad (ec);
5634
5635                         if (IsRef) {
5636                                 //
5637                                 // If we are a reference, we loaded on the stack a pointer
5638                                 // Now lets load the real value
5639                                 //
5640                                 ec.EmitLoadFromPtr (type);
5641                         }
5642
5643                         if (leave_copy) {
5644                                 ec.Emit (OpCodes.Dup);
5645
5646                                 if (IsRef) {
5647                                         temp = new LocalTemporary (Type);
5648                                         temp.Store (ec);
5649                                 }
5650                         }
5651                 }
5652
5653                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy,
5654                                         bool prepare_for_load)
5655                 {
5656                         HoistedVariable hv = GetHoistedVariable (ec);
5657                         if (hv != null) {
5658                                 hv.EmitAssign (ec, source, leave_copy, prepare_for_load);
5659                                 return;
5660                         }
5661
5662                         New n_source = source as New;
5663                         if (n_source != null) {
5664                                 if (!n_source.Emit (ec, this)) {
5665                                         if (leave_copy) {
5666                                                 EmitLoad (ec);
5667                                                 if (IsRef)
5668                                                         ec.EmitLoadFromPtr (type);
5669                                         }
5670                                         return;
5671                                 }
5672                         } else {
5673                                 if (IsRef)
5674                                         EmitLoad (ec);
5675
5676                                 source.Emit (ec);
5677                         }
5678
5679                         if (leave_copy) {
5680                                 ec.Emit (OpCodes.Dup);
5681                                 if (IsRef) {
5682                                         temp = new LocalTemporary (Type);
5683                                         temp.Store (ec);
5684                                 }
5685                         }
5686
5687                         if (IsRef)
5688                                 ec.EmitStoreFromPtr (type);
5689                         else
5690                                 Variable.EmitAssign (ec);
5691
5692                         if (temp != null) {
5693                                 temp.Emit (ec);
5694                                 temp.Release (ec);
5695                         }
5696                 }
5697
5698                 public override Expression EmitToField (EmitContext ec)
5699                 {
5700                         HoistedVariable hv = GetHoistedVariable (ec);
5701                         if (hv != null) {
5702                                 return hv.EmitToField (ec);
5703                         }
5704
5705                         return base.EmitToField (ec);
5706                 }
5707
5708                 public HoistedVariable GetHoistedVariable (ResolveContext rc)
5709                 {
5710                         return GetHoistedVariable (rc.CurrentAnonymousMethod);
5711                 }
5712
5713                 public HoistedVariable GetHoistedVariable (EmitContext ec)
5714                 {
5715                         return GetHoistedVariable (ec.CurrentAnonymousMethod);
5716                 }
5717
5718                 public override string GetSignatureForError ()
5719                 {
5720                         return Name;
5721                 }
5722
5723                 public bool IsHoisted {
5724                         get { return GetHoistedVariable ((AnonymousExpression) null) != null; }
5725                 }
5726         }
5727
5728         //
5729         // Resolved reference to a local variable
5730         //
5731         public class LocalVariableReference : VariableReference
5732         {
5733                 public LocalVariable local_info;
5734
5735                 public LocalVariableReference (LocalVariable li, Location l)
5736                 {
5737                         this.local_info = li;
5738                         loc = l;
5739                 }
5740
5741                 public override VariableInfo VariableInfo {
5742                         get { return local_info.VariableInfo; }
5743                 }
5744
5745                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
5746                 {
5747                         return local_info.HoistedVariant;
5748                 }
5749
5750                 #region Properties
5751
5752                 //
5753                 // A local variable is always fixed
5754                 //
5755                 public override bool IsFixed {
5756                         get {
5757                                 return true;
5758                         }
5759                 }
5760
5761                 public override bool IsLockedByStatement {
5762                         get {
5763                                 return local_info.IsLocked;
5764                         }
5765                         set {
5766                                 local_info.IsLocked = value;
5767                         }
5768                 }
5769
5770                 public override bool IsRef {
5771                         get { return false; }
5772                 }
5773
5774                 public override string Name {
5775                         get { return local_info.Name; }
5776                 }
5777
5778                 #endregion
5779
5780                 public override void FlowAnalysis (FlowAnalysisContext fc)
5781                 {
5782                         VariableInfo variable_info = VariableInfo;
5783                         if (variable_info == null)
5784                                 return;
5785
5786                         if (fc.IsDefinitelyAssigned (variable_info))
5787                                 return;
5788
5789                         fc.Report.Error (165, loc, "Use of unassigned local variable `{0}'", Name);
5790                         variable_info.SetAssigned (fc.DefiniteAssignment, true);
5791                 }
5792
5793                 public override void SetHasAddressTaken ()
5794                 {
5795                         local_info.SetHasAddressTaken ();
5796                 }
5797
5798                 void DoResolveBase (ResolveContext ec)
5799                 {
5800                         //
5801                         // If we are referencing a variable from the external block
5802                         // flag it for capturing
5803                         //
5804                         if (ec.MustCaptureVariable (local_info)) {
5805                                 if (local_info.AddressTaken) {
5806                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
5807                                 } else if (local_info.IsFixed) {
5808                                         ec.Report.Error (1764, loc,
5809                                                 "Cannot use fixed local `{0}' inside an anonymous method, lambda expression or query expression",
5810                                                 GetSignatureForError ());
5811                                 }
5812
5813                                 if (ec.IsVariableCapturingRequired) {
5814                                         AnonymousMethodStorey storey = local_info.Block.Explicit.CreateAnonymousMethodStorey (ec);
5815                                         storey.CaptureLocalVariable (ec, local_info);
5816                                 }
5817                         }
5818
5819                         eclass = ExprClass.Variable;
5820                         type = local_info.Type;
5821                 }
5822
5823                 protected override Expression DoResolve (ResolveContext ec)
5824                 {
5825                         local_info.SetIsUsed ();
5826
5827                         DoResolveBase (ec);
5828                         return this;
5829                 }
5830
5831                 public override Expression DoResolveLValue (ResolveContext ec, Expression rhs)
5832                 {
5833                         //
5834                         // Don't be too pedantic when variable is used as out param or for some broken code
5835                         // which uses property/indexer access to run some initialization
5836                         //
5837                         if (rhs == EmptyExpression.OutAccess || rhs.eclass == ExprClass.PropertyAccess || rhs.eclass == ExprClass.IndexerAccess)
5838                                 local_info.SetIsUsed ();
5839
5840                         if (local_info.IsReadonly && !ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.UsingInitializerScope)) {
5841                                 if (rhs == EmptyExpression.LValueMemberAccess) {
5842                                         // CS1654 already reported
5843                                 } else {
5844                                         int code;
5845                                         string msg;
5846                                         if (rhs == EmptyExpression.OutAccess) {
5847                                                 code = 1657; msg = "Cannot pass `{0}' as a ref or out argument because it is a `{1}'";
5848                                         } else if (rhs == EmptyExpression.LValueMemberOutAccess) {
5849                                                 code = 1655; msg = "Cannot pass members of `{0}' as ref or out arguments because it is a `{1}'";
5850                                         } else if (rhs == EmptyExpression.UnaryAddress) {
5851                                                 code = 459; msg = "Cannot take the address of {1} `{0}'";
5852                                         } else {
5853                                                 code = 1656; msg = "Cannot assign to `{0}' because it is a `{1}'";
5854                                         }
5855                                         ec.Report.Error (code, loc, msg, Name, local_info.GetReadOnlyContext ());
5856                                 }
5857                         }
5858
5859                         if (eclass == ExprClass.Unresolved)
5860                                 DoResolveBase (ec);
5861
5862                         return base.DoResolveLValue (ec, rhs);
5863                 }
5864
5865                 public override int GetHashCode ()
5866                 {
5867                         return local_info.GetHashCode ();
5868                 }
5869
5870                 public override bool Equals (object obj)
5871                 {
5872                         LocalVariableReference lvr = obj as LocalVariableReference;
5873                         if (lvr == null)
5874                                 return false;
5875
5876                         return local_info == lvr.local_info;
5877                 }
5878
5879                 protected override ILocalVariable Variable {
5880                         get { return local_info; }
5881                 }
5882
5883                 public override string ToString ()
5884                 {
5885                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
5886                 }
5887
5888                 protected override void CloneTo (CloneContext clonectx, Expression t)
5889                 {
5890                         // Nothing
5891                 }
5892         }
5893
5894         /// <summary>
5895         ///   This represents a reference to a parameter in the intermediate
5896         ///   representation.
5897         /// </summary>
5898         public class ParameterReference : VariableReference
5899         {
5900                 protected ParametersBlock.ParameterInfo pi;
5901
5902                 public ParameterReference (ParametersBlock.ParameterInfo pi, Location loc)
5903                 {
5904                         this.pi = pi;
5905                         this.loc = loc;
5906                 }
5907
5908                 #region Properties
5909
5910                 public override bool IsLockedByStatement {
5911                         get {
5912                                 return pi.IsLocked;
5913                         }
5914                         set     {
5915                                 pi.IsLocked = value;
5916                         }
5917                 }
5918
5919                 public override bool IsRef {
5920                         get { return (pi.Parameter.ModFlags & Parameter.Modifier.RefOutMask) != 0; }
5921                 }
5922
5923                 bool HasOutModifier {
5924                         get { return (pi.Parameter.ModFlags & Parameter.Modifier.OUT) != 0; }
5925                 }
5926
5927                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
5928                 {
5929                         return pi.Parameter.HoistedVariant;
5930                 }
5931
5932                 //
5933                 // A ref or out parameter is classified as a moveable variable, even
5934                 // if the argument given for the parameter is a fixed variable
5935                 //
5936                 public override bool IsFixed {
5937                         get { return !IsRef; }
5938                 }
5939
5940                 public override string Name {
5941                         get { return Parameter.Name; }
5942                 }
5943
5944                 public Parameter Parameter {
5945                         get { return pi.Parameter; }
5946                 }
5947
5948                 public override VariableInfo VariableInfo {
5949                         get { return pi.VariableInfo; }
5950                 }
5951
5952                 protected override ILocalVariable Variable {
5953                         get { return Parameter; }
5954                 }
5955
5956                 #endregion
5957
5958                 public override void AddressOf (EmitContext ec, AddressOp mode)
5959                 {
5960                         //
5961                         // ParameterReferences might already be a reference
5962                         //
5963                         if (IsRef) {
5964                                 EmitLoad (ec);
5965                                 return;
5966                         }
5967
5968                         base.AddressOf (ec, mode);
5969                 }
5970
5971                 public override void SetHasAddressTaken ()
5972                 {
5973                         Parameter.HasAddressTaken = true;
5974                 }
5975
5976                 bool DoResolveBase (ResolveContext ec)
5977                 {
5978                         if (eclass != ExprClass.Unresolved)
5979                                 return true;
5980
5981                         type = pi.ParameterType;
5982                         eclass = ExprClass.Variable;
5983
5984                         //
5985                         // If we are referencing a parameter from the external block
5986                         // flag it for capturing
5987                         //
5988                         if (ec.MustCaptureVariable (pi)) {
5989                                 if (Parameter.HasAddressTaken)
5990                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
5991
5992                                 if (IsRef) {
5993                                         ec.Report.Error (1628, loc,
5994                                                 "Parameter `{0}' cannot be used inside `{1}' when using `ref' or `out' modifier",
5995                                                 Name, ec.CurrentAnonymousMethod.ContainerType);
5996                                 }
5997
5998                                 if (ec.IsVariableCapturingRequired && !pi.Block.ParametersBlock.IsExpressionTree) {
5999                                         AnonymousMethodStorey storey = pi.Block.Explicit.CreateAnonymousMethodStorey (ec);
6000                                         storey.CaptureParameter (ec, pi, this);
6001                                 }
6002                         }
6003
6004                         return true;
6005                 }
6006
6007                 public override int GetHashCode ()
6008                 {
6009                         return Name.GetHashCode ();
6010                 }
6011
6012                 public override bool Equals (object obj)
6013                 {
6014                         ParameterReference pr = obj as ParameterReference;
6015                         if (pr == null)
6016                                 return false;
6017
6018                         return Name == pr.Name;
6019                 }
6020
6021                 protected override void CloneTo (CloneContext clonectx, Expression target)
6022                 {
6023                         // Nothing to clone
6024                         return;
6025                 }
6026
6027                 public override Expression CreateExpressionTree (ResolveContext ec)
6028                 {
6029                         HoistedVariable hv = GetHoistedVariable (ec);
6030                         if (hv != null)
6031                                 return hv.CreateExpressionTree ();
6032
6033                         return Parameter.ExpressionTreeVariableReference ();
6034                 }
6035
6036                 protected override Expression DoResolve (ResolveContext ec)
6037                 {
6038                         if (!DoResolveBase (ec))
6039                                 return null;
6040
6041                         return this;
6042                 }
6043
6044                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6045                 {
6046                         if (!DoResolveBase (ec))
6047                                 return null;
6048
6049                         if (Parameter.HoistedVariant != null)
6050                                 Parameter.HoistedVariant.IsAssigned = true;
6051
6052                         return base.DoResolveLValue (ec, right_side);
6053                 }
6054
6055                 public override void FlowAnalysis (FlowAnalysisContext fc)
6056                 {
6057                         VariableInfo variable_info = VariableInfo;
6058                         if (variable_info == null)
6059                                 return;
6060
6061                         if (fc.IsDefinitelyAssigned (variable_info))
6062                                 return;
6063
6064                         fc.Report.Error (269, loc, "Use of unassigned out parameter `{0}'", Name);
6065                         fc.SetVariableAssigned (variable_info);
6066                 }
6067         }
6068
6069         /// <summary>
6070         ///   Invocation of methods or delegates.
6071         /// </summary>
6072         public class Invocation : ExpressionStatement
6073         {
6074                 protected Arguments arguments;
6075                 protected Expression expr;
6076                 protected MethodGroupExpr mg;
6077
6078                 public Invocation (Expression expr, Arguments arguments)
6079                 {
6080                         this.expr = expr;
6081                         this.arguments = arguments;
6082                         if (expr != null) {
6083                                 loc = expr.Location;
6084                         }
6085                 }
6086
6087                 #region Properties
6088                 public Arguments Arguments {
6089                         get {
6090                                 return arguments;
6091                         }
6092                 }
6093
6094                 public Expression Exp {
6095                         get {
6096                                 return expr;
6097                         }
6098                 }
6099
6100                 public MethodGroupExpr MethodGroup {
6101                         get {
6102                                 return mg;
6103                         }
6104                 }
6105
6106                 public override Location StartLocation {
6107                         get {
6108                                 return expr.StartLocation;
6109                         }
6110                 }
6111
6112                 #endregion
6113
6114                 public override MethodGroupExpr CanReduceLambda (AnonymousMethodBody body)
6115                 {
6116                         if (MethodGroup == null)
6117                                 return null;
6118
6119                         var candidate = MethodGroup.BestCandidate;
6120                         if (candidate == null || !(candidate.IsStatic || Exp is This))
6121                                 return null;
6122
6123                         var args_count = arguments == null ? 0 : arguments.Count;
6124                         if (args_count != body.Parameters.Count)
6125                                 return null;
6126
6127                         var lambda_parameters = body.Block.Parameters.FixedParameters;
6128                         for (int i = 0; i < args_count; ++i) {
6129                                 var pr = arguments[i].Expr as ParameterReference;
6130                                 if (pr == null)
6131                                         return null;
6132
6133                                 if (lambda_parameters[i] != pr.Parameter)
6134                                         return null;
6135
6136                                 if ((lambda_parameters[i].ModFlags & Parameter.Modifier.RefOutMask) != (pr.Parameter.ModFlags & Parameter.Modifier.RefOutMask))
6137                                         return null;
6138                         }
6139
6140                         var emg = MethodGroup as ExtensionMethodGroupExpr;
6141                         if (emg != null) {
6142                                 var mg = MethodGroupExpr.CreatePredefined (candidate, candidate.DeclaringType, MethodGroup.Location);
6143                                 if (candidate.IsGeneric) {
6144                                         var targs = new TypeExpression [candidate.Arity];
6145                                         for (int i = 0; i < targs.Length; ++i) {
6146                                                 targs[i] = new TypeExpression (candidate.TypeArguments[i], MethodGroup.Location);
6147                                         }
6148
6149                                         mg.SetTypeArguments (null, new TypeArguments (targs));
6150                                 }
6151
6152                                 return mg;
6153                         }
6154
6155                         return MethodGroup;
6156                 }
6157
6158                 protected override void CloneTo (CloneContext clonectx, Expression t)
6159                 {
6160                         Invocation target = (Invocation) t;
6161
6162                         if (arguments != null)
6163                                 target.arguments = arguments.Clone (clonectx);
6164
6165                         target.expr = expr.Clone (clonectx);
6166                 }
6167
6168                 public override bool ContainsEmitWithAwait ()
6169                 {
6170                         if (arguments != null && arguments.ContainsEmitWithAwait ())
6171                                 return true;
6172
6173                         return mg.ContainsEmitWithAwait ();
6174                 }
6175
6176                 public override Expression CreateExpressionTree (ResolveContext ec)
6177                 {
6178                         Expression instance = mg.IsInstance ?
6179                                 mg.InstanceExpression.CreateExpressionTree (ec) :
6180                                 new NullLiteral (loc);
6181
6182                         var args = Arguments.CreateForExpressionTree (ec, arguments,
6183                                 instance,
6184                                 mg.CreateExpressionTree (ec));
6185
6186                         return CreateExpressionFactoryCall (ec, "Call", args);
6187                 }
6188
6189                 protected override Expression DoResolve (ResolveContext ec)
6190                 {
6191                         Expression member_expr;
6192                         var atn = expr as ATypeNameExpression;
6193                         if (atn != null) {
6194                                 member_expr = atn.LookupNameExpression (ec, MemberLookupRestrictions.InvocableOnly | MemberLookupRestrictions.ReadAccess);
6195                                 if (member_expr != null)
6196                                         member_expr = member_expr.Resolve (ec);
6197                         } else {
6198                                 member_expr = expr.Resolve (ec);
6199                         }
6200
6201                         if (member_expr == null)
6202                                 return null;
6203
6204                         //
6205                         // Next, evaluate all the expressions in the argument list
6206                         //
6207                         bool dynamic_arg = false;
6208                         if (arguments != null)
6209                                 arguments.Resolve (ec, out dynamic_arg);
6210
6211                         TypeSpec expr_type = member_expr.Type;
6212                         if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
6213                                 return DoResolveDynamic (ec, member_expr);
6214
6215                         mg = member_expr as MethodGroupExpr;
6216                         Expression invoke = null;
6217
6218                         if (mg == null) {
6219                                 if (expr_type != null && expr_type.IsDelegate) {
6220                                         invoke = new DelegateInvocation (member_expr, arguments, loc);
6221                                         invoke = invoke.Resolve (ec);
6222                                         if (invoke == null || !dynamic_arg)
6223                                                 return invoke;
6224                                 } else {
6225                                         if (member_expr is RuntimeValueExpression) {
6226                                                 ec.Report.Error (Report.RuntimeErrorId, loc, "Cannot invoke a non-delegate type `{0}'",
6227                                                         member_expr.Type.GetSignatureForError ());
6228                                                 return null;
6229                                         }
6230
6231                                         MemberExpr me = member_expr as MemberExpr;
6232                                         if (me == null) {
6233                                                 member_expr.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup, loc);
6234                                                 return null;
6235                                         }
6236
6237                                         ec.Report.Error (1955, loc, "The member `{0}' cannot be used as method or delegate",
6238                                                         member_expr.GetSignatureForError ());
6239                                         return null;
6240                                 }
6241                         }
6242
6243                         if (invoke == null) {
6244                                 mg = DoResolveOverload (ec);
6245                                 if (mg == null)
6246                                         return null;
6247                         }
6248
6249                         if (dynamic_arg)
6250                                 return DoResolveDynamic (ec, member_expr);
6251
6252                         var method = mg.BestCandidate;
6253                         type = mg.BestCandidateReturnType;
6254
6255                         if (arguments == null && method.DeclaringType.BuiltinType == BuiltinTypeSpec.Type.Object && method.Name == Destructor.MetadataName) {
6256                                 if (mg.IsBase)
6257                                         ec.Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
6258                                 else
6259                                         ec.Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
6260                                 return null;
6261                         }
6262
6263                         IsSpecialMethodInvocation (ec, method, loc);
6264
6265                         eclass = ExprClass.Value;
6266                         return this;
6267                 }
6268
6269                 protected virtual Expression DoResolveDynamic (ResolveContext ec, Expression memberExpr)
6270                 {
6271                         Arguments args;
6272                         DynamicMemberBinder dmb = memberExpr as DynamicMemberBinder;
6273                         if (dmb != null) {
6274                                 args = dmb.Arguments;
6275                                 if (arguments != null)
6276                                         args.AddRange (arguments);
6277                         } else if (mg == null) {
6278                                 if (arguments == null)
6279                                         args = new Arguments (1);
6280                                 else
6281                                         args = arguments;
6282
6283                                 args.Insert (0, new Argument (memberExpr));
6284                                 this.expr = null;
6285                         } else {
6286                                 if (mg.IsBase) {
6287                                         ec.Report.Error (1971, loc,
6288                                                 "The base call to method `{0}' cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access",
6289                                                 mg.Name);
6290                                         return null;
6291                                 }
6292
6293                                 if (arguments == null)
6294                                         args = new Arguments (1);
6295                                 else
6296                                         args = arguments;
6297
6298                                 MemberAccess ma = expr as MemberAccess;
6299                                 if (ma != null) {
6300                                         var left_type = ma.LeftExpression as TypeExpr;
6301                                         if (left_type != null) {
6302                                                 args.Insert (0, new Argument (new TypeOf (left_type.Type, loc).Resolve (ec), Argument.AType.DynamicTypeName));
6303                                         } else {
6304                                                 //
6305                                                 // Any value type has to be pass as by-ref to get back the same
6306                                                 // instance on which the member was called
6307                                                 //
6308                                                 var mod = ma.LeftExpression is IMemoryLocation && TypeSpec.IsValueType (ma.LeftExpression.Type) ?
6309                                                         Argument.AType.Ref : Argument.AType.None;
6310                                                 args.Insert (0, new Argument (ma.LeftExpression.Resolve (ec), mod));
6311                                         }
6312                                 } else {        // is SimpleName
6313                                         if (ec.IsStatic) {
6314                                                 args.Insert (0, new Argument (new TypeOf (ec.CurrentType, loc).Resolve (ec), Argument.AType.DynamicTypeName));
6315                                         } else {
6316                                                 args.Insert (0, new Argument (new This (loc).Resolve (ec)));
6317                                         }
6318                                 }
6319                         }
6320
6321                         return new DynamicInvocation (expr as ATypeNameExpression, args, loc).Resolve (ec);
6322                 }
6323
6324                 protected virtual MethodGroupExpr DoResolveOverload (ResolveContext ec)
6325                 {
6326                         return mg.OverloadResolve (ec, ref arguments, null, OverloadResolver.Restrictions.None);
6327                 }
6328
6329                 public override void FlowAnalysis (FlowAnalysisContext fc)
6330                 {
6331                         if (mg.IsConditionallyExcluded)
6332                                 return;
6333
6334                         mg.FlowAnalysis (fc);
6335
6336                         if (arguments != null)
6337                                 arguments.FlowAnalysis (fc);
6338                 }
6339
6340                 public override string GetSignatureForError ()
6341                 {
6342                         return mg.GetSignatureForError ();
6343                 }
6344
6345                 //
6346                 // If a member is a method or event, or if it is a constant, field or property of either a delegate type
6347                 // or the type dynamic, then the member is invocable
6348                 //
6349                 public static bool IsMemberInvocable (MemberSpec member)
6350                 {
6351                         switch (member.Kind) {
6352                         case MemberKind.Event:
6353                                 return true;
6354                         case MemberKind.Field:
6355                         case MemberKind.Property:
6356                                 var m = member as IInterfaceMemberSpec;
6357                                 return m.MemberType.IsDelegate || m.MemberType.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
6358                         default:
6359                                 return false;
6360                         }
6361                 }
6362
6363                 public static bool IsSpecialMethodInvocation (ResolveContext ec, MethodSpec method, Location loc)
6364                 {
6365                         if (!method.IsReservedMethod)
6366                                 return false;
6367
6368                         if (ec.HasSet (ResolveContext.Options.InvokeSpecialName) || ec.CurrentMemberDefinition.IsCompilerGenerated)
6369                                 return false;
6370
6371                         ec.Report.SymbolRelatedToPreviousError (method);
6372                         ec.Report.Error (571, loc, "`{0}': cannot explicitly call operator or accessor",
6373                                 method.GetSignatureForError ());
6374
6375                         return true;
6376                 }
6377
6378                 public override void Emit (EmitContext ec)
6379                 {
6380                         if (mg.IsConditionallyExcluded)
6381                                 return;
6382
6383                         mg.EmitCall (ec, arguments);
6384                 }
6385
6386                 public override void EmitStatement (EmitContext ec)
6387                 {
6388                         Emit (ec);
6389
6390                         //
6391                         // Pop the return value if there is one
6392                         //
6393                         if (type.Kind != MemberKind.Void)
6394                                 ec.Emit (OpCodes.Pop);
6395                 }
6396
6397                 public override SLE.Expression MakeExpression (BuilderContext ctx)
6398                 {
6399                         return MakeExpression (ctx, mg.InstanceExpression, mg.BestCandidate, arguments);
6400                 }
6401
6402                 public static SLE.Expression MakeExpression (BuilderContext ctx, Expression instance, MethodSpec mi, Arguments args)
6403                 {
6404 #if STATIC
6405                         throw new NotSupportedException ();
6406 #else
6407                         var instance_expr = instance == null ? null : instance.MakeExpression (ctx);
6408                         return SLE.Expression.Call (instance_expr, (MethodInfo) mi.GetMetaInfo (), Arguments.MakeExpression (args, ctx));
6409 #endif
6410                 }
6411
6412                 public override object Accept (StructuralVisitor visitor)
6413                 {
6414                         return visitor.Visit (this);
6415                 }
6416         }
6417
6418         //
6419         // Implements simple new expression
6420         //
6421         public class New : ExpressionStatement, IMemoryLocation
6422         {
6423                 protected Arguments arguments;
6424
6425                 //
6426                 // During bootstrap, it contains the RequestedType,
6427                 // but if `type' is not null, it *might* contain a NewDelegate
6428                 // (because of field multi-initialization)
6429                 //
6430                 protected Expression RequestedType;
6431
6432                 protected MethodSpec method;
6433
6434                 public New (Expression requested_type, Arguments arguments, Location l)
6435                 {
6436                         RequestedType = requested_type;
6437                         this.arguments = arguments;
6438                         loc = l;
6439                 }
6440
6441                 #region Properties
6442                 public Arguments Arguments {
6443                         get {
6444                                 return arguments;
6445                         }
6446                 }
6447
6448                 //
6449                 // Returns true for resolved `new S()'
6450                 //
6451                 public bool IsDefaultStruct {
6452                         get {
6453                                 return arguments == null && type.IsStruct && GetType () == typeof (New);
6454                         }
6455                 }
6456
6457                 public Expression TypeExpression {
6458                         get {
6459                                 return RequestedType;
6460                         }
6461                 }
6462
6463                 #endregion
6464
6465                 /// <summary>
6466                 /// Converts complex core type syntax like 'new int ()' to simple constant
6467                 /// </summary>
6468                 public static Constant Constantify (TypeSpec t, Location loc)
6469                 {
6470                         switch (t.BuiltinType) {
6471                         case BuiltinTypeSpec.Type.Int:
6472                                 return new IntConstant (t, 0, loc);
6473                         case BuiltinTypeSpec.Type.UInt:
6474                                 return new UIntConstant (t, 0, loc);
6475                         case BuiltinTypeSpec.Type.Long:
6476                                 return new LongConstant (t, 0, loc);
6477                         case BuiltinTypeSpec.Type.ULong:
6478                                 return new ULongConstant (t, 0, loc);
6479                         case BuiltinTypeSpec.Type.Float:
6480                                 return new FloatConstant (t, 0, loc);
6481                         case BuiltinTypeSpec.Type.Double:
6482                                 return new DoubleConstant (t, 0, loc);
6483                         case BuiltinTypeSpec.Type.Short:
6484                                 return new ShortConstant (t, 0, loc);
6485                         case BuiltinTypeSpec.Type.UShort:
6486                                 return new UShortConstant (t, 0, loc);
6487                         case BuiltinTypeSpec.Type.SByte:
6488                                 return new SByteConstant (t, 0, loc);
6489                         case BuiltinTypeSpec.Type.Byte:
6490                                 return new ByteConstant (t, 0, loc);
6491                         case BuiltinTypeSpec.Type.Char:
6492                                 return new CharConstant (t, '\0', loc);
6493                         case BuiltinTypeSpec.Type.Bool:
6494                                 return new BoolConstant (t, false, loc);
6495                         case BuiltinTypeSpec.Type.Decimal:
6496                                 return new DecimalConstant (t, 0, loc);
6497                         }
6498
6499                         if (t.IsEnum)
6500                                 return new EnumConstant (Constantify (EnumSpec.GetUnderlyingType (t), loc), t);
6501
6502                         if (t.IsNullableType)
6503                                 return Nullable.LiftedNull.Create (t, loc);
6504
6505                         return null;
6506                 }
6507
6508                 public override bool ContainsEmitWithAwait ()
6509                 {
6510                         return arguments != null && arguments.ContainsEmitWithAwait ();
6511                 }
6512
6513                 //
6514                 // Checks whether the type is an interface that has the
6515                 // [ComImport, CoClass] attributes and must be treated
6516                 // specially
6517                 //
6518                 public Expression CheckComImport (ResolveContext ec)
6519                 {
6520                         if (!type.IsInterface)
6521                                 return null;
6522
6523                         //
6524                         // Turn the call into:
6525                         // (the-interface-stated) (new class-referenced-in-coclassattribute ())
6526                         //
6527                         var real_class = type.MemberDefinition.GetAttributeCoClass ();
6528                         if (real_class == null)
6529                                 return null;
6530
6531                         New proxy = new New (new TypeExpression (real_class, loc), arguments, loc);
6532                         Cast cast = new Cast (new TypeExpression (type, loc), proxy, loc);
6533                         return cast.Resolve (ec);
6534                 }
6535
6536                 public override Expression CreateExpressionTree (ResolveContext ec)
6537                 {
6538                         Arguments args;
6539                         if (method == null) {
6540                                 args = new Arguments (1);
6541                                 args.Add (new Argument (new TypeOf (type, loc)));
6542                         } else {
6543                                 args = Arguments.CreateForExpressionTree (ec,
6544                                         arguments, new TypeOfMethod (method, loc));
6545                         }
6546
6547                         return CreateExpressionFactoryCall (ec, "New", args);
6548                 }
6549
6550                 protected override Expression DoResolve (ResolveContext ec)
6551                 {
6552                         type = RequestedType.ResolveAsType (ec);
6553                         if (type == null)
6554                                 return null;
6555
6556                         eclass = ExprClass.Value;
6557
6558                         if (type.IsPointer) {
6559                                 ec.Report.Error (1919, loc, "Unsafe type `{0}' cannot be used in an object creation expression",
6560                                         type.GetSignatureForError ());
6561                                 return null;
6562                         }
6563
6564                         if (arguments == null) {
6565                                 Constant c = Constantify (type, RequestedType.Location);
6566                                 if (c != null)
6567                                         return ReducedExpression.Create (c, this);
6568                         }
6569
6570                         if (type.IsDelegate) {
6571                                 return (new NewDelegate (type, arguments, loc)).Resolve (ec);
6572                         }
6573
6574                         var tparam = type as TypeParameterSpec;
6575                         if (tparam != null) {
6576                                 //
6577                                 // Check whether the type of type parameter can be constructed. BaseType can be a struct for method overrides
6578                                 // where type parameter constraint is inflated to struct
6579                                 //
6580                                 if ((tparam.SpecialConstraint & (SpecialConstraint.Struct | SpecialConstraint.Constructor)) == 0 && !TypeSpec.IsValueType (tparam)) {
6581                                         ec.Report.Error (304, loc,
6582                                                 "Cannot create an instance of the variable type `{0}' because it does not have the new() constraint",
6583                                                 type.GetSignatureForError ());
6584                                 }
6585
6586                                 if ((arguments != null) && (arguments.Count != 0)) {
6587                                         ec.Report.Error (417, loc,
6588                                                 "`{0}': cannot provide arguments when creating an instance of a variable type",
6589                                                 type.GetSignatureForError ());
6590                                 }
6591
6592                                 return this;
6593                         }
6594
6595                         if (type.IsStatic) {
6596                                 ec.Report.SymbolRelatedToPreviousError (type);
6597                                 ec.Report.Error (712, loc, "Cannot create an instance of the static class `{0}'", type.GetSignatureForError ());
6598                                 return null;
6599                         }
6600
6601                         if (type.IsInterface || type.IsAbstract){
6602                                 if (!TypeManager.IsGenericType (type)) {
6603                                         RequestedType = CheckComImport (ec);
6604                                         if (RequestedType != null)
6605                                                 return RequestedType;
6606                                 }
6607
6608                                 ec.Report.SymbolRelatedToPreviousError (type);
6609                                 ec.Report.Error (144, loc, "Cannot create an instance of the abstract class or interface `{0}'", type.GetSignatureForError ());
6610                                 return null;
6611                         }
6612
6613                         //
6614                         // Any struct always defines parameterless constructor
6615                         //
6616                         if (type.IsStruct && arguments == null)
6617                                 return this;
6618
6619                         bool dynamic;
6620                         if (arguments != null) {
6621                                 arguments.Resolve (ec, out dynamic);
6622                         } else {
6623                                 dynamic = false;
6624                         }
6625
6626                         method = ConstructorLookup (ec, type, ref arguments, loc);
6627
6628                         if (dynamic) {
6629                                 arguments.Insert (0, new Argument (new TypeOf (type, loc).Resolve (ec), Argument.AType.DynamicTypeName));
6630                                 return new DynamicConstructorBinder (type, arguments, loc).Resolve (ec);
6631                         }
6632
6633                         return this;
6634                 }
6635
6636                 bool DoEmitTypeParameter (EmitContext ec)
6637                 {
6638                         var m = ec.Module.PredefinedMembers.ActivatorCreateInstance.Resolve (loc);
6639                         if (m == null)
6640                                 return true;
6641
6642                         var ctor_factory = m.MakeGenericMethod (ec.MemberContext, type);
6643                         var tparam = (TypeParameterSpec) type;
6644
6645                         if (tparam.IsReferenceType) {
6646                                 ec.Emit (OpCodes.Call, ctor_factory);
6647                                 return true;
6648                         }
6649
6650                         // Allow DoEmit() to be called multiple times.
6651                         // We need to create a new LocalTemporary each time since
6652                         // you can't share LocalBuilders among ILGeneators.
6653                         LocalTemporary temp = new LocalTemporary (type);
6654
6655                         Label label_activator = ec.DefineLabel ();
6656                         Label label_end = ec.DefineLabel ();
6657
6658                         temp.AddressOf (ec, AddressOp.Store);
6659                         ec.Emit (OpCodes.Initobj, type);
6660
6661                         temp.Emit (ec);
6662                         ec.Emit (OpCodes.Box, type);
6663                         ec.Emit (OpCodes.Brfalse, label_activator);
6664
6665                         temp.AddressOf (ec, AddressOp.Store);
6666                         ec.Emit (OpCodes.Initobj, type);
6667                         temp.Emit (ec);
6668                         temp.Release (ec);
6669                         ec.Emit (OpCodes.Br_S, label_end);
6670
6671                         ec.MarkLabel (label_activator);
6672
6673                         ec.Emit (OpCodes.Call, ctor_factory);
6674                         ec.MarkLabel (label_end);
6675                         return true;
6676                 }
6677
6678                 //
6679                 // This Emit can be invoked in two contexts:
6680                 //    * As a mechanism that will leave a value on the stack (new object)
6681                 //    * As one that wont (init struct)
6682                 //
6683                 // If we are dealing with a ValueType, we have a few
6684                 // situations to deal with:
6685                 //
6686                 //    * The target is a ValueType, and we have been provided
6687                 //      the instance (this is easy, we are being assigned).
6688                 //
6689                 //    * The target of New is being passed as an argument,
6690                 //      to a boxing operation or a function that takes a
6691                 //      ValueType.
6692                 //
6693                 //      In this case, we need to create a temporary variable
6694                 //      that is the argument of New.
6695                 //
6696                 // Returns whether a value is left on the stack
6697                 //
6698                 // *** Implementation note ***
6699                 //
6700                 // To benefit from this optimization, each assignable expression
6701                 // has to manually cast to New and call this Emit.
6702                 //
6703                 // TODO: It's worth to implement it for arrays and fields
6704                 //
6705                 public virtual bool Emit (EmitContext ec, IMemoryLocation target)
6706                 {
6707                         bool is_value_type = TypeSpec.IsValueType (type);
6708                         VariableReference vr = target as VariableReference;
6709
6710                         if (target != null && is_value_type && (vr != null || method == null)) {
6711                                 target.AddressOf (ec, AddressOp.Store);
6712                         } else if (vr != null && vr.IsRef) {
6713                                 vr.EmitLoad (ec);
6714                         }
6715
6716                         if (arguments != null) {
6717                                 if (ec.HasSet (BuilderContext.Options.AsyncBody) && (arguments.Count > (this is NewInitialize ? 0 : 1)) && arguments.ContainsEmitWithAwait ())
6718                                         arguments = arguments.Emit (ec, false, true);
6719
6720                                 arguments.Emit (ec);
6721                         }
6722
6723                         if (is_value_type) {
6724                                 if (method == null) {
6725                                         ec.Emit (OpCodes.Initobj, type);
6726                                         return false;
6727                                 }
6728
6729                                 if (vr != null) {
6730                                         ec.MarkCallEntry (loc);
6731                                         ec.Emit (OpCodes.Call, method);
6732                                         return false;
6733                                 }
6734                         }
6735
6736                         if (type is TypeParameterSpec)
6737                                 return DoEmitTypeParameter (ec);
6738
6739                         ec.MarkCallEntry (loc);
6740                         ec.Emit (OpCodes.Newobj, method);
6741                         return true;
6742                 }
6743
6744                 public override void Emit (EmitContext ec)
6745                 {
6746                         LocalTemporary v = null;
6747                         if (method == null && TypeSpec.IsValueType (type)) {
6748                                 // TODO: Use temporary variable from pool
6749                                 v = new LocalTemporary (type);
6750                         }
6751
6752                         if (!Emit (ec, v))
6753                                 v.Emit (ec);
6754                 }
6755
6756                 public override void EmitStatement (EmitContext ec)
6757                 {
6758                         LocalTemporary v = null;
6759                         if (method == null && TypeSpec.IsValueType (type)) {
6760                                 // TODO: Use temporary variable from pool
6761                                 v = new LocalTemporary (type);
6762                         }
6763
6764                         if (Emit (ec, v))
6765                                 ec.Emit (OpCodes.Pop);
6766                 }
6767
6768                 public override void FlowAnalysis (FlowAnalysisContext fc)
6769                 {
6770                         if (arguments != null)
6771                                 arguments.FlowAnalysis (fc);
6772                 }
6773
6774                 public void AddressOf (EmitContext ec, AddressOp mode)
6775                 {
6776                         EmitAddressOf (ec, mode);
6777                 }
6778
6779                 protected virtual IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp mode)
6780                 {
6781                         LocalTemporary value_target = new LocalTemporary (type);
6782
6783                         if (type is TypeParameterSpec) {
6784                                 DoEmitTypeParameter (ec);
6785                                 value_target.Store (ec);
6786                                 value_target.AddressOf (ec, mode);
6787                                 return value_target;
6788                         }
6789
6790                         value_target.AddressOf (ec, AddressOp.Store);
6791
6792                         if (method == null) {
6793                                 ec.Emit (OpCodes.Initobj, type);
6794                         } else {
6795                                 if (arguments != null)
6796                                         arguments.Emit (ec);
6797
6798                                 ec.Emit (OpCodes.Call, method);
6799                         }
6800
6801                         value_target.AddressOf (ec, mode);
6802                         return value_target;
6803                 }
6804
6805                 protected override void CloneTo (CloneContext clonectx, Expression t)
6806                 {
6807                         New target = (New) t;
6808
6809                         target.RequestedType = RequestedType.Clone (clonectx);
6810                         if (arguments != null){
6811                                 target.arguments = arguments.Clone (clonectx);
6812                         }
6813                 }
6814
6815                 public override SLE.Expression MakeExpression (BuilderContext ctx)
6816                 {
6817 #if STATIC
6818                         return base.MakeExpression (ctx);
6819 #else
6820                         return SLE.Expression.New ((ConstructorInfo) method.GetMetaInfo (), Arguments.MakeExpression (arguments, ctx));
6821 #endif
6822                 }
6823
6824                 public override object Accept (StructuralVisitor visitor)
6825                 {
6826                         return visitor.Visit (this);
6827                 }
6828         }
6829
6830         //
6831         // Array initializer expression, the expression is allowed in
6832         // variable or field initialization only which makes it tricky as
6833         // the type has to be infered based on the context either from field
6834         // type or variable type (think of multiple declarators)
6835         //
6836         public class ArrayInitializer : Expression
6837         {
6838                 List<Expression> elements;
6839                 BlockVariable variable;
6840
6841                 public ArrayInitializer (List<Expression> init, Location loc)
6842                 {
6843                         elements = init;
6844                         this.loc = loc;
6845                 }
6846
6847                 public ArrayInitializer (int count, Location loc)
6848                         : this (new List<Expression> (count), loc)
6849                 {
6850                 }
6851
6852                 public ArrayInitializer (Location loc)
6853                         : this (4, loc)
6854                 {
6855                 }
6856
6857                 #region Properties
6858
6859                 public int Count {
6860                         get { return elements.Count; }
6861                 }
6862
6863                 public List<Expression> Elements {
6864                         get {
6865                                 return elements;
6866                         }
6867                 }
6868
6869                 public Expression this [int index] {
6870                         get {
6871                                 return elements [index];
6872                         }
6873                 }
6874
6875                 public BlockVariable VariableDeclaration {
6876                         get {
6877                                 return variable;
6878                         }
6879                         set {
6880                                 variable = value;
6881                         }
6882                 }
6883
6884                 #endregion
6885
6886                 public void Add (Expression expr)
6887                 {
6888                         elements.Add (expr);
6889                 }
6890
6891                 public override bool ContainsEmitWithAwait ()
6892                 {
6893                         throw new NotSupportedException ();
6894                 }
6895
6896                 public override Expression CreateExpressionTree (ResolveContext ec)
6897                 {
6898                         throw new NotSupportedException ("ET");
6899                 }
6900
6901                 protected override void CloneTo (CloneContext clonectx, Expression t)
6902                 {
6903                         var target = (ArrayInitializer) t;
6904
6905                         target.elements = new List<Expression> (elements.Count);
6906                         foreach (var element in elements)
6907                                 target.elements.Add (element.Clone (clonectx));
6908                 }
6909
6910                 protected override Expression DoResolve (ResolveContext rc)
6911                 {
6912                         var current_field = rc.CurrentMemberDefinition as FieldBase;
6913                         TypeExpression type;
6914                         if (current_field != null && rc.CurrentAnonymousMethod == null) {
6915                                 type = new TypeExpression (current_field.MemberType, current_field.Location);
6916                         } else if (variable != null) {
6917                                 if (variable.TypeExpression is VarExpr) {
6918                                         rc.Report.Error (820, loc, "An implicitly typed local variable declarator cannot use an array initializer");
6919                                         return EmptyExpression.Null;
6920                                 }
6921
6922                                 type = new TypeExpression (variable.Variable.Type, variable.Variable.Location);
6923                         } else {
6924                                 throw new NotImplementedException ("Unexpected array initializer context");
6925                         }
6926
6927                         return new ArrayCreation (type, this).Resolve (rc);
6928                 }
6929
6930                 public override void Emit (EmitContext ec)
6931                 {
6932                         throw new InternalErrorException ("Missing Resolve call");
6933                 }
6934
6935                 public override void FlowAnalysis (FlowAnalysisContext fc)
6936                 {
6937                         throw new InternalErrorException ("Missing Resolve call");
6938                 }
6939
6940                 public override object Accept (StructuralVisitor visitor)
6941                 {
6942                         return visitor.Visit (this);
6943                 }
6944         }
6945
6946         /// <summary>
6947         ///   14.5.10.2: Represents an array creation expression.
6948         /// </summary>
6949         ///
6950         /// <remarks>
6951         ///   There are two possible scenarios here: one is an array creation
6952         ///   expression that specifies the dimensions and optionally the
6953         ///   initialization data and the other which does not need dimensions
6954         ///   specified but where initialization data is mandatory.
6955         /// </remarks>
6956         public class ArrayCreation : Expression
6957         {
6958                 FullNamedExpression requested_base_type;
6959                 ArrayInitializer initializers;
6960
6961                 //
6962                 // The list of Argument types.
6963                 // This is used to construct the `newarray' or constructor signature
6964                 //
6965                 protected List<Expression> arguments;
6966
6967                 protected TypeSpec array_element_type;
6968                 int num_arguments;
6969                 protected int dimensions;
6970                 protected readonly ComposedTypeSpecifier rank;
6971                 Expression first_emit;
6972                 LocalTemporary first_emit_temp;
6973
6974                 protected List<Expression> array_data;
6975
6976                 Dictionary<int, int> bounds;
6977
6978 #if STATIC
6979                 // The number of constants in array initializers
6980                 int const_initializers_count;
6981                 bool only_constant_initializers;
6982 #endif
6983                 public ArrayCreation (FullNamedExpression requested_base_type, List<Expression> exprs, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location l)
6984                         : this (requested_base_type, rank, initializers, l)
6985                 {
6986                         arguments = new List<Expression> (exprs);
6987                         num_arguments = arguments.Count;
6988                 }
6989
6990                 //
6991                 // For expressions like int[] foo = new int[] { 1, 2, 3 };
6992                 //
6993                 public ArrayCreation (FullNamedExpression requested_base_type, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
6994                 {
6995                         this.requested_base_type = requested_base_type;
6996                         this.rank = rank;
6997                         this.initializers = initializers;
6998                         this.loc = loc;
6999
7000                         if (rank != null)
7001                                 num_arguments = rank.Dimension;
7002                 }
7003
7004                 //
7005                 // For compiler generated single dimensional arrays only
7006                 //
7007                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers, Location loc)
7008                         : this (requested_base_type, ComposedTypeSpecifier.SingleDimension, initializers, loc)
7009                 {
7010                 }
7011
7012                 //
7013                 // For expressions like int[] foo = { 1, 2, 3 };
7014                 //
7015                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers)
7016                         : this (requested_base_type, null, initializers, initializers.Location)
7017                 {
7018                 }
7019
7020                 public ComposedTypeSpecifier Rank {
7021                         get {
7022                                 return this.rank;
7023                         }
7024                 }
7025
7026                 public FullNamedExpression TypeExpression {
7027                         get {
7028                                 return this.requested_base_type;
7029                         }
7030                 }
7031
7032                 public ArrayInitializer Initializers {
7033                         get {
7034                                 return this.initializers;
7035                         }
7036                 }
7037
7038                 bool CheckIndices (ResolveContext ec, ArrayInitializer probe, int idx, bool specified_dims, int child_bounds)
7039                 {
7040                         if (initializers != null && bounds == null) {
7041                                 //
7042                                 // We use this to store all the data values in the order in which we
7043                                 // will need to store them in the byte blob later
7044                                 //
7045                                 array_data = new List<Expression> (probe.Count);
7046                                 bounds = new Dictionary<int, int> ();
7047                         }
7048
7049                         if (specified_dims) {
7050                                 Expression a = arguments [idx];
7051                                 a = a.Resolve (ec);
7052                                 if (a == null)
7053                                         return false;
7054
7055                                 a = ConvertExpressionToArrayIndex (ec, a);
7056                                 if (a == null)
7057                                         return false;
7058
7059                                 arguments[idx] = a;
7060
7061                                 if (initializers != null) {
7062                                         Constant c = a as Constant;
7063                                         if (c == null && a is ArrayIndexCast)
7064                                                 c = ((ArrayIndexCast) a).Child as Constant;
7065
7066                                         if (c == null) {
7067                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
7068                                                 return false;
7069                                         }
7070
7071                                         int value;
7072                                         try {
7073                                                 value = System.Convert.ToInt32 (c.GetValue ());
7074                                         } catch {
7075                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
7076                                                 return false;
7077                                         }
7078
7079                                         // TODO: probe.Count does not fit ulong in
7080                                         if (value != probe.Count) {
7081                                                 ec.Report.Error (847, loc, "An array initializer of length `{0}' was expected", value.ToString ());
7082                                                 return false;
7083                                         }
7084
7085                                         bounds[idx] = value;
7086                                 }
7087                         }
7088
7089                         if (initializers == null)
7090                                 return true;
7091
7092                         for (int i = 0; i < probe.Count; ++i) {
7093                                 var o = probe [i];
7094                                 if (o is ArrayInitializer) {
7095                                         var sub_probe = o as ArrayInitializer;
7096                                         if (idx + 1 >= dimensions){
7097                                                 ec.Report.Error (623, loc, "Array initializers can only be used in a variable or field initializer. Try using a new expression instead");
7098                                                 return false;
7099                                         }
7100
7101                                         // When we don't have explicitly specified dimensions, record whatever dimension we first encounter at each level
7102                                         if (!bounds.ContainsKey(idx + 1))
7103                                                 bounds[idx + 1] = sub_probe.Count;
7104
7105                                         if (bounds[idx + 1] != sub_probe.Count) {
7106                                                 ec.Report.Error(847, sub_probe.Location, "An array initializer of length `{0}' was expected", bounds[idx + 1].ToString());
7107                                                 return false;
7108                                         }
7109
7110                                         bool ret = CheckIndices (ec, sub_probe, idx + 1, specified_dims, child_bounds - 1);
7111                                         if (!ret)
7112                                                 return false;
7113                                 } else if (child_bounds > 1) {
7114                                         ec.Report.Error (846, o.Location, "A nested array initializer was expected");
7115                                 } else {
7116                                         Expression element = ResolveArrayElement (ec, o);
7117                                         if (element == null)
7118                                                 continue;
7119 #if STATIC
7120                                         // Initializers with the default values can be ignored
7121                                         Constant c = element as Constant;
7122                                         if (c != null) {
7123                                                 if (!c.IsDefaultInitializer (array_element_type)) {
7124                                                         ++const_initializers_count;
7125                                                 }
7126                                         } else {
7127                                                 only_constant_initializers = false;
7128                                         }
7129 #endif
7130                                         array_data.Add (element);
7131                                 }
7132                         }
7133
7134                         return true;
7135                 }
7136
7137                 public override bool ContainsEmitWithAwait ()
7138                 {
7139                         foreach (var arg in arguments) {
7140                                 if (arg.ContainsEmitWithAwait ())
7141                                         return true;
7142                         }
7143
7144                         return InitializersContainAwait ();
7145                 }
7146
7147                 public override Expression CreateExpressionTree (ResolveContext ec)
7148                 {
7149                         Arguments args;
7150
7151                         if (array_data == null) {
7152                                 args = new Arguments (arguments.Count + 1);
7153                                 args.Add (new Argument (new TypeOf (array_element_type, loc)));
7154                                 foreach (Expression a in arguments)
7155                                         args.Add (new Argument (a.CreateExpressionTree (ec)));
7156
7157                                 return CreateExpressionFactoryCall (ec, "NewArrayBounds", args);
7158                         }
7159
7160                         if (dimensions > 1) {
7161                                 ec.Report.Error (838, loc, "An expression tree cannot contain a multidimensional array initializer");
7162                                 return null;
7163                         }
7164
7165                         args = new Arguments (array_data == null ? 1 : array_data.Count + 1);
7166                         args.Add (new Argument (new TypeOf (array_element_type, loc)));
7167                         if (array_data != null) {
7168                                 for (int i = 0; i < array_data.Count; ++i) {
7169                                         Expression e = array_data [i];
7170                                         args.Add (new Argument (e.CreateExpressionTree (ec)));
7171                                 }
7172                         }
7173
7174                         return CreateExpressionFactoryCall (ec, "NewArrayInit", args);
7175                 }
7176
7177                 void UpdateIndices (ResolveContext rc)
7178                 {
7179                         int i = 0;
7180                         for (var probe = initializers; probe != null;) {
7181                                 Expression e = new IntConstant (rc.BuiltinTypes, probe.Count, Location.Null);
7182                                 arguments.Add (e);
7183                                 bounds[i++] = probe.Count;
7184
7185                                 if (probe.Count > 0 && probe [0] is ArrayInitializer) {
7186                                         probe = (ArrayInitializer) probe[0];
7187                                 } else if (dimensions > i) {
7188                                         continue;
7189                                 } else {
7190                                         return;
7191                                 }
7192                         }
7193                 }
7194
7195                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
7196                 {
7197                         ec.Report.Error (248, loc, "Cannot create an array with a negative size");
7198                 }
7199
7200                 public override void FlowAnalysis (FlowAnalysisContext fc)
7201                 {
7202                         foreach (var arg in arguments)
7203                                 arg.FlowAnalysis (fc);
7204
7205                         if (array_data != null) {
7206                                 foreach (var ad in array_data)
7207                                         ad.FlowAnalysis (fc);
7208                         }
7209                 }
7210
7211                 bool InitializersContainAwait ()
7212                 {
7213                         if (array_data == null)
7214                                 return false;
7215
7216                         foreach (var expr in array_data) {
7217                                 if (expr.ContainsEmitWithAwait ())
7218                                         return true;
7219                         }
7220
7221                         return false;
7222                 }
7223
7224                 protected virtual Expression ResolveArrayElement (ResolveContext ec, Expression element)
7225                 {
7226                         element = element.Resolve (ec);
7227                         if (element == null)
7228                                 return null;
7229
7230                         if (element is CompoundAssign.TargetExpression) {
7231                                 if (first_emit != null)
7232                                         throw new InternalErrorException ("Can only handle one mutator at a time");
7233                                 first_emit = element;
7234                                 element = first_emit_temp = new LocalTemporary (element.Type);
7235                         }
7236
7237                         return Convert.ImplicitConversionRequired (
7238                                 ec, element, array_element_type, loc);
7239                 }
7240
7241                 protected bool ResolveInitializers (ResolveContext ec)
7242                 {
7243 #if STATIC
7244                         only_constant_initializers = true;
7245 #endif
7246
7247                         if (arguments != null) {
7248                                 bool res = true;
7249                                 for (int i = 0; i < arguments.Count; ++i) {
7250                                         res &= CheckIndices (ec, initializers, i, true, dimensions);
7251                                         if (initializers != null)
7252                                                 break;
7253                                 }
7254
7255                                 return res;
7256                         }
7257
7258                         arguments = new List<Expression> ();
7259
7260                         if (!CheckIndices (ec, initializers, 0, false, dimensions))
7261                                 return false;
7262
7263                         UpdateIndices (ec);
7264
7265                         return true;
7266                 }
7267
7268                 //
7269                 // Resolved the type of the array
7270                 //
7271                 bool ResolveArrayType (ResolveContext ec)
7272                 {
7273                         //
7274                         // Lookup the type
7275                         //
7276                         FullNamedExpression array_type_expr;
7277                         if (num_arguments > 0) {
7278                                 array_type_expr = new ComposedCast (requested_base_type, rank);
7279                         } else {
7280                                 array_type_expr = requested_base_type;
7281                         }
7282
7283                         type = array_type_expr.ResolveAsType (ec);
7284                         if (array_type_expr == null)
7285                                 return false;
7286
7287                         var ac = type as ArrayContainer;
7288                         if (ac == null) {
7289                                 ec.Report.Error (622, loc, "Can only use array initializer expressions to assign to array types. Try using a new expression instead");
7290                                 return false;
7291                         }
7292
7293                         array_element_type = ac.Element;
7294                         dimensions = ac.Rank;
7295
7296                         return true;
7297                 }
7298
7299                 protected override Expression DoResolve (ResolveContext ec)
7300                 {
7301                         if (type != null)
7302                                 return this;
7303
7304                         if (!ResolveArrayType (ec))
7305                                 return null;
7306
7307                         //
7308                         // validate the initializers and fill in any missing bits
7309                         //
7310                         if (!ResolveInitializers (ec))
7311                                 return null;
7312
7313                         eclass = ExprClass.Value;
7314                         return this;
7315                 }
7316
7317                 byte [] MakeByteBlob ()
7318                 {
7319                         int factor;
7320                         byte [] data;
7321                         byte [] element;
7322                         int count = array_data.Count;
7323
7324                         TypeSpec element_type = array_element_type;
7325                         if (element_type.IsEnum)
7326                                 element_type = EnumSpec.GetUnderlyingType (element_type);
7327
7328                         factor = BuiltinTypeSpec.GetSize (element_type);
7329                         if (factor == 0)
7330                                 throw new Exception ("unrecognized type in MakeByteBlob: " + element_type);
7331
7332                         data = new byte [(count * factor + 3) & ~3];
7333                         int idx = 0;
7334
7335                         for (int i = 0; i < count; ++i) {
7336                                 var c = array_data[i] as Constant;
7337                                 if (c == null) {
7338                                         idx += factor;
7339                                         continue;
7340                                 }
7341
7342                                 object v = c.GetValue ();
7343
7344                                 switch (element_type.BuiltinType) {
7345                                 case BuiltinTypeSpec.Type.Long:
7346                                         long lval = (long) v;
7347
7348                                         for (int j = 0; j < factor; ++j) {
7349                                                 data[idx + j] = (byte) (lval & 0xFF);
7350                                                 lval = (lval >> 8);
7351                                         }
7352                                         break;
7353                                 case BuiltinTypeSpec.Type.ULong:
7354                                         ulong ulval = (ulong) v;
7355
7356                                         for (int j = 0; j < factor; ++j) {
7357                                                 data[idx + j] = (byte) (ulval & 0xFF);
7358                                                 ulval = (ulval >> 8);
7359                                         }
7360                                         break;
7361                                 case BuiltinTypeSpec.Type.Float:
7362                                         var fval = SingleConverter.SingleToInt32Bits((float) v);
7363
7364                                         data[idx] = (byte) (fval & 0xff);
7365                                         data[idx + 1] = (byte) ((fval >> 8) & 0xff);
7366                                         data[idx + 2] = (byte) ((fval >> 16) & 0xff);
7367                                         data[idx + 3] = (byte) (fval >> 24);
7368                                         break;
7369                                 case BuiltinTypeSpec.Type.Double:
7370                                         element = BitConverter.GetBytes ((double) v);
7371
7372                                         for (int j = 0; j < factor; ++j)
7373                                                 data[idx + j] = element[j];
7374
7375                                         // FIXME: Handle the ARM float format.
7376                                         if (!BitConverter.IsLittleEndian)
7377                                                 System.Array.Reverse (data, idx, 8);
7378                                         break;
7379                                 case BuiltinTypeSpec.Type.Char:
7380                                         int chval = (int) ((char) v);
7381
7382                                         data[idx] = (byte) (chval & 0xff);
7383                                         data[idx + 1] = (byte) (chval >> 8);
7384                                         break;
7385                                 case BuiltinTypeSpec.Type.Short:
7386                                         int sval = (int) ((short) v);
7387
7388                                         data[idx] = (byte) (sval & 0xff);
7389                                         data[idx + 1] = (byte) (sval >> 8);
7390                                         break;
7391                                 case BuiltinTypeSpec.Type.UShort:
7392                                         int usval = (int) ((ushort) v);
7393
7394                                         data[idx] = (byte) (usval & 0xff);
7395                                         data[idx + 1] = (byte) (usval >> 8);
7396                                         break;
7397                                 case BuiltinTypeSpec.Type.Int:
7398                                         int val = (int) v;
7399
7400                                         data[idx] = (byte) (val & 0xff);
7401                                         data[idx + 1] = (byte) ((val >> 8) & 0xff);
7402                                         data[idx + 2] = (byte) ((val >> 16) & 0xff);
7403                                         data[idx + 3] = (byte) (val >> 24);
7404                                         break;
7405                                 case BuiltinTypeSpec.Type.UInt:
7406                                         uint uval = (uint) v;
7407
7408                                         data[idx] = (byte) (uval & 0xff);
7409                                         data[idx + 1] = (byte) ((uval >> 8) & 0xff);
7410                                         data[idx + 2] = (byte) ((uval >> 16) & 0xff);
7411                                         data[idx + 3] = (byte) (uval >> 24);
7412                                         break;
7413                                 case BuiltinTypeSpec.Type.SByte:
7414                                         data[idx] = (byte) (sbyte) v;
7415                                         break;
7416                                 case BuiltinTypeSpec.Type.Byte:
7417                                         data[idx] = (byte) v;
7418                                         break;
7419                                 case BuiltinTypeSpec.Type.Bool:
7420                                         data[idx] = (byte) ((bool) v ? 1 : 0);
7421                                         break;
7422                                 case BuiltinTypeSpec.Type.Decimal:
7423                                         int[] bits = Decimal.GetBits ((decimal) v);
7424                                         int p = idx;
7425
7426                                         // FIXME: For some reason, this doesn't work on the MS runtime.
7427                                         int[] nbits = new int[4];
7428                                         nbits[0] = bits[3];
7429                                         nbits[1] = bits[2];
7430                                         nbits[2] = bits[0];
7431                                         nbits[3] = bits[1];
7432
7433                                         for (int j = 0; j < 4; j++) {
7434                                                 data[p++] = (byte) (nbits[j] & 0xff);
7435                                                 data[p++] = (byte) ((nbits[j] >> 8) & 0xff);
7436                                                 data[p++] = (byte) ((nbits[j] >> 16) & 0xff);
7437                                                 data[p++] = (byte) (nbits[j] >> 24);
7438                                         }
7439                                         break;
7440                                 default:
7441                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + element_type);
7442                                 }
7443
7444                                 idx += factor;
7445                         }
7446
7447                         return data;
7448                 }
7449
7450 #if NET_4_0 || MOBILE_DYNAMIC
7451                 public override SLE.Expression MakeExpression (BuilderContext ctx)
7452                 {
7453 #if STATIC
7454                         return base.MakeExpression (ctx);
7455 #else
7456                         var initializers = new SLE.Expression [array_data.Count];
7457                         for (var i = 0; i < initializers.Length; i++) {
7458                                 if (array_data [i] == null)
7459                                         initializers [i] = SLE.Expression.Default (array_element_type.GetMetaInfo ());
7460                                 else
7461                                         initializers [i] = array_data [i].MakeExpression (ctx);
7462                         }
7463
7464                         return SLE.Expression.NewArrayInit (array_element_type.GetMetaInfo (), initializers);
7465 #endif
7466                 }
7467 #endif
7468 #if STATIC
7469                 //
7470                 // Emits the initializers for the array
7471                 //
7472                 void EmitStaticInitializers (EmitContext ec, FieldExpr stackArray)
7473                 {
7474                         var m = ec.Module.PredefinedMembers.RuntimeHelpersInitializeArray.Resolve (loc);
7475                         if (m == null)
7476                                 return;
7477
7478                         //
7479                         // First, the static data
7480                         //
7481                         byte [] data = MakeByteBlob ();
7482                         var fb = ec.CurrentTypeDefinition.Module.MakeStaticData (data, loc);
7483
7484                         if (stackArray == null) {
7485                                 ec.Emit (OpCodes.Dup);
7486                         } else {
7487                                 stackArray.Emit (ec);
7488                         }
7489
7490                         ec.Emit (OpCodes.Ldtoken, fb);
7491                         ec.Emit (OpCodes.Call, m);
7492                 }
7493 #endif
7494
7495                 //
7496                 // Emits pieces of the array that can not be computed at compile
7497                 // time (variables and string locations).
7498                 //
7499                 // This always expect the top value on the stack to be the array
7500                 //
7501                 void EmitDynamicInitializers (EmitContext ec, bool emitConstants, StackFieldExpr stackArray)
7502                 {
7503                         int dims = bounds.Count;
7504                         var current_pos = new int [dims];
7505
7506                         for (int i = 0; i < array_data.Count; i++){
7507
7508                                 Expression e = array_data [i];
7509                                 var c = e as Constant;
7510
7511                                 // Constant can be initialized via StaticInitializer
7512                                 if (c == null || (c != null && emitConstants && !c.IsDefaultInitializer (array_element_type))) {
7513
7514                                         var etype = e.Type;
7515
7516                                         if (stackArray != null) {
7517                                                 if (e.ContainsEmitWithAwait ()) {
7518                                                         e = e.EmitToField (ec);
7519                                                 }
7520
7521                                                 stackArray.EmitLoad (ec);
7522                                         } else {
7523                                                 ec.Emit (OpCodes.Dup);
7524                                         }
7525
7526                                         for (int idx = 0; idx < dims; idx++)
7527                                                 ec.EmitInt (current_pos [idx]);
7528
7529                                         //
7530                                         // If we are dealing with a struct, get the
7531                                         // address of it, so we can store it.
7532                                         //
7533                                         if (dims == 1 && etype.IsStruct && !BuiltinTypeSpec.IsPrimitiveType (etype))
7534                                                 ec.Emit (OpCodes.Ldelema, etype);
7535
7536                                         e.Emit (ec);
7537
7538                                         ec.EmitArrayStore ((ArrayContainer) type);
7539                                 }
7540
7541                                 //
7542                                 // Advance counter
7543                                 //
7544                                 for (int j = dims - 1; j >= 0; j--){
7545                                         current_pos [j]++;
7546                                         if (current_pos [j] < bounds [j])
7547                                                 break;
7548                                         current_pos [j] = 0;
7549                                 }
7550                         }
7551
7552                         if (stackArray != null)
7553                                 stackArray.PrepareCleanup (ec);
7554                 }
7555
7556                 public override void Emit (EmitContext ec)
7557                 {
7558                         EmitToFieldSource (ec);
7559                 }
7560
7561                 protected sealed override FieldExpr EmitToFieldSource (EmitContext ec)
7562                 {
7563                         if (first_emit != null) {
7564                                 first_emit.Emit (ec);
7565                                 first_emit_temp.Store (ec);
7566                         }
7567
7568                         StackFieldExpr await_stack_field;
7569                         if (ec.HasSet (BuilderContext.Options.AsyncBody) && InitializersContainAwait ()) {
7570                                 await_stack_field = ec.GetTemporaryField (type);
7571                                 ec.EmitThis ();
7572                         } else {
7573                                 await_stack_field = null;
7574                         }
7575
7576                         EmitExpressionsList (ec, arguments);
7577
7578                         ec.EmitArrayNew ((ArrayContainer) type);
7579
7580                         if (initializers == null)
7581                                 return await_stack_field;
7582
7583                         if (await_stack_field != null)
7584                                 await_stack_field.EmitAssignFromStack (ec);
7585
7586 #if STATIC
7587                         //
7588                         // Emit static initializer for arrays which contain more than 2 items and
7589                         // the static initializer will initialize at least 25% of array values or there
7590                         // is more than 10 items to be initialized
7591                         //
7592                         // NOTE: const_initializers_count does not contain default constant values.
7593                         //
7594                         if (const_initializers_count > 2 && (array_data.Count > 10 || const_initializers_count * 4 > (array_data.Count)) &&
7595                                 (BuiltinTypeSpec.IsPrimitiveType (array_element_type) || array_element_type.IsEnum)) {
7596                                 EmitStaticInitializers (ec, await_stack_field);
7597
7598                                 if (!only_constant_initializers)
7599                                         EmitDynamicInitializers (ec, false, await_stack_field);
7600                         } else
7601 #endif
7602                         {
7603                                 EmitDynamicInitializers (ec, true, await_stack_field);
7604                         }
7605
7606                         if (first_emit_temp != null)
7607                                 first_emit_temp.Release (ec);
7608
7609                         return await_stack_field;
7610                 }
7611
7612                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
7613                 {
7614                         // no multi dimensional or jagged arrays
7615                         if (arguments.Count != 1 || array_element_type.IsArray) {
7616                                 base.EncodeAttributeValue (rc, enc, targetType);
7617                                 return;
7618                         }
7619
7620                         // No array covariance, except for array -> object
7621                         if (type != targetType) {
7622                                 if (targetType.BuiltinType != BuiltinTypeSpec.Type.Object) {
7623                                         base.EncodeAttributeValue (rc, enc, targetType);
7624                                         return;
7625                                 }
7626
7627                                 if (enc.Encode (type) == AttributeEncoder.EncodedTypeProperties.DynamicType) {
7628                                         Attribute.Error_AttributeArgumentIsDynamic (rc, loc);
7629                                         return;
7630                                 }
7631                         }
7632
7633                         // Single dimensional array of 0 size
7634                         if (array_data == null) {
7635                                 IntConstant ic = arguments[0] as IntConstant;
7636                                 if (ic == null || !ic.IsDefaultValue) {
7637                                         base.EncodeAttributeValue (rc, enc, targetType);
7638                                 } else {
7639                                         enc.Encode (0);
7640                                 }
7641
7642                                 return;
7643                         }
7644
7645                         enc.Encode (array_data.Count);
7646                         foreach (var element in array_data) {
7647                                 element.EncodeAttributeValue (rc, enc, array_element_type);
7648                         }
7649                 }
7650
7651                 protected override void CloneTo (CloneContext clonectx, Expression t)
7652                 {
7653                         ArrayCreation target = (ArrayCreation) t;
7654
7655                         if (requested_base_type != null)
7656                                 target.requested_base_type = (FullNamedExpression)requested_base_type.Clone (clonectx);
7657
7658                         if (arguments != null){
7659                                 target.arguments = new List<Expression> (arguments.Count);
7660                                 foreach (Expression e in arguments)
7661                                         target.arguments.Add (e.Clone (clonectx));
7662                         }
7663
7664                         if (initializers != null)
7665                                 target.initializers = (ArrayInitializer) initializers.Clone (clonectx);
7666                 }
7667
7668                 public override object Accept (StructuralVisitor visitor)
7669                 {
7670                         return visitor.Visit (this);
7671                 }
7672         }
7673
7674         //
7675         // Represents an implicitly typed array epxression
7676         //
7677         class ImplicitlyTypedArrayCreation : ArrayCreation
7678         {
7679                 TypeInferenceContext best_type_inference;
7680
7681                 public ImplicitlyTypedArrayCreation (ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
7682                         : base (null, rank, initializers, loc)
7683                 {
7684                 }
7685
7686                 public ImplicitlyTypedArrayCreation (ArrayInitializer initializers, Location loc)
7687                         : base (null, initializers, loc)
7688                 {
7689                 }
7690
7691                 protected override Expression DoResolve (ResolveContext ec)
7692                 {
7693                         if (type != null)
7694                                 return this;
7695
7696                         dimensions = rank.Dimension;
7697
7698                         best_type_inference = new TypeInferenceContext ();
7699
7700                         if (!ResolveInitializers (ec))
7701                                 return null;
7702
7703                         best_type_inference.FixAllTypes (ec);
7704                         array_element_type = best_type_inference.InferredTypeArguments[0];
7705                         best_type_inference = null;
7706
7707                         if (array_element_type == null ||
7708                                 array_element_type == InternalType.NullLiteral || array_element_type == InternalType.MethodGroup || array_element_type == InternalType.AnonymousMethod ||
7709                                 arguments.Count != rank.Dimension) {
7710                                 ec.Report.Error (826, loc,
7711                                         "The type of an implicitly typed array cannot be inferred from the initializer. Try specifying array type explicitly");
7712                                 return null;
7713                         }
7714
7715                         //
7716                         // At this point we found common base type for all initializer elements
7717                         // but we have to be sure that all static initializer elements are of
7718                         // same type
7719                         //
7720                         UnifyInitializerElement (ec);
7721
7722                         type = ArrayContainer.MakeType (ec.Module, array_element_type, dimensions);
7723                         eclass = ExprClass.Value;
7724                         return this;
7725                 }
7726
7727                 //
7728                 // Converts static initializer only
7729                 //
7730                 void UnifyInitializerElement (ResolveContext ec)
7731                 {
7732                         for (int i = 0; i < array_data.Count; ++i) {
7733                                 Expression e = array_data[i];
7734                                 if (e != null)
7735                                         array_data [i] = Convert.ImplicitConversion (ec, e, array_element_type, Location.Null);
7736                         }
7737                 }
7738
7739                 protected override Expression ResolveArrayElement (ResolveContext ec, Expression element)
7740                 {
7741                         element = element.Resolve (ec);
7742                         if (element != null)
7743                                 best_type_inference.AddCommonTypeBound (element.Type);
7744
7745                         return element;
7746                 }
7747         }
7748
7749         sealed class CompilerGeneratedThis : This
7750         {
7751                 public CompilerGeneratedThis (TypeSpec type, Location loc)
7752                         : base (loc)
7753                 {
7754                         this.type = type;
7755                         eclass = ExprClass.Variable;
7756                 }
7757
7758                 protected override Expression DoResolve (ResolveContext ec)
7759                 {
7760                         return this;
7761                 }
7762
7763                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
7764                 {
7765                         return null;
7766                 }
7767         }
7768
7769         /// <summary>
7770         ///   Represents the `this' construct
7771         /// </summary>
7772
7773         public class This : VariableReference
7774         {
7775                 sealed class ThisVariable : ILocalVariable
7776                 {
7777                         public static readonly ILocalVariable Instance = new ThisVariable ();
7778
7779                         public void Emit (EmitContext ec)
7780                         {
7781                                 ec.EmitThis ();
7782                         }
7783
7784                         public void EmitAssign (EmitContext ec)
7785                         {
7786                                 throw new InvalidOperationException ();
7787                         }
7788
7789                         public void EmitAddressOf (EmitContext ec)
7790                         {
7791                                 ec.EmitThis ();
7792                         }
7793                 }
7794
7795                 VariableInfo variable_info;
7796
7797                 public This (Location loc)
7798                 {
7799                         this.loc = loc;
7800                 }
7801
7802                 #region Properties
7803
7804                 public override string Name {
7805                         get { return "this"; }
7806                 }
7807
7808                 public override bool IsLockedByStatement {
7809                         get {
7810                                 return false;
7811                         }
7812                         set {
7813                         }
7814                 }
7815
7816                 public override bool IsRef {
7817                         get { return type.IsStruct; }
7818                 }
7819
7820                 public override bool IsSideEffectFree {
7821                         get {
7822                                 return true;
7823                         }
7824                 }
7825
7826                 protected override ILocalVariable Variable {
7827                         get { return ThisVariable.Instance; }
7828                 }
7829
7830                 public override VariableInfo VariableInfo {
7831                         get { return variable_info; }
7832                 }
7833
7834                 public override bool IsFixed {
7835                         get { return false; }
7836                 }
7837
7838                 #endregion
7839
7840                 void CheckStructThisDefiniteAssignment (FlowAnalysisContext fc)
7841                 {
7842                         //
7843                         // It's null for all cases when we don't need to check `this'
7844                         // definitive assignment
7845                         //
7846                         if (variable_info == null)
7847                                 return;
7848
7849                         if (fc.IsDefinitelyAssigned (variable_info))
7850                                 return;
7851
7852                         fc.Report.Error (188, loc, "The `this' object cannot be used before all of its fields are assigned to");
7853                 }
7854
7855                 protected virtual void Error_ThisNotAvailable (ResolveContext ec)
7856                 {
7857                         if (ec.IsStatic && !ec.HasSet (ResolveContext.Options.ConstantScope)) {
7858                                 ec.Report.Error (26, loc, "Keyword `this' is not valid in a static property, static method, or static field initializer");
7859                         } else if (ec.CurrentAnonymousMethod != null) {
7860                                 ec.Report.Error (1673, loc,
7861                                         "Anonymous methods inside structs cannot access instance members of `this'. " +
7862                                         "Consider copying `this' to a local variable outside the anonymous method and using the local instead");
7863                         } else {
7864                                 ec.Report.Error (27, loc, "Keyword `this' is not available in the current context");
7865                         }
7866                 }
7867
7868                 public override void FlowAnalysis (FlowAnalysisContext fc)
7869                 {
7870                         CheckStructThisDefiniteAssignment (fc);
7871                 }
7872
7873                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
7874                 {
7875                         if (ae == null)
7876                                 return null;
7877
7878                         AnonymousMethodStorey storey = ae.Storey;
7879                         return storey != null ? storey.HoistedThis : null;
7880                 }
7881
7882                 public static bool IsThisAvailable (ResolveContext ec, bool ignoreAnonymous)
7883                 {
7884                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope))
7885                                 return false;
7886
7887                         if (ignoreAnonymous || ec.CurrentAnonymousMethod == null)
7888                                 return true;
7889
7890                         if (ec.CurrentType.IsStruct && !(ec.CurrentAnonymousMethod is StateMachineInitializer))
7891                                 return false;
7892
7893                         return true;
7894                 }
7895
7896                 public virtual void ResolveBase (ResolveContext ec)
7897                 {
7898                         eclass = ExprClass.Variable;
7899                         type = ec.CurrentType;
7900
7901                         if (!IsThisAvailable (ec, false)) {
7902                                 Error_ThisNotAvailable (ec);
7903                                 return;
7904                         }
7905
7906                         var block = ec.CurrentBlock;
7907                         if (block != null) {
7908                                 var top = block.ParametersBlock.TopBlock;
7909                                 if (top.ThisVariable != null)
7910                                         variable_info = top.ThisVariable.VariableInfo;
7911
7912                                 AnonymousExpression am = ec.CurrentAnonymousMethod;
7913                                 if (am != null && ec.IsVariableCapturingRequired && !block.Explicit.HasCapturedThis) {
7914                                         //
7915                                         // Hoisted this is almost like hoisted variable but not exactly. When
7916                                         // there is no variable hoisted we can simply emit an instance method
7917                                         // without lifting this into a storey. Unfotunatelly this complicates
7918                                         // things in other cases because we don't know where this will be hoisted
7919                                         // until top-level block is fully resolved
7920                                         //
7921                                         top.AddThisReferenceFromChildrenBlock (block.Explicit);
7922                                         am.SetHasThisAccess ();
7923                                 }
7924                         }
7925                 }
7926
7927                 protected override Expression DoResolve (ResolveContext ec)
7928                 {
7929                         ResolveBase (ec);
7930                         return this;
7931                 }
7932
7933                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
7934                 {
7935                         if (eclass == ExprClass.Unresolved)
7936                                 ResolveBase (ec);
7937
7938                         if (type.IsClass){
7939                                 if (right_side == EmptyExpression.UnaryAddress)
7940                                         ec.Report.Error (459, loc, "Cannot take the address of `this' because it is read-only");
7941                                 else if (right_side == EmptyExpression.OutAccess)
7942                                         ec.Report.Error (1605, loc, "Cannot pass `this' as a ref or out argument because it is read-only");
7943                                 else
7944                                         ec.Report.Error (1604, loc, "Cannot assign to `this' because it is read-only");
7945                         }
7946
7947                         return this;
7948                 }
7949
7950                 public override int GetHashCode()
7951                 {
7952                         throw new NotImplementedException ();
7953                 }
7954
7955                 public override bool Equals (object obj)
7956                 {
7957                         This t = obj as This;
7958                         if (t == null)
7959                                 return false;
7960
7961                         return true;
7962                 }
7963
7964                 protected override void CloneTo (CloneContext clonectx, Expression t)
7965                 {
7966                         // Nothing
7967                 }
7968
7969                 public override void SetHasAddressTaken ()
7970                 {
7971                         // Nothing
7972                 }
7973
7974                 public override object Accept (StructuralVisitor visitor)
7975                 {
7976                         return visitor.Visit (this);
7977                 }
7978         }
7979
7980         /// <summary>
7981         ///   Represents the `__arglist' construct
7982         /// </summary>
7983         public class ArglistAccess : Expression
7984         {
7985                 public ArglistAccess (Location loc)
7986                 {
7987                         this.loc = loc;
7988                 }
7989
7990                 protected override void CloneTo (CloneContext clonectx, Expression target)
7991                 {
7992                         // nothing.
7993                 }
7994
7995                 public override bool ContainsEmitWithAwait ()
7996                 {
7997                         return false;
7998                 }
7999
8000                 public override Expression CreateExpressionTree (ResolveContext ec)
8001                 {
8002                         throw new NotSupportedException ("ET");
8003                 }
8004
8005                 protected override Expression DoResolve (ResolveContext ec)
8006                 {
8007                         eclass = ExprClass.Variable;
8008                         type = ec.Module.PredefinedTypes.RuntimeArgumentHandle.Resolve ();
8009
8010                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope) || !ec.CurrentBlock.ParametersBlock.Parameters.HasArglist) {
8011                                 ec.Report.Error (190, loc,
8012                                         "The __arglist construct is valid only within a variable argument method");
8013                         }
8014
8015                         return this;
8016                 }
8017
8018                 public override void Emit (EmitContext ec)
8019                 {
8020                         ec.Emit (OpCodes.Arglist);
8021                 }
8022
8023                 public override object Accept (StructuralVisitor visitor)
8024                 {
8025                         return visitor.Visit (this);
8026                 }
8027         }
8028
8029         /// <summary>
8030         ///   Represents the `__arglist (....)' construct
8031         /// </summary>
8032         public class Arglist : Expression
8033         {
8034                 Arguments arguments;
8035
8036                 public Arglist (Location loc)
8037                         : this (null, loc)
8038                 {
8039                 }
8040
8041                 public Arglist (Arguments args, Location l)
8042                 {
8043                         arguments = args;
8044                         loc = l;
8045                 }
8046
8047                 public Arguments Arguments {
8048                         get {
8049                                 return arguments;
8050                         }
8051                 }
8052
8053                 public MetaType[] ArgumentTypes {
8054                     get {
8055                                 if (arguments == null)
8056                                         return MetaType.EmptyTypes;
8057
8058                                 var retval = new MetaType[arguments.Count];
8059                                 for (int i = 0; i < retval.Length; i++)
8060                                         retval[i] = arguments[i].Expr.Type.GetMetaInfo ();
8061
8062                         return retval;
8063                     }
8064                 }
8065
8066                 public override bool ContainsEmitWithAwait ()
8067                 {
8068                         throw new NotImplementedException ();
8069                 }
8070
8071                 public override Expression CreateExpressionTree (ResolveContext ec)
8072                 {
8073                         ec.Report.Error (1952, loc, "An expression tree cannot contain a method with variable arguments");
8074                         return null;
8075                 }
8076
8077                 protected override Expression DoResolve (ResolveContext ec)
8078                 {
8079                         eclass = ExprClass.Variable;
8080                         type = InternalType.Arglist;
8081                         if (arguments != null) {
8082                                 bool dynamic;   // Can be ignored as there is always only 1 overload
8083                                 arguments.Resolve (ec, out dynamic);
8084                         }
8085
8086                         return this;
8087                 }
8088
8089                 public override void Emit (EmitContext ec)
8090                 {
8091                         if (arguments != null)
8092                                 arguments.Emit (ec);
8093                 }
8094
8095                 protected override void CloneTo (CloneContext clonectx, Expression t)
8096                 {
8097                         Arglist target = (Arglist) t;
8098
8099                         if (arguments != null)
8100                                 target.arguments = arguments.Clone (clonectx);
8101                 }
8102
8103                 public override object Accept (StructuralVisitor visitor)
8104                 {
8105                         return visitor.Visit (this);
8106                 }
8107         }
8108
8109         public class RefValueExpr : ShimExpression, IAssignMethod
8110         {
8111                 FullNamedExpression texpr;
8112
8113                 public RefValueExpr (Expression expr, FullNamedExpression texpr, Location loc)
8114                         : base (expr)
8115                 {
8116                         this.texpr = texpr;
8117                         this.loc = loc;
8118                 }
8119
8120                 public FullNamedExpression TypeExpression {
8121                         get {
8122                                 return texpr;
8123                         }
8124                 }
8125
8126                 public override bool ContainsEmitWithAwait ()
8127                 {
8128                         return false;
8129                 }
8130
8131                 protected override Expression DoResolve (ResolveContext rc)
8132                 {
8133                         expr = expr.Resolve (rc);
8134                         type = texpr.ResolveAsType (rc);
8135                         if (expr == null || type == null)
8136                                 return null;
8137
8138                         expr = Convert.ImplicitConversionRequired (rc, expr, rc.Module.PredefinedTypes.TypedReference.Resolve (), loc);
8139                         eclass = ExprClass.Value;
8140                         return this;
8141                 }
8142
8143                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
8144                 {
8145                         return DoResolve (rc);
8146                 }
8147
8148                 public override void Emit (EmitContext ec)
8149                 {
8150                         expr.Emit (ec);
8151                         ec.Emit (OpCodes.Refanyval, type);
8152                         ec.EmitLoadFromPtr (type);
8153                 }
8154
8155                 public void Emit (EmitContext ec, bool leave_copy)
8156                 {
8157                         throw new NotImplementedException ();
8158                 }
8159
8160                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
8161                 {
8162                         expr.Emit (ec);
8163                         ec.Emit (OpCodes.Refanyval, type);
8164                         source.Emit (ec);
8165
8166                         LocalTemporary temporary = null;
8167                         if (leave_copy) {
8168                                 ec.Emit (OpCodes.Dup);
8169                                 temporary = new LocalTemporary (source.Type);
8170                                 temporary.Store (ec);
8171                         }
8172
8173                         ec.EmitStoreFromPtr (type);
8174
8175                         if (temporary != null) {
8176                                 temporary.Emit (ec);
8177                                 temporary.Release (ec);
8178                         }
8179                 }
8180
8181                 public override object Accept (StructuralVisitor visitor)
8182                 {
8183                         return visitor.Visit (this);
8184                 }
8185         }
8186
8187         public class RefTypeExpr : ShimExpression
8188         {
8189                 public RefTypeExpr (Expression expr, Location loc)
8190                         : base (expr)
8191                 {
8192                         this.loc = loc;
8193                 }
8194
8195                 protected override Expression DoResolve (ResolveContext rc)
8196                 {
8197                         expr = expr.Resolve (rc);
8198                         if (expr == null)
8199                                 return null;
8200
8201                         expr = Convert.ImplicitConversionRequired (rc, expr, rc.Module.PredefinedTypes.TypedReference.Resolve (), loc);
8202                         if (expr == null)
8203                                 return null;
8204
8205                         type = rc.BuiltinTypes.Type;
8206                         eclass = ExprClass.Value;
8207                         return this;
8208                 }
8209
8210                 public override void Emit (EmitContext ec)
8211                 {
8212                         expr.Emit (ec);
8213                         ec.Emit (OpCodes.Refanytype);
8214                         var m = ec.Module.PredefinedMembers.TypeGetTypeFromHandle.Resolve (loc);
8215                         if (m != null)
8216                                 ec.Emit (OpCodes.Call, m);
8217                 }
8218
8219                 public override object Accept (StructuralVisitor visitor)
8220                 {
8221                         return visitor.Visit (this);
8222                 }
8223         }
8224
8225         public class MakeRefExpr : ShimExpression
8226         {
8227                 public MakeRefExpr (Expression expr, Location loc)
8228                         : base (expr)
8229                 {
8230                         this.loc = loc;
8231                 }
8232
8233                 public override bool ContainsEmitWithAwait ()
8234                 {
8235                         throw new NotImplementedException ();
8236                 }
8237
8238                 protected override Expression DoResolve (ResolveContext rc)
8239                 {
8240                         expr = expr.ResolveLValue (rc, EmptyExpression.LValueMemberAccess);
8241                         type = rc.Module.PredefinedTypes.TypedReference.Resolve ();
8242                         eclass = ExprClass.Value;
8243                         return this;
8244                 }
8245
8246                 public override void Emit (EmitContext ec)
8247                 {
8248                         ((IMemoryLocation) expr).AddressOf (ec, AddressOp.Load);
8249                         ec.Emit (OpCodes.Mkrefany, expr.Type);
8250                 }
8251
8252                 public override object Accept (StructuralVisitor visitor)
8253                 {
8254                         return visitor.Visit (this);
8255                 }
8256         }
8257
8258         /// <summary>
8259         ///   Implements the typeof operator
8260         /// </summary>
8261         public class TypeOf : Expression {
8262                 FullNamedExpression QueriedType;
8263                 TypeSpec typearg;
8264
8265                 public TypeOf (FullNamedExpression queried_type, Location l)
8266                 {
8267                         QueriedType = queried_type;
8268                         loc = l;
8269                 }
8270
8271                 //
8272                 // Use this constructor for any compiler generated typeof expression
8273                 //
8274                 public TypeOf (TypeSpec type, Location loc)
8275                 {
8276                         this.typearg = type;
8277                         this.loc = loc;
8278                 }
8279
8280                 #region Properties
8281
8282                 public override bool IsSideEffectFree {
8283                         get {
8284                                 return true;
8285                         }
8286                 }
8287
8288                 public TypeSpec TypeArgument {
8289                         get {
8290                                 return typearg;
8291                         }
8292                 }
8293
8294                 public FullNamedExpression TypeExpression {
8295                         get {
8296                                 return QueriedType;
8297                         }
8298                 }
8299
8300                 #endregion
8301
8302
8303                 protected override void CloneTo (CloneContext clonectx, Expression t)
8304                 {
8305                         TypeOf target = (TypeOf) t;
8306                         if (QueriedType != null)
8307                                 target.QueriedType = (FullNamedExpression) QueriedType.Clone (clonectx);
8308                 }
8309
8310                 public override bool ContainsEmitWithAwait ()
8311                 {
8312                         return false;
8313                 }
8314
8315                 public override Expression CreateExpressionTree (ResolveContext ec)
8316                 {
8317                         Arguments args = new Arguments (2);
8318                         args.Add (new Argument (this));
8319                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
8320                         return CreateExpressionFactoryCall (ec, "Constant", args);
8321                 }
8322
8323                 protected override Expression DoResolve (ResolveContext ec)
8324                 {
8325                         if (eclass != ExprClass.Unresolved)
8326                                 return this;
8327
8328                         if (typearg == null) {
8329                                 //
8330                                 // Pointer types are allowed without explicit unsafe, they are just tokens
8331                                 //
8332                                 using (ec.Set (ResolveContext.Options.UnsafeScope)) {
8333                                         typearg = QueriedType.ResolveAsType (ec);
8334                                 }
8335
8336                                 if (typearg == null)
8337                                         return null;
8338
8339                                 if (typearg.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
8340                                         ec.Report.Error (1962, QueriedType.Location,
8341                                                 "The typeof operator cannot be used on the dynamic type");
8342                                 }
8343                         }
8344
8345                         type = ec.BuiltinTypes.Type;
8346
8347                         // Even though what is returned is a type object, it's treated as a value by the compiler.
8348                         // In particular, 'typeof (Foo).X' is something totally different from 'Foo.X'.
8349                         eclass = ExprClass.Value;
8350                         return this;
8351                 }
8352
8353                 static bool ContainsDynamicType (TypeSpec type)
8354                 {
8355                         if (type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
8356                                 return true;
8357
8358                         var element_container = type as ElementTypeSpec;
8359                         if (element_container != null)
8360                                 return ContainsDynamicType (element_container.Element);
8361
8362                         foreach (var t in type.TypeArguments) {
8363                                 if (ContainsDynamicType (t)) {
8364                                         return true;
8365                                 }
8366                         }
8367
8368                         return false;
8369                 }
8370
8371                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
8372                 {
8373                         // Target type is not System.Type therefore must be object
8374                         // and we need to use different encoding sequence
8375                         if (targetType != type)
8376                                 enc.Encode (type);
8377
8378                         if (typearg is InflatedTypeSpec) {
8379                                 var gt = typearg;
8380                                 do {
8381                                         if (InflatedTypeSpec.ContainsTypeParameter (gt)) {
8382                                                 rc.Module.Compiler.Report.Error (416, loc, "`{0}': an attribute argument cannot use type parameters",
8383                                                         typearg.GetSignatureForError ());
8384                                                 return;
8385                                         }
8386
8387                                         gt = gt.DeclaringType;
8388                                 } while (gt != null);
8389                         }
8390
8391                         if (ContainsDynamicType (typearg)) {
8392                                 Attribute.Error_AttributeArgumentIsDynamic (rc, loc);
8393                                 return;
8394                         }
8395
8396                         enc.EncodeTypeName (typearg);
8397                 }
8398
8399                 public override void Emit (EmitContext ec)
8400                 {
8401                         ec.Emit (OpCodes.Ldtoken, typearg);
8402                         var m = ec.Module.PredefinedMembers.TypeGetTypeFromHandle.Resolve (loc);
8403                         if (m != null)
8404                                 ec.Emit (OpCodes.Call, m);
8405                 }
8406
8407                 public override object Accept (StructuralVisitor visitor)
8408                 {
8409                         return visitor.Visit (this);
8410                 }
8411         }
8412
8413         sealed class TypeOfMethod : TypeOfMember<MethodSpec>
8414         {
8415                 public TypeOfMethod (MethodSpec method, Location loc)
8416                         : base (method, loc)
8417                 {
8418                 }
8419
8420                 protected override Expression DoResolve (ResolveContext ec)
8421                 {
8422                         if (member.IsConstructor) {
8423                                 type = ec.Module.PredefinedTypes.ConstructorInfo.Resolve ();
8424                         } else {
8425                                 type = ec.Module.PredefinedTypes.MethodInfo.Resolve ();
8426                         }
8427
8428                         if (type == null)
8429                                 return null;
8430
8431                         return base.DoResolve (ec);
8432                 }
8433
8434                 public override void Emit (EmitContext ec)
8435                 {
8436                         ec.Emit (OpCodes.Ldtoken, member);
8437
8438                         base.Emit (ec);
8439                         ec.Emit (OpCodes.Castclass, type);
8440                 }
8441
8442                 protected override PredefinedMember<MethodSpec> GetTypeFromHandle (EmitContext ec)
8443                 {
8444                         return ec.Module.PredefinedMembers.MethodInfoGetMethodFromHandle;
8445                 }
8446
8447                 protected override PredefinedMember<MethodSpec> GetTypeFromHandleGeneric (EmitContext ec)
8448                 {
8449                         return ec.Module.PredefinedMembers.MethodInfoGetMethodFromHandle2;
8450                 }
8451         }
8452
8453         abstract class TypeOfMember<T> : Expression where T : MemberSpec
8454         {
8455                 protected readonly T member;
8456
8457                 protected TypeOfMember (T member, Location loc)
8458                 {
8459                         this.member = member;
8460                         this.loc = loc;
8461                 }
8462
8463                 public override bool IsSideEffectFree {
8464                         get {
8465                                 return true;
8466                         }
8467                 }
8468
8469                 public override bool ContainsEmitWithAwait ()
8470                 {
8471                         return false;
8472                 }
8473
8474                 public override Expression CreateExpressionTree (ResolveContext ec)
8475                 {
8476                         Arguments args = new Arguments (2);
8477                         args.Add (new Argument (this));
8478                         args.Add (new Argument (new TypeOf (type, loc)));
8479                         return CreateExpressionFactoryCall (ec, "Constant", args);
8480                 }
8481
8482                 protected override Expression DoResolve (ResolveContext ec)
8483                 {
8484                         eclass = ExprClass.Value;
8485                         return this;
8486                 }
8487
8488                 public override void Emit (EmitContext ec)
8489                 {
8490                         bool is_generic = member.DeclaringType.IsGenericOrParentIsGeneric;
8491                         PredefinedMember<MethodSpec> p;
8492                         if (is_generic) {
8493                                 p = GetTypeFromHandleGeneric (ec);
8494                                 ec.Emit (OpCodes.Ldtoken, member.DeclaringType);
8495                         } else {
8496                                 p = GetTypeFromHandle (ec);
8497                         }
8498
8499                         var mi = p.Resolve (loc);
8500                         if (mi != null)
8501                                 ec.Emit (OpCodes.Call, mi);
8502                 }
8503
8504                 protected abstract PredefinedMember<MethodSpec> GetTypeFromHandle (EmitContext ec);
8505                 protected abstract PredefinedMember<MethodSpec> GetTypeFromHandleGeneric (EmitContext ec);
8506         }
8507
8508         sealed class TypeOfField : TypeOfMember<FieldSpec>
8509         {
8510                 public TypeOfField (FieldSpec field, Location loc)
8511                         : base (field, loc)
8512                 {
8513                 }
8514
8515                 protected override Expression DoResolve (ResolveContext ec)
8516                 {
8517                         type = ec.Module.PredefinedTypes.FieldInfo.Resolve ();
8518                         if (type == null)
8519                                 return null;
8520
8521                         return base.DoResolve (ec);
8522                 }
8523
8524                 public override void Emit (EmitContext ec)
8525                 {
8526                         ec.Emit (OpCodes.Ldtoken, member);
8527                         base.Emit (ec);
8528                 }
8529
8530                 protected override PredefinedMember<MethodSpec> GetTypeFromHandle (EmitContext ec)
8531                 {
8532                         return ec.Module.PredefinedMembers.FieldInfoGetFieldFromHandle;
8533                 }
8534
8535                 protected override PredefinedMember<MethodSpec> GetTypeFromHandleGeneric (EmitContext ec)
8536                 {
8537                         return ec.Module.PredefinedMembers.FieldInfoGetFieldFromHandle2;
8538                 }
8539         }
8540
8541         /// <summary>
8542         ///   Implements the sizeof expression
8543         /// </summary>
8544         public class SizeOf : Expression {
8545                 readonly Expression texpr;
8546                 TypeSpec type_queried;
8547
8548                 public SizeOf (Expression queried_type, Location l)
8549                 {
8550                         this.texpr = queried_type;
8551                         loc = l;
8552                 }
8553
8554                 public override bool IsSideEffectFree {
8555                         get {
8556                                 return true;
8557                         }
8558                 }
8559
8560                 public Expression TypeExpression {
8561                         get {
8562                                 return texpr;
8563                         }
8564                 }
8565
8566                 public override bool ContainsEmitWithAwait ()
8567                 {
8568                         return false;
8569                 }
8570
8571                 public override Expression CreateExpressionTree (ResolveContext ec)
8572                 {
8573                         Error_PointerInsideExpressionTree (ec);
8574                         return null;
8575                 }
8576
8577                 protected override Expression DoResolve (ResolveContext ec)
8578                 {
8579                         type_queried = texpr.ResolveAsType (ec);
8580                         if (type_queried == null)
8581                                 return null;
8582
8583                         if (type_queried.IsEnum)
8584                                 type_queried = EnumSpec.GetUnderlyingType (type_queried);
8585
8586                         int size_of = BuiltinTypeSpec.GetSize (type_queried);
8587                         if (size_of > 0) {
8588                                 return new IntConstant (ec.BuiltinTypes, size_of, loc);
8589                         }
8590
8591                         if (!TypeManager.VerifyUnmanaged (ec.Module, type_queried, loc)){
8592                                 return null;
8593                         }
8594
8595                         if (!ec.IsUnsafe) {
8596                                 ec.Report.Error (233, loc,
8597                                         "`{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
8598                                         type_queried.GetSignatureForError ());
8599                         }
8600
8601                         type = ec.BuiltinTypes.Int;
8602                         eclass = ExprClass.Value;
8603                         return this;
8604                 }
8605
8606                 public override void Emit (EmitContext ec)
8607                 {
8608                         ec.Emit (OpCodes.Sizeof, type_queried);
8609                 }
8610
8611                 protected override void CloneTo (CloneContext clonectx, Expression t)
8612                 {
8613                 }
8614
8615                 public override object Accept (StructuralVisitor visitor)
8616                 {
8617                         return visitor.Visit (this);
8618                 }
8619         }
8620
8621         /// <summary>
8622         ///   Implements the qualified-alias-member (::) expression.
8623         /// </summary>
8624         public class QualifiedAliasMember : MemberAccess
8625         {
8626                 readonly string alias;
8627                 public static readonly string GlobalAlias = "global";
8628
8629                 public QualifiedAliasMember (string alias, string identifier, Location l)
8630                         : base (null, identifier, l)
8631                 {
8632                         this.alias = alias;
8633                 }
8634
8635                 public QualifiedAliasMember (string alias, string identifier, TypeArguments targs, Location l)
8636                         : base (null, identifier, targs, l)
8637                 {
8638                         this.alias = alias;
8639                 }
8640
8641                 public QualifiedAliasMember (string alias, string identifier, int arity, Location l)
8642                         : base (null, identifier, arity, l)
8643                 {
8644                         this.alias = alias;
8645                 }
8646
8647                 public string Alias {
8648                         get {
8649                                 return alias;
8650                         }
8651                 }
8652
8653                 public override FullNamedExpression ResolveAsTypeOrNamespace (IMemberContext ec)
8654                 {
8655                         if (alias == GlobalAlias) {
8656                                 expr = new NamespaceExpression (ec.Module.GlobalRootNamespace, loc);
8657                                 return base.ResolveAsTypeOrNamespace (ec);
8658                         }
8659
8660                         int errors = ec.Module.Compiler.Report.Errors;
8661                         expr = ec.LookupNamespaceAlias (alias);
8662                         if (expr == null) {
8663                                 if (errors == ec.Module.Compiler.Report.Errors)
8664                                         ec.Module.Compiler.Report.Error (432, loc, "Alias `{0}' not found", alias);
8665                                 return null;
8666                         }
8667
8668                         return base.ResolveAsTypeOrNamespace (ec);
8669                 }
8670
8671                 protected override Expression DoResolve (ResolveContext ec)
8672                 {
8673                         return ResolveAsTypeOrNamespace (ec);
8674                 }
8675
8676                 public override string GetSignatureForError ()
8677                 {
8678                         string name = Name;
8679                         if (targs != null) {
8680                                 name = Name + "<" + targs.GetSignatureForError () + ">";
8681                         }
8682
8683                         return alias + "::" + name;
8684                 }
8685
8686                 public override Expression LookupNameExpression (ResolveContext rc, MemberLookupRestrictions restrictions)
8687                 {
8688                         if ((restrictions & MemberLookupRestrictions.InvocableOnly) != 0) {
8689                                 rc.Module.Compiler.Report.Error (687, loc,
8690                                         "The namespace alias qualifier `::' cannot be used to invoke a method. Consider using `.' instead",
8691                                         GetSignatureForError ());
8692
8693                                 return null;
8694                         }
8695
8696                         return DoResolve (rc);
8697                 }
8698
8699                 protected override void CloneTo (CloneContext clonectx, Expression t)
8700                 {
8701                         // Nothing
8702                 }
8703
8704                 public override object Accept (StructuralVisitor visitor)
8705                 {
8706                         return visitor.Visit (this);
8707                 }
8708         }
8709
8710         /// <summary>
8711         ///   Implements the member access expression
8712         /// </summary>
8713         public class MemberAccess : ATypeNameExpression
8714         {
8715                 protected Expression expr;
8716
8717                 public MemberAccess (Expression expr, string id)
8718                         : base (id, expr.Location)
8719                 {
8720                         this.expr = expr;
8721                 }
8722
8723                 public MemberAccess (Expression expr, string identifier, Location loc)
8724                         : base (identifier, loc)
8725                 {
8726                         this.expr = expr;
8727                 }
8728
8729                 public MemberAccess (Expression expr, string identifier, TypeArguments args, Location loc)
8730                         : base (identifier, args, loc)
8731                 {
8732                         this.expr = expr;
8733                 }
8734
8735                 public MemberAccess (Expression expr, string identifier, int arity, Location loc)
8736                         : base (identifier, arity, loc)
8737                 {
8738                         this.expr = expr;
8739                 }
8740
8741                 public Expression LeftExpression {
8742                         get {
8743                                 return expr;
8744                         }
8745                 }
8746
8747                 public override Location StartLocation {
8748                         get {
8749                                 return expr == null ? loc : expr.StartLocation;
8750                         }
8751                 }
8752
8753                 protected override Expression DoResolve (ResolveContext rc)
8754                 {
8755                         var e = LookupNameExpression (rc, MemberLookupRestrictions.ReadAccess);
8756                         if (e != null)
8757                                 e = e.Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.Type | ResolveFlags.MethodGroup);
8758
8759                         return e;
8760                 }
8761
8762                 public override Expression DoResolveLValue (ResolveContext rc, Expression rhs)
8763                 {
8764                         var e = LookupNameExpression (rc, MemberLookupRestrictions.None);
8765
8766                         if (e is TypeExpr) {
8767                                 e.Error_UnexpectedKind (rc, ResolveFlags.VariableOrValue, loc);
8768                                 return null;
8769                         }
8770
8771                         if (e != null)
8772                                 e = e.ResolveLValue (rc, rhs);
8773
8774                         return e;
8775                 }
8776
8777                 protected virtual void Error_OperatorCannotBeApplied (ResolveContext rc, TypeSpec type)
8778                 {
8779                         if (type == InternalType.NullLiteral && rc.IsRuntimeBinder)
8780                                 rc.Report.Error (Report.RuntimeErrorId, loc, "Cannot perform member binding on `null' value");
8781                         else
8782                                 expr.Error_OperatorCannotBeApplied (rc, loc, ".", type);
8783                 }
8784
8785                 public static bool IsValidDotExpression (TypeSpec type)
8786                 {
8787                         const MemberKind dot_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.Delegate | MemberKind.Enum |
8788                                 MemberKind.Interface | MemberKind.TypeParameter | MemberKind.ArrayType;
8789
8790                         return (type.Kind & dot_kinds) != 0 || type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
8791                 }
8792
8793                 public override Expression LookupNameExpression (ResolveContext rc, MemberLookupRestrictions restrictions)
8794                 {
8795                         var sn = expr as SimpleName;
8796                         const ResolveFlags flags = ResolveFlags.VariableOrValue | ResolveFlags.Type;
8797
8798                         if (sn != null) {
8799                                 expr = sn.LookupNameExpression (rc, MemberLookupRestrictions.ReadAccess | MemberLookupRestrictions.ExactArity);
8800
8801                                 //
8802                                 // Resolve expression which does have type set as we need expression type
8803                                 // with disable flow analysis as we don't know whether left side expression
8804                                 // is used as variable or type
8805                                 //
8806                                 if (expr is VariableReference || expr is ConstantExpr || expr is Linq.TransparentMemberAccess) {
8807                                         expr = expr.Resolve (rc);
8808                                 } else if (expr is TypeParameterExpr) {
8809                                         expr.Error_UnexpectedKind (rc, flags, sn.Location);
8810                                         expr = null;
8811                                 }
8812                         } else {
8813                                 expr = expr.Resolve (rc, flags);
8814                         }
8815
8816                         if (expr == null)
8817                                 return null;
8818
8819                         var ns = expr as NamespaceExpression;
8820                         if (ns != null) {
8821                                 var retval = ns.LookupTypeOrNamespace (rc, Name, Arity, LookupMode.Normal, loc);
8822
8823                                 if (retval == null) {
8824                                         ns.Error_NamespaceDoesNotExist (rc, Name, Arity);
8825                                         return null;
8826                                 }
8827
8828                                 if (HasTypeArguments)
8829                                         return new GenericTypeExpr (retval.Type, targs, loc);
8830
8831                                 return retval;
8832                         }
8833
8834                         MemberExpr me;
8835                         TypeSpec expr_type = expr.Type;
8836                         if (expr_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
8837                                 me = expr as MemberExpr;
8838                                 if (me != null)
8839                                         me.ResolveInstanceExpression (rc, null);
8840
8841                                 Arguments args = new Arguments (1);
8842                                 args.Add (new Argument (expr));
8843                                 return new DynamicMemberBinder (Name, args, loc);
8844                         }
8845
8846                         if (!IsValidDotExpression (expr_type)) {
8847                                 Error_OperatorCannotBeApplied (rc, expr_type);
8848                                 return null;
8849                         }
8850
8851                         var lookup_arity = Arity;
8852                         bool errorMode = false;
8853                         Expression member_lookup;
8854                         while (true) {
8855                                 member_lookup = MemberLookup (rc, errorMode, expr_type, Name, lookup_arity, restrictions, loc);
8856                                 if (member_lookup == null) {
8857                                         //
8858                                         // Try to look for extension method when member lookup failed
8859                                         //
8860                                         if (MethodGroupExpr.IsExtensionMethodArgument (expr)) {
8861                                                 var methods = rc.LookupExtensionMethod (expr_type, Name, lookup_arity);
8862                                                 if (methods != null) {
8863                                                         var emg = new ExtensionMethodGroupExpr (methods, expr, loc);
8864                                                         if (HasTypeArguments) {
8865                                                                 if (!targs.Resolve (rc))
8866                                                                         return null;
8867
8868                                                                 emg.SetTypeArguments (rc, targs);
8869                                                         }
8870
8871                                                         // TODO: it should really skip the checks bellow
8872                                                         return emg.Resolve (rc);
8873                                                 }
8874                                         }
8875                                 }
8876
8877                                 if (errorMode) {
8878                                         if (member_lookup == null) {
8879                                                 var dep = expr_type.GetMissingDependencies ();
8880                                                 if (dep != null) {
8881                                                         ImportedTypeDefinition.Error_MissingDependency (rc, dep, loc);
8882                                                 } else if (expr is TypeExpr) {
8883                                                         base.Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
8884                                                 } else {
8885                                                         Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
8886                                                 }
8887
8888                                                 return null;
8889                                         }
8890
8891                                         if (member_lookup is MethodGroupExpr || member_lookup is PropertyExpr) {
8892                                                 // Leave it to overload resolution to report correct error
8893                                         } else if (!(member_lookup is TypeExpr)) {
8894                                                 // TODO: rc.SymbolRelatedToPreviousError
8895                                                 ErrorIsInaccesible (rc, member_lookup.GetSignatureForError (), loc);
8896                                         }
8897                                         break;
8898                                 }
8899
8900                                 if (member_lookup != null)
8901                                         break;
8902
8903                                 lookup_arity = 0;
8904                                 restrictions &= ~MemberLookupRestrictions.InvocableOnly;
8905                                 errorMode = true;
8906                         }
8907
8908                         TypeExpr texpr = member_lookup as TypeExpr;
8909                         if (texpr != null) {
8910                                 if (!(expr is TypeExpr) && (sn == null || expr.ProbeIdenticalTypeName (rc, expr, sn) == expr)) {
8911                                         rc.Report.Error (572, loc, "`{0}': cannot reference a type through an expression. Consider using `{1}' instead",
8912                                                 Name, texpr.GetSignatureForError ());
8913                                 }
8914
8915                                 if (!texpr.Type.IsAccessible (rc)) {
8916                                         rc.Report.SymbolRelatedToPreviousError (member_lookup.Type);
8917                                         ErrorIsInaccesible (rc, member_lookup.Type.GetSignatureForError (), loc);
8918                                         return null;
8919                                 }
8920
8921                                 if (HasTypeArguments) {
8922                                         return new GenericTypeExpr (member_lookup.Type, targs, loc);
8923                                 }
8924
8925                                 return member_lookup;
8926                         }
8927
8928                         me = member_lookup as MemberExpr;
8929
8930                         if (sn != null && me.IsStatic && (expr = me.ProbeIdenticalTypeName (rc, expr, sn)) != expr) {
8931                                 sn = null;
8932                         }
8933
8934                         me = me.ResolveMemberAccess (rc, expr, sn);
8935
8936                         if (Arity > 0) {
8937                                 if (!targs.Resolve (rc))
8938                                         return null;
8939
8940                                 me.SetTypeArguments (rc, targs);
8941                         }
8942
8943                         return me;
8944                 }
8945
8946                 public override FullNamedExpression ResolveAsTypeOrNamespace (IMemberContext rc)
8947                 {
8948                         FullNamedExpression fexpr = expr as FullNamedExpression;
8949                         if (fexpr == null) {
8950                                 expr.ResolveAsType (rc);
8951                                 return null;
8952                         }
8953
8954                         FullNamedExpression expr_resolved = fexpr.ResolveAsTypeOrNamespace (rc);
8955
8956                         if (expr_resolved == null)
8957                                 return null;
8958
8959                         var ns = expr_resolved as NamespaceExpression;
8960                         if (ns != null) {
8961                                 FullNamedExpression retval = ns.LookupTypeOrNamespace (rc, Name, Arity, LookupMode.Normal, loc);
8962
8963                                 if (retval == null) {
8964                                         ns.Error_NamespaceDoesNotExist (rc, Name, Arity);
8965                                 } else if (HasTypeArguments) {
8966                                         retval = new GenericTypeExpr (retval.Type, targs, loc);
8967                                         if (retval.ResolveAsType (rc) == null)
8968                                                 return null;
8969                                 }
8970
8971                                 return retval;
8972                         }
8973
8974                         var tnew_expr = expr_resolved.ResolveAsType (rc);
8975                         if (tnew_expr == null)
8976                                 return null;
8977
8978                         TypeSpec expr_type = tnew_expr;
8979                         if (TypeManager.IsGenericParameter (expr_type)) {
8980                                 rc.Module.Compiler.Report.Error (704, loc, "A nested type cannot be specified through a type parameter `{0}'",
8981                                         tnew_expr.GetSignatureForError ());
8982                                 return null;
8983                         }
8984
8985                         var qam = this as QualifiedAliasMember;
8986                         if (qam != null) {
8987                                 rc.Module.Compiler.Report.Error (431, loc,
8988                                         "Alias `{0}' cannot be used with `::' since it denotes a type. Consider replacing `::' with `.'",
8989                                         qam.Alias);
8990
8991                         }
8992
8993                         TypeSpec nested = null;
8994                         while (expr_type != null) {
8995                                 nested = MemberCache.FindNestedType (expr_type, Name, Arity);
8996                                 if (nested == null) {
8997                                         if (expr_type == tnew_expr) {
8998                                                 Error_IdentifierNotFound (rc, expr_type, Name);
8999                                                 return null;
9000                                         }
9001
9002                                         expr_type = tnew_expr;
9003                                         nested = MemberCache.FindNestedType (expr_type, Name, Arity);
9004                                         ErrorIsInaccesible (rc, nested.GetSignatureForError (), loc);
9005                                         break;
9006                                 }
9007
9008                                 if (nested.IsAccessible (rc))
9009                                         break;
9010
9011                                 //
9012                                 // Keep looking after inaccessible candidate but only if
9013                                 // we are not in same context as the definition itself
9014                                 //
9015                                 if (expr_type.MemberDefinition == rc.CurrentMemberDefinition)
9016                                         break;
9017
9018                                 expr_type = expr_type.BaseType;
9019                         }
9020
9021                         TypeExpr texpr;
9022                         if (Arity > 0) {
9023                                 if (HasTypeArguments) {
9024                                         texpr = new GenericTypeExpr (nested, targs, loc);
9025                                 } else {
9026                                         texpr = new GenericOpenTypeExpr (nested, loc);
9027                                 }
9028                         } else {
9029                                 texpr = new TypeExpression (nested, loc);
9030                         }
9031
9032                         if (texpr.ResolveAsType (rc) == null)
9033                                 return null;
9034
9035                         return texpr;
9036                 }
9037
9038                 protected virtual void Error_IdentifierNotFound (IMemberContext rc, TypeSpec expr_type, string identifier)
9039                 {
9040                         var nested = MemberCache.FindNestedType (expr_type, Name, -System.Math.Max (1, Arity));
9041
9042                         if (nested != null) {
9043                                 Error_TypeArgumentsCannotBeUsed (rc, nested, expr.Location);
9044                                 return;
9045                         }
9046
9047                         var any_other_member = MemberLookup (rc, false, expr_type, Name, 0, MemberLookupRestrictions.None, loc);
9048                         if (any_other_member != null) {
9049                                 Error_UnexpectedKind (rc, any_other_member, "type", any_other_member.ExprClassName, loc);
9050                                 return;
9051                         }
9052
9053                         rc.Module.Compiler.Report.Error (426, loc, "The nested type `{0}' does not exist in the type `{1}'",
9054                                 Name, expr_type.GetSignatureForError ());
9055                 }
9056
9057                 protected override void Error_InvalidExpressionStatement (Report report, Location loc)
9058                 {
9059                         base.Error_InvalidExpressionStatement (report, LeftExpression.Location);
9060                 }
9061
9062                 protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
9063                 {
9064                         if (ec.Module.Compiler.Settings.Version > LanguageVersion.ISO_2 && !ec.IsRuntimeBinder && MethodGroupExpr.IsExtensionMethodArgument (expr)) {
9065                                 ec.Report.SymbolRelatedToPreviousError (type);
9066
9067                                 var cand = ec.Module.GlobalRootNamespace.FindExtensionMethodNamespaces (ec, name, Arity);
9068                                 string missing;
9069                                 // a using directive or an assembly reference
9070                                 if (cand != null) {
9071                                         missing = "`" + string.Join ("' or `", cand.ToArray ()) + "' using directive";
9072                                 } else {
9073                                         missing = "an assembly reference";
9074                                 }
9075
9076                                 ec.Report.Error (1061, loc,
9077                                         "Type `{0}' does not contain a definition for `{1}' and no extension method `{1}' of type `{0}' could be found. Are you missing {2}?",
9078                                         type.GetSignatureForError (), name, missing);
9079                                 return;
9080                         }
9081
9082                         base.Error_TypeDoesNotContainDefinition (ec, type, name);
9083                 }
9084
9085                 public override string GetSignatureForError ()
9086                 {
9087                         return expr.GetSignatureForError () + "." + base.GetSignatureForError ();
9088                 }
9089
9090                 protected override void CloneTo (CloneContext clonectx, Expression t)
9091                 {
9092                         MemberAccess target = (MemberAccess) t;
9093
9094                         target.expr = expr.Clone (clonectx);
9095                 }
9096
9097                 public override object Accept (StructuralVisitor visitor)
9098                 {
9099                         return visitor.Visit (this);
9100                 }
9101         }
9102
9103         /// <summary>
9104         ///   Implements checked expressions
9105         /// </summary>
9106         public class CheckedExpr : Expression {
9107
9108                 public Expression Expr;
9109
9110                 public CheckedExpr (Expression e, Location l)
9111                 {
9112                         Expr = e;
9113                         loc = l;
9114                 }
9115
9116                 public override bool ContainsEmitWithAwait ()
9117                 {
9118                         return Expr.ContainsEmitWithAwait ();
9119                 }
9120
9121                 public override Expression CreateExpressionTree (ResolveContext ec)
9122                 {
9123                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
9124                                 return Expr.CreateExpressionTree (ec);
9125                 }
9126
9127                 protected override Expression DoResolve (ResolveContext ec)
9128                 {
9129                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
9130                                 Expr = Expr.Resolve (ec);
9131
9132                         if (Expr == null)
9133                                 return null;
9134
9135                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
9136                                 return Expr;
9137
9138                         eclass = Expr.eclass;
9139                         type = Expr.Type;
9140                         return this;
9141                 }
9142
9143                 public override void Emit (EmitContext ec)
9144                 {
9145                         using (ec.With (EmitContext.Options.CheckedScope, true))
9146                                 Expr.Emit (ec);
9147                 }
9148
9149                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
9150                 {
9151                         using (ec.With (EmitContext.Options.CheckedScope, true))
9152                                 Expr.EmitBranchable (ec, target, on_true);
9153                 }
9154
9155                 public override void FlowAnalysis (FlowAnalysisContext fc)
9156                 {
9157                         Expr.FlowAnalysis (fc);
9158                 }
9159
9160                 public override SLE.Expression MakeExpression (BuilderContext ctx)
9161                 {
9162                         using (ctx.With (BuilderContext.Options.CheckedScope, true)) {
9163                                 return Expr.MakeExpression (ctx);
9164                         }
9165                 }
9166
9167                 protected override void CloneTo (CloneContext clonectx, Expression t)
9168                 {
9169                         CheckedExpr target = (CheckedExpr) t;
9170
9171                         target.Expr = Expr.Clone (clonectx);
9172                 }
9173
9174                 public override object Accept (StructuralVisitor visitor)
9175                 {
9176                         return visitor.Visit (this);
9177                 }
9178         }
9179
9180         /// <summary>
9181         ///   Implements the unchecked expression
9182         /// </summary>
9183         public class UnCheckedExpr : Expression {
9184
9185                 public Expression Expr;
9186
9187                 public UnCheckedExpr (Expression e, Location l)
9188                 {
9189                         Expr = e;
9190                         loc = l;
9191                 }
9192
9193                 public override bool ContainsEmitWithAwait ()
9194                 {
9195                         return Expr.ContainsEmitWithAwait ();
9196                 }
9197
9198                 public override Expression CreateExpressionTree (ResolveContext ec)
9199                 {
9200                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
9201                                 return Expr.CreateExpressionTree (ec);
9202                 }
9203
9204                 protected override Expression DoResolve (ResolveContext ec)
9205                 {
9206                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
9207                                 Expr = Expr.Resolve (ec);
9208
9209                         if (Expr == null)
9210                                 return null;
9211
9212                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
9213                                 return Expr;
9214
9215                         eclass = Expr.eclass;
9216                         type = Expr.Type;
9217                         return this;
9218                 }
9219
9220                 public override void Emit (EmitContext ec)
9221                 {
9222                         using (ec.With (EmitContext.Options.CheckedScope, false))
9223                                 Expr.Emit (ec);
9224                 }
9225
9226                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
9227                 {
9228                         using (ec.With (EmitContext.Options.CheckedScope, false))
9229                                 Expr.EmitBranchable (ec, target, on_true);
9230                 }
9231
9232                 public override void FlowAnalysis (FlowAnalysisContext fc)
9233                 {
9234                         Expr.FlowAnalysis (fc);
9235                 }
9236
9237                 protected override void CloneTo (CloneContext clonectx, Expression t)
9238                 {
9239                         UnCheckedExpr target = (UnCheckedExpr) t;
9240
9241                         target.Expr = Expr.Clone (clonectx);
9242                 }
9243
9244                 public override object Accept (StructuralVisitor visitor)
9245                 {
9246                         return visitor.Visit (this);
9247                 }
9248         }
9249
9250         /// <summary>
9251         ///   An Element Access expression.
9252         ///
9253         ///   During semantic analysis these are transformed into
9254         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
9255         /// </summary>
9256         public class ElementAccess : Expression
9257         {
9258                 public Arguments Arguments;
9259                 public Expression Expr;
9260
9261                 public ElementAccess (Expression e, Arguments args, Location loc)
9262                 {
9263                         Expr = e;
9264                         this.loc = loc;
9265                         this.Arguments = args;
9266                 }
9267
9268                 public override Location StartLocation {
9269                         get {
9270                                 return Expr.StartLocation;
9271                         }
9272                 }
9273
9274                 public override bool ContainsEmitWithAwait ()
9275                 {
9276                         return Expr.ContainsEmitWithAwait () || Arguments.ContainsEmitWithAwait ();
9277                 }
9278
9279                 //
9280                 // We perform some simple tests, and then to "split" the emit and store
9281                 // code we create an instance of a different class, and return that.
9282                 //
9283                 Expression CreateAccessExpression (ResolveContext ec)
9284                 {
9285                         if (type.IsArray)
9286                                 return (new ArrayAccess (this, loc));
9287
9288                         if (type.IsPointer)
9289                                 return MakePointerAccess (ec, type);
9290
9291                         FieldExpr fe = Expr as FieldExpr;
9292                         if (fe != null) {
9293                                 var ff = fe.Spec as FixedFieldSpec;
9294                                 if (ff != null) {
9295                                         return MakePointerAccess (ec, ff.ElementType);
9296                                 }
9297                         }
9298
9299                         var indexers = MemberCache.FindMembers (type, MemberCache.IndexerNameAlias, false);
9300                         if (indexers != null || type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
9301                                 return new IndexerExpr (indexers, type, this);
9302                         }
9303
9304                         if (type != InternalType.ErrorType) {
9305                                 ec.Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
9306                                         type.GetSignatureForError ());
9307                         }
9308
9309                         return null;
9310                 }
9311
9312                 public override Expression CreateExpressionTree (ResolveContext ec)
9313                 {
9314                         Arguments args = Arguments.CreateForExpressionTree (ec, Arguments,
9315                                 Expr.CreateExpressionTree (ec));
9316
9317                         return CreateExpressionFactoryCall (ec, "ArrayIndex", args);
9318                 }
9319
9320                 Expression MakePointerAccess (ResolveContext rc, TypeSpec type)
9321                 {
9322                         if (Arguments.Count != 1){
9323                                 rc.Report.Error (196, loc, "A pointer must be indexed by only one value");
9324                                 return null;
9325                         }
9326
9327                         var arg = Arguments[0];
9328                         if (arg is NamedArgument)
9329                                 Error_NamedArgument ((NamedArgument) arg, rc.Report);
9330
9331                         var index = arg.Expr.Resolve (rc);
9332                         if (index == null)
9333                                 return null;
9334
9335                         index = ConvertExpressionToArrayIndex (rc, index, true);
9336
9337                         Expression p = new PointerArithmetic (Binary.Operator.Addition, Expr, index, type, loc);
9338                         return new Indirection (p, loc);
9339                 }
9340
9341                 protected override Expression DoResolve (ResolveContext ec)
9342                 {
9343                         Expr = Expr.Resolve (ec);
9344                         if (Expr == null)
9345                                 return null;
9346
9347                         type = Expr.Type;
9348
9349                         // TODO: Create 1 result for Resolve and ResolveLValue ?
9350                         var res = CreateAccessExpression (ec);
9351                         if (res == null)
9352                                 return null;
9353
9354                         return res.Resolve (ec);
9355                 }
9356
9357                 public override Expression DoResolveLValue (ResolveContext ec, Expression rhs)
9358                 {
9359                         Expr = Expr.Resolve (ec);
9360                         if (Expr == null)
9361                                 return null;
9362
9363                         type = Expr.Type;
9364
9365                         var res = CreateAccessExpression (ec);
9366                         if (res == null)
9367                                 return null;
9368
9369                         return res.ResolveLValue (ec, rhs);
9370                 }
9371
9372                 public override void Emit (EmitContext ec)
9373                 {
9374                         throw new Exception ("Should never be reached");
9375                 }
9376
9377                 public static void Error_NamedArgument (NamedArgument na, Report Report)
9378                 {
9379                         Report.Error (1742, na.Location, "An element access expression cannot use named argument");
9380                 }
9381
9382                 public override void FlowAnalysis (FlowAnalysisContext fc)
9383                 {
9384                         Expr.FlowAnalysis (fc);
9385                         Arguments.FlowAnalysis (fc);
9386                 }
9387
9388                 public override string GetSignatureForError ()
9389                 {
9390                         return Expr.GetSignatureForError ();
9391                 }
9392
9393                 protected override void CloneTo (CloneContext clonectx, Expression t)
9394                 {
9395                         ElementAccess target = (ElementAccess) t;
9396
9397                         target.Expr = Expr.Clone (clonectx);
9398                         if (Arguments != null)
9399                                 target.Arguments = Arguments.Clone (clonectx);
9400                 }
9401
9402                 public override object Accept (StructuralVisitor visitor)
9403                 {
9404                         return visitor.Visit (this);
9405                 }
9406         }
9407
9408         /// <summary>
9409         ///   Implements array access
9410         /// </summary>
9411         public class ArrayAccess : Expression, IDynamicAssign, IMemoryLocation {
9412                 //
9413                 // Points to our "data" repository
9414                 //
9415                 ElementAccess ea;
9416
9417                 LocalTemporary temp;
9418                 bool prepared;
9419                 bool? has_await_args;
9420
9421                 public ArrayAccess (ElementAccess ea_data, Location l)
9422                 {
9423                         ea = ea_data;
9424                         loc = l;
9425                 }
9426
9427                 public void AddressOf (EmitContext ec, AddressOp mode)
9428                 {
9429                         var ac = (ArrayContainer) ea.Expr.Type;
9430
9431                         LoadInstanceAndArguments (ec, false, false);
9432
9433                         if (ac.Element.IsGenericParameter && mode == AddressOp.Load)
9434                                 ec.Emit (OpCodes.Readonly);
9435
9436                         ec.EmitArrayAddress (ac);
9437                 }
9438
9439                 public override Expression CreateExpressionTree (ResolveContext ec)
9440                 {
9441                         return ea.CreateExpressionTree (ec);
9442                 }
9443
9444                 public override bool ContainsEmitWithAwait ()
9445                 {
9446                         return ea.ContainsEmitWithAwait ();
9447                 }
9448
9449                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
9450                 {
9451                         return DoResolve (ec);
9452                 }
9453
9454                 protected override Expression DoResolve (ResolveContext ec)
9455                 {
9456                         // dynamic is used per argument in ConvertExpressionToArrayIndex case
9457                         bool dynamic;
9458                         ea.Arguments.Resolve (ec, out dynamic);
9459
9460                         var ac = ea.Expr.Type as ArrayContainer;
9461                         int rank = ea.Arguments.Count;
9462                         if (ac.Rank != rank) {
9463                                 ec.Report.Error (22, ea.Location, "Wrong number of indexes `{0}' inside [], expected `{1}'",
9464                                           rank.ToString (), ac.Rank.ToString ());
9465                                 return null;
9466                         }
9467
9468                         type = ac.Element;
9469                         if (type.IsPointer && !ec.IsUnsafe) {
9470                                 UnsafeError (ec, ea.Location);
9471                         }
9472
9473                         foreach (Argument a in ea.Arguments) {
9474                                 if (a is NamedArgument)
9475                                         ElementAccess.Error_NamedArgument ((NamedArgument) a, ec.Report);
9476
9477                                 a.Expr = ConvertExpressionToArrayIndex (ec, a.Expr);
9478                         }
9479
9480                         eclass = ExprClass.Variable;
9481
9482                         return this;
9483                 }
9484
9485                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
9486                 {
9487                         ec.Report.Warning (251, 2, loc, "Indexing an array with a negative index (array indices always start at zero)");
9488                 }
9489
9490                 public override void FlowAnalysis (FlowAnalysisContext fc)
9491                 {
9492                         ea.FlowAnalysis (fc);
9493                 }
9494
9495                 //
9496                 // Load the array arguments into the stack.
9497                 //
9498                 void LoadInstanceAndArguments (EmitContext ec, bool duplicateArguments, bool prepareAwait)
9499                 {
9500                         if (prepareAwait) {
9501                                 ea.Expr = ea.Expr.EmitToField (ec);
9502                         } else if (duplicateArguments) {
9503                                 ea.Expr.Emit (ec);
9504                                 ec.Emit (OpCodes.Dup);
9505
9506                                 var copy = new LocalTemporary (ea.Expr.Type);
9507                                 copy.Store (ec);
9508                                 ea.Expr = copy;
9509                         } else {
9510                                 ea.Expr.Emit (ec);
9511                         }
9512
9513                         var dup_args = ea.Arguments.Emit (ec, duplicateArguments, prepareAwait);
9514                         if (dup_args != null)
9515                                 ea.Arguments = dup_args;
9516                 }
9517
9518                 public void Emit (EmitContext ec, bool leave_copy)
9519                 {
9520                         var ac = ea.Expr.Type as ArrayContainer;
9521
9522                         if (prepared) {
9523                                 ec.EmitLoadFromPtr (type);
9524                         } else {
9525                                 if (!has_await_args.HasValue && ec.HasSet (BuilderContext.Options.AsyncBody) && ea.Arguments.ContainsEmitWithAwait ()) {
9526                                         LoadInstanceAndArguments (ec, false, true);
9527                                 }
9528
9529                                 LoadInstanceAndArguments (ec, false, false);
9530                                 ec.EmitArrayLoad (ac);
9531                         }
9532
9533                         if (leave_copy) {
9534                                 ec.Emit (OpCodes.Dup);
9535                                 temp = new LocalTemporary (this.type);
9536                                 temp.Store (ec);
9537                         }
9538                 }
9539
9540                 public override void Emit (EmitContext ec)
9541                 {
9542                         Emit (ec, false);
9543                 }
9544
9545                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
9546                 {
9547                         var ac = (ArrayContainer) ea.Expr.Type;
9548                         TypeSpec t = source.Type;
9549
9550                         has_await_args = ec.HasSet (BuilderContext.Options.AsyncBody) && (ea.Arguments.ContainsEmitWithAwait () || source.ContainsEmitWithAwait ());
9551
9552                         //
9553                         // When we are dealing with a struct, get the address of it to avoid value copy
9554                         // Same cannot be done for reference type because array covariance and the
9555                         // check in ldelema requires to specify the type of array element stored at the index
9556                         //
9557                         if (t.IsStruct && ((isCompound && !(source is DynamicExpressionStatement)) || !BuiltinTypeSpec.IsPrimitiveType (t))) {
9558                                 LoadInstanceAndArguments (ec, false, has_await_args.Value);
9559
9560                                 if (has_await_args.Value) {
9561                                         if (source.ContainsEmitWithAwait ()) {
9562                                                 source = source.EmitToField (ec);
9563                                                 isCompound = false;
9564                                                 prepared = true;
9565                                         }
9566
9567                                         LoadInstanceAndArguments (ec, isCompound, false);
9568                                 } else {
9569                                         prepared = true;
9570                                 }
9571
9572                                 ec.EmitArrayAddress (ac);
9573
9574                                 if (isCompound) {
9575                                         ec.Emit (OpCodes.Dup);
9576                                         prepared = true;
9577                                 }
9578                         } else {
9579                                 LoadInstanceAndArguments (ec, isCompound, has_await_args.Value);
9580
9581                                 if (has_await_args.Value) {
9582                                         if (source.ContainsEmitWithAwait ())
9583                                                 source = source.EmitToField (ec);
9584
9585                                         LoadInstanceAndArguments (ec, false, false);
9586                                 }
9587                         }
9588
9589                         source.Emit (ec);
9590
9591                         if (isCompound) {
9592                                 var lt = ea.Expr as LocalTemporary;
9593                                 if (lt != null)
9594                                         lt.Release (ec);
9595                         }
9596
9597                         if (leave_copy) {
9598                                 ec.Emit (OpCodes.Dup);
9599                                 temp = new LocalTemporary (this.type);
9600                                 temp.Store (ec);
9601                         }
9602
9603                         if (prepared) {
9604                                 ec.EmitStoreFromPtr (t);
9605                         } else {
9606                                 ec.EmitArrayStore (ac);
9607                         }
9608
9609                         if (temp != null) {
9610                                 temp.Emit (ec);
9611                                 temp.Release (ec);
9612                         }
9613                 }
9614
9615                 public override Expression EmitToField (EmitContext ec)
9616                 {
9617                         //
9618                         // Have to be specialized for arrays to get access to
9619                         // underlying element. Instead of another result copy we
9620                         // need direct access to element
9621                         //
9622                         // Consider:
9623                         //
9624                         // CallRef (ref a[await Task.Factory.StartNew (() => 1)]);
9625                         //
9626                         ea.Expr = ea.Expr.EmitToField (ec);
9627                         return this;
9628                 }
9629
9630                 public SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
9631                 {
9632 #if NET_4_0 || MOBILE_DYNAMIC
9633                         return SLE.Expression.ArrayAccess (ea.Expr.MakeExpression (ctx), MakeExpressionArguments (ctx));
9634 #else
9635                         throw new NotImplementedException ();
9636 #endif
9637                 }
9638
9639                 public override SLE.Expression MakeExpression (BuilderContext ctx)
9640                 {
9641                         return SLE.Expression.ArrayIndex (ea.Expr.MakeExpression (ctx), MakeExpressionArguments (ctx));
9642                 }
9643
9644                 SLE.Expression[] MakeExpressionArguments (BuilderContext ctx)
9645                 {
9646                         using (ctx.With (BuilderContext.Options.CheckedScope, true)) {
9647                                 return Arguments.MakeExpression (ea.Arguments, ctx);
9648                         }
9649                 }
9650         }
9651
9652         //
9653         // Indexer access expression
9654         //
9655         sealed class IndexerExpr : PropertyOrIndexerExpr<IndexerSpec>, OverloadResolver.IBaseMembersProvider
9656         {
9657                 IList<MemberSpec> indexers;
9658                 Arguments arguments;
9659                 TypeSpec queried_type;
9660
9661                 public IndexerExpr (IList<MemberSpec> indexers, TypeSpec queriedType, ElementAccess ea)
9662                         : base (ea.Location)
9663                 {
9664                         this.indexers = indexers;
9665                         this.queried_type = queriedType;
9666                         this.InstanceExpression = ea.Expr;
9667                         this.arguments = ea.Arguments;
9668                 }
9669
9670                 #region Properties
9671
9672                 protected override Arguments Arguments {
9673                         get {
9674                                 return arguments;
9675                         }
9676                         set {
9677                                 arguments = value;
9678                         }
9679                 }
9680
9681                 protected override TypeSpec DeclaringType {
9682                         get {
9683                                 return best_candidate.DeclaringType;
9684                         }
9685                 }
9686
9687                 public override bool IsInstance {
9688                         get {
9689                                 return true;
9690                         }
9691                 }
9692
9693                 public override bool IsStatic {
9694                         get {
9695                                 return false;
9696                         }
9697                 }
9698
9699                 public override string KindName {
9700                         get { return "indexer"; }
9701                 }
9702
9703                 public override string Name {
9704                         get {
9705                                 return "this";
9706                         }
9707                 }
9708
9709                 #endregion
9710
9711                 public override bool ContainsEmitWithAwait ()
9712                 {
9713                         return base.ContainsEmitWithAwait () || arguments.ContainsEmitWithAwait ();
9714                 }
9715
9716                 public override Expression CreateExpressionTree (ResolveContext ec)
9717                 {
9718                         Arguments args = Arguments.CreateForExpressionTree (ec, arguments,
9719                                 InstanceExpression.CreateExpressionTree (ec),
9720                                 new TypeOfMethod (Getter, loc));
9721
9722                         return CreateExpressionFactoryCall (ec, "Call", args);
9723                 }
9724
9725                 public override void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
9726                 {
9727                         LocalTemporary await_source_arg = null;
9728
9729                         if (isCompound) {
9730                                 emitting_compound_assignment = true;
9731                                 if (source is DynamicExpressionStatement) {
9732                                         Emit (ec, false);
9733                                 } else {
9734                                         source.Emit (ec);
9735                                 }
9736                                 emitting_compound_assignment = false;
9737
9738                                 if (has_await_arguments) {
9739                                         await_source_arg = new LocalTemporary (Type);
9740                                         await_source_arg.Store (ec);
9741
9742                                         arguments.Add (new Argument (await_source_arg));
9743
9744                                         if (leave_copy) {
9745                                                 temp = await_source_arg;
9746                                         }
9747
9748                                         has_await_arguments = false;
9749                                 } else {
9750                                         arguments = null;
9751
9752                                         if (leave_copy) {
9753                                                 ec.Emit (OpCodes.Dup);
9754                                                 temp = new LocalTemporary (Type);
9755                                                 temp.Store (ec);
9756                                         }
9757                                 }
9758                         } else {
9759                                 if (leave_copy) {
9760                                         if (ec.HasSet (BuilderContext.Options.AsyncBody) && (arguments.ContainsEmitWithAwait () || source.ContainsEmitWithAwait ())) {
9761                                                 source = source.EmitToField (ec);
9762                                         } else {
9763                                                 temp = new LocalTemporary (Type);
9764                                                 source.Emit (ec);
9765                                                 temp.Store (ec);
9766                                                 source = temp;
9767                                         }
9768                                 }
9769
9770                                 arguments.Add (new Argument (source));
9771                         }
9772
9773                         var call = new CallEmitter ();
9774                         call.InstanceExpression = InstanceExpression;
9775                         if (arguments == null)
9776                                 call.InstanceExpressionOnStack = true;
9777
9778                         call.Emit (ec, Setter, arguments, loc);
9779
9780                         if (temp != null) {
9781                                 temp.Emit (ec);
9782                                 temp.Release (ec);
9783                         } else if (leave_copy) {
9784                                 source.Emit (ec);
9785                         }
9786
9787                         if (await_source_arg != null) {
9788                                 await_source_arg.Release (ec);
9789                         }
9790                 }
9791
9792                 public override void FlowAnalysis (FlowAnalysisContext fc)
9793                 {
9794                         // TODO: Check the order
9795                         base.FlowAnalysis (fc);
9796                         arguments.FlowAnalysis (fc);
9797                 }
9798
9799                 public override string GetSignatureForError ()
9800                 {
9801                         return best_candidate.GetSignatureForError ();
9802                 }
9803
9804                 public override SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
9805                 {
9806 #if STATIC
9807                         throw new NotSupportedException ();
9808 #else
9809                         var value = new[] { source.MakeExpression (ctx) };
9810                         var args = Arguments.MakeExpression (arguments, ctx).Concat (value);
9811 #if NET_4_0 || MOBILE_DYNAMIC
9812                         return SLE.Expression.Block (
9813                                         SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Setter.GetMetaInfo (), args),
9814                                         value [0]);
9815 #else
9816                         return args.First ();
9817 #endif
9818 #endif
9819                 }
9820
9821                 public override SLE.Expression MakeExpression (BuilderContext ctx)
9822                 {
9823 #if STATIC
9824                         return base.MakeExpression (ctx);
9825 #else
9826                         var args = Arguments.MakeExpression (arguments, ctx);
9827                         return SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Getter.GetMetaInfo (), args);
9828 #endif
9829                 }
9830
9831                 protected override Expression OverloadResolve (ResolveContext rc, Expression right_side)
9832                 {
9833                         if (best_candidate != null)
9834                                 return this;
9835
9836                         eclass = ExprClass.IndexerAccess;
9837
9838                         bool dynamic;
9839                         arguments.Resolve (rc, out dynamic);
9840
9841                         if (indexers == null && InstanceExpression.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
9842                                 dynamic = true;
9843                         } else {
9844                                 var res = new OverloadResolver (indexers, OverloadResolver.Restrictions.None, loc);
9845                                 res.BaseMembersProvider = this;
9846                                 res.InstanceQualifier = this;
9847
9848                                 // TODO: Do I need 2 argument sets?
9849                                 best_candidate = res.ResolveMember<IndexerSpec> (rc, ref arguments);
9850                                 if (best_candidate != null)
9851                                         type = res.BestCandidateReturnType;
9852                                 else if (!res.BestCandidateIsDynamic)
9853                                         return null;
9854                         }
9855
9856                         //
9857                         // It has dynamic arguments
9858                         //
9859                         if (dynamic) {
9860                                 Arguments args = new Arguments (arguments.Count + 1);
9861                                 if (IsBase) {
9862                                         rc.Report.Error (1972, loc,
9863                                                 "The indexer base access cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access");
9864                                 } else {
9865                                         args.Add (new Argument (InstanceExpression));
9866                                 }
9867                                 args.AddRange (arguments);
9868
9869                                 best_candidate = null;
9870                                 return new DynamicIndexBinder (args, loc);
9871                         }
9872
9873                         //
9874                         // Try to avoid resolving left expression again
9875                         //
9876                         if (right_side != null)
9877                                 ResolveInstanceExpression (rc, right_side);
9878
9879                         return this;
9880                 }
9881
9882                 protected override void CloneTo (CloneContext clonectx, Expression t)
9883                 {
9884                         IndexerExpr target = (IndexerExpr) t;
9885
9886                         if (arguments != null)
9887                                 target.arguments = arguments.Clone (clonectx);
9888                 }
9889
9890                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
9891                 {
9892                         Error_TypeArgumentsCannotBeUsed (ec, "indexer", GetSignatureForError (), loc);
9893                 }
9894
9895                 #region IBaseMembersProvider Members
9896
9897                 IList<MemberSpec> OverloadResolver.IBaseMembersProvider.GetBaseMembers (TypeSpec baseType)
9898                 {
9899                         return baseType == null ? null : MemberCache.FindMembers (baseType, MemberCache.IndexerNameAlias, false);
9900                 }
9901
9902                 IParametersMember OverloadResolver.IBaseMembersProvider.GetOverrideMemberParameters (MemberSpec member)
9903                 {
9904                         if (queried_type == member.DeclaringType)
9905                                 return null;
9906
9907                         var filter = new MemberFilter (MemberCache.IndexerNameAlias, 0, MemberKind.Indexer, ((IndexerSpec) member).Parameters, null);
9908                         return MemberCache.FindMember (queried_type, filter, BindingRestriction.InstanceOnly | BindingRestriction.OverrideOnly) as IParametersMember;
9909                 }
9910
9911                 MethodGroupExpr OverloadResolver.IBaseMembersProvider.LookupExtensionMethod (ResolveContext rc)
9912                 {
9913                         return null;
9914                 }
9915
9916                 #endregion
9917         }
9918
9919         //
9920         // A base access expression
9921         //
9922         public class BaseThis : This
9923         {
9924                 public BaseThis (Location loc)
9925                         : base (loc)
9926                 {
9927                 }
9928
9929                 public BaseThis (TypeSpec type, Location loc)
9930                         : base (loc)
9931                 {
9932                         this.type = type;
9933                         eclass = ExprClass.Variable;
9934                 }
9935
9936                 #region Properties
9937
9938                 public override string Name {
9939                         get {
9940                                 return "base";
9941                         }
9942                 }
9943
9944                 #endregion
9945
9946                 public override Expression CreateExpressionTree (ResolveContext ec)
9947                 {
9948                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
9949                         return base.CreateExpressionTree (ec);
9950                 }
9951
9952                 public override void Emit (EmitContext ec)
9953                 {
9954                         base.Emit (ec);
9955
9956                         if (type == ec.Module.Compiler.BuiltinTypes.ValueType) {
9957                                 var context_type = ec.CurrentType;
9958                                 ec.Emit (OpCodes.Ldobj, context_type);
9959                                 ec.Emit (OpCodes.Box, context_type);
9960                         }
9961                 }
9962
9963                 protected override void Error_ThisNotAvailable (ResolveContext ec)
9964                 {
9965                         if (ec.IsStatic) {
9966                                 ec.Report.Error (1511, loc, "Keyword `base' is not available in a static method");
9967                         } else {
9968                                 ec.Report.Error (1512, loc, "Keyword `base' is not available in the current context");
9969                         }
9970                 }
9971
9972                 public override void ResolveBase (ResolveContext ec)
9973                 {
9974                         base.ResolveBase (ec);
9975                         type = ec.CurrentType.BaseType;
9976                 }
9977
9978                 public override object Accept (StructuralVisitor visitor)
9979                 {
9980                         return visitor.Visit (this);
9981                 }
9982         }
9983
9984         /// <summary>
9985         ///   This class exists solely to pass the Type around and to be a dummy
9986         ///   that can be passed to the conversion functions (this is used by
9987         ///   foreach implementation to typecast the object return value from
9988         ///   get_Current into the proper type.  All code has been generated and
9989         ///   we only care about the side effect conversions to be performed
9990         ///
9991         ///   This is also now used as a placeholder where a no-action expression
9992         ///   is needed (the `New' class).
9993         /// </summary>
9994         public class EmptyExpression : Expression
9995         {
9996                 sealed class OutAccessExpression : EmptyExpression
9997                 {
9998                         public OutAccessExpression (TypeSpec t)
9999                                 : base (t)
10000                         {
10001                         }
10002
10003                         public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
10004                         {
10005                                 rc.Report.Error (206, right_side.Location,
10006                                         "A property, indexer or dynamic member access may not be passed as `ref' or `out' parameter");
10007
10008                                 return null;
10009                         }
10010                 }
10011
10012                 public static readonly EmptyExpression LValueMemberAccess = new EmptyExpression (InternalType.FakeInternalType);
10013                 public static readonly EmptyExpression LValueMemberOutAccess = new EmptyExpression (InternalType.FakeInternalType);
10014                 public static readonly EmptyExpression UnaryAddress = new EmptyExpression (InternalType.FakeInternalType);
10015                 public static readonly EmptyExpression EventAddition = new EmptyExpression (InternalType.FakeInternalType);
10016                 public static readonly EmptyExpression EventSubtraction = new EmptyExpression (InternalType.FakeInternalType);
10017                 public static readonly EmptyExpression MissingValue = new EmptyExpression (InternalType.FakeInternalType);
10018                 public static readonly Expression Null = new EmptyExpression (InternalType.FakeInternalType);
10019                 public static readonly EmptyExpression OutAccess = new OutAccessExpression (InternalType.FakeInternalType);
10020
10021                 public EmptyExpression (TypeSpec t)
10022                 {
10023                         type = t;
10024                         eclass = ExprClass.Value;
10025                         loc = Location.Null;
10026                 }
10027
10028                 protected override void CloneTo (CloneContext clonectx, Expression target)
10029                 {
10030                 }
10031
10032                 public override bool ContainsEmitWithAwait ()
10033                 {
10034                         return false;
10035                 }
10036
10037                 public override Expression CreateExpressionTree (ResolveContext ec)
10038                 {
10039                         throw new NotSupportedException ("ET");
10040                 }
10041
10042                 protected override Expression DoResolve (ResolveContext ec)
10043                 {
10044                         return this;
10045                 }
10046
10047                 public override void Emit (EmitContext ec)
10048                 {
10049                         // nothing, as we only exist to not do anything.
10050                 }
10051
10052                 public override void EmitSideEffect (EmitContext ec)
10053                 {
10054                 }
10055
10056                 public override object Accept (StructuralVisitor visitor)
10057                 {
10058                         return visitor.Visit (this);
10059                 }
10060         }
10061
10062         sealed class EmptyAwaitExpression : EmptyExpression
10063         {
10064                 public EmptyAwaitExpression (TypeSpec type)
10065                         : base (type)
10066                 {
10067                 }
10068
10069                 public override bool ContainsEmitWithAwait ()
10070                 {
10071                         return true;
10072                 }
10073         }
10074
10075         //
10076         // Empty statement expression
10077         //
10078         public sealed class EmptyExpressionStatement : ExpressionStatement
10079         {
10080                 public static readonly EmptyExpressionStatement Instance = new EmptyExpressionStatement ();
10081
10082                 private EmptyExpressionStatement ()
10083                 {
10084                         loc = Location.Null;
10085                 }
10086
10087                 public override bool ContainsEmitWithAwait ()
10088                 {
10089                         return false;
10090                 }
10091
10092                 public override Expression CreateExpressionTree (ResolveContext ec)
10093                 {
10094                         return null;
10095                 }
10096
10097                 public override void EmitStatement (EmitContext ec)
10098                 {
10099                         // Do nothing
10100                 }
10101
10102                 protected override Expression DoResolve (ResolveContext ec)
10103                 {
10104                         eclass = ExprClass.Value;
10105                         type = ec.BuiltinTypes.Object;
10106                         return this;
10107                 }
10108
10109                 public override void Emit (EmitContext ec)
10110                 {
10111                         // Do nothing
10112                 }
10113
10114                 public override object Accept (StructuralVisitor visitor)
10115                 {
10116                         return visitor.Visit (this);
10117                 }
10118         }
10119
10120         public class ErrorExpression : EmptyExpression
10121         {
10122                 public static readonly ErrorExpression Instance = new ErrorExpression ();
10123
10124                 private ErrorExpression ()
10125                         : base (InternalType.ErrorType)
10126                 {
10127                 }
10128
10129                 public override Expression CreateExpressionTree (ResolveContext ec)
10130                 {
10131                         return this;
10132                 }
10133
10134                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
10135                 {
10136                         return this;
10137                 }
10138
10139                 public override void Error_ValueAssignment (ResolveContext rc, Expression rhs)
10140                 {
10141                 }
10142
10143                 public override void Error_UnexpectedKind (ResolveContext ec, ResolveFlags flags, Location loc)
10144                 {
10145                 }
10146
10147                 public override void Error_ValueCannotBeConverted (ResolveContext ec, TypeSpec target, bool expl)
10148                 {
10149                 }
10150
10151                 public override void Error_OperatorCannotBeApplied (ResolveContext rc, Location loc, string oper, TypeSpec t)
10152                 {
10153                 }
10154
10155                 public override object Accept (StructuralVisitor visitor)
10156                 {
10157                         return visitor.Visit (this);
10158                 }
10159         }
10160
10161         public class UserCast : Expression {
10162                 MethodSpec method;
10163                 Expression source;
10164
10165                 public UserCast (MethodSpec method, Expression source, Location l)
10166                 {
10167                         if (source == null)
10168                                 throw new ArgumentNullException ("source");
10169
10170                         this.method = method;
10171                         this.source = source;
10172                         type = method.ReturnType;
10173                         loc = l;
10174                 }
10175
10176                 public Expression Source {
10177                         get {
10178                                 return source;
10179                         }
10180                 }
10181
10182                 public override bool ContainsEmitWithAwait ()
10183                 {
10184                         return source.ContainsEmitWithAwait ();
10185                 }
10186
10187                 public override Expression CreateExpressionTree (ResolveContext ec)
10188                 {
10189                         Arguments args = new Arguments (3);
10190                         args.Add (new Argument (source.CreateExpressionTree (ec)));
10191                         args.Add (new Argument (new TypeOf (type, loc)));
10192                         args.Add (new Argument (new TypeOfMethod (method, loc)));
10193                         return CreateExpressionFactoryCall (ec, "Convert", args);
10194                 }
10195
10196                 protected override Expression DoResolve (ResolveContext ec)
10197                 {
10198                         ObsoleteAttribute oa = method.GetAttributeObsolete ();
10199                         if (oa != null)
10200                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
10201
10202                         eclass = ExprClass.Value;
10203                         return this;
10204                 }
10205
10206                 public override void Emit (EmitContext ec)
10207                 {
10208                         source.Emit (ec);
10209                         ec.MarkCallEntry (loc);
10210                         ec.Emit (OpCodes.Call, method);
10211                 }
10212
10213                 public override void FlowAnalysis (FlowAnalysisContext fc)
10214                 {
10215                         source.FlowAnalysis (fc);
10216                 }
10217
10218                 public override string GetSignatureForError ()
10219                 {
10220                         return TypeManager.CSharpSignature (method);
10221                 }
10222
10223                 public override SLE.Expression MakeExpression (BuilderContext ctx)
10224                 {
10225 #if STATIC
10226                         return base.MakeExpression (ctx);
10227 #else
10228                         return SLE.Expression.Convert (source.MakeExpression (ctx), type.GetMetaInfo (), (MethodInfo) method.GetMetaInfo ());
10229 #endif
10230                 }
10231         }
10232
10233         //
10234         // Holds additional type specifiers like ?, *, []
10235         //
10236         public class ComposedTypeSpecifier
10237         {
10238                 public static readonly ComposedTypeSpecifier SingleDimension = new ComposedTypeSpecifier (1, Location.Null);
10239
10240                 public readonly int Dimension;
10241                 public readonly Location Location;
10242
10243                 public ComposedTypeSpecifier (int specifier, Location loc)
10244                 {
10245                         this.Dimension = specifier;
10246                         this.Location = loc;
10247                 }
10248
10249                 #region Properties
10250                 public bool IsNullable {
10251                         get {
10252                                 return Dimension == -1;
10253                         }
10254                 }
10255
10256                 public bool IsPointer {
10257                         get {
10258                                 return Dimension == -2;
10259                         }
10260                 }
10261
10262                 public ComposedTypeSpecifier Next { get; set; }
10263
10264                 #endregion
10265
10266                 public static ComposedTypeSpecifier CreateArrayDimension (int dimension, Location loc)
10267                 {
10268                         return new ComposedTypeSpecifier (dimension, loc);
10269                 }
10270
10271                 public static ComposedTypeSpecifier CreateNullable (Location loc)
10272                 {
10273                         return new ComposedTypeSpecifier (-1, loc);
10274                 }
10275
10276                 public static ComposedTypeSpecifier CreatePointer (Location loc)
10277                 {
10278                         return new ComposedTypeSpecifier (-2, loc);
10279                 }
10280
10281                 public string GetSignatureForError ()
10282                 {
10283                         string s =
10284                                 IsPointer ? "*" :
10285                                 IsNullable ? "?" :
10286                                 ArrayContainer.GetPostfixSignature (Dimension);
10287
10288                         return Next != null ? s + Next.GetSignatureForError () : s;
10289                 }
10290         }
10291
10292         // <summary>
10293         //   This class is used to "construct" the type during a typecast
10294         //   operation.  Since the Type.GetType class in .NET can parse
10295         //   the type specification, we just use this to construct the type
10296         //   one bit at a time.
10297         // </summary>
10298         public class ComposedCast : TypeExpr {
10299                 FullNamedExpression left;
10300                 ComposedTypeSpecifier spec;
10301
10302                 public ComposedCast (FullNamedExpression left, ComposedTypeSpecifier spec)
10303                 {
10304                         if (spec == null)
10305                                 throw new ArgumentNullException ("spec");
10306
10307                         this.left = left;
10308                         this.spec = spec;
10309                         this.loc = left.Location;
10310                 }
10311
10312                 public override TypeSpec ResolveAsType (IMemberContext ec)
10313                 {
10314                         type = left.ResolveAsType (ec);
10315                         if (type == null)
10316                                 return null;
10317
10318                         eclass = ExprClass.Type;
10319
10320                         var single_spec = spec;
10321
10322                         if (single_spec.IsNullable) {
10323                                 type = new Nullable.NullableType (type, loc).ResolveAsType (ec);
10324                                 if (type == null)
10325                                         return null;
10326
10327                                 single_spec = single_spec.Next;
10328                         } else if (single_spec.IsPointer) {
10329                                 if (!TypeManager.VerifyUnmanaged (ec.Module, type, loc))
10330                                         return null;
10331
10332                                 if (!ec.IsUnsafe) {
10333                                         UnsafeError (ec.Module.Compiler.Report, loc);
10334                                 }
10335
10336                                 do {
10337                                         type = PointerContainer.MakeType (ec.Module, type);
10338                                         single_spec = single_spec.Next;
10339                                 } while (single_spec != null && single_spec.IsPointer);
10340                         }
10341
10342                         if (single_spec != null && single_spec.Dimension > 0) {
10343                                 if (type.IsSpecialRuntimeType) {
10344                                         ec.Module.Compiler.Report.Error (611, loc, "Array elements cannot be of type `{0}'", type.GetSignatureForError ());
10345                                 } else if (type.IsStatic) {
10346                                         ec.Module.Compiler.Report.SymbolRelatedToPreviousError (type);
10347                                         ec.Module.Compiler.Report.Error (719, loc, "Array elements cannot be of static type `{0}'",
10348                                                 type.GetSignatureForError ());
10349                                 } else {
10350                                         MakeArray (ec.Module, single_spec);
10351                                 }
10352                         }
10353
10354                         return type;
10355                 }
10356
10357                 void MakeArray (ModuleContainer module, ComposedTypeSpecifier spec)
10358                 {
10359                         if (spec.Next != null)
10360                                 MakeArray (module, spec.Next);
10361
10362                         type = ArrayContainer.MakeType (module, type, spec.Dimension);
10363                 }
10364
10365                 public override string GetSignatureForError ()
10366                 {
10367                         return left.GetSignatureForError () + spec.GetSignatureForError ();
10368                 }
10369
10370                 public override object Accept (StructuralVisitor visitor)
10371                 {
10372                         return visitor.Visit (this);
10373                 }
10374         }
10375
10376         class FixedBufferPtr : Expression
10377         {
10378                 readonly Expression array;
10379
10380                 public FixedBufferPtr (Expression array, TypeSpec array_type, Location l)
10381                 {
10382                         this.type = array_type;
10383                         this.array = array;
10384                         this.loc = l;
10385                 }
10386
10387                 public override bool ContainsEmitWithAwait ()
10388                 {
10389                         throw new NotImplementedException ();
10390                 }
10391
10392                 public override Expression CreateExpressionTree (ResolveContext ec)
10393                 {
10394                         Error_PointerInsideExpressionTree (ec);
10395                         return null;
10396                 }
10397
10398                 public override void Emit(EmitContext ec)
10399                 {
10400                         array.Emit (ec);
10401                 }
10402
10403                 protected override Expression DoResolve (ResolveContext ec)
10404                 {
10405                         type = PointerContainer.MakeType (ec.Module, type);
10406                         eclass = ExprClass.Value;
10407                         return this;
10408                 }
10409         }
10410
10411
10412         //
10413         // This class is used to represent the address of an array, used
10414         // only by the Fixed statement, this generates "&a [0]" construct
10415         // for fixed (char *pa = a)
10416         //
10417         class ArrayPtr : FixedBufferPtr
10418         {
10419                 public ArrayPtr (Expression array, TypeSpec array_type, Location l):
10420                         base (array, array_type, l)
10421                 {
10422                 }
10423
10424                 public override void Emit (EmitContext ec)
10425                 {
10426                         base.Emit (ec);
10427
10428                         ec.EmitInt (0);
10429                         ec.Emit (OpCodes.Ldelema, ((PointerContainer) type).Element);
10430                 }
10431         }
10432
10433         //
10434         // Encapsulates a conversion rules required for array indexes
10435         //
10436         public class ArrayIndexCast : TypeCast
10437         {
10438                 public ArrayIndexCast (Expression expr, TypeSpec returnType)
10439                         : base (expr, returnType)
10440                 {
10441                         if (expr.Type == returnType) // int -> int
10442                                 throw new ArgumentException ("unnecessary array index conversion");
10443                 }
10444
10445                 public override Expression CreateExpressionTree (ResolveContext ec)
10446                 {
10447                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
10448                                 return base.CreateExpressionTree (ec);
10449                         }
10450                 }
10451
10452                 public override void Emit (EmitContext ec)
10453                 {
10454                         child.Emit (ec);
10455
10456                         switch (child.Type.BuiltinType) {
10457                         case BuiltinTypeSpec.Type.UInt:
10458                                 ec.Emit (OpCodes.Conv_U);
10459                                 break;
10460                         case BuiltinTypeSpec.Type.Long:
10461                                 ec.Emit (OpCodes.Conv_Ovf_I);
10462                                 break;
10463                         case BuiltinTypeSpec.Type.ULong:
10464                                 ec.Emit (OpCodes.Conv_Ovf_I_Un);
10465                                 break;
10466                         default:
10467                                 throw new InternalErrorException ("Cannot emit cast to unknown array element type", type);
10468                         }
10469                 }
10470         }
10471
10472         //
10473         // Implements the `stackalloc' keyword
10474         //
10475         public class StackAlloc : Expression {
10476                 TypeSpec otype;
10477                 Expression t;
10478                 Expression count;
10479
10480                 public StackAlloc (Expression type, Expression count, Location l)
10481                 {
10482                         t = type;
10483                         this.count = count;
10484                         loc = l;
10485                 }
10486
10487                 public Expression TypeExpression {
10488                         get {
10489                                 return this.t;
10490                         }
10491                 }
10492
10493                 public Expression CountExpression {
10494                         get {
10495                                 return this.count;
10496                         }
10497                 }
10498
10499                 public override bool ContainsEmitWithAwait ()
10500                 {
10501                         return false;
10502                 }
10503
10504                 public override Expression CreateExpressionTree (ResolveContext ec)
10505                 {
10506                         throw new NotSupportedException ("ET");
10507                 }
10508
10509                 protected override Expression DoResolve (ResolveContext ec)
10510                 {
10511                         count = count.Resolve (ec);
10512                         if (count == null)
10513                                 return null;
10514
10515                         if (count.Type.BuiltinType != BuiltinTypeSpec.Type.UInt){
10516                                 count = Convert.ImplicitConversionRequired (ec, count, ec.BuiltinTypes.Int, loc);
10517                                 if (count == null)
10518                                         return null;
10519                         }
10520
10521                         Constant c = count as Constant;
10522                         if (c != null && c.IsNegative) {
10523                                 ec.Report.Error (247, loc, "Cannot use a negative size with stackalloc");
10524                         }
10525
10526                         if (ec.HasAny (ResolveContext.Options.CatchScope | ResolveContext.Options.FinallyScope)) {
10527                                 ec.Report.Error (255, loc, "Cannot use stackalloc in finally or catch");
10528                         }
10529
10530                         otype = t.ResolveAsType (ec);
10531                         if (otype == null)
10532                                 return null;
10533
10534                         if (!TypeManager.VerifyUnmanaged (ec.Module, otype, loc))
10535                                 return null;
10536
10537                         type = PointerContainer.MakeType (ec.Module, otype);
10538                         eclass = ExprClass.Value;
10539
10540                         return this;
10541                 }
10542
10543                 public override void Emit (EmitContext ec)
10544                 {
10545                         int size = BuiltinTypeSpec.GetSize (otype);
10546
10547                         count.Emit (ec);
10548
10549                         if (size == 0)
10550                                 ec.Emit (OpCodes.Sizeof, otype);
10551                         else
10552                                 ec.EmitInt (size);
10553
10554                         ec.Emit (OpCodes.Mul_Ovf_Un);
10555                         ec.Emit (OpCodes.Localloc);
10556                 }
10557
10558                 protected override void CloneTo (CloneContext clonectx, Expression t)
10559                 {
10560                         StackAlloc target = (StackAlloc) t;
10561                         target.count = count.Clone (clonectx);
10562                         target.t = t.Clone (clonectx);
10563                 }
10564
10565                 public override object Accept (StructuralVisitor visitor)
10566                 {
10567                         return visitor.Visit (this);
10568                 }
10569         }
10570
10571         //
10572         // An object initializer expression
10573         //
10574         public class ElementInitializer : Assign
10575         {
10576                 public readonly string Name;
10577
10578                 public ElementInitializer (string name, Expression initializer, Location loc)
10579                         : base (null, initializer, loc)
10580                 {
10581                         this.Name = name;
10582                 }
10583
10584                 protected override void CloneTo (CloneContext clonectx, Expression t)
10585                 {
10586                         ElementInitializer target = (ElementInitializer) t;
10587                         target.source = source.Clone (clonectx);
10588                 }
10589
10590                 public override Expression CreateExpressionTree (ResolveContext ec)
10591                 {
10592                         Arguments args = new Arguments (2);
10593                         FieldExpr fe = target as FieldExpr;
10594                         if (fe != null)
10595                                 args.Add (new Argument (fe.CreateTypeOfExpression ()));
10596                         else
10597                                 args.Add (new Argument (((PropertyExpr) target).CreateSetterTypeOfExpression (ec)));
10598
10599                         string mname;
10600                         Expression arg_expr;
10601                         var cinit = source as CollectionOrObjectInitializers;
10602                         if (cinit == null) {
10603                                 mname = "Bind";
10604                                 arg_expr = source.CreateExpressionTree (ec);
10605                         } else {
10606                                 mname = cinit.IsEmpty || cinit.Initializers[0] is ElementInitializer ? "MemberBind" : "ListBind";
10607                                 arg_expr = cinit.CreateExpressionTree (ec, !cinit.IsEmpty);
10608                         }
10609
10610                         args.Add (new Argument (arg_expr));
10611                         return CreateExpressionFactoryCall (ec, mname, args);
10612                 }
10613
10614                 protected override Expression DoResolve (ResolveContext ec)
10615                 {
10616                         if (source == null)
10617                                 return EmptyExpressionStatement.Instance;
10618
10619                         var t = ec.CurrentInitializerVariable.Type;
10620                         if (t.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
10621                                 Arguments args = new Arguments (1);
10622                                 args.Add (new Argument (ec.CurrentInitializerVariable));
10623                                 target = new DynamicMemberBinder (Name, args, loc);
10624                         } else {
10625
10626                                 var member = MemberLookup (ec, false, t, Name, 0, MemberLookupRestrictions.ExactArity, loc);
10627                                 if (member == null) {
10628                                         member = Expression.MemberLookup (ec, true, t, Name, 0, MemberLookupRestrictions.ExactArity, loc);
10629
10630                                         if (member != null) {
10631                                                 // TODO: ec.Report.SymbolRelatedToPreviousError (member);
10632                                                 ErrorIsInaccesible (ec, member.GetSignatureForError (), loc);
10633                                                 return null;
10634                                         }
10635                                 }
10636
10637                                 if (member == null) {
10638                                         Error_TypeDoesNotContainDefinition (ec, loc, t, Name);
10639                                         return null;
10640                                 }
10641
10642                                 if (!(member is PropertyExpr || member is FieldExpr)) {
10643                                         ec.Report.Error (1913, loc,
10644                                                 "Member `{0}' cannot be initialized. An object initializer may only be used for fields, or properties",
10645                                                 member.GetSignatureForError ());
10646
10647                                         return null;
10648                                 }
10649
10650                                 var me = member as MemberExpr;
10651                                 if (me.IsStatic) {
10652                                         ec.Report.Error (1914, loc,
10653                                                 "Static field or property `{0}' cannot be assigned in an object initializer",
10654                                                 me.GetSignatureForError ());
10655                                 }
10656
10657                                 target = me;
10658                                 me.InstanceExpression = ec.CurrentInitializerVariable;
10659                         }
10660
10661                         if (source is CollectionOrObjectInitializers) {
10662                                 Expression previous = ec.CurrentInitializerVariable;
10663                                 ec.CurrentInitializerVariable = target;
10664                                 source = source.Resolve (ec);
10665                                 ec.CurrentInitializerVariable = previous;
10666                                 if (source == null)
10667                                         return null;
10668
10669                                 eclass = source.eclass;
10670                                 type = source.Type;
10671                                 return this;
10672                         }
10673
10674                         return base.DoResolve (ec);
10675                 }
10676
10677                 public override void EmitStatement (EmitContext ec)
10678                 {
10679                         if (source is CollectionOrObjectInitializers)
10680                                 source.Emit (ec);
10681                         else
10682                                 base.EmitStatement (ec);
10683                 }
10684         }
10685
10686         //
10687         // A collection initializer expression
10688         //
10689         class CollectionElementInitializer : Invocation
10690         {
10691                 public class ElementInitializerArgument : Argument
10692                 {
10693                         public ElementInitializerArgument (Expression e)
10694                                 : base (e)
10695                         {
10696                         }
10697                 }
10698
10699                 sealed class AddMemberAccess : MemberAccess
10700                 {
10701                         public AddMemberAccess (Expression expr, Location loc)
10702                                 : base (expr, "Add", loc)
10703                         {
10704                         }
10705
10706                         protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
10707                         {
10708                                 if (TypeManager.HasElementType (type))
10709                                         return;
10710
10711                                 base.Error_TypeDoesNotContainDefinition (ec, type, name);
10712                         }
10713                 }
10714
10715                 public CollectionElementInitializer (Expression argument)
10716                         : base (null, new Arguments (1))
10717                 {
10718                         base.arguments.Add (new ElementInitializerArgument (argument));
10719                         this.loc = argument.Location;
10720                 }
10721
10722                 public CollectionElementInitializer (List<Expression> arguments, Location loc)
10723                         : base (null, new Arguments (arguments.Count))
10724                 {
10725                         foreach (Expression e in arguments)
10726                                 base.arguments.Add (new ElementInitializerArgument (e));
10727
10728                         this.loc = loc;
10729                 }
10730
10731                 public CollectionElementInitializer (Location loc)
10732                         : base (null, null)
10733                 {
10734                         this.loc = loc;
10735                 }
10736
10737                 public override Expression CreateExpressionTree (ResolveContext ec)
10738                 {
10739                         Arguments args = new Arguments (2);
10740                         args.Add (new Argument (mg.CreateExpressionTree (ec)));
10741
10742                         var expr_initializers = new ArrayInitializer (arguments.Count, loc);
10743                         foreach (Argument a in arguments)
10744                                 expr_initializers.Add (a.CreateExpressionTree (ec));
10745
10746                         args.Add (new Argument (new ArrayCreation (
10747                                 CreateExpressionTypeExpression (ec, loc), expr_initializers, loc)));
10748                         return CreateExpressionFactoryCall (ec, "ElementInit", args);
10749                 }
10750
10751                 protected override void CloneTo (CloneContext clonectx, Expression t)
10752                 {
10753                         CollectionElementInitializer target = (CollectionElementInitializer) t;
10754                         if (arguments != null)
10755                                 target.arguments = arguments.Clone (clonectx);
10756                 }
10757
10758                 protected override Expression DoResolve (ResolveContext ec)
10759                 {
10760                         base.expr = new AddMemberAccess (ec.CurrentInitializerVariable, loc);
10761
10762                         return base.DoResolve (ec);
10763                 }
10764         }
10765
10766         //
10767         // A block of object or collection initializers
10768         //
10769         public class CollectionOrObjectInitializers : ExpressionStatement
10770         {
10771                 IList<Expression> initializers;
10772                 bool is_collection_initialization;
10773
10774                 public CollectionOrObjectInitializers (Location loc)
10775                         : this (new Expression[0], loc)
10776                 {
10777                 }
10778
10779                 public CollectionOrObjectInitializers (IList<Expression> initializers, Location loc)
10780                 {
10781                         this.initializers = initializers;
10782                         this.loc = loc;
10783                 }
10784
10785                 public IList<Expression> Initializers {
10786                         get {
10787                                 return initializers;
10788                         }
10789                 }
10790
10791                 public bool IsEmpty {
10792                         get {
10793                                 return initializers.Count == 0;
10794                         }
10795                 }
10796
10797                 public bool IsCollectionInitializer {
10798                         get {
10799                                 return is_collection_initialization;
10800                         }
10801                 }
10802
10803                 protected override void CloneTo (CloneContext clonectx, Expression target)
10804                 {
10805                         CollectionOrObjectInitializers t = (CollectionOrObjectInitializers) target;
10806
10807                         t.initializers = new List<Expression> (initializers.Count);
10808                         foreach (var e in initializers)
10809                                 t.initializers.Add (e.Clone (clonectx));
10810                 }
10811
10812                 public override bool ContainsEmitWithAwait ()
10813                 {
10814                         foreach (var e in initializers) {
10815                                 if (e.ContainsEmitWithAwait ())
10816                                         return true;
10817                         }
10818
10819                         return false;
10820                 }
10821
10822                 public override Expression CreateExpressionTree (ResolveContext ec)
10823                 {
10824                         return CreateExpressionTree (ec, false);
10825                 }
10826
10827                 public Expression CreateExpressionTree (ResolveContext ec, bool inferType)
10828                 {
10829                         var expr_initializers = new ArrayInitializer (initializers.Count, loc);
10830                         foreach (Expression e in initializers) {
10831                                 Expression expr = e.CreateExpressionTree (ec);
10832                                 if (expr != null)
10833                                         expr_initializers.Add (expr);
10834                         }
10835
10836                         if (inferType)
10837                                 return new ImplicitlyTypedArrayCreation (expr_initializers, loc);
10838
10839                         return new ArrayCreation (new TypeExpression (ec.Module.PredefinedTypes.MemberBinding.Resolve (), loc), expr_initializers, loc);
10840                 }
10841
10842                 protected override Expression DoResolve (ResolveContext ec)
10843                 {
10844                         List<string> element_names = null;
10845                         for (int i = 0; i < initializers.Count; ++i) {
10846                                 Expression initializer = initializers [i];
10847                                 ElementInitializer element_initializer = initializer as ElementInitializer;
10848
10849                                 if (i == 0) {
10850                                         if (element_initializer != null) {
10851                                                 element_names = new List<string> (initializers.Count);
10852                                                 element_names.Add (element_initializer.Name);
10853                                         } else if (initializer is CompletingExpression){
10854                                                 initializer.Resolve (ec);
10855                                                 throw new InternalErrorException ("This line should never be reached");
10856                                         } else {
10857                                                 var t = ec.CurrentInitializerVariable.Type;
10858                                                 // LAMESPEC: The collection must implement IEnumerable only, no dynamic support
10859                                                 if (!t.ImplementsInterface (ec.BuiltinTypes.IEnumerable, false) && t.BuiltinType != BuiltinTypeSpec.Type.Dynamic) {
10860                                                         ec.Report.Error (1922, loc, "A field or property `{0}' cannot be initialized with a collection " +
10861                                                                 "object initializer because type `{1}' does not implement `{2}' interface",
10862                                                                 ec.CurrentInitializerVariable.GetSignatureForError (),
10863                                                                 ec.CurrentInitializerVariable.Type.GetSignatureForError (),
10864                                                                 ec.BuiltinTypes.IEnumerable.GetSignatureForError ());
10865                                                         return null;
10866                                                 }
10867                                                 is_collection_initialization = true;
10868                                         }
10869                                 } else {
10870                                         if (is_collection_initialization != (element_initializer == null)) {
10871                                                 ec.Report.Error (747, initializer.Location, "Inconsistent `{0}' member declaration",
10872                                                         is_collection_initialization ? "collection initializer" : "object initializer");
10873                                                 continue;
10874                                         }
10875
10876                                         if (!is_collection_initialization) {
10877                                                 if (element_names.Contains (element_initializer.Name)) {
10878                                                         ec.Report.Error (1912, element_initializer.Location,
10879                                                                 "An object initializer includes more than one member `{0}' initialization",
10880                                                                 element_initializer.Name);
10881                                                 } else {
10882                                                         element_names.Add (element_initializer.Name);
10883                                                 }
10884                                         }
10885                                 }
10886
10887                                 Expression e = initializer.Resolve (ec);
10888                                 if (e == EmptyExpressionStatement.Instance)
10889                                         initializers.RemoveAt (i--);
10890                                 else
10891                                         initializers [i] = e;
10892                         }
10893
10894                         type = ec.CurrentInitializerVariable.Type;
10895                         if (is_collection_initialization) {
10896                                 if (TypeManager.HasElementType (type)) {
10897                                         ec.Report.Error (1925, loc, "Cannot initialize object of type `{0}' with a collection initializer",
10898                                                 type.GetSignatureForError ());
10899                                 }
10900                         }
10901
10902                         eclass = ExprClass.Variable;
10903                         return this;
10904                 }
10905
10906                 public override void Emit (EmitContext ec)
10907                 {
10908                         EmitStatement (ec);
10909                 }
10910
10911                 public override void EmitStatement (EmitContext ec)
10912                 {
10913                         foreach (ExpressionStatement e in initializers) {
10914                                 // TODO: need location region
10915                                 ec.Mark (e.Location);
10916                                 e.EmitStatement (ec);
10917                         }
10918                 }
10919
10920                 public override void FlowAnalysis (FlowAnalysisContext fc)
10921                 {
10922                         foreach (var initializer in initializers)
10923                                 initializer.FlowAnalysis (fc);
10924                 }
10925         }
10926
10927         //
10928         // New expression with element/object initializers
10929         //
10930         public class NewInitialize : New
10931         {
10932                 //
10933                 // This class serves as a proxy for variable initializer target instances.
10934                 // A real variable is assigned later when we resolve left side of an
10935                 // assignment
10936                 //
10937                 sealed class InitializerTargetExpression : Expression, IMemoryLocation
10938                 {
10939                         NewInitialize new_instance;
10940
10941                         public InitializerTargetExpression (NewInitialize newInstance)
10942                         {
10943                                 this.type = newInstance.type;
10944                                 this.loc = newInstance.loc;
10945                                 this.eclass = newInstance.eclass;
10946                                 this.new_instance = newInstance;
10947                         }
10948
10949                         public override bool ContainsEmitWithAwait ()
10950                         {
10951                                 return false;
10952                         }
10953
10954                         public override Expression CreateExpressionTree (ResolveContext ec)
10955                         {
10956                                 // Should not be reached
10957                                 throw new NotSupportedException ("ET");
10958                         }
10959
10960                         protected override Expression DoResolve (ResolveContext ec)
10961                         {
10962                                 return this;
10963                         }
10964
10965                         public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
10966                         {
10967                                 return this;
10968                         }
10969
10970                         public override void Emit (EmitContext ec)
10971                         {
10972                                 Expression e = (Expression) new_instance.instance;
10973                                 e.Emit (ec);
10974                         }
10975
10976                         public override Expression EmitToField (EmitContext ec)
10977                         {
10978                                 return (Expression) new_instance.instance;
10979                         }
10980
10981                         #region IMemoryLocation Members
10982
10983                         public void AddressOf (EmitContext ec, AddressOp mode)
10984                         {
10985                                 new_instance.instance.AddressOf (ec, mode);
10986                         }
10987
10988                         #endregion
10989                 }
10990
10991                 CollectionOrObjectInitializers initializers;
10992                 IMemoryLocation instance;
10993                 DynamicExpressionStatement dynamic;
10994
10995                 public NewInitialize (FullNamedExpression requested_type, Arguments arguments, CollectionOrObjectInitializers initializers, Location l)
10996                         : base (requested_type, arguments, l)
10997                 {
10998                         this.initializers = initializers;
10999                 }
11000
11001                 public CollectionOrObjectInitializers Initializers {
11002                         get {
11003                                 return initializers;
11004                         }
11005                 }
11006
11007                 protected override void CloneTo (CloneContext clonectx, Expression t)
11008                 {
11009                         base.CloneTo (clonectx, t);
11010
11011                         NewInitialize target = (NewInitialize) t;
11012                         target.initializers = (CollectionOrObjectInitializers) initializers.Clone (clonectx);
11013                 }
11014
11015                 public override bool ContainsEmitWithAwait ()
11016                 {
11017                         return base.ContainsEmitWithAwait () || initializers.ContainsEmitWithAwait ();
11018                 }
11019
11020                 public override Expression CreateExpressionTree (ResolveContext ec)
11021                 {
11022                         Arguments args = new Arguments (2);
11023                         args.Add (new Argument (base.CreateExpressionTree (ec)));
11024                         if (!initializers.IsEmpty)
11025                                 args.Add (new Argument (initializers.CreateExpressionTree (ec, initializers.IsCollectionInitializer)));
11026
11027                         return CreateExpressionFactoryCall (ec,
11028                                 initializers.IsCollectionInitializer ? "ListInit" : "MemberInit",
11029                                 args);
11030                 }
11031
11032                 protected override Expression DoResolve (ResolveContext ec)
11033                 {
11034                         Expression e = base.DoResolve (ec);
11035                         if (type == null)
11036                                 return null;
11037
11038                         if (type.IsDelegate) {
11039                                 ec.Report.Error (1958, Initializers.Location,
11040                                         "Object and collection initializers cannot be used to instantiate a delegate");
11041                         }
11042
11043                         Expression previous = ec.CurrentInitializerVariable;
11044                         ec.CurrentInitializerVariable = new InitializerTargetExpression (this);
11045                         initializers.Resolve (ec);
11046                         ec.CurrentInitializerVariable = previous;
11047
11048                         dynamic = e as DynamicExpressionStatement;
11049                         if (dynamic != null)
11050                                 return this;
11051
11052                         return e;
11053                 }
11054
11055                 public override bool Emit (EmitContext ec, IMemoryLocation target)
11056                 {
11057                         bool left_on_stack;
11058                         if (dynamic != null) {
11059                                 dynamic.Emit (ec);
11060                                 left_on_stack = true;
11061                         } else {
11062                                 left_on_stack = base.Emit (ec, target);
11063                         }
11064
11065                         if (initializers.IsEmpty)
11066                                 return left_on_stack;
11067
11068                         LocalTemporary temp = null;
11069
11070                         instance = target as LocalTemporary;
11071
11072                         if (instance == null) {
11073                                 if (!left_on_stack) {
11074                                         VariableReference vr = target as VariableReference;
11075
11076                                         // FIXME: This still does not work correctly for pre-set variables
11077                                         if (vr != null && vr.IsRef)
11078                                                 target.AddressOf (ec, AddressOp.Load);
11079
11080                                         ((Expression) target).Emit (ec);
11081                                         left_on_stack = true;
11082                                 }
11083
11084                                 if (ec.HasSet (BuilderContext.Options.AsyncBody) && initializers.ContainsEmitWithAwait ()) {
11085                                         instance = new EmptyAwaitExpression (Type).EmitToField (ec) as IMemoryLocation;
11086                                 } else {
11087                                         temp = new LocalTemporary (type);
11088                                         instance = temp;
11089                                 }
11090                         }
11091
11092                         if (left_on_stack && temp != null)
11093                                 temp.Store (ec);
11094
11095                         initializers.Emit (ec);
11096
11097                         if (left_on_stack) {
11098                                 if (temp != null) {
11099                                         temp.Emit (ec);
11100                                         temp.Release (ec);
11101                                 } else {
11102                                         ((Expression) instance).Emit (ec);
11103                                 }
11104                         }
11105
11106                         return left_on_stack;
11107                 }
11108
11109                 protected override IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp Mode)
11110                 {
11111                         instance = base.EmitAddressOf (ec, Mode);
11112
11113                         if (!initializers.IsEmpty)
11114                                 initializers.Emit (ec);
11115
11116                         return instance;
11117                 }
11118
11119                 public override void FlowAnalysis (FlowAnalysisContext fc)
11120                 {
11121                         base.FlowAnalysis (fc);
11122                         initializers.FlowAnalysis (fc);
11123                 }
11124
11125                 public override object Accept (StructuralVisitor visitor)
11126                 {
11127                         return visitor.Visit (this);
11128                 }
11129         }
11130
11131         public class NewAnonymousType : New
11132         {
11133                 static readonly AnonymousTypeParameter[] EmptyParameters = new AnonymousTypeParameter[0];
11134
11135                 List<AnonymousTypeParameter> parameters;
11136                 readonly TypeContainer parent;
11137                 AnonymousTypeClass anonymous_type;
11138
11139                 public NewAnonymousType (List<AnonymousTypeParameter> parameters, TypeContainer parent, Location loc)
11140                          : base (null, null, loc)
11141                 {
11142                         this.parameters = parameters;
11143                         this.parent = parent;
11144                 }
11145
11146                 public List<AnonymousTypeParameter> Parameters {
11147                         get {
11148                                 return this.parameters;
11149                         }
11150                 }
11151
11152                 protected override void CloneTo (CloneContext clonectx, Expression target)
11153                 {
11154                         if (parameters == null)
11155                                 return;
11156
11157                         NewAnonymousType t = (NewAnonymousType) target;
11158                         t.parameters = new List<AnonymousTypeParameter> (parameters.Count);
11159                         foreach (AnonymousTypeParameter atp in parameters)
11160                                 t.parameters.Add ((AnonymousTypeParameter) atp.Clone (clonectx));
11161                 }
11162
11163                 AnonymousTypeClass CreateAnonymousType (ResolveContext ec, IList<AnonymousTypeParameter> parameters)
11164                 {
11165                         AnonymousTypeClass type = parent.Module.GetAnonymousType (parameters);
11166                         if (type != null)
11167                                 return type;
11168
11169                         type = AnonymousTypeClass.Create (parent, parameters, loc);
11170                         if (type == null)
11171                                 return null;
11172
11173                         int errors = ec.Report.Errors;
11174                         type.CreateContainer ();
11175                         type.DefineContainer ();
11176                         type.Define ();
11177                         if ((ec.Report.Errors - errors) == 0) {
11178                                 parent.Module.AddAnonymousType (type);
11179                                 type.PrepareEmit ();
11180                         }
11181
11182                         return type;
11183                 }
11184
11185                 public override Expression CreateExpressionTree (ResolveContext ec)
11186                 {
11187                         if (parameters == null)
11188                                 return base.CreateExpressionTree (ec);
11189
11190                         var init = new ArrayInitializer (parameters.Count, loc);
11191                         foreach (var m in anonymous_type.Members) {
11192                                 var p = m as Property;
11193                                 if (p != null)
11194                                         init.Add (new TypeOfMethod (MemberCache.GetMember (type, p.Get.Spec), loc));
11195                         }
11196
11197                         var ctor_args = new ArrayInitializer (arguments.Count, loc);
11198                         foreach (Argument a in arguments)
11199                                 ctor_args.Add (a.CreateExpressionTree (ec));
11200
11201                         Arguments args = new Arguments (3);
11202                         args.Add (new Argument (new TypeOfMethod (method, loc)));
11203                         args.Add (new Argument (new ArrayCreation (CreateExpressionTypeExpression (ec, loc), ctor_args, loc)));
11204                         args.Add (new Argument (new ImplicitlyTypedArrayCreation (init, loc)));
11205
11206                         return CreateExpressionFactoryCall (ec, "New", args);
11207                 }
11208
11209                 protected override Expression DoResolve (ResolveContext ec)
11210                 {
11211                         if (ec.HasSet (ResolveContext.Options.ConstantScope)) {
11212                                 ec.Report.Error (836, loc, "Anonymous types cannot be used in this expression");
11213                                 return null;
11214                         }
11215
11216                         if (parameters == null) {
11217                                 anonymous_type = CreateAnonymousType (ec, EmptyParameters);
11218                                 RequestedType = new TypeExpression (anonymous_type.Definition, loc);
11219                                 return base.DoResolve (ec);
11220                         }
11221
11222                         bool error = false;
11223                         arguments = new Arguments (parameters.Count);
11224                         var t_args = new TypeSpec [parameters.Count];
11225                         for (int i = 0; i < parameters.Count; ++i) {
11226                                 Expression e = parameters [i].Resolve (ec);
11227                                 if (e == null) {
11228                                         error = true;
11229                                         continue;
11230                                 }
11231
11232                                 arguments.Add (new Argument (e));
11233                                 t_args [i] = e.Type;
11234                         }
11235
11236                         if (error)
11237                                 return null;
11238
11239                         anonymous_type = CreateAnonymousType (ec, parameters);
11240                         if (anonymous_type == null)
11241                                 return null;
11242
11243                         type = anonymous_type.Definition.MakeGenericType (ec.Module, t_args);
11244                         method = (MethodSpec) MemberCache.FindMember (type, MemberFilter.Constructor (null), BindingRestriction.DeclaredOnly);
11245                         eclass = ExprClass.Value;
11246                         return this;
11247                 }
11248
11249                 public override object Accept (StructuralVisitor visitor)
11250                 {
11251                         return visitor.Visit (this);
11252                 }
11253         }
11254
11255         public class AnonymousTypeParameter : ShimExpression
11256         {
11257                 public readonly string Name;
11258
11259                 public AnonymousTypeParameter (Expression initializer, string name, Location loc)
11260                         : base (initializer)
11261                 {
11262                         this.Name = name;
11263                         this.loc = loc;
11264                 }
11265
11266                 public AnonymousTypeParameter (Parameter parameter)
11267                         : base (new SimpleName (parameter.Name, parameter.Location))
11268                 {
11269                         this.Name = parameter.Name;
11270                         this.loc = parameter.Location;
11271                 }
11272
11273                 public override bool Equals (object o)
11274                 {
11275                         AnonymousTypeParameter other = o as AnonymousTypeParameter;
11276                         return other != null && Name == other.Name;
11277                 }
11278
11279                 public override int GetHashCode ()
11280                 {
11281                         return Name.GetHashCode ();
11282                 }
11283
11284                 protected override Expression DoResolve (ResolveContext ec)
11285                 {
11286                         Expression e = expr.Resolve (ec);
11287                         if (e == null)
11288                                 return null;
11289
11290                         if (e.eclass == ExprClass.MethodGroup) {
11291                                 Error_InvalidInitializer (ec, e.ExprClassName);
11292                                 return null;
11293                         }
11294
11295                         type = e.Type;
11296                         if (type.Kind == MemberKind.Void || type == InternalType.NullLiteral || type == InternalType.AnonymousMethod || type.IsPointer) {
11297                                 Error_InvalidInitializer (ec, type.GetSignatureForError ());
11298                                 return null;
11299                         }
11300
11301                         return e;
11302                 }
11303
11304                 protected virtual void Error_InvalidInitializer (ResolveContext ec, string initializer)
11305                 {
11306                         ec.Report.Error (828, loc, "An anonymous type property `{0}' cannot be initialized with `{1}'",
11307                                 Name, initializer);
11308                 }
11309         }
11310
11311         public class CatchFilterExpression : BooleanExpression
11312         {
11313                 public CatchFilterExpression (Expression expr, Location loc)
11314                         : base (expr)
11315                 {
11316                         this.loc = loc;
11317                 }
11318         }
11319 }