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 //
  11
  12 using System;
  13 using System.Collections.Generic;
  14 using System.Linq;
  15 using SLE = System.Linq.Expressions;
  16
  17 #if STATIC
  18 using MetaType = IKVM.Reflection.Type;
  19 using IKVM.Reflection;
  20 using IKVM.Reflection.Emit;
  21 #else
  22 using MetaType = System.Type;
  23 using System.Reflection;
  24 using System.Reflection.Emit;
  25 #endif
  26
  27 namespace Mono.CSharp
  28 {
  29         //
  30         // This is an user operator expression, automatically created during
  31         // resolve phase
  32         //
  33         public class UserOperatorCall : Expression {
  34                 protected readonly Arguments arguments;
  35                 protected readonly MethodSpec oper;
  36                 readonly Func<ResolveContext, Expression, Expression> expr_tree;
  37
  38                 public UserOperatorCall (MethodSpec oper, Arguments args, Func<ResolveContext, Expression, Expression> expr_tree, Location loc)
  39                 {
  40                         this.oper = oper;
  41                         this.arguments = args;
  42                         this.expr_tree = expr_tree;
  43
  44                         type = oper.ReturnType;
  45                         eclass = ExprClass.Value;
  46                         this.loc = loc;
  47                 }
  48
  49                 public override Expression CreateExpressionTree (ResolveContext ec)
  50                 {
  51                         if (expr_tree != null)
  52                                 return expr_tree (ec, new TypeOfMethod (oper, loc));
  53
  54                         Arguments args = Arguments.CreateForExpressionTree (ec, arguments,
  55                                 new NullLiteral (loc),
  56                                 new TypeOfMethod (oper, loc));
  57
  58                         return CreateExpressionFactoryCall (ec, "Call", args);
  59                 }
  60
  61                 protected override void CloneTo (CloneContext context, Expression target)
  62                 {
  63                         // Nothing to clone
  64                 }
  65
  66                 protected override Expression DoResolve (ResolveContext ec)
  67                 {
  68                         //
  69                         // We are born fully resolved
  70                         //
  71                         return this;
  72                 }
  73
  74                 public override void Emit (EmitContext ec)
  75                 {
  76                         Invocation.EmitCall (ec, null, oper, arguments, loc);
  77                 }
  78
  79                 public override SLE.Expression MakeExpression (BuilderContext ctx)
  80                 {
  81 #if STATIC
  82                         return base.MakeExpression (ctx);
  83 #else
  84                         return SLE.Expression.Call ((MethodInfo) oper.GetMetaInfo (), Arguments.MakeExpression (arguments, ctx));
  85 #endif
  86                 }
  87         }
  88
  89         public class ParenthesizedExpression : ShimExpression
  90         {
  91                 public ParenthesizedExpression (Expression expr)
  92                         : base (expr)
  93                 {
  94                         loc = expr.Location;
  95                 }
  96
  97                 protected override Expression DoResolve (ResolveContext ec)
  98                 {
  99                         return expr.Resolve (ec);
 100                 }
 101
 102                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 103                 {
 104                         return expr.DoResolveLValue (ec, right_side);
 105                 }
 106         }
 107
 108         //
 109         //   Unary implements unary expressions.
 110         //
 111         public class Unary : Expression
 112         {
 113                 public enum Operator : byte {
 114                         UnaryPlus, UnaryNegation, LogicalNot, OnesComplement,
 115                         AddressOf,  TOP
 116                 }
 117
 118                 static TypeSpec[][] predefined_operators;
 119
 120                 public readonly Operator Oper;
 121                 public Expression Expr;
 122                 Expression enum_conversion;
 123
 124                 public Unary (Operator op, Expression expr, Location loc)
 125                 {
 126                         Oper = op;
 127                         Expr = expr;
 128                         this.loc = loc;
 129                 }
 130
 131                 // <summary>
 132                 //   This routine will attempt to simplify the unary expression when the
 133                 //   argument is a constant.
 134                 // </summary>
 135                 Constant TryReduceConstant (ResolveContext ec, Constant e)
 136                 {
 137                         if (e is EmptyConstantCast)
 138                                 return TryReduceConstant (ec, ((EmptyConstantCast) e).child);
 139
 140                         if (e is SideEffectConstant) {
 141                                 Constant r = TryReduceConstant (ec, ((SideEffectConstant) e).value);
 142                                 return r == null ? null : new SideEffectConstant (r, e, r.Location);
 143                         }
 144
 145                         TypeSpec expr_type = e.Type;
 146
 147                         switch (Oper){
 148                         case Operator.UnaryPlus:
 149                                 // Unary numeric promotions
 150                                 if (expr_type == TypeManager.byte_type)
 151                                         return new IntConstant (((ByteConstant)e).Value, e.Location);
 152                                 if (expr_type == TypeManager.sbyte_type)
 153                                         return new IntConstant (((SByteConstant)e).Value, e.Location);
 154                                 if (expr_type == TypeManager.short_type)
 155                                         return new IntConstant (((ShortConstant)e).Value, e.Location);
 156                                 if (expr_type == TypeManager.ushort_type)
 157                                         return new IntConstant (((UShortConstant)e).Value, e.Location);
 158                                 if (expr_type == TypeManager.char_type)
 159                                         return new IntConstant (((CharConstant)e).Value, e.Location);
 160
 161                                 // Predefined operators
 162                                 if (expr_type == TypeManager.int32_type || expr_type == TypeManager.uint32_type ||
 163                                     expr_type == TypeManager.int64_type || expr_type == TypeManager.uint64_type ||
 164                                     expr_type == TypeManager.float_type || expr_type == TypeManager.double_type ||
 165                                     expr_type == TypeManager.decimal_type) {
 166                                         return e;
 167                                 }
 168
 169                                 return null;
 170
 171                         case Operator.UnaryNegation:
 172                                 // Unary numeric promotions
 173                                 if (expr_type == TypeManager.byte_type)
 174                                         return new IntConstant (-((ByteConstant)e).Value, e.Location);
 175                                 if (expr_type == TypeManager.sbyte_type)
 176                                         return new IntConstant (-((SByteConstant)e).Value, e.Location);
 177                                 if (expr_type == TypeManager.short_type)
 178                                         return new IntConstant (-((ShortConstant)e).Value, e.Location);
 179                                 if (expr_type == TypeManager.ushort_type)
 180                                         return new IntConstant (-((UShortConstant)e).Value, e.Location);
 181                                 if (expr_type == TypeManager.char_type)
 182                                         return new IntConstant (-((CharConstant)e).Value, e.Location);
 183
 184                                 // Predefined operators
 185                                 if (expr_type == TypeManager.int32_type) {
 186                                         int value = ((IntConstant)e).Value;
 187                                         if (value == int.MinValue) {
 188                                                 if (ec.ConstantCheckState) {
 189                                                         ConstantFold.Error_CompileTimeOverflow (ec, loc);
 190                                                         return null;
 191                                                 }
 192                                                 return e;
 193                                         }
 194                                         return new IntConstant (-value, e.Location);
 195                                 }
 196                                 if (expr_type == TypeManager.int64_type) {
 197                                         long value = ((LongConstant)e).Value;
 198                                         if (value == long.MinValue) {
 199                                                 if (ec.ConstantCheckState) {
 200                                                         ConstantFold.Error_CompileTimeOverflow (ec, loc);
 201                                                         return null;
 202                                                 }
 203                                                 return e;
 204                                         }
 205                                         return new LongConstant (-value, e.Location);
 206                                 }
 207
 208                                 if (expr_type == TypeManager.uint32_type) {
 209                                         UIntLiteral uil = e as UIntLiteral;
 210                                         if (uil != null) {
 211                                                 if (uil.Value == int.MaxValue + (uint) 1)
 212                                                         return new IntLiteral (int.MinValue, e.Location);
 213                                                 return new LongLiteral (-uil.Value, e.Location);
 214                                         }
 215                                         return new LongConstant (-((UIntConstant)e).Value, e.Location);
 216                                 }
 217
 218                                 if (expr_type == TypeManager.uint64_type) {
 219                                         ULongLiteral ull = e as ULongLiteral;
 220                                         if (ull != null && ull.Value == 9223372036854775808)
 221                                                 return new LongLiteral (long.MinValue, e.Location);
 222                                         return null;
 223                                 }
 224
 225                                 if (expr_type == TypeManager.float_type) {
 226                                         FloatLiteral fl = e as FloatLiteral;
 227                                         // For better error reporting
 228                                         if (fl != null)
 229                                                 return new FloatLiteral (-fl.Value, e.Location);
 230
 231                                         return new FloatConstant (-((FloatConstant)e).Value, e.Location);
 232                                 }
 233                                 if (expr_type == TypeManager.double_type) {
 234                                         DoubleLiteral dl = e as DoubleLiteral;
 235                                         // For better error reporting
 236                                         if (dl != null)
 237                                                 return new DoubleLiteral (-dl.Value, e.Location);
 238
 239                                         return new DoubleConstant (-((DoubleConstant)e).Value, e.Location);
 240                                 }
 241                                 if (expr_type == TypeManager.decimal_type)
 242                                         return new DecimalConstant (-((DecimalConstant)e).Value, e.Location);
 243
 244                                 return null;
 245
 246                         case Operator.LogicalNot:
 247                                 if (expr_type != TypeManager.bool_type)
 248                                         return null;
 249
 250                                 bool b = (bool)e.GetValue ();
 251                                 return new BoolConstant (!b, e.Location);
 252
 253                         case Operator.OnesComplement:
 254                                 // Unary numeric promotions
 255                                 if (expr_type == TypeManager.byte_type)
 256                                         return new IntConstant (~((ByteConstant)e).Value, e.Location);
 257                                 if (expr_type == TypeManager.sbyte_type)
 258                                         return new IntConstant (~((SByteConstant)e).Value, e.Location);
 259                                 if (expr_type == TypeManager.short_type)
 260                                         return new IntConstant (~((ShortConstant)e).Value, e.Location);
 261                                 if (expr_type == TypeManager.ushort_type)
 262                                         return new IntConstant (~((UShortConstant)e).Value, e.Location);
 263                                 if (expr_type == TypeManager.char_type)
 264                                         return new IntConstant (~((CharConstant)e).Value, e.Location);
 265
 266                                 // Predefined operators
 267                                 if (expr_type == TypeManager.int32_type)
 268                                         return new IntConstant (~((IntConstant)e).Value, e.Location);
 269                                 if (expr_type == TypeManager.uint32_type)
 270                                         return new UIntConstant (~((UIntConstant)e).Value, e.Location);
 271                                 if (expr_type == TypeManager.int64_type)
 272                                         return new LongConstant (~((LongConstant)e).Value, e.Location);
 273                                 if (expr_type == TypeManager.uint64_type){
 274                                         return new ULongConstant (~((ULongConstant)e).Value, e.Location);
 275                                 }
 276                                 if (e is EnumConstant) {
 277                                         e = TryReduceConstant (ec, ((EnumConstant)e).Child);
 278                                         if (e != null)
 279                                                 e = new EnumConstant (e, expr_type);
 280                                         return e;
 281                                 }
 282                                 return null;
 283                         }
 284                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 285                 }
 286
 287                 protected virtual Expression ResolveOperator (ResolveContext ec, Expression expr)
 288                 {
 289                         eclass = ExprClass.Value;
 290
 291                         if (predefined_operators == null)
 292                                 CreatePredefinedOperatorsTable ();
 293
 294                         TypeSpec expr_type = expr.Type;
 295                         Expression best_expr;
 296
 297                         //
 298                         // Primitive types first
 299                         //
 300                         if (TypeManager.IsPrimitiveType (expr_type)) {
 301                                 best_expr = ResolvePrimitivePredefinedType (expr);
 302                                 if (best_expr == null)
 303                                         return null;
 304
 305                                 type = best_expr.Type;
 306                                 Expr = best_expr;
 307                                 return this;
 308                         }
 309
 310                         //
 311                         // E operator ~(E x);
 312                         //
 313                         if (Oper == Operator.OnesComplement && TypeManager.IsEnumType (expr_type))
 314                                 return ResolveEnumOperator (ec, expr);
 315
 316                         return ResolveUserType (ec, expr);
 317                 }
 318
 319                 protected virtual Expression ResolveEnumOperator (ResolveContext ec, Expression expr)
 320                 {
 321                         TypeSpec underlying_type = EnumSpec.GetUnderlyingType (expr.Type);
 322                         Expression best_expr = ResolvePrimitivePredefinedType (EmptyCast.Create (expr, underlying_type));
 323                         if (best_expr == null)
 324                                 return null;
 325
 326                         Expr = best_expr;
 327                         enum_conversion = Convert.ExplicitNumericConversion (new EmptyExpression (best_expr.Type), underlying_type);
 328                         type = expr.Type;
 329                         return EmptyCast.Create (this, type);
 330                 }
 331
 332                 public override Expression CreateExpressionTree (ResolveContext ec)
 333                 {
 334                         return CreateExpressionTree (ec, null);
 335                 }
 336
 337                 Expression CreateExpressionTree (ResolveContext ec, Expression user_op)
 338                 {
 339                         string method_name;
 340                         switch (Oper) {
 341                         case Operator.AddressOf:
 342                                 Error_PointerInsideExpressionTree (ec);
 343                                 return null;
 344                         case Operator.UnaryNegation:
 345                                 if (ec.HasSet (ResolveContext.Options.CheckedScope) && user_op == null && !IsFloat (type))
 346                                         method_name = "NegateChecked";
 347                                 else
 348                                         method_name = "Negate";
 349                                 break;
 350                         case Operator.OnesComplement:
 351                         case Operator.LogicalNot:
 352                                 method_name = "Not";
 353                                 break;
 354                         case Operator.UnaryPlus:
 355                                 method_name = "UnaryPlus";
 356                                 break;
 357                         default:
 358                                 throw new InternalErrorException ("Unknown unary operator " + Oper.ToString ());
 359                         }
 360
 361                         Arguments args = new Arguments (2);
 362                         args.Add (new Argument (Expr.CreateExpressionTree (ec)));
 363                         if (user_op != null)
 364                                 args.Add (new Argument (user_op));
 365
 366                         return CreateExpressionFactoryCall (ec, method_name, args);
 367                 }
 368
 369                 static void CreatePredefinedOperatorsTable ()
 370                 {
 371                         predefined_operators = new TypeSpec [(int) Operator.TOP] [];
 372
 373                         //
 374                         // 7.6.1 Unary plus operator
 375                         //
 376                         predefined_operators [(int) Operator.UnaryPlus] = new TypeSpec [] {
 377                                 TypeManager.int32_type, TypeManager.uint32_type,
 378                                 TypeManager.int64_type, TypeManager.uint64_type,
 379                                 TypeManager.float_type, TypeManager.double_type,
 380                                 TypeManager.decimal_type
 381                         };
 382
 383                         //
 384                         // 7.6.2 Unary minus operator
 385                         //
 386                         predefined_operators [(int) Operator.UnaryNegation] = new TypeSpec [] {
 387                                 TypeManager.int32_type,
 388                                 TypeManager.int64_type,
 389                                 TypeManager.float_type, TypeManager.double_type,
 390                                 TypeManager.decimal_type
 391                         };
 392
 393                         //
 394                         // 7.6.3 Logical negation operator
 395                         //
 396                         predefined_operators [(int) Operator.LogicalNot] = new TypeSpec [] {
 397                                 TypeManager.bool_type
 398                         };
 399
 400                         //
 401                         // 7.6.4 Bitwise complement operator
 402                         //
 403                         predefined_operators [(int) Operator.OnesComplement] = new TypeSpec [] {
 404                                 TypeManager.int32_type, TypeManager.uint32_type,
 405                                 TypeManager.int64_type, TypeManager.uint64_type
 406                         };
 407                 }
 408
 409                 //
 410                 // Unary numeric promotions
 411                 //
 412                 static Expression DoNumericPromotion (Operator op, Expression expr)
 413                 {
 414                         TypeSpec expr_type = expr.Type;
 415                         if ((op == Operator.UnaryPlus || op == Operator.UnaryNegation || op == Operator.OnesComplement) &&
 416                                 expr_type == TypeManager.byte_type || expr_type == TypeManager.sbyte_type ||
 417                                 expr_type == TypeManager.short_type || expr_type == TypeManager.ushort_type ||
 418                                 expr_type == TypeManager.char_type)
 419                                 return Convert.ImplicitNumericConversion (expr, TypeManager.int32_type);
 420
 421                         if (op == Operator.UnaryNegation && expr_type == TypeManager.uint32_type)
 422                                 return Convert.ImplicitNumericConversion (expr, TypeManager.int64_type);
 423
 424                         return expr;
 425                 }
 426
 427                 protected override Expression DoResolve (ResolveContext ec)
 428                 {
 429                         if (Oper == Operator.AddressOf) {
 430                                 return ResolveAddressOf (ec);
 431                         }
 432
 433                         Expr = Expr.Resolve (ec);
 434                         if (Expr == null)
 435                                 return null;
 436
 437                         if (Expr.Type == InternalType.Dynamic) {
 438                                 Arguments args = new Arguments (1);
 439                                 args.Add (new Argument (Expr));
 440                                 return new DynamicUnaryConversion (GetOperatorExpressionTypeName (), args, loc).Resolve (ec);
 441                         }
 442
 443                         if (TypeManager.IsNullableType (Expr.Type))
 444                                 return new Nullable.LiftedUnaryOperator (Oper, Expr, loc).Resolve (ec);
 445
 446                         //
 447                         // Attempt to use a constant folding operation.
 448                         //
 449                         Constant cexpr = Expr as Constant;
 450                         if (cexpr != null) {
 451                                 cexpr = TryReduceConstant (ec, cexpr);
 452                                 if (cexpr != null)
 453                                         return cexpr.Resolve (ec);
 454                         }
 455
 456                         Expression expr = ResolveOperator (ec, Expr);
 457                         if (expr == null)
 458                                 Error_OperatorCannotBeApplied (ec, loc, OperName (Oper), Expr.Type);
 459
 460                         //
 461                         // Reduce unary operator on predefined types
 462                         //
 463                         if (expr == this && Oper == Operator.UnaryPlus)
 464                                 return Expr;
 465
 466                         return expr;
 467                 }
 468
 469                 public override Expression DoResolveLValue (ResolveContext ec, Expression right)
 470                 {
 471                         return null;
 472                 }
 473
 474                 public override void Emit (EmitContext ec)
 475                 {
 476                         EmitOperator (ec, type);
 477                 }
 478
 479                 protected void EmitOperator (EmitContext ec, TypeSpec type)
 480                 {
 481                         switch (Oper) {
 482                         case Operator.UnaryPlus:
 483                                 Expr.Emit (ec);
 484                                 break;
 485
 486                         case Operator.UnaryNegation:
 487                                 if (ec.HasSet (EmitContext.Options.CheckedScope) && !IsFloat (type)) {
 488                                         ec.Emit (OpCodes.Ldc_I4_0);
 489                                         if (type == TypeManager.int64_type)
 490                                                 ec.Emit (OpCodes.Conv_U8);
 491                                         Expr.Emit (ec);
 492                                         ec.Emit (OpCodes.Sub_Ovf);
 493                                 } else {
 494                                         Expr.Emit (ec);
 495                                         ec.Emit (OpCodes.Neg);
 496                                 }
 497
 498                                 break;
 499
 500                         case Operator.LogicalNot:
 501                                 Expr.Emit (ec);
 502                                 ec.Emit (OpCodes.Ldc_I4_0);
 503                                 ec.Emit (OpCodes.Ceq);
 504                                 break;
 505
 506                         case Operator.OnesComplement:
 507                                 Expr.Emit (ec);
 508                                 ec.Emit (OpCodes.Not);
 509                                 break;
 510
 511                         case Operator.AddressOf:
 512                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 513                                 break;
 514
 515                         default:
 516                                 throw new Exception ("This should not happen: Operator = "
 517                                                      + Oper.ToString ());
 518                         }
 519
 520                         //
 521                         // Same trick as in Binary expression
 522                         //
 523                         if (enum_conversion != null)
 524                                 enum_conversion.Emit (ec);
 525                 }
 526
 527                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
 528                 {
 529                         if (Oper == Operator.LogicalNot)
 530                                 Expr.EmitBranchable (ec, target, !on_true);
 531                         else
 532                                 base.EmitBranchable (ec, target, on_true);
 533                 }
 534
 535                 public override void EmitSideEffect (EmitContext ec)
 536                 {
 537                         Expr.EmitSideEffect (ec);
 538                 }
 539
 540                 public static void Error_OperatorCannotBeApplied (ResolveContext ec, Location loc, string oper, TypeSpec t)
 541                 {
 542                         ec.Report.Error (23, loc, "The `{0}' operator cannot be applied to operand of type `{1}'",
 543                                 oper, TypeManager.CSharpName (t));
 544                 }
 545
 546                 //
 547                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
 548                 //
 549                 string GetOperatorExpressionTypeName ()
 550                 {
 551                         switch (Oper) {
 552                         case Operator.OnesComplement:
 553                                 return "OnesComplement";
 554                         case Operator.LogicalNot:
 555                                 return "Not";
 556                         case Operator.UnaryNegation:
 557                                 return "Negate";
 558                         case Operator.UnaryPlus:
 559                                 return "UnaryPlus";
 560                         default:
 561                                 throw new NotImplementedException ("Unknown express type operator " + Oper.ToString ());
 562                         }
 563                 }
 564
 565                 static bool IsFloat (TypeSpec t)
 566                 {
 567                         return t == TypeManager.float_type || t == TypeManager.double_type;
 568                 }
 569
 570                 //
 571                 // Returns a stringified representation of the Operator
 572                 //
 573                 public static string OperName (Operator oper)
 574                 {
 575                         switch (oper) {
 576                         case Operator.UnaryPlus:
 577                                 return "+";
 578                         case Operator.UnaryNegation:
 579                                 return "-";
 580                         case Operator.LogicalNot:
 581                                 return "!";
 582                         case Operator.OnesComplement:
 583                                 return "~";
 584                         case Operator.AddressOf:
 585                                 return "&";
 586                         }
 587
 588                         throw new NotImplementedException (oper.ToString ());
 589                 }
 590
 591                 public override SLE.Expression MakeExpression (BuilderContext ctx)
 592                 {
 593                         var expr = Expr.MakeExpression (ctx);
 594                         bool is_checked = ctx.HasSet (BuilderContext.Options.CheckedScope);
 595
 596                         switch (Oper) {
 597                         case Operator.UnaryNegation:
 598                                 return is_checked ? SLE.Expression.NegateChecked (expr) : SLE.Expression.Negate (expr);
 599                         case Operator.LogicalNot:
 600                                 return SLE.Expression.Not (expr);
 601 #if NET_4_0
 602                         case Operator.OnesComplement:
 603                                 return SLE.Expression.OnesComplement (expr);
 604 #endif
 605                         default:
 606                                 throw new NotImplementedException (Oper.ToString ());
 607                         }
 608                 }
 609
 610                 public static void Reset ()
 611                 {
 612                         predefined_operators = null;
 613                 }
 614
 615                 Expression ResolveAddressOf (ResolveContext ec)
 616                 {
 617                         if (!ec.IsUnsafe)
 618                                 UnsafeError (ec, loc);
 619
 620                         Expr = Expr.DoResolveLValue (ec, EmptyExpression.UnaryAddress);
 621                         if (Expr == null || Expr.eclass != ExprClass.Variable) {
 622                                 ec.Report.Error (211, loc, "Cannot take the address of the given expression");
 623                                 return null;
 624                         }
 625
 626                         if (!TypeManager.VerifyUnmanaged (ec.Compiler, Expr.Type, loc)) {
 627                                 return null;
 628                         }
 629
 630                         IVariableReference vr = Expr as IVariableReference;
 631                         bool is_fixed;
 632                         if (vr != null) {
 633                                 VariableInfo vi = vr.VariableInfo;
 634                                 if (vi != null) {
 635                                         if (vi.LocalInfo != null)
 636                                                 vi.LocalInfo.SetIsUsed ();
 637
 638                                         //
 639                                         // A variable is considered definitely assigned if you take its address.
 640                                         //
 641                                         vi.SetAssigned (ec);
 642                                 }
 643
 644                                 is_fixed = vr.IsFixed;
 645                                 vr.SetHasAddressTaken ();
 646
 647                                 if (vr.IsHoisted) {
 648                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, vr, loc);
 649                                 }
 650                         } else {
 651                                 IFixedExpression fe = Expr as IFixedExpression;
 652                                 is_fixed = fe != null && fe.IsFixed;
 653                         }
 654
 655                         if (!is_fixed && !ec.HasSet (ResolveContext.Options.FixedInitializerScope)) {
 656                                 ec.Report.Error (212, loc, "You can only take the address of unfixed expression inside of a fixed statement initializer");
 657                         }
 658
 659                         type = PointerContainer.MakeType (Expr.Type);
 660                         eclass = ExprClass.Value;
 661                         return this;
 662                 }
 663
 664                 Expression ResolvePrimitivePredefinedType (Expression expr)
 665                 {
 666                         expr = DoNumericPromotion (Oper, expr);
 667                         TypeSpec expr_type = expr.Type;
 668                         TypeSpec[] predefined = predefined_operators [(int) Oper];
 669                         foreach (TypeSpec t in predefined) {
 670                                 if (t == expr_type)
 671                                         return expr;
 672                         }
 673                         return null;
 674                 }
 675
 676                 //
 677                 // Perform user-operator overload resolution
 678                 //
 679                 protected virtual Expression ResolveUserOperator (ResolveContext ec, Expression expr)
 680                 {
 681                         CSharp.Operator.OpType op_type;
 682                         switch (Oper) {
 683                         case Operator.LogicalNot:
 684                                 op_type = CSharp.Operator.OpType.LogicalNot; break;
 685                         case Operator.OnesComplement:
 686                                 op_type = CSharp.Operator.OpType.OnesComplement; break;
 687                         case Operator.UnaryNegation:
 688                                 op_type = CSharp.Operator.OpType.UnaryNegation; break;
 689                         case Operator.UnaryPlus:
 690                                 op_type = CSharp.Operator.OpType.UnaryPlus; break;
 691                         default:
 692                                 throw new InternalErrorException (Oper.ToString ());
 693                         }
 694
 695                         var methods = MemberCache.GetUserOperator (expr.Type, op_type, false);
 696                         if (methods == null)
 697                                 return null;
 698
 699                         Arguments args = new Arguments (1);
 700                         args.Add (new Argument (expr));
 701
 702                         var res = new OverloadResolver (methods, OverloadResolver.Restrictions.BaseMembersIncluded | OverloadResolver.Restrictions.NoBaseMembers, loc);
 703                         var oper = res.ResolveOperator (ec, ref args);
 704
 705                         if (oper == null)
 706                                 return null;
 707
 708                         Expr = args [0].Expr;
 709                         return new UserOperatorCall (oper, args, CreateExpressionTree, expr.Location);
 710                 }
 711
 712                 //
 713                 // Unary user type overload resolution
 714                 //
 715                 Expression ResolveUserType (ResolveContext ec, Expression expr)
 716                 {
 717                         Expression best_expr = ResolveUserOperator (ec, expr);
 718                         if (best_expr != null)
 719                                 return best_expr;
 720
 721                         TypeSpec[] predefined = predefined_operators [(int) Oper];
 722                         foreach (TypeSpec t in predefined) {
 723                                 Expression oper_expr = Convert.ImplicitUserConversion (ec, expr, t, expr.Location);
 724                                 if (oper_expr == null)
 725                                         continue;
 726
 727                                 //
 728                                 // decimal type is predefined but has user-operators
 729                                 //
 730                                 if (oper_expr.Type == TypeManager.decimal_type)
 731                                         oper_expr = ResolveUserType (ec, oper_expr);
 732                                 else
 733                                         oper_expr = ResolvePrimitivePredefinedType (oper_expr);
 734
 735                                 if (oper_expr == null)
 736                                         continue;
 737
 738                                 if (best_expr == null) {
 739                                         best_expr = oper_expr;
 740                                         continue;
 741                                 }
 742
 743                                 int result = OverloadResolver.BetterTypeConversion (ec, best_expr.Type, t);
 744                                 if (result == 0) {
 745                                         ec.Report.Error (35, loc, "Operator `{0}' is ambiguous on an operand of type `{1}'",
 746                                                 OperName (Oper), TypeManager.CSharpName (expr.Type));
 747                                         break;
 748                                 }
 749
 750                                 if (result == 2)
 751                                         best_expr = oper_expr;
 752                         }
 753
 754                         if (best_expr == null)
 755                                 return null;
 756
 757                         //
 758                         // HACK: Decimal user-operator is included in standard operators
 759                         //
 760                         if (best_expr.Type == TypeManager.decimal_type)
 761                                 return best_expr;
 762
 763                         Expr = best_expr;
 764                         type = best_expr.Type;
 765                         return this;
 766                 }
 767
 768                 protected override void CloneTo (CloneContext clonectx, Expression t)
 769                 {
 770                         Unary target = (Unary) t;
 771
 772                         target.Expr = Expr.Clone (clonectx);
 773                 }
 774         }
 775
 776         //
 777         // Unary operators are turned into Indirection expressions
 778         // after semantic analysis (this is so we can take the address
 779         // of an indirection).
 780         //
 781         public class Indirection : Expression, IMemoryLocation, IAssignMethod, IFixedExpression {
 782                 Expression expr;
 783                 LocalTemporary temporary;
 784                 bool prepared;
 785
 786                 public Indirection (Expression expr, Location l)
 787                 {
 788                         this.expr = expr;
 789                         loc = l;
 790                 }
 791
 792                 public override Expression CreateExpressionTree (ResolveContext ec)
 793                 {
 794                         Error_PointerInsideExpressionTree (ec);
 795                         return null;
 796                 }
 797
 798                 protected override void CloneTo (CloneContext clonectx, Expression t)
 799                 {
 800                         Indirection target = (Indirection) t;
 801                         target.expr = expr.Clone (clonectx);
 802                 }
 803
 804                 public override void Emit (EmitContext ec)
 805                 {
 806                         if (!prepared)
 807                                 expr.Emit (ec);
 808
 809                         ec.EmitLoadFromPtr (Type);
 810                 }
 811
 812                 public void Emit (EmitContext ec, bool leave_copy)
 813                 {
 814                         Emit (ec);
 815                         if (leave_copy) {
 816                                 ec.Emit (OpCodes.Dup);
 817                                 temporary = new LocalTemporary (expr.Type);
 818                                 temporary.Store (ec);
 819                         }
 820                 }
 821
 822                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 823                 {
 824                         prepared = prepare_for_load;
 825
 826                         expr.Emit (ec);
 827
 828                         if (prepare_for_load)
 829                                 ec.Emit (OpCodes.Dup);
 830
 831                         source.Emit (ec);
 832                         if (leave_copy) {
 833                                 ec.Emit (OpCodes.Dup);
 834                                 temporary = new LocalTemporary (expr.Type);
 835                                 temporary.Store (ec);
 836                         }
 837
 838                         ec.EmitStoreFromPtr (type);
 839
 840                         if (temporary != null) {
 841                                 temporary.Emit (ec);
 842                                 temporary.Release (ec);
 843                         }
 844                 }
 845
 846                 public void AddressOf (EmitContext ec, AddressOp Mode)
 847                 {
 848                         expr.Emit (ec);
 849                 }
 850
 851                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 852                 {
 853                         return DoResolve (ec);
 854                 }
 855
 856                 protected override Expression DoResolve (ResolveContext ec)
 857                 {
 858                         expr = expr.Resolve (ec);
 859                         if (expr == null)
 860                                 return null;
 861
 862                         if (!ec.IsUnsafe)
 863                                 UnsafeError (ec, loc);
 864
 865                         var pc = expr.Type as PointerContainer;
 866
 867                         if (pc == null) {
 868                                 ec.Report.Error (193, loc, "The * or -> operator must be applied to a pointer");
 869                                 return null;
 870                         }
 871
 872                         type = pc.Element;
 873
 874                         if (type.BuildinType == BuildinTypeSpec.Type.Void) {
 875                                 Error_VoidPointerOperation (ec);
 876                                 return null;
 877                         }
 878
 879                         eclass = ExprClass.Variable;
 880                         return this;
 881                 }
 882
 883                 public bool IsFixed {
 884                         get { return true; }
 885                 }
 886
 887                 public override string ToString ()
 888                 {
 889                         return "*(" + expr + ")";
 890                 }
 891         }
 892
 893         /// <summary>
 894         ///   Unary Mutator expressions (pre and post ++ and --)
 895         /// </summary>
 896         ///
 897         /// <remarks>
 898         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 899         ///   ExpressionStatement becuase the pre/post increment/decrement
 900         ///   operators can be used in a statement context.
 901         ///
 902         /// FIXME: Idea, we could split this up in two classes, one simpler
 903         /// for the common case, and one with the extra fields for more complex
 904         /// classes (indexers require temporary access;  overloaded require method)
 905         ///
 906         /// </remarks>
 907         public class UnaryMutator : ExpressionStatement
 908         {
 909                 class DynamicPostMutator : Expression, IAssignMethod
 910                 {
 911                         LocalTemporary temp;
 912                         Expression expr;
 913
 914                         public DynamicPostMutator (Expression expr)
 915                         {
 916                                 this.expr = expr;
 917                                 this.type = expr.Type;
 918                                 this.loc = expr.Location;
 919                         }
 920
 921                         public override Expression CreateExpressionTree (ResolveContext ec)
 922                         {
 923                                 throw new NotImplementedException ("ET");
 924                         }
 925
 926                         protected override Expression DoResolve (ResolveContext rc)
 927                         {
 928                                 eclass = expr.eclass;
 929                                 return this;
 930                         }
 931
 932                         public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 933                         {
 934                                 expr.DoResolveLValue (ec, right_side);
 935                                 return DoResolve (ec);
 936                         }
 937
 938                         public override void Emit (EmitContext ec)
 939                         {
 940                                 temp.Emit (ec);
 941                         }
 942
 943                         public void Emit (EmitContext ec, bool leave_copy)
 944                         {
 945                                 throw new NotImplementedException ();
 946                         }
 947
 948                         //
 949                         // Emits target assignment using unmodified source value
 950                         //
 951                         public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 952                         {
 953                                 //
 954                                 // Allocate temporary variable to keep original value before it's modified
 955                                 //
 956                                 temp = new LocalTemporary (type);
 957                                 expr.Emit (ec);
 958                                 temp.Store (ec);
 959
 960                                 ((IAssignMethod) expr).EmitAssign (ec, source, false, prepare_for_load);
 961
 962                                 if (leave_copy)
 963                                         Emit (ec);
 964
 965                                 temp.Release (ec);
 966                                 temp = null;
 967                         }
 968                 }
 969
 970                 [Flags]
 971                 public enum Mode : byte {
 972                         IsIncrement    = 0,
 973                         IsDecrement    = 1,
 974                         IsPre          = 0,
 975                         IsPost         = 2,
 976
 977                         PreIncrement   = 0,
 978                         PreDecrement   = IsDecrement,
 979                         PostIncrement  = IsPost,
 980                         PostDecrement  = IsPost | IsDecrement
 981                 }
 982
 983                 Mode mode;
 984                 bool is_expr, recurse;
 985
 986                 Expression expr;
 987
 988                 // Holds the real operation
 989                 Expression operation;
 990
 991                 static TypeSpec[] predefined;
 992
 993                 public UnaryMutator (Mode m, Expression e, Location loc)
 994                 {
 995                         mode = m;
 996                         this.loc = loc;
 997                         expr = e;
 998                 }
 999
1000                 public override Expression CreateExpressionTree (ResolveContext ec)
1001                 {
1002                         return new SimpleAssign (this, this).CreateExpressionTree (ec);
1003                 }
1004
1005                 void CreatePredefinedOperators ()
1006                 {
1007                         //
1008                         // Predefined ++ and -- operators exist for the following types:
1009                         // sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal
1010                         //
1011                         predefined = new TypeSpec[] {
1012                                 TypeManager.int32_type,
1013
1014                                 TypeManager.sbyte_type,
1015                                 TypeManager.byte_type,
1016                                 TypeManager.short_type,
1017                                 TypeManager.ushort_type,
1018                                 TypeManager.uint32_type,
1019                                 TypeManager.int64_type,
1020                                 TypeManager.uint64_type,
1021                                 TypeManager.char_type,
1022                                 TypeManager.float_type,
1023                                 TypeManager.double_type,
1024                                 TypeManager.decimal_type
1025                         };
1026                 }
1027
1028                 protected override Expression DoResolve (ResolveContext ec)
1029                 {
1030                         expr = expr.Resolve (ec);
1031
1032                         if (expr == null)
1033                                 return null;
1034
1035                         if (expr.Type == InternalType.Dynamic) {
1036                                 //
1037                                 // Handle postfix unary operators using local
1038                                 // temporary variable
1039                                 //
1040                                 if ((mode & Mode.IsPost) != 0)
1041                                         expr = new DynamicPostMutator (expr);
1042
1043                                 Arguments args = new Arguments (1);
1044                                 args.Add (new Argument (expr));
1045                                 return new SimpleAssign (expr, new DynamicUnaryConversion (GetOperatorExpressionTypeName (), args, loc)).Resolve (ec);
1046                         }
1047
1048                         if (TypeManager.IsNullableType (expr.Type))
1049                                 return new Nullable.LiftedUnaryMutator (mode, expr, loc).Resolve (ec);
1050
1051                         eclass = ExprClass.Value;
1052                         type = expr.Type;
1053
1054                         if (expr is RuntimeValueExpression) {
1055                                 operation = expr;
1056                         } else {
1057                                 // Use itself at the top of the stack
1058                                 operation = new EmptyExpression (type);
1059                         }
1060
1061                         //
1062                         // The operand of the prefix/postfix increment decrement operators
1063                         // should be an expression that is classified as a variable,
1064                         // a property access or an indexer access
1065                         //
1066                         // TODO: Move to parser, expr is ATypeNameExpression
1067                         if (expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.IndexerAccess || expr.eclass == ExprClass.PropertyAccess) {
1068                                 expr = expr.ResolveLValue (ec, expr);
1069                         } else {
1070                                 ec.Report.Error (1059, loc, "The operand of an increment or decrement operator must be a variable, property or indexer");
1071                         }
1072
1073                         //
1074                         // Step 1: Try to find a user operator, it has priority over predefined ones
1075                         //
1076                         var user_op = IsDecrement ? Operator.OpType.Decrement : Operator.OpType.Increment;
1077                         var methods = MemberCache.GetUserOperator (type, user_op, false);
1078
1079                         if (methods != null) {
1080                                 Arguments args = new Arguments (1);
1081                                 args.Add (new Argument (expr));
1082
1083                                 var res = new OverloadResolver (methods, OverloadResolver.Restrictions.BaseMembersIncluded | OverloadResolver.Restrictions.NoBaseMembers, loc);
1084                                 var method = res.ResolveOperator (ec, ref args);
1085                                 if (method == null)
1086                                         return null;
1087
1088                                 args[0].Expr = operation;
1089                                 operation = new UserOperatorCall (method, args, null, loc);
1090                                 operation = Convert.ImplicitConversionRequired (ec, operation, type, loc);
1091                                 return this;
1092                         }
1093
1094                         //
1095                         // Step 2: Try predefined types
1096                         //
1097                         if (predefined == null)
1098                                 CreatePredefinedOperators ();
1099
1100                         // Predefined without user conversion first for speed-up
1101                         Expression source = null;
1102                         bool primitive_type = false;
1103                         foreach (var t in predefined) {
1104                                 if (t == type) {
1105                                         source = operation;
1106                                         primitive_type = true;
1107                                         break;
1108                                 }
1109                         }
1110
1111                         // ++/-- on pointer variables of all types except void*
1112                         if (source == null && type.IsPointer) {
1113                                 if (((PointerContainer) type).Element.BuildinType == BuildinTypeSpec.Type.Void) {
1114                                         Error_VoidPointerOperation (ec);
1115                                         return null;
1116                                 }
1117
1118                                 source = operation;
1119                         }
1120
1121                         if (source == null) {
1122                                 // LAMESPEC: It should error on ambiguous operators but that would make us incompatible
1123                                 foreach (var t in predefined) {
1124                                         source = Convert.ImplicitUserConversion (ec, operation, t, loc);
1125                                         if (source != null) {
1126                                                 break;
1127                                         }
1128                                 }
1129                         }
1130
1131                         // ++/-- on enum types
1132                         if (source == null && type.IsEnum)
1133                                 source = operation;
1134
1135                         if (source == null) {
1136                                 Unary.Error_OperatorCannotBeApplied (ec, loc, Operator.GetName (user_op), type);
1137                                 return null;
1138                         }
1139
1140                         var one = new IntConstant (1, loc);
1141                         var op = IsDecrement ? Binary.Operator.Subtraction : Binary.Operator.Addition;
1142                         operation = new Binary (op, source, one, loc);
1143                         operation = operation.Resolve (ec);
1144                         if (operation == null)
1145                                 throw new NotImplementedException ("should not be reached");
1146
1147                         if (operation.Type != type) {
1148                                 if (primitive_type)
1149                                         operation = Convert.ExplicitNumericConversion (operation, type);
1150                                 else
1151                                         operation = Convert.ImplicitConversionRequired (ec, operation, type, loc);
1152                         }
1153
1154                         return this;
1155                 }
1156
1157                 void EmitCode (EmitContext ec, bool is_expr)
1158                 {
1159                         recurse = true;
1160                         this.is_expr = is_expr;
1161                         ((IAssignMethod) expr).EmitAssign (ec, this, is_expr && (mode == Mode.PreIncrement || mode == Mode.PreDecrement), true);
1162                 }
1163
1164                 public override void Emit (EmitContext ec)
1165                 {
1166                         //
1167                         // We use recurse to allow ourselfs to be the source
1168                         // of an assignment. This little hack prevents us from
1169                         // having to allocate another expression
1170                         //
1171                         if (recurse) {
1172                                 ((IAssignMethod) expr).Emit (ec, is_expr && (mode == Mode.PostIncrement || mode == Mode.PostDecrement));
1173
1174                                 operation.Emit (ec);
1175
1176                                 recurse = false;
1177                                 return;
1178                         }
1179
1180                         EmitCode (ec, true);
1181                 }
1182
1183                 public override void EmitStatement (EmitContext ec)
1184                 {
1185                         EmitCode (ec, false);
1186                 }
1187
1188                 //
1189                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
1190                 //
1191                 string GetOperatorExpressionTypeName ()
1192                 {
1193                         return IsDecrement ? "Decrement" : "Increment";
1194                 }
1195
1196                 bool IsDecrement {
1197                         get { return (mode & Mode.IsDecrement) != 0; }
1198                 }
1199
1200
1201 #if NET_4_0
1202                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1203                 {
1204                         var target = ((RuntimeValueExpression) expr).MetaObject.Expression;
1205                         var source = SLE.Expression.Convert (operation.MakeExpression (ctx), target.Type);
1206                         return SLE.Expression.Assign (target, source);
1207                 }
1208 #endif
1209
1210                 public static void Reset ()
1211                 {
1212                         predefined = null;
1213                 }
1214
1215                 protected override void CloneTo (CloneContext clonectx, Expression t)
1216                 {
1217                         UnaryMutator target = (UnaryMutator) t;
1218
1219                         target.expr = expr.Clone (clonectx);
1220                 }
1221         }
1222
1223         /// <summary>
1224         ///   Base class for the `Is' and `As' classes.
1225         /// </summary>
1226         ///
1227         /// <remarks>
1228         ///   FIXME: Split this in two, and we get to save the `Operator' Oper
1229         ///   size.
1230         /// </remarks>
1231         public abstract class Probe : Expression {
1232                 public Expression ProbeType;
1233                 protected Expression expr;
1234                 protected TypeExpr probe_type_expr;
1235
1236                 public Probe (Expression expr, Expression probe_type, Location l)
1237                 {
1238                         ProbeType = probe_type;
1239                         loc = l;
1240                         this.expr = expr;
1241                 }
1242
1243                 public Expression Expr {
1244                         get {
1245                                 return expr;
1246                         }
1247                 }
1248
1249                 protected override Expression DoResolve (ResolveContext ec)
1250                 {
1251                         probe_type_expr = ProbeType.ResolveAsTypeTerminal (ec, false);
1252                         if (probe_type_expr == null)
1253                                 return null;
1254
1255                         expr = expr.Resolve (ec);
1256                         if (expr == null)
1257                                 return null;
1258
1259                         if (probe_type_expr.Type.IsStatic) {
1260                                 ec.Report.Error (-244, loc, "The `{0}' operator cannot be applied to an operand of a static type",
1261                                         OperatorName);
1262                         }
1263
1264                         if (expr.Type.IsPointer || probe_type_expr.Type.IsPointer) {
1265                                 ec.Report.Error (244, loc, "The `{0}' operator cannot be applied to an operand of pointer type",
1266                                         OperatorName);
1267                                 return null;
1268                         }
1269
1270                         if (expr.Type == InternalType.AnonymousMethod) {
1271                                 ec.Report.Error (837, loc, "The `{0}' operator cannot be applied to a lambda expression or anonymous method",
1272                                         OperatorName);
1273                                 return null;
1274                         }
1275
1276                         return this;
1277                 }
1278
1279                 protected abstract string OperatorName { get; }
1280
1281                 protected override void CloneTo (CloneContext clonectx, Expression t)
1282                 {
1283                         Probe target = (Probe) t;
1284
1285                         target.expr = expr.Clone (clonectx);
1286                         target.ProbeType = ProbeType.Clone (clonectx);
1287                 }
1288
1289         }
1290
1291         /// <summary>
1292         ///   Implementation of the `is' operator.
1293         /// </summary>
1294         public class Is : Probe {
1295                 Nullable.Unwrap expr_unwrap;
1296
1297                 public Is (Expression expr, Expression probe_type, Location l)
1298                         : base (expr, probe_type, l)
1299                 {
1300                 }
1301
1302                 public override Expression CreateExpressionTree (ResolveContext ec)
1303                 {
1304                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1305                                 expr.CreateExpressionTree (ec),
1306                                 new TypeOf (probe_type_expr, loc));
1307
1308                         return CreateExpressionFactoryCall (ec, "TypeIs", args);
1309                 }
1310
1311                 public override void Emit (EmitContext ec)
1312                 {
1313                         if (expr_unwrap != null) {
1314                                 expr_unwrap.EmitCheck (ec);
1315                                 return;
1316                         }
1317
1318                         expr.Emit (ec);
1319                         ec.Emit (OpCodes.Isinst, probe_type_expr.Type);
1320                         ec.Emit (OpCodes.Ldnull);
1321                         ec.Emit (OpCodes.Cgt_Un);
1322                 }
1323
1324                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
1325                 {
1326                         if (expr_unwrap != null) {
1327                                 expr_unwrap.EmitCheck (ec);
1328                         } else {
1329                                 expr.Emit (ec);
1330                                 ec.Emit (OpCodes.Isinst, probe_type_expr.Type);
1331                         }
1332                         ec.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
1333                 }
1334
1335                 Expression CreateConstantResult (ResolveContext ec, bool result)
1336                 {
1337                         if (result)
1338                                 ec.Report.Warning (183, 1, loc, "The given expression is always of the provided (`{0}') type",
1339                                         TypeManager.CSharpName (probe_type_expr.Type));
1340                         else
1341                                 ec.Report.Warning (184, 1, loc, "The given expression is never of the provided (`{0}') type",
1342                                         TypeManager.CSharpName (probe_type_expr.Type));
1343
1344                         return ReducedExpression.Create (new BoolConstant (result, loc).Resolve (ec), this);
1345                 }
1346
1347                 protected override Expression DoResolve (ResolveContext ec)
1348                 {
1349                         if (base.DoResolve (ec) == null)
1350                                 return null;
1351
1352                         TypeSpec d = expr.Type;
1353                         bool d_is_nullable = false;
1354
1355                         //
1356                         // If E is a method group or the null literal, or if the type of E is a reference
1357                         // type or a nullable type and the value of E is null, the result is false
1358                         //
1359                         if (expr.IsNull || expr.eclass == ExprClass.MethodGroup)
1360                                 return CreateConstantResult (ec, false);
1361
1362                         if (TypeManager.IsNullableType (d)) {
1363                                 var ut = Nullable.NullableInfo.GetUnderlyingType (d);
1364                                 if (!ut.IsGenericParameter) {
1365                                         d = ut;
1366                                         d_is_nullable = true;
1367                                 }
1368                         }
1369
1370                         type = TypeManager.bool_type;
1371                         eclass = ExprClass.Value;
1372                         TypeSpec t = probe_type_expr.Type;
1373                         bool t_is_nullable = false;
1374                         if (TypeManager.IsNullableType (t)) {
1375                                 var ut = Nullable.NullableInfo.GetUnderlyingType (t);
1376                                 if (!ut.IsGenericParameter) {
1377                                         t = ut;
1378                                         t_is_nullable = true;
1379                                 }
1380                         }
1381
1382                         if (TypeManager.IsStruct (t)) {
1383                                 if (d == t) {
1384                                         //
1385                                         // D and T are the same value types but D can be null
1386                                         //
1387                                         if (d_is_nullable && !t_is_nullable) {
1388                                                 expr_unwrap = Nullable.Unwrap.Create (expr, false);
1389                                                 return this;
1390                                         }
1391
1392                                         //
1393                                         // The result is true if D and T are the same value types
1394                                         //
1395                                         return CreateConstantResult (ec, true);
1396                                 }
1397
1398                                 var tp = d as TypeParameterSpec;
1399                                 if (tp != null)
1400                                         return ResolveGenericParameter (ec, t, tp);
1401
1402                                 //
1403                                 // An unboxing conversion exists
1404                                 //
1405                                 if (Convert.ExplicitReferenceConversionExists (d, t))
1406                                         return this;
1407                         } else {
1408                                 if (TypeManager.IsGenericParameter (t))
1409                                         return ResolveGenericParameter (ec, d, (TypeParameterSpec) t);
1410
1411                                 if (t == InternalType.Dynamic) {
1412                                         ec.Report.Warning (1981, 3, loc,
1413                                                 "Using `{0}' to test compatibility with `{1}' is identical to testing compatibility with `object'",
1414                                                 OperatorName, t.GetSignatureForError ());
1415                                 }
1416
1417                                 if (TypeManager.IsStruct (d) && d != TypeManager.void_type) {
1418                                         if (Convert.ImplicitBoxingConversion (null, d, t) != null)
1419                                                 return CreateConstantResult (ec, true);
1420                                 } else {
1421                                         if (TypeManager.IsGenericParameter (d))
1422                                                 return ResolveGenericParameter (ec, t, (TypeParameterSpec) d);
1423
1424                                         if (InflatedTypeSpec.ContainsTypeParameter (d))
1425                                                 return this;
1426
1427                                         if (Convert.ImplicitReferenceConversionExists (expr, t) ||
1428                                                 Convert.ExplicitReferenceConversionExists (d, t)) {
1429                                                 return this;
1430                                         }
1431                                 }
1432                         }
1433
1434                         return CreateConstantResult (ec, false);
1435                 }
1436
1437                 Expression ResolveGenericParameter (ResolveContext ec, TypeSpec d, TypeParameterSpec t)
1438                 {
1439                         if (t.IsReferenceType) {
1440                                 if (TypeManager.IsStruct (d))
1441                                         return CreateConstantResult (ec, false);
1442                         }
1443
1444                         if (TypeManager.IsGenericParameter (expr.Type)) {
1445                                 if (t.IsValueType && expr.Type == d)
1446                                         return CreateConstantResult (ec, true);
1447
1448                                 expr = new BoxedCast (expr, d);
1449                         }
1450
1451                         return this;
1452                 }
1453
1454                 protected override string OperatorName {
1455                         get { return "is"; }
1456                 }
1457         }
1458
1459         /// <summary>
1460         ///   Implementation of the `as' operator.
1461         /// </summary>
1462         public class As : Probe {
1463                 Expression resolved_type;
1464
1465                 public As (Expression expr, Expression probe_type, Location l)
1466                         : base (expr, probe_type, l)
1467                 {
1468                 }
1469
1470                 public override Expression CreateExpressionTree (ResolveContext ec)
1471                 {
1472                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1473                                 expr.CreateExpressionTree (ec),
1474                                 new TypeOf (probe_type_expr, loc));
1475
1476                         return CreateExpressionFactoryCall (ec, "TypeAs", args);
1477                 }
1478
1479                 public override void Emit (EmitContext ec)
1480                 {
1481                         expr.Emit (ec);
1482
1483                         ec.Emit (OpCodes.Isinst, type);
1484
1485                         if (TypeManager.IsGenericParameter (type) || TypeManager.IsNullableType (type))
1486                                 ec.Emit (OpCodes.Unbox_Any, type);
1487                 }
1488
1489                 protected override Expression DoResolve (ResolveContext ec)
1490                 {
1491                         if (resolved_type == null) {
1492                                 resolved_type = base.DoResolve (ec);
1493
1494                                 if (resolved_type == null)
1495                                         return null;
1496                         }
1497
1498                         type = probe_type_expr.Type;
1499                         eclass = ExprClass.Value;
1500                         TypeSpec etype = expr.Type;
1501
1502                         if (!TypeManager.IsReferenceType (type) && !TypeManager.IsNullableType (type)) {
1503                                 if (TypeManager.IsGenericParameter (type)) {
1504                                         ec.Report.Error (413, loc,
1505                                                 "The `as' operator cannot be used with a non-reference type parameter `{0}'. Consider adding `class' or a reference type constraint",
1506                                                 probe_type_expr.GetSignatureForError ());
1507                                 } else {
1508                                         ec.Report.Error (77, loc,
1509                                                 "The `as' operator cannot be used with a non-nullable value type `{0}'",
1510                                                 TypeManager.CSharpName (type));
1511                                 }
1512                                 return null;
1513                         }
1514
1515                         if (expr.IsNull && TypeManager.IsNullableType (type)) {
1516                                 return Nullable.LiftedNull.CreateFromExpression (ec, this);
1517                         }
1518
1519                         // If the compile-time type of E is dynamic, unlike the cast operator the as operator is not dynamically bound
1520                         if (etype == InternalType.Dynamic) {
1521                                 return this;
1522                         }
1523
1524                         Expression e = Convert.ImplicitConversionStandard (ec, expr, type, loc);
1525                         if (e != null) {
1526                                 e = EmptyCast.Create (e, type);
1527                                 return ReducedExpression.Create (e, this).Resolve (ec);
1528                         }
1529
1530                         if (Convert.ExplicitReferenceConversionExists (etype, type)){
1531                                 if (TypeManager.IsGenericParameter (etype))
1532                                         expr = new BoxedCast (expr, etype);
1533
1534                                 return this;
1535                         }
1536
1537                         if (InflatedTypeSpec.ContainsTypeParameter (etype) || InflatedTypeSpec.ContainsTypeParameter (type)) {
1538                                 expr = new BoxedCast (expr, etype);
1539                                 return this;
1540                         }
1541
1542                         ec.Report.Error (39, loc, "Cannot convert type `{0}' to `{1}' via a built-in conversion",
1543                                 TypeManager.CSharpName (etype), TypeManager.CSharpName (type));
1544
1545                         return null;
1546                 }
1547
1548                 protected override string OperatorName {
1549                         get { return "as"; }
1550                 }
1551         }
1552
1553         //
1554         // This represents a typecast in the source language.
1555         //
1556         public class Cast : ShimExpression {
1557                 Expression target_type;
1558
1559                 public Cast (Expression cast_type, Expression expr, Location loc)
1560                         : base (expr)
1561                 {
1562                         this.target_type = cast_type;
1563                         this.loc = loc;
1564                 }
1565
1566                 public Expression TargetType {
1567                         get { return target_type; }
1568                 }
1569
1570                 protected override Expression DoResolve (ResolveContext ec)
1571                 {
1572                         expr = expr.Resolve (ec);
1573                         if (expr == null)
1574                                 return null;
1575
1576                         TypeExpr target = target_type.ResolveAsTypeTerminal (ec, false);
1577                         if (target == null)
1578                                 return null;
1579
1580                         type = target.Type;
1581
1582                         if (type.IsStatic) {
1583                                 ec.Report.Error (716, loc, "Cannot convert to static type `{0}'", TypeManager.CSharpName (type));
1584                                 return null;
1585                         }
1586
1587                         eclass = ExprClass.Value;
1588
1589                         Constant c = expr as Constant;
1590                         if (c != null) {
1591                                 c = c.TryReduce (ec, type, loc);
1592                                 if (c != null)
1593                                         return c;
1594                         }
1595
1596                         if (type.IsPointer && !ec.IsUnsafe) {
1597                                 UnsafeError (ec, loc);
1598                         }
1599
1600                         var res = Convert.ExplicitConversion (ec, expr, type, loc);
1601                         if (res == expr)
1602                                 return EmptyCast.Create (res, type);
1603
1604                         return res;
1605                 }
1606
1607                 protected override void CloneTo (CloneContext clonectx, Expression t)
1608                 {
1609                         Cast target = (Cast) t;
1610
1611                         target.target_type = target_type.Clone (clonectx);
1612                         target.expr = expr.Clone (clonectx);
1613                 }
1614         }
1615
1616         public class ImplicitCast : ShimExpression
1617         {
1618                 bool arrayAccess;
1619
1620                 public ImplicitCast (Expression expr, TypeSpec target, bool arrayAccess)
1621                         : base (expr)
1622                 {
1623                         this.loc = expr.Location;
1624                         this.type = target;
1625                         this.arrayAccess = arrayAccess;
1626                 }
1627
1628                 protected override Expression DoResolve (ResolveContext ec)
1629                 {
1630                         expr = expr.Resolve (ec);
1631                         if (expr == null)
1632                                 return null;
1633
1634                         if (arrayAccess)
1635                                 expr = ConvertExpressionToArrayIndex (ec, expr);
1636                         else
1637                                 expr = Convert.ImplicitConversionRequired (ec, expr, type, loc);
1638
1639                         return expr;
1640                 }
1641         }
1642
1643         //
1644         // C# 2.0 Default value expression
1645         //
1646         public class DefaultValueExpression : Expression
1647         {
1648                 Expression expr;
1649
1650                 public DefaultValueExpression (Expression expr, Location loc)
1651                 {
1652                         this.expr = expr;
1653                         this.loc = loc;
1654                 }
1655
1656                 public override Expression CreateExpressionTree (ResolveContext ec)
1657                 {
1658                         Arguments args = new Arguments (2);
1659                         args.Add (new Argument (this));
1660                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1661                         return CreateExpressionFactoryCall (ec, "Constant", args);
1662                 }
1663
1664                 protected override Expression DoResolve (ResolveContext ec)
1665                 {
1666                         TypeExpr texpr = expr.ResolveAsTypeTerminal (ec, false);
1667                         if (texpr == null)
1668                                 return null;
1669
1670                         type = texpr.Type;
1671
1672                         if (type.IsStatic) {
1673                                 ec.Report.Error (-244, loc, "The `default value' operator cannot be applied to an operand of a static type");
1674                         }
1675
1676                         if (type.IsPointer)
1677                                 return new NullLiteral (Location).ConvertImplicitly (ec, type);
1678
1679                         if (TypeManager.IsReferenceType (type))
1680                                 return new NullConstant (type, loc);
1681
1682                         Constant c = New.Constantify (type, expr.Location);
1683                         if (c != null)
1684                                 return c.Resolve (ec);
1685
1686                         eclass = ExprClass.Variable;
1687                         return this;
1688                 }
1689
1690                 public override void Emit (EmitContext ec)
1691                 {
1692                         LocalTemporary temp_storage = new LocalTemporary(type);
1693
1694                         temp_storage.AddressOf(ec, AddressOp.LoadStore);
1695                         ec.Emit(OpCodes.Initobj, type);
1696                         temp_storage.Emit(ec);
1697                 }
1698
1699 #if NET_4_0 && !STATIC
1700                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1701                 {
1702                         return SLE.Expression.Default (type.GetMetaInfo ());
1703                 }
1704 #endif
1705
1706                 protected override void CloneTo (CloneContext clonectx, Expression t)
1707                 {
1708                         DefaultValueExpression target = (DefaultValueExpression) t;
1709
1710                         target.expr = expr.Clone (clonectx);
1711                 }
1712         }
1713
1714         /// <summary>
1715         ///   Binary operators
1716         /// </summary>
1717         public class Binary : Expression, IDynamicBinder
1718         {
1719                 protected class PredefinedOperator {
1720                         protected readonly TypeSpec left;
1721                         protected readonly TypeSpec right;
1722                         public readonly Operator OperatorsMask;
1723                         public TypeSpec ReturnType;
1724
1725                         public PredefinedOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask)
1726                                 : this (ltype, rtype, op_mask, ltype)
1727                         {
1728                         }
1729
1730                         public PredefinedOperator (TypeSpec type, Operator op_mask, TypeSpec return_type)
1731                                 : this (type, type, op_mask, return_type)
1732                         {
1733                         }
1734
1735                         public PredefinedOperator (TypeSpec type, Operator op_mask)
1736                                 : this (type, type, op_mask, type)
1737                         {
1738                         }
1739
1740                         public PredefinedOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask, TypeSpec return_type)
1741                         {
1742                                 if ((op_mask & Operator.ValuesOnlyMask) != 0)
1743                                         throw new InternalErrorException ("Only masked values can be used");
1744
1745                                 this.left = ltype;
1746                                 this.right = rtype;
1747                                 this.OperatorsMask = op_mask;
1748                                 this.ReturnType = return_type;
1749                         }
1750
1751                         public virtual Expression ConvertResult (ResolveContext ec, Binary b)
1752                         {
1753                                 b.type = ReturnType;
1754
1755                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
1756                                 b.right = Convert.ImplicitConversion (ec, b.right, right, b.right.Location);
1757
1758                                 //
1759                                 // A user operators does not support multiple user conversions, but decimal type
1760                                 // is considered to be predefined type therefore we apply predefined operators rules
1761                                 // and then look for decimal user-operator implementation
1762                                 //
1763                                 if (left == TypeManager.decimal_type)
1764                                         return b.ResolveUserOperator (ec, b.left, b.right);
1765
1766                                 var c = b.right as Constant;
1767                                 if (c != null) {
1768                                         if (c.IsDefaultValue && (b.oper == Operator.Addition || b.oper == Operator.Subtraction || (b.oper == Operator.BitwiseOr && !(b is Nullable.LiftedBinaryOperator))))
1769                                                 return ReducedExpression.Create (b.left, b).Resolve (ec);
1770                                         if ((b.oper == Operator.Multiply || b.oper == Operator.Division) && c.IsOneInteger)
1771                                                 return ReducedExpression.Create (b.left, b).Resolve (ec);
1772                                         return b;
1773                                 }
1774
1775                                 c = b.left as Constant;
1776                                 if (c != null) {
1777                                         if (c.IsDefaultValue && (b.oper == Operator.Addition || b.oper == Operator.Subtraction || (b.oper == Operator.BitwiseOr && !(b is Nullable.LiftedBinaryOperator))))
1778                                                 return ReducedExpression.Create (b.right, b).Resolve (ec);
1779                                         if (b.oper == Operator.Multiply && c.IsOneInteger)
1780                                                 return ReducedExpression.Create (b.right, b).Resolve (ec);
1781                                         return b;
1782                                 }
1783
1784                                 return b;
1785                         }
1786
1787                         public bool IsPrimitiveApplicable (TypeSpec ltype, TypeSpec rtype)
1788                         {
1789                                 //
1790                                 // We are dealing with primitive types only
1791                                 //
1792                                 return left == ltype && ltype == rtype;
1793                         }
1794
1795                         public virtual bool IsApplicable (ResolveContext ec, Expression lexpr, Expression rexpr)
1796                         {
1797                                 // Quick path
1798                                 if (left == lexpr.Type && right == rexpr.Type)
1799                                         return true;
1800
1801                                 return Convert.ImplicitConversionExists (ec, lexpr, left) &&
1802                                         Convert.ImplicitConversionExists (ec, rexpr, right);
1803                         }
1804
1805                         public PredefinedOperator ResolveBetterOperator (ResolveContext ec, PredefinedOperator best_operator)
1806                         {
1807                                 int result = 0;
1808                                 if (left != null && best_operator.left != null) {
1809                                         result = OverloadResolver.BetterTypeConversion (ec, best_operator.left, left);
1810                                 }
1811
1812                                 //
1813                                 // When second argument is same as the first one, the result is same
1814                                 //
1815                                 if (right != null && (left != right || best_operator.left != best_operator.right)) {
1816                                         result |= OverloadResolver.BetterTypeConversion (ec, best_operator.right, right);
1817                                 }
1818
1819                                 if (result == 0 || result > 2)
1820                                         return null;
1821
1822                                 return result == 1 ? best_operator : this;
1823                         }
1824                 }
1825
1826                 class PredefinedStringOperator : PredefinedOperator {
1827                         public PredefinedStringOperator (TypeSpec type, Operator op_mask)
1828                                 : base (type, op_mask, type)
1829                         {
1830                                 ReturnType = TypeManager.string_type;
1831                         }
1832
1833                         public PredefinedStringOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask)
1834                                 : base (ltype, rtype, op_mask)
1835                         {
1836                                 ReturnType = TypeManager.string_type;
1837                         }
1838
1839                         public override Expression ConvertResult (ResolveContext ec, Binary b)
1840                         {
1841                                 //
1842                                 // Use original expression for nullable arguments
1843                                 //
1844                                 Nullable.Unwrap unwrap = b.left as Nullable.Unwrap;
1845                                 if (unwrap != null)
1846                                         b.left = unwrap.Original;
1847
1848                                 unwrap = b.right as Nullable.Unwrap;
1849                                 if (unwrap != null)
1850                                         b.right = unwrap.Original;
1851
1852                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
1853                                 b.right = Convert.ImplicitConversion (ec, b.right, right, b.right.Location);
1854
1855                                 //
1856                                 // Start a new concat expression using converted expression
1857                                 //
1858                                 return StringConcat.Create (ec, b.left, b.right, b.loc);
1859                         }
1860                 }
1861
1862                 class PredefinedShiftOperator : PredefinedOperator {
1863                         public PredefinedShiftOperator (TypeSpec ltype, Operator op_mask) :
1864                                 base (ltype, TypeManager.int32_type, op_mask)
1865                         {
1866                         }
1867
1868                         public override Expression ConvertResult (ResolveContext ec, Binary b)
1869                         {
1870                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
1871
1872                                 Expression expr_tree_expr = Convert.ImplicitConversion (ec, b.right, TypeManager.int32_type, b.right.Location);
1873
1874                                 int right_mask = left == TypeManager.int32_type || left == TypeManager.uint32_type ? 0x1f : 0x3f;
1875
1876                                 //
1877                                 // b = b.left >> b.right & (0x1f|0x3f)
1878                                 //
1879                                 b.right = new Binary (Operator.BitwiseAnd,
1880                                         b.right, new IntConstant (right_mask, b.right.Location), b.loc).Resolve (ec);
1881
1882                                 //
1883                                 // Expression tree representation does not use & mask
1884                                 //
1885                                 b.right = ReducedExpression.Create (b.right, expr_tree_expr).Resolve (ec);
1886                                 b.type = ReturnType;
1887
1888                                 //
1889                                 // Optimize shift by 0
1890                                 //
1891                                 var c = b.right as Constant;
1892                                 if (c != null && c.IsDefaultValue)
1893                                         return ReducedExpression.Create (b.left, b).Resolve (ec);
1894
1895                                 return b;
1896                         }
1897                 }
1898
1899                 class PredefinedEqualityOperator : PredefinedOperator
1900                 {
1901                         MethodSpec equal_method, inequal_method;
1902
1903                         public PredefinedEqualityOperator (TypeSpec arg, TypeSpec retType)
1904                                 : base (arg, arg, Operator.EqualityMask, retType)
1905                         {
1906                         }
1907
1908                         public override Expression ConvertResult (ResolveContext ec, Binary b)
1909                         {
1910                                 b.type = ReturnType;
1911
1912                                 b.left = Convert.ImplicitConversion (ec, b.left, left, b.left.Location);
1913                                 b.right = Convert.ImplicitConversion (ec, b.right, right, b.right.Location);
1914
1915                                 Arguments args = new Arguments (2);
1916                                 args.Add (new Argument (b.left));
1917                                 args.Add (new Argument (b.right));
1918
1919                                 MethodSpec method;
1920                                 if (b.oper == Operator.Equality) {
1921                                         if (equal_method == null) {
1922                                                 equal_method = TypeManager.GetPredefinedMethod (left,
1923                                                         new MemberFilter (CSharp.Operator.GetMetadataName (CSharp.Operator.OpType.Equality), 0, MemberKind.Operator, null, ReturnType), b.loc);
1924                                         }
1925
1926                                         method = equal_method;
1927                                 } else {
1928                                         if (inequal_method == null) {
1929                                                 inequal_method = TypeManager.GetPredefinedMethod (left,
1930                                                         new MemberFilter (CSharp.Operator.GetMetadataName (CSharp.Operator.OpType.Inequality), 0, MemberKind.Operator, null, ReturnType), b.loc);
1931                                         }
1932
1933                                         method = inequal_method;
1934                                 }
1935
1936                                 return new UserOperatorCall (method, args, b.CreateExpressionTree, b.loc);
1937                         }
1938                 }
1939
1940                 class PredefinedPointerOperator : PredefinedOperator
1941                 {
1942                         public PredefinedPointerOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask)
1943                                 : base (ltype, rtype, op_mask)
1944                         {
1945                         }
1946
1947                         public PredefinedPointerOperator (TypeSpec ltype, TypeSpec rtype, Operator op_mask, TypeSpec retType)
1948                                 : base (ltype, rtype, op_mask, retType)
1949                         {
1950                         }
1951
1952                         public PredefinedPointerOperator (TypeSpec type, Operator op_mask, TypeSpec return_type)
1953                                 : base (type, op_mask, return_type)
1954                         {
1955                         }
1956
1957                         public override bool IsApplicable (ResolveContext ec, Expression lexpr, Expression rexpr)
1958                         {
1959                                 if (left == null) {
1960                                         if (!lexpr.Type.IsPointer)
1961                                                 return false;
1962                                 } else {
1963                                         if (!Convert.ImplicitConversionExists (ec, lexpr, left))
1964                                                 return false;
1965                                 }
1966
1967                                 if (right == null) {
1968                                         if (!rexpr.Type.IsPointer)
1969                                                 return false;
1970                                 } else {
1971                                         if (!Convert.ImplicitConversionExists (ec, rexpr, right))
1972                                                 return false;
1973                                 }
1974
1975                                 return true;
1976                         }
1977
1978                         public override Expression ConvertResult (ResolveContext ec, Binary b)
1979                         {
1980                                 if (left != null) {
1981                                         b.left = EmptyCast.Create (b.left, left);
1982                                 } else if (right != null) {
1983                                         b.right = EmptyCast.Create (b.right, right);
1984                                 }
1985
1986                                 TypeSpec r_type = ReturnType;
1987                                 Expression left_arg, right_arg;
1988                                 if (r_type == null) {
1989                                         if (left == null) {
1990                                                 left_arg = b.left;
1991                                                 right_arg = b.right;
1992                                                 r_type = b.left.Type;
1993                                         } else {
1994                                                 left_arg = b.right;
1995                                                 right_arg = b.left;
1996                                                 r_type = b.right.Type;
1997                                         }
1998                                 } else {
1999                                         left_arg = b.left;
2000                                         right_arg = b.right;
2001                                 }
2002
2003                                 return new PointerArithmetic (b.oper, left_arg, right_arg, r_type, b.loc).Resolve (ec);
2004                         }
2005                 }
2006
2007                 [Flags]
2008                 public enum Operator {
2009                         Multiply        = 0 | ArithmeticMask,
2010                         Division        = 1 | ArithmeticMask,
2011                         Modulus         = 2 | ArithmeticMask,
2012                         Addition        = 3 | ArithmeticMask | AdditionMask,
2013                         Subtraction = 4 | ArithmeticMask | SubtractionMask,
2014
2015                         LeftShift       = 5 | ShiftMask,
2016                         RightShift      = 6 | ShiftMask,
2017
2018                         LessThan        = 7 | ComparisonMask | RelationalMask,
2019                         GreaterThan     = 8 | ComparisonMask | RelationalMask,
2020                         LessThanOrEqual         = 9 | ComparisonMask | RelationalMask,
2021                         GreaterThanOrEqual      = 10 | ComparisonMask | RelationalMask,
2022                         Equality        = 11 | ComparisonMask | EqualityMask,
2023                         Inequality      = 12 | ComparisonMask | EqualityMask,
2024
2025                         BitwiseAnd      = 13 | BitwiseMask,
2026                         ExclusiveOr     = 14 | BitwiseMask,
2027                         BitwiseOr       = 15 | BitwiseMask,
2028
2029                         LogicalAnd      = 16 | LogicalMask,
2030                         LogicalOr       = 17 | LogicalMask,
2031
2032                         //
2033                         // Operator masks
2034                         //
2035                         ValuesOnlyMask  = ArithmeticMask - 1,
2036                         ArithmeticMask  = 1 << 5,
2037                         ShiftMask               = 1 << 6,
2038                         ComparisonMask  = 1 << 7,
2039                         EqualityMask    = 1 << 8,
2040                         BitwiseMask             = 1 << 9,
2041                         LogicalMask             = 1 << 10,
2042                         AdditionMask    = 1 << 11,
2043                         SubtractionMask = 1 << 12,
2044                         RelationalMask  = 1 << 13
2045                 }
2046
2047                 protected enum State
2048                 {
2049                         None = 0,
2050                         Compound = 1 << 1,
2051                         LeftNullLifted = 1 << 2,
2052                         RightNullLifted = 1 << 3
2053                 }
2054
2055                 readonly Operator oper;
2056                 protected Expression left, right;
2057                 protected State state;
2058                 Expression enum_conversion;
2059
2060                 static PredefinedOperator[] standard_operators;
2061                 static PredefinedOperator[] equality_operators;
2062                 static PredefinedOperator[] pointer_operators;
2063
2064                 public Binary (Operator oper, Expression left, Expression right, bool isCompound, Location loc)
2065                         : this (oper, left, right, loc)
2066                 {
2067                         if (isCompound)
2068                                 state |= State.Compound;
2069                 }
2070
2071                 public Binary (Operator oper, Expression left, Expression right, Location loc)
2072                 {
2073                         this.oper = oper;
2074                         this.left = left;
2075                         this.right = right;
2076                         this.loc = loc;
2077                 }
2078
2079                 #region Properties
2080
2081                 public bool IsCompound {
2082                         get {
2083                                 return (state & State.Compound) != 0;
2084                         }
2085                 }
2086
2087                 public Operator Oper {
2088                         get {
2089                                 return oper;
2090                         }
2091                 }
2092
2093                 #endregion
2094
2095                 /// <summary>
2096                 ///   Returns a stringified representation of the Operator
2097                 /// </summary>
2098                 string OperName (Operator oper)
2099                 {
2100                         string s;
2101                         switch (oper){
2102                         case Operator.Multiply:
2103                                 s = "*";
2104                                 break;
2105                         case Operator.Division:
2106                                 s = "/";
2107                                 break;
2108                         case Operator.Modulus:
2109                                 s = "%";
2110                                 break;
2111                         case Operator.Addition:
2112                                 s = "+";
2113                                 break;
2114                         case Operator.Subtraction:
2115                                 s = "-";
2116                                 break;
2117                         case Operator.LeftShift:
2118                                 s = "<<";
2119                                 break;
2120                         case Operator.RightShift:
2121                                 s = ">>";
2122                                 break;
2123                         case Operator.LessThan:
2124                                 s = "<";
2125                                 break;
2126                         case Operator.GreaterThan:
2127                                 s = ">";
2128                                 break;
2129                         case Operator.LessThanOrEqual:
2130                                 s = "<=";
2131                                 break;
2132                         case Operator.GreaterThanOrEqual:
2133                                 s = ">=";
2134                                 break;
2135                         case Operator.Equality:
2136                                 s = "==";
2137                                 break;
2138                         case Operator.Inequality:
2139                                 s = "!=";
2140                                 break;
2141                         case Operator.BitwiseAnd:
2142                                 s = "&";
2143                                 break;
2144                         case Operator.BitwiseOr:
2145                                 s = "|";
2146                                 break;
2147                         case Operator.ExclusiveOr:
2148                                 s = "^";
2149                                 break;
2150                         case Operator.LogicalOr:
2151                                 s = "||";
2152                                 break;
2153                         case Operator.LogicalAnd:
2154                                 s = "&&";
2155                                 break;
2156                         default:
2157                                 s = oper.ToString ();
2158                                 break;
2159                         }
2160
2161                         if (IsCompound)
2162                                 return s + "=";
2163
2164                         return s;
2165                 }
2166
2167                 public static void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right, Operator oper, Location loc)
2168                 {
2169                         new Binary (oper, left, right, loc).Error_OperatorCannotBeApplied (ec, left, right);
2170                 }
2171
2172                 public static void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right, string oper, Location loc)
2173                 {
2174                         string l, r;
2175                         l = TypeManager.CSharpName (left.Type);
2176                         r = TypeManager.CSharpName (right.Type);
2177
2178                         ec.Report.Error (19, loc, "Operator `{0}' cannot be applied to operands of type `{1}' and `{2}'",
2179                                 oper, l, r);
2180                 }
2181
2182                 protected void Error_OperatorCannotBeApplied (ResolveContext ec, Expression left, Expression right)
2183                 {
2184                         Error_OperatorCannotBeApplied (ec, left, right, OperName (oper), loc);
2185                 }
2186
2187                 //
2188                 // Converts operator to System.Linq.Expressions.ExpressionType enum name
2189                 //
2190                 string GetOperatorExpressionTypeName ()
2191                 {
2192                         switch (oper) {
2193                         case Operator.Addition:
2194                                 return IsCompound ? "AddAssign" : "Add";
2195                         case Operator.BitwiseAnd:
2196                                 return IsCompound ? "AndAssign" : "And";
2197                         case Operator.BitwiseOr:
2198                                 return IsCompound ? "OrAssign" : "Or";
2199                         case Operator.Division:
2200                                 return IsCompound ? "DivideAssign" : "Divide";
2201                         case Operator.ExclusiveOr:
2202                                 return IsCompound ? "ExclusiveOrAssign" : "ExclusiveOr";
2203                         case Operator.Equality:
2204                                 return "Equal";
2205                         case Operator.GreaterThan:
2206                                 return "GreaterThan";
2207                         case Operator.GreaterThanOrEqual:
2208                                 return "GreaterThanOrEqual";
2209                         case Operator.Inequality:
2210                                 return "NotEqual";
2211                         case Operator.LeftShift:
2212                                 return IsCompound ? "LeftShiftAssign" : "LeftShift";
2213                         case Operator.LessThan:
2214                                 return "LessThan";
2215                         case Operator.LessThanOrEqual:
2216                                 return "LessThanOrEqual";
2217                         case Operator.LogicalAnd:
2218                                 return "And";
2219                         case Operator.LogicalOr:
2220                                 return "Or";
2221                         case Operator.Modulus:
2222                                 return IsCompound ? "ModuloAssign" : "Modulo";
2223                         case Operator.Multiply:
2224                                 return IsCompound ? "MultiplyAssign" : "Multiply";
2225                         case Operator.RightShift:
2226                                 return IsCompound ? "RightShiftAssign" : "RightShift";
2227                         case Operator.Subtraction:
2228                                 return IsCompound ? "SubtractAssign" : "Subtract";
2229                         default:
2230                                 throw new NotImplementedException ("Unknown expression type operator " + oper.ToString ());
2231                         }
2232                 }
2233
2234                 static CSharp.Operator.OpType ConvertBinaryToUserOperator (Operator op)
2235                 {
2236                         switch (op) {
2237                         case Operator.Addition:
2238                                 return CSharp.Operator.OpType.Addition;
2239                         case Operator.BitwiseAnd:
2240                         case Operator.LogicalAnd:
2241                                 return CSharp.Operator.OpType.BitwiseAnd;
2242                         case Operator.BitwiseOr:
2243                         case Operator.LogicalOr:
2244                                 return CSharp.Operator.OpType.BitwiseOr;
2245                         case Operator.Division:
2246                                 return CSharp.Operator.OpType.Division;
2247                         case Operator.Equality:
2248                                 return CSharp.Operator.OpType.Equality;
2249                         case Operator.ExclusiveOr:
2250                                 return CSharp.Operator.OpType.ExclusiveOr;
2251                         case Operator.GreaterThan:
2252                                 return CSharp.Operator.OpType.GreaterThan;
2253                         case Operator.GreaterThanOrEqual:
2254                                 return CSharp.Operator.OpType.GreaterThanOrEqual;
2255                         case Operator.Inequality:
2256                                 return CSharp.Operator.OpType.Inequality;
2257                         case Operator.LeftShift:
2258                                 return CSharp.Operator.OpType.LeftShift;
2259                         case Operator.LessThan:
2260                                 return CSharp.Operator.OpType.LessThan;
2261                         case Operator.LessThanOrEqual:
2262                                 return CSharp.Operator.OpType.LessThanOrEqual;
2263                         case Operator.Modulus:
2264                                 return CSharp.Operator.OpType.Modulus;
2265                         case Operator.Multiply:
2266                                 return CSharp.Operator.OpType.Multiply;
2267                         case Operator.RightShift:
2268                                 return CSharp.Operator.OpType.RightShift;
2269                         case Operator.Subtraction:
2270                                 return CSharp.Operator.OpType.Subtraction;
2271                         default:
2272                                 throw new InternalErrorException (op.ToString ());
2273                         }
2274                 }
2275
2276                 public static void EmitOperatorOpcode (EmitContext ec, Operator oper, TypeSpec l)
2277                 {
2278                         OpCode opcode;
2279
2280                         switch (oper){
2281                         case Operator.Multiply:
2282                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2283                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2284                                                 opcode = OpCodes.Mul_Ovf;
2285                                         else if (!IsFloat (l))
2286                                                 opcode = OpCodes.Mul_Ovf_Un;
2287                                         else
2288                                                 opcode = OpCodes.Mul;
2289                                 } else
2290                                         opcode = OpCodes.Mul;
2291
2292                                 break;
2293
2294                         case Operator.Division:
2295                                 if (IsUnsigned (l))
2296                                         opcode = OpCodes.Div_Un;
2297                                 else
2298                                         opcode = OpCodes.Div;
2299                                 break;
2300
2301                         case Operator.Modulus:
2302                                 if (IsUnsigned (l))
2303                                         opcode = OpCodes.Rem_Un;
2304                                 else
2305                                         opcode = OpCodes.Rem;
2306                                 break;
2307
2308                         case Operator.Addition:
2309                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2310                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2311                                                 opcode = OpCodes.Add_Ovf;
2312                                         else if (!IsFloat (l))
2313                                                 opcode = OpCodes.Add_Ovf_Un;
2314                                         else
2315                                                 opcode = OpCodes.Add;
2316                                 } else
2317                                         opcode = OpCodes.Add;
2318                                 break;
2319
2320                         case Operator.Subtraction:
2321                                 if (ec.HasSet (EmitContext.Options.CheckedScope)) {
2322                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2323                                                 opcode = OpCodes.Sub_Ovf;
2324                                         else if (!IsFloat (l))
2325                                                 opcode = OpCodes.Sub_Ovf_Un;
2326                                         else
2327                                                 opcode = OpCodes.Sub;
2328                                 } else
2329                                         opcode = OpCodes.Sub;
2330                                 break;
2331
2332                         case Operator.RightShift:
2333                                 if (IsUnsigned (l))
2334                                         opcode = OpCodes.Shr_Un;
2335                                 else
2336                                         opcode = OpCodes.Shr;
2337                                 break;
2338
2339                         case Operator.LeftShift:
2340                                 opcode = OpCodes.Shl;
2341                                 break;
2342
2343                         case Operator.Equality:
2344                                 opcode = OpCodes.Ceq;
2345                                 break;
2346
2347                         case Operator.Inequality:
2348                                 ec.Emit (OpCodes.Ceq);
2349                                 ec.Emit (OpCodes.Ldc_I4_0);
2350
2351                                 opcode = OpCodes.Ceq;
2352                                 break;
2353
2354                         case Operator.LessThan:
2355                                 if (IsUnsigned (l))
2356                                         opcode = OpCodes.Clt_Un;
2357                                 else
2358                                         opcode = OpCodes.Clt;
2359                                 break;
2360
2361                         case Operator.GreaterThan:
2362                                 if (IsUnsigned (l))
2363                                         opcode = OpCodes.Cgt_Un;
2364                                 else
2365                                         opcode = OpCodes.Cgt;
2366                                 break;
2367
2368                         case Operator.LessThanOrEqual:
2369                                 if (IsUnsigned (l) || IsFloat (l))
2370                                         ec.Emit (OpCodes.Cgt_Un);
2371                                 else
2372                                         ec.Emit (OpCodes.Cgt);
2373                                 ec.Emit (OpCodes.Ldc_I4_0);
2374
2375                                 opcode = OpCodes.Ceq;
2376                                 break;
2377
2378                         case Operator.GreaterThanOrEqual:
2379                                 if (IsUnsigned (l) || IsFloat (l))
2380                                         ec.Emit (OpCodes.Clt_Un);
2381                                 else
2382                                         ec.Emit (OpCodes.Clt);
2383
2384                                 ec.Emit (OpCodes.Ldc_I4_0);
2385
2386                                 opcode = OpCodes.Ceq;
2387                                 break;
2388
2389                         case Operator.BitwiseOr:
2390                                 opcode = OpCodes.Or;
2391                                 break;
2392
2393                         case Operator.BitwiseAnd:
2394                                 opcode = OpCodes.And;
2395                                 break;
2396
2397                         case Operator.ExclusiveOr:
2398                                 opcode = OpCodes.Xor;
2399                                 break;
2400
2401                         default:
2402                                 throw new InternalErrorException (oper.ToString ());
2403                         }
2404
2405                         ec.Emit (opcode);
2406                 }
2407
2408                 static bool IsUnsigned (TypeSpec t)
2409                 {
2410                         if (t.IsPointer)
2411                                 return true;
2412
2413                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
2414                                 t == TypeManager.ushort_type || t == TypeManager.byte_type);
2415                 }
2416
2417                 static bool IsFloat (TypeSpec t)
2418                 {
2419                         return t == TypeManager.float_type || t == TypeManager.double_type;
2420                 }
2421
2422                 public static void Reset ()
2423                 {
2424                         equality_operators = pointer_operators = standard_operators = null;
2425                 }
2426
2427                 Expression ResolveOperator (ResolveContext ec)
2428                 {
2429                         TypeSpec l = left.Type;
2430                         TypeSpec r = right.Type;
2431                         Expression expr;
2432                         bool primitives_only = false;
2433
2434                         if (standard_operators == null)
2435                                 CreateStandardOperatorsTable ();
2436
2437                         //
2438                         // Handles predefined primitive types
2439                         //
2440                         if (TypeManager.IsPrimitiveType (l) && TypeManager.IsPrimitiveType (r)) {
2441                                 if ((oper & Operator.ShiftMask) == 0) {
2442                                         if (l != TypeManager.bool_type && !DoBinaryOperatorPromotion (ec))
2443                                                 return null;
2444
2445                                         primitives_only = true;
2446                                 }
2447                         } else {
2448                                 // Pointers
2449                                 if (l.IsPointer || r.IsPointer)
2450                                         return ResolveOperatorPointer (ec, l, r);
2451
2452                                 // Enums
2453                                 bool lenum = l.IsEnum;
2454                                 bool renum = r.IsEnum;
2455                                 if (lenum || renum) {
2456                                         expr = ResolveOperatorEnum (ec, lenum, renum, l, r);
2457
2458                                         if (expr != null)
2459                                                 return expr;
2460                                 }
2461
2462                                 // Delegates
2463                                 if ((oper == Operator.Addition || oper == Operator.Subtraction) && (l.IsDelegate || r.IsDelegate)) {
2464
2465                                         expr = ResolveOperatorDelegate (ec, l, r);
2466
2467                                         // TODO: Can this be ambiguous
2468                                         if (expr != null)
2469                                                 return expr;
2470                                 }
2471
2472                                 // User operators
2473                                 expr = ResolveUserOperator (ec, left, right);
2474                                 if (expr != null)
2475                                         return expr;
2476
2477                                 // Predefined reference types equality
2478                                 if ((oper & Operator.EqualityMask) != 0) {
2479                                         expr = ResolveOperatorEquality (ec, l, r);
2480                                         if (expr != null)
2481                                                 return expr;
2482                                 }
2483                         }
2484
2485                         return ResolveOperatorPredefined (ec, standard_operators, primitives_only, null);
2486                 }
2487
2488                 // at least one of 'left' or 'right' is an enumeration constant (EnumConstant or SideEffectConstant or ...)
2489                 // if 'left' is not an enumeration constant, create one from the type of 'right'
2490                 Constant EnumLiftUp (ResolveContext ec, Constant left, Constant right, Location loc)
2491                 {
2492                         switch (oper) {
2493                         case Operator.BitwiseOr:
2494                         case Operator.BitwiseAnd:
2495                         case Operator.ExclusiveOr:
2496                         case Operator.Equality:
2497                         case Operator.Inequality:
2498                         case Operator.LessThan:
2499                         case Operator.LessThanOrEqual:
2500                         case Operator.GreaterThan:
2501                         case Operator.GreaterThanOrEqual:
2502                                 if (TypeManager.IsEnumType (left.Type))
2503                                         return left;
2504
2505                                 if (left.IsZeroInteger)
2506                                         return left.TryReduce (ec, right.Type, loc);
2507
2508                                 break;
2509
2510                         case Operator.Addition:
2511                         case Operator.Subtraction:
2512                                 return left;
2513
2514                         case Operator.Multiply:
2515                         case Operator.Division:
2516                         case Operator.Modulus:
2517                         case Operator.LeftShift:
2518                         case Operator.RightShift:
2519                                 if (TypeManager.IsEnumType (right.Type) || TypeManager.IsEnumType (left.Type))
2520                                         break;
2521                                 return left;
2522                         }
2523                         Error_OperatorCannotBeApplied (ec, this.left, this.right);
2524                         return null;
2525                 }
2526
2527                 //
2528                 // The `|' operator used on types which were extended is dangerous
2529                 //
2530                 void CheckBitwiseOrOnSignExtended (ResolveContext ec)
2531                 {
2532                         OpcodeCast lcast = left as OpcodeCast;
2533                         if (lcast != null) {
2534                                 if (IsUnsigned (lcast.UnderlyingType))
2535                                         lcast = null;
2536                         }
2537
2538                         OpcodeCast rcast = right as OpcodeCast;
2539                         if (rcast != null) {
2540                                 if (IsUnsigned (rcast.UnderlyingType))
2541                                         rcast = null;
2542                         }
2543
2544                         if (lcast == null && rcast == null)
2545                                 return;
2546
2547                         // FIXME: consider constants
2548
2549                         ec.Report.Warning (675, 3, loc,
2550                                 "The operator `|' used on the sign-extended type `{0}'. Consider casting to a smaller unsigned type first",
2551                                 TypeManager.CSharpName (lcast != null ? lcast.UnderlyingType : rcast.UnderlyingType));
2552                 }
2553
2554                 static void CreatePointerOperatorsTable ()
2555                 {
2556                         var temp = new List<PredefinedPointerOperator> ();
2557
2558                         //
2559                         // Pointer arithmetic:
2560                         //
2561                         // T* operator + (T* x, int y);         T* operator - (T* x, int y);
2562                         // T* operator + (T* x, uint y);        T* operator - (T* x, uint y);
2563                         // T* operator + (T* x, long y);        T* operator - (T* x, long y);
2564                         // T* operator + (T* x, ulong y);       T* operator - (T* x, ulong y);
2565                         //
2566                         temp.Add (new PredefinedPointerOperator (null, TypeManager.int32_type, Operator.AdditionMask | Operator.SubtractionMask));
2567                         temp.Add (new PredefinedPointerOperator (null, TypeManager.uint32_type, Operator.AdditionMask | Operator.SubtractionMask));
2568                         temp.Add (new PredefinedPointerOperator (null, TypeManager.int64_type, Operator.AdditionMask | Operator.SubtractionMask));
2569                         temp.Add (new PredefinedPointerOperator (null, TypeManager.uint64_type, Operator.AdditionMask | Operator.SubtractionMask));
2570
2571                         //
2572                         // T* operator + (int y,   T* x);
2573                         // T* operator + (uint y,  T *x);
2574                         // T* operator + (long y,  T *x);
2575                         // T* operator + (ulong y, T *x);
2576                         //
2577                         temp.Add (new PredefinedPointerOperator (TypeManager.int32_type, null, Operator.AdditionMask, null));
2578                         temp.Add (new PredefinedPointerOperator (TypeManager.uint32_type, null, Operator.AdditionMask, null));
2579                         temp.Add (new PredefinedPointerOperator (TypeManager.int64_type, null, Operator.AdditionMask, null));
2580                         temp.Add (new PredefinedPointerOperator (TypeManager.uint64_type, null, Operator.AdditionMask, null));
2581
2582                         //
2583                         // long operator - (T* x, T *y)
2584                         //
2585                         temp.Add (new PredefinedPointerOperator (null, Operator.SubtractionMask, TypeManager.int64_type));
2586
2587                         pointer_operators = temp.ToArray ();
2588                 }
2589
2590                 static void CreateStandardOperatorsTable ()
2591                 {
2592                         var temp = new List<PredefinedOperator> ();
2593                         TypeSpec bool_type = TypeManager.bool_type;
2594
2595                         temp.Add (new PredefinedOperator (TypeManager.int32_type, Operator.ArithmeticMask | Operator.BitwiseMask));
2596                         temp.Add (new PredefinedOperator (TypeManager.uint32_type, Operator.ArithmeticMask | Operator.BitwiseMask));
2597                         temp.Add (new PredefinedOperator (TypeManager.int64_type, Operator.ArithmeticMask | Operator.BitwiseMask));
2598                         temp.Add (new PredefinedOperator (TypeManager.uint64_type, Operator.ArithmeticMask | Operator.BitwiseMask));
2599                         temp.Add (new PredefinedOperator (TypeManager.float_type, Operator.ArithmeticMask));
2600                         temp.Add (new PredefinedOperator (TypeManager.double_type, Operator.ArithmeticMask));
2601                         temp.Add (new PredefinedOperator (TypeManager.decimal_type, Operator.ArithmeticMask));
2602
2603                         temp.Add (new PredefinedOperator (TypeManager.int32_type, Operator.ComparisonMask, bool_type));
2604                         temp.Add (new PredefinedOperator (TypeManager.uint32_type, Operator.ComparisonMask, bool_type));
2605                         temp.Add (new PredefinedOperator (TypeManager.int64_type, Operator.ComparisonMask, bool_type));
2606                         temp.Add (new PredefinedOperator (TypeManager.uint64_type, Operator.ComparisonMask, bool_type));
2607                         temp.Add (new PredefinedOperator (TypeManager.float_type, Operator.ComparisonMask, bool_type));
2608                         temp.Add (new PredefinedOperator (TypeManager.double_type, Operator.ComparisonMask, bool_type));
2609                         temp.Add (new PredefinedOperator (TypeManager.decimal_type, Operator.ComparisonMask, bool_type));
2610
2611                         temp.Add (new PredefinedStringOperator (TypeManager.string_type, Operator.AdditionMask));
2612                         temp.Add (new PredefinedStringOperator (TypeManager.string_type, TypeManager.object_type, Operator.AdditionMask));
2613                         temp.Add (new PredefinedStringOperator (TypeManager.object_type, TypeManager.string_type, Operator.AdditionMask));
2614
2615                         temp.Add (new PredefinedOperator (bool_type,
2616                                 Operator.BitwiseMask | Operator.LogicalMask | Operator.EqualityMask, bool_type));
2617
2618                         temp.Add (new PredefinedShiftOperator (TypeManager.int32_type, Operator.ShiftMask));
2619                         temp.Add (new PredefinedShiftOperator (TypeManager.uint32_type, Operator.ShiftMask));
2620                         temp.Add (new PredefinedShiftOperator (TypeManager.int64_type, Operator.ShiftMask));
2621                         temp.Add (new PredefinedShiftOperator (TypeManager.uint64_type, Operator.ShiftMask));
2622
2623                         standard_operators = temp.ToArray ();
2624
2625                         var equality = new List<PredefinedOperator> () {
2626                                 new PredefinedEqualityOperator (TypeManager.string_type, bool_type),
2627                                 new PredefinedEqualityOperator (TypeManager.delegate_type, bool_type),
2628                                 new PredefinedOperator (bool_type, Operator.EqualityMask, bool_type)
2629                         };
2630
2631                         equality_operators = equality.ToArray ();
2632                 }
2633
2634                 //
2635                 // Rules used during binary numeric promotion
2636                 //
2637                 static bool DoNumericPromotion (ResolveContext rc, ref Expression prim_expr, ref Expression second_expr, TypeSpec type)
2638                 {
2639                         Expression temp;
2640                         TypeSpec etype;
2641
2642                         Constant c = prim_expr as Constant;
2643                         if (c != null) {
2644                                 temp = c.ConvertImplicitly (rc, type);
2645                                 if (temp != null) {
2646                                         prim_expr = temp;
2647                                         return true;
2648                                 }
2649                         }
2650
2651                         if (type == TypeManager.uint32_type) {
2652                                 etype = prim_expr.Type;
2653                                 if (etype == TypeManager.int32_type || etype == TypeManager.short_type || etype == TypeManager.sbyte_type) {
2654                                         type = TypeManager.int64_type;
2655
2656                                         if (type != second_expr.Type) {
2657                                                 c = second_expr as Constant;
2658                                                 if (c != null)
2659                                                         temp = c.ConvertImplicitly (rc, type);
2660                                                 else
2661                                                         temp = Convert.ImplicitNumericConversion (second_expr, type);
2662                                                 if (temp == null)
2663                                                         return false;
2664                                                 second_expr = temp;
2665                                         }
2666                                 }
2667                         } else if (type == TypeManager.uint64_type) {
2668                                 //
2669                                 // A compile-time error occurs if the other operand is of type sbyte, short, int, or long
2670                                 //
2671                                 if (type == TypeManager.int32_type || type == TypeManager.int64_type ||
2672                                         type == TypeManager.short_type || type == TypeManager.sbyte_type)
2673                                         return false;
2674                         }
2675
2676                         temp = Convert.ImplicitNumericConversion (prim_expr, type);
2677                         if (temp == null)
2678                                 return false;
2679
2680                         prim_expr = temp;
2681                         return true;
2682                 }
2683
2684                 //
2685                 // 7.2.6.2 Binary numeric promotions
2686                 //
2687                 public bool DoBinaryOperatorPromotion (ResolveContext ec)
2688                 {
2689                         TypeSpec ltype = left.Type;
2690                         TypeSpec rtype = right.Type;
2691                         Expression temp;
2692
2693                         foreach (TypeSpec t in ConstantFold.BinaryPromotionsTypes) {
2694                                 if (t == ltype)
2695                                         return t == rtype || DoNumericPromotion (ec, ref right, ref left, t);
2696
2697                                 if (t == rtype)
2698                                         return t == ltype || DoNumericPromotion (ec, ref left, ref right, t);
2699                         }
2700
2701                         TypeSpec int32 = TypeManager.int32_type;
2702                         if (ltype != int32) {
2703                                 Constant c = left as Constant;
2704                                 if (c != null)
2705                                         temp = c.ConvertImplicitly (ec, int32);
2706                                 else
2707                                         temp = Convert.ImplicitNumericConversion (left, int32);
2708
2709                                 if (temp == null)
2710                                         return false;
2711                                 left = temp;
2712                         }
2713
2714                         if (rtype != int32) {
2715                                 Constant c = right as Constant;
2716                                 if (c != null)
2717                                         temp = c.ConvertImplicitly (ec, int32);
2718                                 else
2719                                         temp = Convert.ImplicitNumericConversion (right, int32);
2720
2721                                 if (temp == null)
2722                                         return false;
2723                                 right = temp;
2724                         }
2725
2726                         return true;
2727                 }
2728
2729                 protected override Expression DoResolve (ResolveContext ec)
2730                 {
2731                         if (left == null)
2732                                 return null;
2733
2734                         if ((oper == Operator.Subtraction) && (left is ParenthesizedExpression)) {
2735                                 left = ((ParenthesizedExpression) left).Expr;
2736                                 left = left.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.Type);
2737                                 if (left == null)
2738                                         return null;
2739
2740                                 if (left.eclass == ExprClass.Type) {
2741                                         ec.Report.Error (75, loc, "To cast a negative value, you must enclose the value in parentheses");
2742                                         return null;
2743                                 }
2744                         } else
2745                                 left = left.Resolve (ec);
2746
2747                         if (left == null)
2748                                 return null;
2749
2750                         Constant lc = left as Constant;
2751
2752                         if (lc != null && lc.Type == TypeManager.bool_type &&
2753                                 ((oper == Operator.LogicalAnd && lc.IsDefaultValue) ||
2754                                  (oper == Operator.LogicalOr && !lc.IsDefaultValue))) {
2755
2756                                 // FIXME: resolve right expression as unreachable
2757                                 // right.Resolve (ec);
2758
2759                                 ec.Report.Warning (429, 4, loc, "Unreachable expression code detected");
2760                                 return left;
2761                         }
2762
2763                         right = right.Resolve (ec);
2764                         if (right == null)
2765                                 return null;
2766
2767                         eclass = ExprClass.Value;
2768                         Constant rc = right as Constant;
2769
2770                         // The conversion rules are ignored in enum context but why
2771                         if (!ec.HasSet (ResolveContext.Options.EnumScope) && lc != null && rc != null && (TypeManager.IsEnumType (left.Type) || TypeManager.IsEnumType (right.Type))) {
2772                                 lc = EnumLiftUp (ec, lc, rc, loc);
2773                                 if (lc != null)
2774                                         rc = EnumLiftUp (ec, rc, lc, loc);
2775                         }
2776
2777                         if (rc != null && lc != null) {
2778                                 int prev_e = ec.Report.Errors;
2779                                 Expression e = ConstantFold.BinaryFold (ec, oper, lc, rc, loc);
2780                                 if (e != null)
2781                                         e = e.Resolve (ec);
2782
2783                                 if (e != null || ec.Report.Errors != prev_e)
2784                                         return e;
2785                         }
2786
2787                         // Comparison warnings
2788                         if ((oper & Operator.ComparisonMask) != 0) {
2789                                 if (left.Equals (right)) {
2790                                         ec.Report.Warning (1718, 3, loc, "A comparison made to same variable. Did you mean to compare something else?");
2791                                 }
2792                                 CheckUselessComparison (ec, lc, right.Type);
2793                                 CheckUselessComparison (ec, rc, left.Type);
2794                         }
2795
2796                         if (left.Type == InternalType.Dynamic || right.Type == InternalType.Dynamic) {
2797                                 var lt = left.Type;
2798                                 var rt = right.Type;
2799                                 if (lt == TypeManager.void_type || lt == InternalType.MethodGroup || lt == InternalType.AnonymousMethod ||
2800                                         rt == TypeManager.void_type || rt == InternalType.MethodGroup || rt == InternalType.AnonymousMethod) {
2801                                         Error_OperatorCannotBeApplied (ec, left, right);
2802                                         return null;
2803                                 }
2804
2805                                 Arguments args;
2806
2807                                 //
2808                                 // Special handling for logical boolean operators which require rhs not to be
2809                                 // evaluated based on lhs value
2810                                 //
2811                                 if ((oper & Operator.LogicalMask) != 0) {
2812                                         Expression cond_left, cond_right, expr;
2813
2814                                         args = new Arguments (2);
2815
2816                                         if (lt == InternalType.Dynamic) {
2817                                                 LocalVariable temp = LocalVariable.CreateCompilerGenerated (lt, ec.CurrentBlock, loc);
2818
2819                                                 var cond_args = new Arguments (1);
2820                                                 cond_args.Add (new Argument (new SimpleAssign (temp.CreateReferenceExpression (ec, loc), left).Resolve (ec)));
2821
2822                                                 //
2823                                                 // dynamic && bool => IsFalse (temp = left) ? temp : temp && right;
2824                                                 // dynamic || bool => IsTrue (temp = left) ? temp : temp || right;
2825                                                 //
2826                                                 left = temp.CreateReferenceExpression (ec, loc);
2827                                                 if (oper == Operator.LogicalAnd) {
2828                                                         expr = DynamicUnaryConversion.CreateIsFalse (cond_args, loc);
2829                                                         cond_left = left;
2830                                                 } else {
2831                                                         expr = DynamicUnaryConversion.CreateIsTrue (cond_args, loc);
2832                                                         cond_left = left;
2833                                                 }
2834
2835                                                 args.Add (new Argument (left));
2836                                                 args.Add (new Argument (right));
2837                                                 cond_right = new DynamicExpressionStatement (this, args, loc);
2838                                         } else {
2839                                                 LocalVariable temp = LocalVariable.CreateCompilerGenerated (TypeManager.bool_type, ec.CurrentBlock, loc);
2840
2841                                                 args.Add (new Argument (temp.CreateReferenceExpression (ec, loc).Resolve (ec)));
2842                                                 args.Add (new Argument (right));
2843                                                 right = new DynamicExpressionStatement (this, args, loc);
2844
2845                                                 //
2846                                                 // bool && dynamic => (temp = left) ? temp && right : temp;
2847                                                 // bool || dynamic => (temp = left) ? temp : temp || right;
2848                                                 //
2849                                                 if (oper == Operator.LogicalAnd) {
2850                                                         cond_left = right;
2851                                                         cond_right = temp.CreateReferenceExpression (ec, loc);
2852                                                 } else {
2853                                                         cond_left = temp.CreateReferenceExpression (ec, loc);
2854                                                         cond_right = right;
2855                                                 }
2856
2857                                                 expr = new BooleanExpression (new SimpleAssign (temp.CreateReferenceExpression (ec, loc), left));
2858                                         }
2859
2860                                         return new Conditional (expr, cond_left, cond_right, loc).Resolve (ec);
2861                                 }
2862
2863                                 args = new Arguments (2);
2864                                 args.Add (new Argument (left));
2865                                 args.Add (new Argument (right));
2866                                 return new DynamicExpressionStatement (this, args, loc).Resolve (ec);
2867                         }
2868
2869                         if (RootContext.Version >= LanguageVersion.ISO_2 &&
2870                                 ((TypeManager.IsNullableType (left.Type) && (right is NullLiteral || TypeManager.IsNullableType (right.Type) || TypeManager.IsValueType (right.Type))) ||
2871                                 (TypeManager.IsValueType (left.Type) && right is NullLiteral) ||
2872                                 (TypeManager.IsNullableType (right.Type) && (left is NullLiteral || TypeManager.IsNullableType (left.Type) || TypeManager.IsValueType (left.Type))) ||
2873                                 (TypeManager.IsValueType (right.Type) && left is NullLiteral))) {
2874                                 var lifted = new Nullable.LiftedBinaryOperator (oper, left, right, loc);
2875                                 lifted.state = state;
2876                                 return lifted.Resolve (ec);
2877                         }
2878
2879                         return DoResolveCore (ec, left, right);
2880                 }
2881
2882                 protected Expression DoResolveCore (ResolveContext ec, Expression left_orig, Expression right_orig)
2883                 {
2884                         Expression expr = ResolveOperator (ec);
2885                         if (expr == null)
2886                                 Error_OperatorCannotBeApplied (ec, left_orig, right_orig);
2887
2888                         if (left == null || right == null)
2889                                 throw new InternalErrorException ("Invalid conversion");
2890
2891                         if (oper == Operator.BitwiseOr)
2892                                 CheckBitwiseOrOnSignExtended (ec);
2893
2894                         return expr;
2895                 }
2896
2897                 public override SLE.Expression MakeExpression (BuilderContext ctx)
2898                 {
2899                         var le = left.MakeExpression (ctx);
2900                         var re = right.MakeExpression (ctx);
2901                         bool is_checked = ctx.HasSet (BuilderContext.Options.CheckedScope);
2902
2903                         switch (oper) {
2904                         case Operator.Addition:
2905                                 return is_checked ? SLE.Expression.AddChecked (le, re) : SLE.Expression.Add (le, re);
2906                         case Operator.BitwiseAnd:
2907                                 return SLE.Expression.And (le, re);
2908                         case Operator.BitwiseOr:
2909                                 return SLE.Expression.Or (le, re);
2910                         case Operator.Division:
2911                                 return SLE.Expression.Divide (le, re);
2912                         case Operator.Equality:
2913                                 return SLE.Expression.Equal (le, re);
2914                         case Operator.ExclusiveOr:
2915                                 return SLE.Expression.ExclusiveOr (le, re);
2916                         case Operator.GreaterThan:
2917                                 return SLE.Expression.GreaterThan (le, re);
2918                         case Operator.GreaterThanOrEqual:
2919                                 return SLE.Expression.GreaterThanOrEqual (le, re);
2920                         case Operator.Inequality:
2921                                 return SLE.Expression.NotEqual (le, re);
2922                         case Operator.LeftShift:
2923                                 return SLE.Expression.LeftShift (le, re);
2924                         case Operator.LessThan:
2925                                 return SLE.Expression.LessThan (le, re);
2926                         case Operator.LessThanOrEqual:
2927                                 return SLE.Expression.LessThanOrEqual (le, re);
2928                         case Operator.LogicalAnd:
2929                                 return SLE.Expression.AndAlso (le, re);
2930                         case Operator.LogicalOr:
2931                                 return SLE.Expression.OrElse (le, re);
2932                         case Operator.Modulus:
2933                                 return SLE.Expression.Modulo (le, re);
2934                         case Operator.Multiply:
2935                                 return is_checked ? SLE.Expression.MultiplyChecked (le, re) : SLE.Expression.Multiply (le, re);
2936                         case Operator.RightShift:
2937                                 return SLE.Expression.RightShift (le, re);
2938                         case Operator.Subtraction:
2939                                 return is_checked ? SLE.Expression.SubtractChecked (le, re) : SLE.Expression.Subtract (le, re);
2940                         default:
2941                                 throw new NotImplementedException (oper.ToString ());
2942                         }
2943                 }
2944
2945                 //
2946                 // D operator + (D x, D y)
2947                 // D operator - (D x, D y)
2948                 //
2949                 Expression ResolveOperatorDelegate (ResolveContext ec, TypeSpec l, TypeSpec r)
2950                 {
2951                         if (l != r && !TypeSpecComparer.Variant.IsEqual (r, l)) {
2952                                 Expression tmp;
2953                                 if (right.eclass == ExprClass.MethodGroup || r == InternalType.AnonymousMethod || r == InternalType.Null) {
2954                                         tmp = Convert.ImplicitConversionRequired (ec, right, l, loc);
2955                                         if (tmp == null)
2956                                                 return null;
2957                                         right = tmp;
2958                                         r = right.Type;
2959                                 } else if (left.eclass == ExprClass.MethodGroup || (l == InternalType.AnonymousMethod || l == InternalType.Null)) {
2960                                         tmp = Convert.ImplicitConversionRequired (ec, left, r, loc);
2961                                         if (tmp == null)
2962                                                 return null;
2963                                         left = tmp;
2964                                         l = left.Type;
2965                                 } else {
2966                                         return null;
2967                                 }
2968                         }
2969
2970                         MethodSpec method;
2971                         Arguments args = new Arguments (2);
2972                         args.Add (new Argument (left));
2973                         args.Add (new Argument (right));
2974
2975                         if (oper == Operator.Addition) {
2976                                 if (TypeManager.delegate_combine_delegate_delegate == null) {
2977                                         TypeManager.delegate_combine_delegate_delegate = TypeManager.GetPredefinedMethod (
2978                                                 TypeManager.delegate_type, "Combine", loc, TypeManager.delegate_type, TypeManager.delegate_type);
2979                                 }
2980
2981                                 method = TypeManager.delegate_combine_delegate_delegate;
2982                         } else if (oper == Operator.Subtraction) {
2983                                 if (TypeManager.delegate_remove_delegate_delegate == null) {
2984                                         TypeManager.delegate_remove_delegate_delegate = TypeManager.GetPredefinedMethod (
2985                                                 TypeManager.delegate_type, "Remove", loc, TypeManager.delegate_type, TypeManager.delegate_type);
2986                                 }
2987
2988                                 method = TypeManager.delegate_remove_delegate_delegate;
2989                         } else {
2990                                 return new EmptyExpression (TypeManager.decimal_type);
2991                         }
2992
2993                         MethodGroupExpr mg = MethodGroupExpr.CreatePredefined (method, TypeManager.delegate_type, loc);
2994                         Expression expr = new UserOperatorCall (mg.BestCandidate, args, CreateExpressionTree, loc);
2995                         return new ClassCast (expr, l);
2996                 }
2997
2998                 //
2999                 // Enumeration operators
3000                 //
3001                 Expression ResolveOperatorEnum (ResolveContext ec, bool lenum, bool renum, TypeSpec ltype, TypeSpec rtype)
3002                 {
3003                         //
3004                         // bool operator == (E x, E y);
3005                         // bool operator != (E x, E y);
3006                         // bool operator < (E x, E y);
3007                         // bool operator > (E x, E y);
3008                         // bool operator <= (E x, E y);
3009                         // bool operator >= (E x, E y);
3010                         //
3011                         // E operator & (E x, E y);
3012                         // E operator | (E x, E y);
3013                         // E operator ^ (E x, E y);
3014                         //
3015                         // U operator - (E e, E f)
3016                         // E operator - (E e, U x)
3017                         // E operator - (U x, E e)      // LAMESPEC: Not covered by the specification
3018                         //
3019                         // E operator + (E e, U x)
3020                         // E operator + (U x, E e)
3021                         //
3022                         Expression ltemp = left;
3023                         Expression rtemp = right;
3024                         TypeSpec underlying_type;
3025                         TypeSpec underlying_type_result;
3026                         TypeSpec res_type;
3027                         Expression expr;
3028
3029                         //
3030                         // LAMESPEC: There is never ambiguous conversion between enum operators
3031                         // the one which contains more enum parameters always wins even if there
3032                         // is an implicit conversion involved
3033                         //
3034                         if ((oper & (Operator.ComparisonMask | Operator.BitwiseMask)) != 0) {
3035                                 if (renum) {
3036                                         underlying_type = EnumSpec.GetUnderlyingType (rtype);
3037                                         expr = Convert.ImplicitConversion (ec, left, rtype, loc);
3038                                         if (expr == null)
3039                                                 return null;
3040
3041                                         left = expr;
3042                                         ltype = expr.Type;
3043                                 } else if (lenum) {
3044                                         underlying_type = EnumSpec.GetUnderlyingType (ltype);
3045                                         expr = Convert.ImplicitConversion (ec, right, ltype, loc);
3046                                         if (expr == null)
3047                                                 return null;
3048
3049                                         right = expr;
3050                                         rtype = expr.Type;
3051                                 } else {
3052                                         return null;
3053                                 }
3054
3055                                 if ((oper & Operator.BitwiseMask) != 0) {
3056                                         res_type = ltype;
3057                                         underlying_type_result = underlying_type;
3058                                 } else {
3059                                         res_type = null;
3060                                         underlying_type_result = null;
3061                                 }
3062                         } else if (oper == Operator.Subtraction) {
3063                                 if (renum) {
3064                                         underlying_type = EnumSpec.GetUnderlyingType (rtype);
3065                                         if (ltype != rtype) {
3066                                                 expr = Convert.ImplicitConversion (ec, left, rtype, left.Location);
3067                                                 if (expr == null) {
3068                                                         expr = Convert.ImplicitConversion (ec, left, underlying_type, left.Location);
3069                                                         if (expr == null)
3070                                                                 return null;
3071
3072                                                         res_type = rtype;
3073                                                 } else {
3074                                                         res_type = underlying_type;
3075                                                 }
3076
3077                                                 left = expr;
3078                                         } else {
3079                                                 res_type = underlying_type;
3080                                         }
3081
3082                                         underlying_type_result = underlying_type;
3083                                 } else if (lenum) {
3084                                         underlying_type = EnumSpec.GetUnderlyingType (ltype);
3085                                         expr = Convert.ImplicitConversion (ec, right, ltype, right.Location);
3086                                         if (expr == null || expr is EnumConstant) {
3087                                                 expr = Convert.ImplicitConversion (ec, right, underlying_type, right.Location);
3088                                                 if (expr == null)
3089                                                         return null;
3090
3091                                                 res_type = ltype;
3092                                         } else {
3093                                                 res_type = underlying_type;
3094                                         }
3095
3096                                         right = expr;
3097                                         underlying_type_result = underlying_type;
3098                                 } else {
3099                                         return null;
3100                                 }
3101                         } else if (oper == Operator.Addition) {
3102                                 if (lenum) {
3103                                         underlying_type = EnumSpec.GetUnderlyingType (ltype);
3104                                         res_type = ltype;
3105
3106                                         if (rtype != underlying_type && (state & (State.RightNullLifted | State.LeftNullLifted)) == 0) {
3107                                                 expr = Convert.ImplicitConversion (ec, right, underlying_type, right.Location);
3108                                                 if (expr == null)
3109                                                         return null;
3110
3111                                                 right = expr;
3112                                         }
3113                                 } else {
3114                                         underlying_type = EnumSpec.GetUnderlyingType (rtype);
3115                                         res_type = rtype;
3116                                         if (ltype != underlying_type) {
3117                                                 expr = Convert.ImplicitConversion (ec, left, underlying_type, left.Location);
3118                                                 if (expr == null)
3119                                                         return null;
3120
3121                                                 left = expr;
3122                                         }
3123                                 }
3124
3125                                 underlying_type_result = underlying_type;
3126                         } else {
3127                                 return null;
3128                         }
3129
3130                         // Unwrap the constant correctly, so DoBinaryOperatorPromotion can do the magic
3131                         // with constants and expressions
3132                         if (left.Type != underlying_type) {
3133                                 if (left is Constant)
3134                                         left = ((Constant) left).ConvertExplicitly (false, underlying_type).Resolve (ec);
3135                                 else
3136                                         left = EmptyCast.Create (left, underlying_type);
3137                         }
3138
3139                         if (right.Type != underlying_type) {
3140                                 if (right is Constant)
3141                                         right = ((Constant) right).ConvertExplicitly (false, underlying_type).Resolve (ec);
3142                                 else
3143                                         right = EmptyCast.Create (right, underlying_type);
3144                         }
3145
3146                         //
3147                         // C# specification uses explicit cast syntax which means binary promotion
3148                         // should happen, however it seems that csc does not do that
3149                         //
3150                         if (!DoBinaryOperatorPromotion (ec)) {
3151                                 left = ltemp;
3152                                 right = rtemp;
3153                                 return null;
3154                         }
3155
3156                         if (underlying_type_result != null && left.Type != underlying_type_result) {
3157                                 enum_conversion = Convert.ExplicitNumericConversion (new EmptyExpression (left.Type), underlying_type_result);
3158                         }
3159
3160                         expr = ResolveOperatorPredefined (ec, standard_operators, true, res_type);
3161                         if (expr == null)
3162                                 return null;
3163
3164                         if (!IsCompound)
3165                                 return expr;
3166
3167                         //
3168                         // Section: 7.16.2
3169                         //
3170
3171                         //
3172                         // If the return type of the selected operator is implicitly convertible to the type of x
3173                         //
3174                         if (Convert.ImplicitConversionExists (ec, expr, ltype))
3175                                 return expr;
3176
3177                         //
3178                         // Otherwise, if the selected operator is a predefined operator, if the return type of the
3179                         // selected operator is explicitly convertible to the type of x, and if y is implicitly
3180                         // convertible to the type of x or the operator is a shift operator, then the operation
3181                         // is evaluated as x = (T)(x op y), where T is the type of x
3182                         //
3183                         expr = Convert.ExplicitConversion (ec, expr, ltype, loc);
3184                         if (expr == null)
3185                                 return null;
3186
3187                         if (Convert.ImplicitConversionExists (ec, ltemp, ltype))
3188                                 return expr;
3189
3190                         return null;
3191                 }
3192
3193                 //
3194                 // 7.9.6 Reference type equality operators
3195                 //
3196                 Expression ResolveOperatorEquality (ResolveContext ec, TypeSpec l, TypeSpec r)
3197                 {
3198                         Expression result;
3199                         type = TypeManager.bool_type;
3200
3201                         //
3202                         // a, Both operands are reference-type values or the value null
3203                         // b, One operand is a value of type T where T is a type-parameter and
3204                         // the other operand is the value null. Furthermore T does not have the
3205                         // value type constraint
3206                         //
3207                         // LAMESPEC: Very confusing details in the specification, basically any
3208                         // reference like type-parameter is allowed
3209                         //
3210                         var tparam_l = l as TypeParameterSpec;
3211                         var tparam_r = r as TypeParameterSpec;
3212                         if (tparam_l != null) {
3213                                 if (right is NullLiteral && !tparam_l.HasSpecialStruct) {
3214                                         left = new BoxedCast (left, TypeManager.object_type);
3215                                         return this;
3216                                 }
3217
3218                                 if (!tparam_l.IsReferenceType)
3219                                         return null;
3220
3221                                 l = tparam_l.GetEffectiveBase ();
3222                                 left = new BoxedCast (left, l);
3223                         } else if (left is NullLiteral && tparam_r == null) {
3224                                 if (!TypeManager.IsReferenceType (r) || r.Kind == MemberKind.InternalCompilerType)
3225                                         return null;
3226
3227                                 return this;
3228                         }
3229
3230                         if (tparam_r != null) {
3231                                 if (left is NullLiteral && !tparam_r.HasSpecialStruct) {
3232                                         right = new BoxedCast (right, TypeManager.object_type);
3233                                         return this;
3234                                 }
3235
3236                                 if (!tparam_r.IsReferenceType)
3237                                         return null;
3238
3239                                 r = tparam_r.GetEffectiveBase ();
3240                                 right = new BoxedCast (right, r);
3241                         } else if (right is NullLiteral) {
3242                                 if (!TypeManager.IsReferenceType (l) || l.Kind == MemberKind.InternalCompilerType)
3243                                         return null;
3244
3245                                 return this;
3246                         }
3247
3248                         //
3249                         // LAMESPEC: method groups can be compared when they convert to other side delegate
3250                         //
3251                         if (l.IsDelegate) {
3252                                 if (right.eclass == ExprClass.MethodGroup) {
3253                                         result = Convert.ImplicitConversion (ec, right, l, loc);
3254                                         if (result == null)
3255                                                 return null;
3256
3257                                         right = result;
3258                                         r = l;
3259                                 } else if (r.IsDelegate && l != r) {
3260                                         return null;
3261                                 }
3262                         } else if (left.eclass == ExprClass.MethodGroup && r.IsDelegate) {
3263                                 result = Convert.ImplicitConversionRequired (ec, left, r, loc);
3264                                 if (result == null)
3265                                         return null;
3266
3267                                 left = result;
3268                                 l = r;
3269                         }
3270
3271                         //
3272                         // bool operator != (string a, string b)
3273                         // bool operator == (string a, string b)
3274                         //
3275                         // bool operator != (Delegate a, Delegate b)
3276                         // bool operator == (Delegate a, Delegate b)
3277                         //
3278                         // bool operator != (bool a, bool b)
3279                         // bool operator == (bool a, bool b)
3280                         //
3281                         // LAMESPEC: Reference equality comparison can apply to value types when
3282                         // they implement an implicit conversion to any of types above.
3283                         //
3284                         if (r != TypeManager.object_type && l != TypeManager.object_type) {
3285                                 result = ResolveOperatorPredefined (ec, equality_operators, false, null);
3286                                 if (result != null)
3287                                         return result;
3288                         }
3289
3290                         //
3291                         // bool operator != (object a, object b)
3292                         // bool operator == (object a, object b)
3293                         //
3294                         // An explicit reference conversion exists from the
3295                         // type of either operand to the type of the other operand.
3296                         //
3297
3298                         // Optimize common path
3299                         if (l == r) {
3300                                 return l.Kind == MemberKind.InternalCompilerType || l.Kind == MemberKind.Struct ? null : this;
3301                         }
3302
3303                         if (!Convert.ExplicitReferenceConversionExists (l, r) &&
3304                                 !Convert.ExplicitReferenceConversionExists (r, l))
3305                                 return null;
3306
3307                         // Reject allowed explicit conversions like int->object
3308                         if (!TypeManager.IsReferenceType (l) || !TypeManager.IsReferenceType (r))
3309                                 return null;
3310
3311                         if (l == TypeManager.string_type || l == TypeManager.delegate_type || MemberCache.GetUserOperator (l, CSharp.Operator.OpType.Equality, false) != null)
3312                                 ec.Report.Warning (253, 2, loc,
3313                                         "Possible unintended reference comparison. Consider casting the right side expression to type `{0}' to get value comparison",
3314                                         l.GetSignatureForError ());
3315
3316                         if (r == TypeManager.string_type || r == TypeManager.delegate_type || MemberCache.GetUserOperator (r, CSharp.Operator.OpType.Equality, false) != null)
3317                                 ec.Report.Warning (252, 2, loc,
3318                                         "Possible unintended reference comparison. Consider casting the left side expression to type `{0}' to get value comparison",
3319                                         r.GetSignatureForError ());
3320
3321                         return this;
3322                 }
3323
3324
3325                 Expression ResolveOperatorPointer (ResolveContext ec, TypeSpec l, TypeSpec r)
3326                 {
3327                         //
3328                         // bool operator == (void* x, void* y);
3329                         // bool operator != (void* x, void* y);
3330                         // bool operator < (void* x, void* y);
3331                         // bool operator > (void* x, void* y);
3332                         // bool operator <= (void* x, void* y);
3333                         // bool operator >= (void* x, void* y);
3334                         //
3335                         if ((oper & Operator.ComparisonMask) != 0) {
3336                                 Expression temp;
3337                                 if (!l.IsPointer) {
3338                                         temp = Convert.ImplicitConversion (ec, left, r, left.Location);
3339                                         if (temp == null)
3340                                                 return null;
3341                                         left = temp;
3342                                 }
3343
3344                                 if (!r.IsPointer) {
3345                                         temp = Convert.ImplicitConversion (ec, right, l, right.Location);
3346                                         if (temp == null)
3347                                                 return null;
3348                                         right = temp;
3349                                 }
3350
3351                                 type = TypeManager.bool_type;
3352                                 return this;
3353                         }
3354
3355                         if (pointer_operators == null)
3356                                 CreatePointerOperatorsTable ();
3357
3358                         return ResolveOperatorPredefined (ec, pointer_operators, false, null);
3359                 }
3360
3361                 //
3362                 // Build-in operators method overloading
3363                 //
3364                 protected virtual Expression ResolveOperatorPredefined (ResolveContext ec, PredefinedOperator [] operators, bool primitives_only, TypeSpec enum_type)
3365                 {
3366                         PredefinedOperator best_operator = null;
3367                         TypeSpec l = left.Type;
3368                         TypeSpec r = right.Type;
3369                         Operator oper_mask = oper & ~Operator.ValuesOnlyMask;
3370
3371                         foreach (PredefinedOperator po in operators) {
3372                                 if ((po.OperatorsMask & oper_mask) == 0)
3373                                         continue;
3374
3375                                 if (primitives_only) {
3376                                         if (!po.IsPrimitiveApplicable (l, r))
3377                                                 continue;
3378                                 } else {
3379                                         if (!po.IsApplicable (ec, left, right))
3380                                                 continue;
3381                                 }
3382
3383                                 if (best_operator == null) {
3384                                         best_operator = po;
3385                                         if (primitives_only)
3386                                                 break;
3387
3388                                         continue;
3389                                 }
3390
3391                                 best_operator = po.ResolveBetterOperator (ec, best_operator);
3392
3393                                 if (best_operator == null) {
3394                                         ec.Report.Error (34, loc, "Operator `{0}' is ambiguous on operands of type `{1}' and `{2}'",
3395                                                 OperName (oper), TypeManager.CSharpName (l), TypeManager.CSharpName (r));
3396
3397                                         best_operator = po;
3398                                         break;
3399                                 }
3400                         }
3401
3402                         if (best_operator == null)
3403                                 return null;
3404
3405                         Expression expr = best_operator.ConvertResult (ec, this);
3406
3407                         //
3408                         // Optimize &/&& constant expressions with 0 value
3409                         //
3410                         if (oper == Operator.BitwiseAnd || oper == Operator.LogicalAnd) {
3411                                 Constant rc = right as Constant;
3412                                 Constant lc = left as Constant;
3413                                 if (((lc != null && lc.IsDefaultValue) || (rc != null && rc.IsDefaultValue)) && !(this is Nullable.LiftedBinaryOperator)) {
3414                                         //
3415                                         // The result is a constant with side-effect
3416                                         //
3417                                         Constant side_effect = rc == null ?
3418                                                 new SideEffectConstant (lc, right, loc) :
3419                                                 new SideEffectConstant (rc, left, loc);
3420
3421                                         return ReducedExpression.Create (side_effect.Resolve (ec), expr);
3422                                 }
3423                         }
3424
3425                         if (enum_type == null)
3426                                 return expr;
3427
3428                         //
3429                         // HACK: required by enum_conversion
3430                         //
3431                         expr.Type = enum_type;
3432                         return EmptyCast.Create (expr, enum_type);
3433                 }
3434
3435                 //
3436                 // Performs user-operator overloading
3437                 //
3438                 protected virtual Expression ResolveUserOperator (ResolveContext ec, Expression left, Expression right)
3439                 {
3440                         var op = ConvertBinaryToUserOperator (oper);
3441                         var l = left.Type;
3442                         if (TypeManager.IsNullableType (l))
3443                                 l = Nullable.NullableInfo.GetUnderlyingType (l);
3444                         var r = right.Type;
3445                         if (TypeManager.IsNullableType (r))
3446                                 r = Nullable.NullableInfo.GetUnderlyingType (r);
3447
3448                         IList<MemberSpec> left_operators = MemberCache.GetUserOperator (l, op, false);
3449                         IList<MemberSpec> right_operators = null;
3450
3451                         if (l != r) {
3452                                 right_operators = MemberCache.GetUserOperator (r, op, false);
3453                                 if (right_operators == null && left_operators == null)
3454                                         return null;
3455                         } else if (left_operators == null) {
3456                                 return null;
3457                         }
3458
3459                         Arguments args = new Arguments (2);
3460                         Argument larg = new Argument (left);
3461                         args.Add (larg);
3462                         Argument rarg = new Argument (right);
3463                         args.Add (rarg);
3464
3465                         //
3466                         // User-defined operator implementations always take precedence
3467                         // over predefined operator implementations
3468                         //
3469                         if (left_operators != null && right_operators != null) {
3470                                 left_operators = CombineUserOperators (left_operators, right_operators);
3471                         } else if (right_operators != null) {
3472                                 left_operators = right_operators;
3473                         }
3474
3475                         var res = new OverloadResolver (left_operators, OverloadResolver.Restrictions.ProbingOnly |
3476                                 OverloadResolver.Restrictions.NoBaseMembers | OverloadResolver.Restrictions.BaseMembersIncluded, loc);
3477
3478                         var oper_method = res.ResolveOperator (ec, ref args);
3479                         if (oper_method == null)
3480                                 return null;
3481
3482                         var llifted = (state & State.LeftNullLifted) != 0;
3483                         var rlifted = (state & State.RightNullLifted) != 0;
3484                         if ((Oper & Operator.EqualityMask) != 0) {
3485                                 var parameters = oper_method.Parameters;
3486                                 // LAMESPEC: No idea why this is not allowed
3487                                 if ((left is Nullable.Unwrap || right is Nullable.Unwrap) && parameters.Types [0] != parameters.Types [1])
3488                                         return null;
3489
3490                                 // Binary operation was lifted but we have found a user operator
3491                                 // which requires value-type argument, we downgrade ourself back to
3492                                 // binary operation
3493                                 // LAMESPEC: The user operator is not called (it cannot be we are passing null to struct)
3494                                 // but compilation succeeds
3495                                 if ((llifted && !parameters.Types[0].IsStruct) || (rlifted && !parameters.Types[1].IsStruct)) {
3496                                         state &= ~(State.LeftNullLifted | State.RightNullLifted);
3497                                 }
3498                         }
3499
3500                         Expression oper_expr;
3501
3502                         // TODO: CreateExpressionTree is allocated every time
3503                         if ((oper & Operator.LogicalMask) != 0) {
3504                                 oper_expr = new ConditionalLogicalOperator (oper_method, args, CreateExpressionTree,
3505                                         oper == Operator.LogicalAnd, loc).Resolve (ec);
3506                         } else {
3507                                 oper_expr = new UserOperatorCall (oper_method, args, CreateExpressionTree, loc);
3508                         }
3509
3510                         if (!llifted)
3511                                 this.left = larg.Expr;
3512
3513                         if (!rlifted)
3514                                 this.right = rarg.Expr;
3515
3516                         return oper_expr;
3517                 }
3518
3519                 //
3520                 // Merge two sets of user operators into one, they are mostly distinguish
3521                 // expect when they share base type and it contains an operator
3522                 //
3523                 static IList<MemberSpec> CombineUserOperators (IList<MemberSpec> left, IList<MemberSpec> right)
3524                 {
3525                         var combined = new List<MemberSpec> (left.Count + right.Count);
3526                         combined.AddRange (left);
3527                         foreach (var r in right) {
3528                                 bool same = false;
3529                                 foreach (var l in left) {
3530                                         if (l.DeclaringType == r.DeclaringType) {
3531                                                 same = true;
3532                                                 break;
3533                                         }
3534                                 }
3535
3536                                 if (!same)
3537                                         combined.Add (r);
3538                         }
3539
3540                         return combined;
3541                 }
3542
3543                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3544                 {
3545                         return null;
3546                 }
3547
3548                 private void CheckUselessComparison (ResolveContext ec, Constant c, TypeSpec type)
3549                 {
3550                         if (c == null || !IsTypeIntegral (type)
3551                                 || c is StringConstant
3552                                 || c is BoolConstant
3553                                 || c is FloatConstant
3554                                 || c is DoubleConstant
3555                                 || c is DecimalConstant
3556                                 )
3557                                 return;
3558
3559                         long value = 0;
3560
3561                         if (c is ULongConstant) {
3562                                 ulong uvalue = ((ULongConstant) c).Value;
3563                                 if (uvalue > long.MaxValue) {
3564                                         if (type == TypeManager.byte_type ||
3565                                             type == TypeManager.sbyte_type ||
3566                                             type == TypeManager.short_type ||
3567                                             type == TypeManager.ushort_type ||
3568                                             type == TypeManager.int32_type ||
3569                                             type == TypeManager.uint32_type ||
3570                                             type == TypeManager.int64_type ||
3571                                                 type == TypeManager.char_type)
3572                                                 WarnUselessComparison (ec, type);
3573                                         return;
3574                                 }
3575                                 value = (long) uvalue;
3576                         }
3577                         else if (c is ByteConstant)
3578                                 value = ((ByteConstant) c).Value;
3579                         else if (c is SByteConstant)
3580                                 value = ((SByteConstant) c).Value;
3581                         else if (c is ShortConstant)
3582                                 value = ((ShortConstant) c).Value;
3583                         else if (c is UShortConstant)
3584                                 value = ((UShortConstant) c).Value;
3585                         else if (c is IntConstant)
3586                                 value = ((IntConstant) c).Value;
3587                         else if (c is UIntConstant)
3588                                 value = ((UIntConstant) c).Value;
3589                         else if (c is LongConstant)
3590                                 value = ((LongConstant) c).Value;
3591                         else if (c is CharConstant)
3592                                 value = ((CharConstant)c).Value;
3593
3594                         if (value == 0)
3595                                 return;
3596
3597                         if (IsValueOutOfRange (value, type))
3598                                 WarnUselessComparison (ec, type);
3599                 }
3600
3601                 static bool IsValueOutOfRange (long value, TypeSpec type)
3602                 {
3603                         if (IsTypeUnsigned (type) && value < 0)
3604                                 return true;
3605                         return type == TypeManager.sbyte_type && (value >= 0x80 || value < -0x80) ||
3606                                 type == TypeManager.byte_type && value >= 0x100 ||
3607                                 type == TypeManager.short_type && (value >= 0x8000 || value < -0x8000) ||
3608                                 type == TypeManager.ushort_type && value >= 0x10000 ||
3609                                 type == TypeManager.int32_type && (value >= 0x80000000 || value < -0x80000000) ||
3610                                 type == TypeManager.uint32_type && value >= 0x100000000;
3611                 }
3612
3613                 private static bool IsTypeIntegral (TypeSpec type)
3614                 {
3615                         return type == TypeManager.uint64_type ||
3616                                 type == TypeManager.int64_type ||
3617                                 type == TypeManager.uint32_type ||
3618                                 type == TypeManager.int32_type ||
3619                                 type == TypeManager.ushort_type ||
3620                                 type == TypeManager.short_type ||
3621                                 type == TypeManager.sbyte_type ||
3622                                 type == TypeManager.byte_type ||
3623                                 type == TypeManager.char_type;
3624                 }
3625
3626                 private static bool IsTypeUnsigned (TypeSpec type)
3627                 {
3628                         return type == TypeManager.uint64_type ||
3629                                 type == TypeManager.uint32_type ||
3630                                 type == TypeManager.ushort_type ||
3631                                 type == TypeManager.byte_type ||
3632                                 type == TypeManager.char_type;
3633                 }
3634
3635                 private void WarnUselessComparison (ResolveContext ec, TypeSpec type)
3636                 {
3637                         ec.Report.Warning (652, 2, loc, "A comparison between a constant and a variable is useless. The constant is out of the range of the variable type `{0}'",
3638                                 TypeManager.CSharpName (type));
3639                 }
3640
3641                 /// <remarks>
3642                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
3643                 ///   context of a conditional bool expression.  This function will return
3644                 ///   false if it is was possible to use EmitBranchable, or true if it was.
3645                 ///
3646                 ///   The expression's code is generated, and we will generate a branch to `target'
3647                 ///   if the resulting expression value is equal to isTrue
3648                 /// </remarks>
3649                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
3650                 {
3651                         //
3652                         // This is more complicated than it looks, but its just to avoid
3653                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
3654                         // but on top of that we want for == and != to use a special path
3655                         // if we are comparing against null
3656                         //
3657                         if ((oper & Operator.EqualityMask) != 0 && (left is Constant || right is Constant)) {
3658                                 bool my_on_true = oper == Operator.Inequality ? on_true : !on_true;
3659
3660                                 //
3661                                 // put the constant on the rhs, for simplicity
3662                                 //
3663                                 if (left is Constant) {
3664                                         Expression swap = right;
3665                                         right = left;
3666                                         left = swap;
3667                                 }
3668
3669                                 //
3670                                 // brtrue/brfalse works with native int only
3671                                 //
3672                                 if (((Constant) right).IsZeroInteger && right.Type != TypeManager.int64_type && right.Type != TypeManager.uint64_type) {
3673                                         left.EmitBranchable (ec, target, my_on_true);
3674                                         return;
3675                                 }
3676                                 if (right.Type == TypeManager.bool_type) {
3677                                         // right is a boolean, and it's not 'false' => it is 'true'
3678                                         left.EmitBranchable (ec, target, !my_on_true);
3679                                         return;
3680                                 }
3681
3682                         } else if (oper == Operator.LogicalAnd) {
3683
3684                                 if (on_true) {
3685                                         Label tests_end = ec.DefineLabel ();
3686
3687                                         left.EmitBranchable (ec, tests_end, false);
3688                                         right.EmitBranchable (ec, target, true);
3689                                         ec.MarkLabel (tests_end);
3690                                 } else {
3691                                         //
3692                                         // This optimizes code like this
3693                                         // if (true && i > 4)
3694                                         //
3695                                         if (!(left is Constant))
3696                                                 left.EmitBranchable (ec, target, false);
3697
3698                                         if (!(right is Constant))
3699                                                 right.EmitBranchable (ec, target, false);
3700                                 }
3701
3702                                 return;
3703
3704                         } else if (oper == Operator.LogicalOr){
3705                                 if (on_true) {
3706                                         left.EmitBranchable (ec, target, true);
3707                                         right.EmitBranchable (ec, target, true);
3708
3709                                 } else {
3710                                         Label tests_end = ec.DefineLabel ();
3711                                         left.EmitBranchable (ec, tests_end, true);
3712                                         right.EmitBranchable (ec, target, false);
3713                                         ec.MarkLabel (tests_end);
3714                                 }
3715
3716                                 return;
3717
3718                         } else if ((oper & Operator.ComparisonMask) == 0) {
3719                                 base.EmitBranchable (ec, target, on_true);
3720                                 return;
3721                         }
3722
3723                         left.Emit (ec);
3724                         right.Emit (ec);
3725
3726                         TypeSpec t = left.Type;
3727                         bool is_float = IsFloat (t);
3728                         bool is_unsigned = is_float || IsUnsigned (t);
3729
3730                         switch (oper){
3731                         case Operator.Equality:
3732                                 if (on_true)
3733                                         ec.Emit (OpCodes.Beq, target);
3734                                 else
3735                                         ec.Emit (OpCodes.Bne_Un, target);
3736                                 break;
3737
3738                         case Operator.Inequality:
3739                                 if (on_true)
3740                                         ec.Emit (OpCodes.Bne_Un, target);
3741                                 else
3742                                         ec.Emit (OpCodes.Beq, target);
3743                                 break;
3744
3745                         case Operator.LessThan:
3746                                 if (on_true)
3747                                         if (is_unsigned && !is_float)
3748                                                 ec.Emit (OpCodes.Blt_Un, target);
3749                                         else
3750                                                 ec.Emit (OpCodes.Blt, target);
3751                                 else
3752                                         if (is_unsigned)
3753                                                 ec.Emit (OpCodes.Bge_Un, target);
3754                                         else
3755                                                 ec.Emit (OpCodes.Bge, target);
3756                                 break;
3757
3758                         case Operator.GreaterThan:
3759                                 if (on_true)
3760                                         if (is_unsigned && !is_float)
3761                                                 ec.Emit (OpCodes.Bgt_Un, target);
3762                                         else
3763                                                 ec.Emit (OpCodes.Bgt, target);
3764                                 else
3765                                         if (is_unsigned)
3766                                                 ec.Emit (OpCodes.Ble_Un, target);
3767                                         else
3768                                                 ec.Emit (OpCodes.Ble, target);
3769                                 break;
3770
3771                         case Operator.LessThanOrEqual:
3772                                 if (on_true)
3773                                         if (is_unsigned && !is_float)
3774                                                 ec.Emit (OpCodes.Ble_Un, target);
3775                                         else
3776                                                 ec.Emit (OpCodes.Ble, target);
3777                                 else
3778                                         if (is_unsigned)
3779                                                 ec.Emit (OpCodes.Bgt_Un, target);
3780                                         else
3781                                                 ec.Emit (OpCodes.Bgt, target);
3782                                 break;
3783
3784
3785                         case Operator.GreaterThanOrEqual:
3786                                 if (on_true)
3787                                         if (is_unsigned && !is_float)
3788                                                 ec.Emit (OpCodes.Bge_Un, target);
3789                                         else
3790                                                 ec.Emit (OpCodes.Bge, target);
3791                                 else
3792                                         if (is_unsigned)
3793                                                 ec.Emit (OpCodes.Blt_Un, target);
3794                                         else
3795                                                 ec.Emit (OpCodes.Blt, target);
3796                                 break;
3797                         default:
3798                                 throw new InternalErrorException (oper.ToString ());
3799                         }
3800                 }
3801
3802                 public override void Emit (EmitContext ec)
3803                 {
3804                         EmitOperator (ec, left.Type);
3805                 }
3806
3807                 protected virtual void EmitOperator (EmitContext ec, TypeSpec l)
3808                 {
3809                         //
3810                         // Handle short-circuit operators differently
3811                         // than the rest
3812                         //
3813                         if ((oper & Operator.LogicalMask) != 0) {
3814                                 Label load_result = ec.DefineLabel ();
3815                                 Label end = ec.DefineLabel ();
3816
3817                                 bool is_or = oper == Operator.LogicalOr;
3818                                 left.EmitBranchable (ec, load_result, is_or);
3819                                 right.Emit (ec);
3820                                 ec.Emit (OpCodes.Br_S, end);
3821
3822                                 ec.MarkLabel (load_result);
3823                                 ec.Emit (is_or ? OpCodes.Ldc_I4_1 : OpCodes.Ldc_I4_0);
3824                                 ec.MarkLabel (end);
3825                                 return;
3826                         }
3827
3828                         //
3829                         // Optimize zero-based operations which cannot be optimized at expression level
3830                         //
3831                         if (oper == Operator.Subtraction) {
3832                                 var lc = left as IntegralConstant;
3833                                 if (lc != null && lc.IsDefaultValue) {
3834                                         right.Emit (ec);
3835                                         ec.Emit (OpCodes.Neg);
3836                                         return;
3837                                 }
3838                         }
3839
3840                         left.Emit (ec);
3841                         right.Emit (ec);
3842                         EmitOperatorOpcode (ec, oper, l);
3843
3844                         //
3845                         // Nullable enum could require underlying type cast and we cannot simply wrap binary
3846                         // expression because that would wrap lifted binary operation
3847                         //
3848                         if (enum_conversion != null)
3849                                 enum_conversion.Emit (ec);
3850                 }
3851
3852                 public override void EmitSideEffect (EmitContext ec)
3853                 {
3854                         if ((oper & Operator.LogicalMask) != 0 ||
3855                                 (ec.HasSet (EmitContext.Options.CheckedScope) && (oper == Operator.Multiply || oper == Operator.Addition || oper == Operator.Subtraction))) {
3856                                 base.EmitSideEffect (ec);
3857                         } else {
3858                                 left.EmitSideEffect (ec);
3859                                 right.EmitSideEffect (ec);
3860                         }
3861                 }
3862
3863                 protected override void CloneTo (CloneContext clonectx, Expression t)
3864                 {
3865                         Binary target = (Binary) t;
3866
3867                         target.left = left.Clone (clonectx);
3868                         target.right = right.Clone (clonectx);
3869                 }
3870
3871                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
3872                 {
3873                         Arguments binder_args = new Arguments (4);
3874
3875                         MemberAccess sle = new MemberAccess (new MemberAccess (
3876                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
3877
3878                         CSharpBinderFlags flags = 0;
3879                         if (ec.HasSet (ResolveContext.Options.CheckedScope))
3880                                 flags = CSharpBinderFlags.CheckedContext;
3881
3882                         if ((oper & Operator.LogicalMask) != 0)
3883                                 flags |= CSharpBinderFlags.BinaryOperationLogical;
3884
3885                         binder_args.Add (new Argument (new EnumConstant (new IntLiteral ((int) flags, loc), ec.Module.PredefinedTypes.BinderFlags.Resolve (loc))));
3886                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), GetOperatorExpressionTypeName (), loc)));
3887                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
3888                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
3889
3890                         return new Invocation (new MemberAccess (new TypeExpression (ec.Module.PredefinedTypes.Binder.TypeSpec, loc), "BinaryOperation", loc), binder_args);
3891                 }
3892
3893                 public override Expression CreateExpressionTree (ResolveContext ec)
3894                 {
3895                         return CreateExpressionTree (ec, null);
3896                 }
3897
3898                 Expression CreateExpressionTree (ResolveContext ec, Expression method)
3899                 {
3900                         string method_name;
3901                         bool lift_arg = false;
3902
3903                         switch (oper) {
3904                         case Operator.Addition:
3905                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
3906                                         method_name = "AddChecked";
3907                                 else
3908                                         method_name = "Add";
3909                                 break;
3910                         case Operator.BitwiseAnd:
3911                                 method_name = "And";
3912                                 break;
3913                         case Operator.BitwiseOr:
3914                                 method_name = "Or";
3915                                 break;
3916                         case Operator.Division:
3917                                 method_name = "Divide";
3918                                 break;
3919                         case Operator.Equality:
3920                                 method_name = "Equal";
3921                                 lift_arg = true;
3922                                 break;
3923                         case Operator.ExclusiveOr:
3924                                 method_name = "ExclusiveOr";
3925                                 break;
3926                         case Operator.GreaterThan:
3927                                 method_name = "GreaterThan";
3928                                 lift_arg = true;
3929                                 break;
3930                         case Operator.GreaterThanOrEqual:
3931                                 method_name = "GreaterThanOrEqual";
3932                                 lift_arg = true;
3933                                 break;
3934                         case Operator.Inequality:
3935                                 method_name = "NotEqual";
3936                                 lift_arg = true;
3937                                 break;
3938                         case Operator.LeftShift:
3939                                 method_name = "LeftShift";
3940                                 break;
3941                         case Operator.LessThan:
3942                                 method_name = "LessThan";
3943                                 lift_arg = true;
3944                                 break;
3945                         case Operator.LessThanOrEqual:
3946                                 method_name = "LessThanOrEqual";
3947                                 lift_arg = true;
3948                                 break;
3949                         case Operator.LogicalAnd:
3950                                 method_name = "AndAlso";
3951                                 break;
3952                         case Operator.LogicalOr:
3953                                 method_name = "OrElse";
3954                                 break;
3955                         case Operator.Modulus:
3956                                 method_name = "Modulo";
3957                                 break;
3958                         case Operator.Multiply:
3959                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
3960                                         method_name = "MultiplyChecked";
3961                                 else
3962                                         method_name = "Multiply";
3963                                 break;
3964                         case Operator.RightShift:
3965                                 method_name = "RightShift";
3966                                 break;
3967                         case Operator.Subtraction:
3968                                 if (method == null && ec.HasSet (ResolveContext.Options.CheckedScope) && !IsFloat (type))
3969                                         method_name = "SubtractChecked";
3970                                 else
3971                                         method_name = "Subtract";
3972                                 break;
3973
3974                         default:
3975                                 throw new InternalErrorException ("Unknown expression tree binary operator " + oper);
3976                         }
3977
3978                         Arguments args = new Arguments (2);
3979                         args.Add (new Argument (left.CreateExpressionTree (ec)));
3980                         args.Add (new Argument (right.CreateExpressionTree (ec)));
3981                         if (method != null) {
3982                                 if (lift_arg)
3983                                         args.Add (new Argument (new BoolLiteral (false, loc)));
3984
3985                                 args.Add (new Argument (method));
3986                         }
3987
3988                         return CreateExpressionFactoryCall (ec, method_name, args);
3989                 }
3990         }
3991
3992         //
3993         // Represents the operation a + b [+ c [+ d [+ ...]]], where a is a string
3994         // b, c, d... may be strings or objects.
3995         //
3996         public class StringConcat : Expression {
3997                 Arguments arguments;
3998                 static IList<MemberSpec> concat_members;
3999
4000                 public StringConcat (Expression left, Expression right, Location loc)
4001                 {
4002                         this.loc = loc;
4003                         type = TypeManager.string_type;
4004                         eclass = ExprClass.Value;
4005
4006                         arguments = new Arguments (2);
4007                 }
4008
4009                 public static StringConcat Create (ResolveContext rc, Expression left, Expression right, Location loc)
4010                 {
4011                         if (left.eclass == ExprClass.Unresolved || right.eclass == ExprClass.Unresolved)
4012                                 throw new ArgumentException ();
4013
4014                         var s = new StringConcat (left, right, loc);
4015                         s.Append (rc, left);
4016                         s.Append (rc, right);
4017                         return s;
4018                 }
4019
4020                 public override Expression CreateExpressionTree (ResolveContext ec)
4021                 {
4022                         Argument arg = arguments [0];
4023                         return CreateExpressionAddCall (ec, arg, arg.CreateExpressionTree (ec), 1);
4024                 }
4025
4026                 //
4027                 // Creates nested calls tree from an array of arguments used for IL emit
4028                 //
4029                 Expression CreateExpressionAddCall (ResolveContext ec, Argument left, Expression left_etree, int pos)
4030                 {
4031                         Arguments concat_args = new Arguments (2);
4032                         Arguments add_args = new Arguments (3);
4033
4034                         concat_args.Add (left);
4035                         add_args.Add (new Argument (left_etree));
4036
4037                         concat_args.Add (arguments [pos]);
4038                         add_args.Add (new Argument (arguments [pos].CreateExpressionTree (ec)));
4039
4040                         var methods = CreateConcatMethodCandidates ();
4041                         if (methods == null)
4042                                 return null;
4043
4044                         var res = new OverloadResolver (methods, OverloadResolver.Restrictions.NoBaseMembers, loc);
4045                         var method = res.ResolveMember<MethodSpec> (ec, ref concat_args);
4046                         if (method == null)
4047                                 return null;
4048
4049                         add_args.Add (new Argument (new TypeOfMethod (method, loc)));
4050
4051                         Expression expr = CreateExpressionFactoryCall (ec, "Add", add_args);
4052                         if (++pos == arguments.Count)
4053                                 return expr;
4054
4055                         left = new Argument (new EmptyExpression (method.ReturnType));
4056                         return CreateExpressionAddCall (ec, left, expr, pos);
4057                 }
4058
4059                 protected override Expression DoResolve (ResolveContext ec)
4060                 {
4061                         return this;
4062                 }
4063
4064                 void Append (ResolveContext rc, Expression operand)
4065                 {
4066                         //
4067                         // Constant folding
4068                         //
4069                         StringConstant sc = operand as StringConstant;
4070                         if (sc != null) {
4071                                 if (arguments.Count != 0) {
4072                                         Argument last_argument = arguments [arguments.Count - 1];
4073                                         StringConstant last_expr_constant = last_argument.Expr as StringConstant;
4074                                         if (last_expr_constant != null) {
4075                                                 last_argument.Expr = new StringConstant (
4076                                                         last_expr_constant.Value + sc.Value, sc.Location).Resolve (rc);
4077                                                 return;
4078                                         }
4079                                 }
4080                         } else {
4081                                 //
4082                                 // Multiple (3+) concatenation are resolved as multiple StringConcat instances
4083                                 //
4084                                 StringConcat concat_oper = operand as StringConcat;
4085                                 if (concat_oper != null) {
4086                                         arguments.AddRange (concat_oper.arguments);
4087                                         return;
4088                                 }
4089                         }
4090
4091                         arguments.Add (new Argument (operand));
4092                 }
4093
4094                 IList<MemberSpec> CreateConcatMethodCandidates ()
4095                 {
4096                         if (concat_members == null) {
4097                                 concat_members = MemberCache.FindMembers (type, "Concat", true);
4098                         }
4099
4100                         return concat_members;
4101                 }
4102
4103                 public override void Emit (EmitContext ec)
4104                 {
4105                         var members = CreateConcatMethodCandidates ();
4106                         var res = new OverloadResolver (members, OverloadResolver.Restrictions.NoBaseMembers, loc);
4107                         var method = res.ResolveMember<MethodSpec> (new ResolveContext (ec.MemberContext), ref arguments);
4108                         if (method != null)
4109                                 Invocation.EmitCall (ec, null, method, arguments, loc);
4110                 }
4111
4112                 public override SLE.Expression MakeExpression (BuilderContext ctx)
4113                 {
4114                         if (arguments.Count != 2)
4115                                 throw new NotImplementedException ("arguments.Count != 2");
4116
4117                         var concat = typeof (string).GetMethod ("Concat", new[] { typeof (object), typeof (object) });
4118                         return SLE.Expression.Add (arguments[0].Expr.MakeExpression (ctx), arguments[1].Expr.MakeExpression (ctx), concat);
4119                 }
4120
4121                 public static void Reset ()
4122                 {
4123                         concat_members = null;
4124                 }
4125         }
4126
4127         //
4128         // User-defined conditional logical operator
4129         //
4130         public class ConditionalLogicalOperator : UserOperatorCall {
4131                 readonly bool is_and;
4132                 Expression oper_expr;
4133
4134                 public ConditionalLogicalOperator (MethodSpec oper, Arguments arguments, Func<ResolveContext, Expression, Expression> expr_tree, bool is_and, Location loc)
4135                         : base (oper, arguments, expr_tree, loc)
4136                 {
4137                         this.is_and = is_and;
4138                         eclass = ExprClass.Unresolved;
4139                 }
4140
4141                 protected override Expression DoResolve (ResolveContext ec)
4142                 {
4143                         AParametersCollection pd = oper.Parameters;
4144                         if (!TypeSpecComparer.IsEqual (type, pd.Types[0]) || !TypeSpecComparer.IsEqual (type, pd.Types[1])) {
4145                                 ec.Report.Error (217, loc,
4146                                         "A user-defined operator `{0}' must have parameters and return values of the same type in order to be applicable as a short circuit operator",
4147                                         oper.GetSignatureForError ());
4148                                 return null;
4149                         }
4150
4151                         Expression left_dup = new EmptyExpression (type);
4152                         Expression op_true = GetOperatorTrue (ec, left_dup, loc);
4153                         Expression op_false = GetOperatorFalse (ec, left_dup, loc);
4154                         if (op_true == null || op_false == null) {
4155                                 ec.Report.Error (218, loc,
4156                                         "The type `{0}' must have operator `true' and operator `false' defined when `{1}' is used as a short circuit operator",
4157                                         TypeManager.CSharpName (type), oper.GetSignatureForError ());
4158                                 return null;
4159                         }
4160
4161                         oper_expr = is_and ? op_false : op_true;
4162                         eclass = ExprClass.Value;
4163                         return this;
4164                 }
4165
4166                 public override void Emit (EmitContext ec)
4167                 {
4168                         Label end_target = ec.DefineLabel ();
4169
4170                         //
4171                         // Emit and duplicate left argument
4172                         //
4173                         arguments [0].Expr.Emit (ec);
4174                         ec.Emit (OpCodes.Dup);
4175                         arguments.RemoveAt (0);
4176
4177                         oper_expr.EmitBranchable (ec, end_target, true);
4178                         base.Emit (ec);
4179                         ec.MarkLabel (end_target);
4180                 }
4181         }
4182
4183         public class PointerArithmetic : Expression {
4184                 Expression left, right;
4185                 Binary.Operator op;
4186
4187                 //
4188                 // We assume that `l' is always a pointer
4189                 //
4190                 public PointerArithmetic (Binary.Operator op, Expression l, Expression r, TypeSpec t, Location loc)
4191                 {
4192                         type = t;
4193                         this.loc = loc;
4194                         left = l;
4195                         right = r;
4196                         this.op = op;
4197                 }
4198
4199                 public override Expression CreateExpressionTree (ResolveContext ec)
4200                 {
4201                         Error_PointerInsideExpressionTree (ec);
4202                         return null;
4203                 }
4204
4205                 protected override Expression DoResolve (ResolveContext ec)
4206                 {
4207                         eclass = ExprClass.Variable;
4208
4209                         var pc = left.Type as PointerContainer;
4210                         if (pc != null && pc.Element.BuildinType == BuildinTypeSpec.Type.Void) {
4211                                 Error_VoidPointerOperation (ec);
4212                                 return null;
4213                         }
4214
4215                         return this;
4216                 }
4217
4218                 public override void Emit (EmitContext ec)
4219                 {
4220                         TypeSpec op_type = left.Type;
4221
4222                         // It must be either array or fixed buffer
4223                         TypeSpec element;
4224                         if (TypeManager.HasElementType (op_type)) {
4225                                 element = TypeManager.GetElementType (op_type);
4226                         } else {
4227                                 FieldExpr fe = left as FieldExpr;
4228                                 if (fe != null)
4229                                         element = ((FixedFieldSpec) (fe.Spec)).ElementType;
4230                                 else
4231                                         element = op_type;
4232                         }
4233
4234                         int size = GetTypeSize (element);
4235                         TypeSpec rtype = right.Type;
4236
4237                         if ((op & Binary.Operator.SubtractionMask) != 0 && rtype.IsPointer){
4238                                 //
4239                                 // handle (pointer - pointer)
4240                                 //
4241                                 left.Emit (ec);
4242                                 right.Emit (ec);
4243                                 ec.Emit (OpCodes.Sub);
4244
4245                                 if (size != 1){
4246                                         if (size == 0)
4247                                                 ec.Emit (OpCodes.Sizeof, element);
4248                                         else
4249                                                 ec.EmitInt (size);
4250                                         ec.Emit (OpCodes.Div);
4251                                 }
4252                                 ec.Emit (OpCodes.Conv_I8);
4253                         } else {
4254                                 //
4255                                 // handle + and - on (pointer op int)
4256                                 //
4257                                 Constant left_const = left as Constant;
4258                                 if (left_const != null) {
4259                                         //
4260                                         // Optimize ((T*)null) pointer operations
4261                                         //
4262                                         if (left_const.IsDefaultValue) {
4263                                                 left = EmptyExpression.Null;
4264                                         } else {
4265                                                 left_const = null;
4266                                         }
4267                                 }
4268
4269                                 left.Emit (ec);
4270
4271                                 var right_const = right as Constant;
4272                                 if (right_const != null) {
4273                                         //
4274                                         // Optimize 0-based arithmetic
4275                                         //
4276                                         if (right_const.IsDefaultValue)
4277                                                 return;
4278
4279                                         if (size != 0)
4280                                                 right = new IntConstant (size, right.Location);
4281                                         else
4282                                                 right = new SizeOf (new TypeExpression (element, right.Location), right.Location);
4283
4284                                         // TODO: Should be the checks resolve context sensitive?
4285                                         ResolveContext rc = new ResolveContext (ec.MemberContext, ResolveContext.Options.UnsafeScope);
4286                                         right = new Binary (Binary.Operator.Multiply, right, right_const, loc).Resolve (rc);
4287                                         if (right == null)
4288                                                 return;
4289                                 }
4290
4291                                 right.Emit (ec);
4292                                 if (rtype == TypeManager.sbyte_type || rtype == TypeManager.byte_type ||
4293                                         rtype == TypeManager.short_type || rtype == TypeManager.ushort_type) {
4294                                         ec.Emit (OpCodes.Conv_I);
4295                                 } else if (rtype == TypeManager.uint32_type) {
4296                                         ec.Emit (OpCodes.Conv_U);
4297                                 }
4298
4299                                 if (right_const == null && size != 1){
4300                                         if (size == 0)
4301                                                 ec.Emit (OpCodes.Sizeof, element);
4302                                         else
4303                                                 ec.EmitInt (size);
4304                                         if (rtype == TypeManager.int64_type || rtype == TypeManager.uint64_type)
4305                                                 ec.Emit (OpCodes.Conv_I8);
4306
4307                                         Binary.EmitOperatorOpcode (ec, Binary.Operator.Multiply, rtype);
4308                                 }
4309
4310                                 if (left_const == null) {
4311                                         if (rtype == TypeManager.int64_type)
4312                                                 ec.Emit (OpCodes.Conv_I);
4313                                         else if (rtype == TypeManager.uint64_type)
4314                                                 ec.Emit (OpCodes.Conv_U);
4315
4316                                         Binary.EmitOperatorOpcode (ec, op, op_type);
4317                                 }
4318                         }
4319                 }
4320         }
4321
4322         //
4323         // A boolean-expression is an expression that yields a result
4324         // of type bool
4325         //
4326         public class BooleanExpression : ShimExpression
4327         {
4328                 public BooleanExpression (Expression expr)
4329                         : base (expr)
4330                 {
4331                         this.loc = expr.Location;
4332                 }
4333
4334                 public override Expression CreateExpressionTree (ResolveContext ec)
4335                 {
4336                         // TODO: We should emit IsTrue (v4) instead of direct user operator
4337                         // call but that would break csc compatibility
4338                         return base.CreateExpressionTree (ec);
4339                 }
4340
4341                 protected override Expression DoResolve (ResolveContext ec)
4342                 {
4343                         // A boolean-expression is required to be of a type
4344                         // that can be implicitly converted to bool or of
4345                         // a type that implements operator true
4346
4347                         expr = expr.Resolve (ec);
4348                         if (expr == null)
4349                                 return null;
4350
4351                         Assign ass = expr as Assign;
4352                         if (ass != null && ass.Source is Constant) {
4353                                 ec.Report.Warning (665, 3, loc,
4354                                         "Assignment in conditional expression is always constant. Did you mean to use `==' instead ?");
4355                         }
4356
4357                         if (expr.Type == TypeManager.bool_type)
4358                                 return expr;
4359
4360                         if (expr.Type == InternalType.Dynamic) {
4361                                 Arguments args = new Arguments (1);
4362                                 args.Add (new Argument (expr));
4363                                 return DynamicUnaryConversion.CreateIsTrue (args, loc).Resolve (ec);
4364                         }
4365
4366                         type = TypeManager.bool_type;
4367                         Expression converted = Convert.ImplicitConversion (ec, expr, type, loc);
4368                         if (converted != null)
4369                                 return converted;
4370
4371                         //
4372                         // If no implicit conversion to bool exists, try using `operator true'
4373                         //
4374                         converted = GetOperatorTrue (ec, expr, loc);
4375                         if (converted == null) {
4376                                 expr.Error_ValueCannotBeConverted (ec, loc, type, false);
4377                                 return null;
4378                         }
4379
4380                         return converted;
4381                 }
4382         }
4383
4384         public class BooleanExpressionFalse : Unary
4385         {
4386                 public BooleanExpressionFalse (Expression expr)
4387                         : base (Operator.LogicalNot, expr, expr.Location)
4388                 {
4389                 }
4390
4391                 protected override Expression ResolveOperator (ResolveContext ec, Expression expr)
4392                 {
4393                         return GetOperatorFalse (ec, expr, loc) ?? base.ResolveOperator (ec, expr);
4394                 }
4395         }
4396
4397         /// <summary>
4398         ///   Implements the ternary conditional operator (?:)
4399         /// </summary>
4400         public class Conditional : Expression {
4401                 Expression expr, true_expr, false_expr;
4402
4403                 public Conditional (Expression expr, Expression true_expr, Expression false_expr, Location loc)
4404                 {
4405                         this.expr = expr;
4406                         this.true_expr = true_expr;
4407                         this.false_expr = false_expr;
4408                         this.loc = loc;
4409                 }
4410
4411                 public Expression Expr {
4412                         get {
4413                                 return expr;
4414                         }
4415                 }
4416
4417                 public Expression TrueExpr {
4418                         get {
4419                                 return true_expr;
4420                         }
4421                 }
4422
4423                 public Expression FalseExpr {
4424                         get {
4425                                 return false_expr;
4426                         }
4427                 }
4428
4429                 public override Expression CreateExpressionTree (ResolveContext ec)
4430                 {
4431                         Arguments args = new Arguments (3);
4432                         args.Add (new Argument (expr.CreateExpressionTree (ec)));
4433                         args.Add (new Argument (true_expr.CreateExpressionTree (ec)));
4434                         args.Add (new Argument (false_expr.CreateExpressionTree (ec)));
4435                         return CreateExpressionFactoryCall (ec, "Condition", args);
4436                 }
4437
4438                 protected override Expression DoResolve (ResolveContext ec)
4439                 {
4440                         expr = expr.Resolve (ec);
4441                         true_expr = true_expr.Resolve (ec);
4442                         false_expr = false_expr.Resolve (ec);
4443
4444                         if (true_expr == null || false_expr == null || expr == null)
4445                                 return null;
4446
4447                         eclass = ExprClass.Value;
4448                         TypeSpec true_type = true_expr.Type;
4449                         TypeSpec false_type = false_expr.Type;
4450                         type = true_type;
4451
4452                         //
4453                         // First, if an implicit conversion exists from true_expr
4454                         // to false_expr, then the result type is of type false_expr.Type
4455                         //
4456                         if (!TypeSpecComparer.IsEqual (true_type, false_type)) {
4457                                 Expression conv = Convert.ImplicitConversion (ec, true_expr, false_type, loc);
4458                                 if (conv != null && true_type != InternalType.Dynamic) {
4459                                         //
4460                                         // Check if both can convert implicitly to each other's type
4461                                         //
4462                                         type = false_type;
4463
4464                                         if (false_type != InternalType.Dynamic && Convert.ImplicitConversion (ec, false_expr, true_type, loc) != null) {
4465                                                 ec.Report.Error (172, true_expr.Location,
4466                                                         "Type of conditional expression cannot be determined as `{0}' and `{1}' convert implicitly to each other",
4467                                                                 true_type.GetSignatureForError (), false_type.GetSignatureForError ());
4468                                                 return null;
4469                                         }
4470
4471                                         true_expr = conv;
4472                                 } else if ((conv = Convert.ImplicitConversion (ec, false_expr, true_type, loc)) != null) {
4473                                         false_expr = conv;
4474                                 } else {
4475                                         ec.Report.Error (173, true_expr.Location,
4476                                                 "Type of conditional expression cannot be determined because there is no implicit conversion between `{0}' and `{1}'",
4477                                                 TypeManager.CSharpName (true_type), TypeManager.CSharpName (false_type));
4478                                         return null;
4479                                 }
4480                         }
4481
4482                         // Dead code optimalization
4483                         Constant c = expr as Constant;
4484                         if (c != null){
4485                                 bool is_false = c.IsDefaultValue;
4486                                 ec.Report.Warning (429, 4, is_false ? true_expr.Location : false_expr.Location, "Unreachable expression code detected");
4487                                 return ReducedExpression.Create (is_false ? false_expr : true_expr, this).Resolve (ec);
4488                         }
4489
4490                         return this;
4491                 }
4492
4493                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
4494                 {
4495                         return null;
4496                 }
4497
4498                 public override void Emit (EmitContext ec)
4499                 {
4500                         Label false_target = ec.DefineLabel ();
4501                         Label end_target = ec.DefineLabel ();
4502
4503                         expr.EmitBranchable (ec, false_target, false);
4504                         true_expr.Emit (ec);
4505
4506                         if (type.IsInterface) {
4507                                 LocalBuilder temp = ec.GetTemporaryLocal (type);
4508                                 ec.Emit (OpCodes.Stloc, temp);
4509                                 ec.Emit (OpCodes.Ldloc, temp);
4510                                 ec.FreeTemporaryLocal (temp, type);
4511                         }
4512
4513                         ec.Emit (OpCodes.Br, end_target);
4514                         ec.MarkLabel (false_target);
4515                         false_expr.Emit (ec);
4516                         ec.MarkLabel (end_target);
4517                 }
4518
4519                 protected override void CloneTo (CloneContext clonectx, Expression t)
4520                 {
4521                         Conditional target = (Conditional) t;
4522
4523                         target.expr = expr.Clone (clonectx);
4524                         target.true_expr = true_expr.Clone (clonectx);
4525                         target.false_expr = false_expr.Clone (clonectx);
4526                 }
4527         }
4528
4529         public abstract class VariableReference : Expression, IAssignMethod, IMemoryLocation, IVariableReference {
4530                 LocalTemporary temp;
4531
4532                 #region Abstract
4533                 public abstract HoistedVariable GetHoistedVariable (AnonymousExpression ae);
4534
4535                 public abstract bool IsLockedByStatement { get; set; }
4536
4537                 public abstract bool IsFixed { get; }
4538                 public abstract bool IsRef { get; }
4539                 public abstract string Name { get; }
4540                 public abstract void SetHasAddressTaken ();
4541
4542                 //
4543                 // Variable IL data, it has to be protected to encapsulate hoisted variables
4544                 //
4545                 protected abstract ILocalVariable Variable { get; }
4546
4547                 //
4548                 // Variable flow-analysis data
4549                 //
4550                 public abstract VariableInfo VariableInfo { get; }
4551                 #endregion
4552
4553                 public virtual void AddressOf (EmitContext ec, AddressOp mode)
4554                 {
4555                         HoistedVariable hv = GetHoistedVariable (ec);
4556                         if (hv != null) {
4557                                 hv.AddressOf (ec, mode);
4558                                 return;
4559                         }
4560
4561                         Variable.EmitAddressOf (ec);
4562                 }
4563
4564                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
4565                 {
4566                         if (IsLockedByStatement) {
4567                                 rc.Report.Warning (728, 2, loc,
4568                                         "Possibly incorrect assignment to `{0}' which is the argument to a using or lock statement",
4569                                         Name);
4570                         }
4571
4572                         return this;
4573                 }
4574
4575                 public override void Emit (EmitContext ec)
4576                 {
4577                         Emit (ec, false);
4578                 }
4579
4580                 public override void EmitSideEffect (EmitContext ec)
4581                 {
4582                         // do nothing
4583                 }
4584
4585                 //
4586                 // This method is used by parameters that are references, that are
4587                 // being passed as references:  we only want to pass the pointer (that
4588                 // is already stored in the parameter, not the address of the pointer,
4589                 // and not the value of the variable).
4590                 //
4591                 public void EmitLoad (EmitContext ec)
4592                 {
4593                         Variable.Emit (ec);
4594                 }
4595
4596                 public void Emit (EmitContext ec, bool leave_copy)
4597                 {
4598                         Report.Debug (64, "VARIABLE EMIT", this, Variable, type, IsRef, loc);
4599
4600                         HoistedVariable hv = GetHoistedVariable (ec);
4601                         if (hv != null) {
4602                                 hv.Emit (ec, leave_copy);
4603                                 return;
4604                         }
4605
4606                         EmitLoad (ec);
4607
4608                         if (IsRef) {
4609                                 //
4610                                 // If we are a reference, we loaded on the stack a pointer
4611                                 // Now lets load the real value
4612                                 //
4613                                 ec.EmitLoadFromPtr (type);
4614                         }
4615
4616                         if (leave_copy) {
4617                                 ec.Emit (OpCodes.Dup);
4618
4619                                 if (IsRef) {
4620                                         temp = new LocalTemporary (Type);
4621                                         temp.Store (ec);
4622                                 }
4623                         }
4624                 }
4625
4626                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy,
4627                                         bool prepare_for_load)
4628                 {
4629                         HoistedVariable hv = GetHoistedVariable (ec);
4630                         if (hv != null) {
4631                                 hv.EmitAssign (ec, source, leave_copy, prepare_for_load);
4632                                 return;
4633                         }
4634
4635                         New n_source = source as New;
4636                         if (n_source != null) {
4637                                 if (!n_source.Emit (ec, this)) {
4638                                         if (leave_copy) {
4639                                                 EmitLoad (ec);
4640                                                 if (IsRef)
4641                                                         ec.EmitLoadFromPtr (type);
4642                                         }
4643                                         return;
4644                                 }
4645                         } else {
4646                                 if (IsRef)
4647                                         EmitLoad (ec);
4648
4649                                 source.Emit (ec);
4650                         }
4651
4652                         if (leave_copy) {
4653                                 ec.Emit (OpCodes.Dup);
4654                                 if (IsRef) {
4655                                         temp = new LocalTemporary (Type);
4656                                         temp.Store (ec);
4657                                 }
4658                         }
4659
4660                         if (IsRef)
4661                                 ec.EmitStoreFromPtr (type);
4662                         else
4663                                 Variable.EmitAssign (ec);
4664
4665                         if (temp != null) {
4666                                 temp.Emit (ec);
4667                                 temp.Release (ec);
4668                         }
4669                 }
4670
4671
4672                 public HoistedVariable GetHoistedVariable (ResolveContext rc)
4673                 {
4674                         return GetHoistedVariable (rc.CurrentAnonymousMethod);
4675                 }
4676
4677                 public HoistedVariable GetHoistedVariable (EmitContext ec)
4678                 {
4679                         return GetHoistedVariable (ec.CurrentAnonymousMethod);
4680                 }
4681
4682                 public override string GetSignatureForError ()
4683                 {
4684                         return Name;
4685                 }
4686
4687                 public bool IsHoisted {
4688                         get { return GetHoistedVariable ((AnonymousExpression) null) != null; }
4689                 }
4690         }
4691
4692         //
4693         // Resolved reference to a local variable
4694         //
4695         public class LocalVariableReference : VariableReference
4696         {
4697                 public LocalVariable local_info;
4698
4699                 public LocalVariableReference (LocalVariable li, Location l)
4700                 {
4701                         this.local_info = li;
4702                         loc = l;
4703                 }
4704
4705                 public override VariableInfo VariableInfo {
4706                         get { return local_info.VariableInfo; }
4707                 }
4708
4709                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
4710                 {
4711                         return local_info.HoistedVariant;
4712                 }
4713
4714                 #region Properties
4715
4716                 //
4717                 // A local variable is always fixed
4718                 //
4719                 public override bool IsFixed {
4720                         get {
4721                                 return true;
4722                         }
4723                 }
4724
4725                 public override bool IsLockedByStatement {
4726                         get {
4727                                 return local_info.IsLocked;
4728                         }
4729                         set {
4730                                 local_info.IsLocked = value;
4731                         }
4732                 }
4733
4734                 public override bool IsRef {
4735                         get { return false; }
4736                 }
4737
4738                 public override string Name {
4739                         get { return local_info.Name; }
4740                 }
4741
4742                 #endregion
4743
4744                 public bool VerifyAssigned (ResolveContext ec)
4745                 {
4746                         VariableInfo variable_info = local_info.VariableInfo;
4747                         return variable_info == null || variable_info.IsAssigned (ec, loc);
4748                 }
4749
4750                 public override void SetHasAddressTaken ()
4751                 {
4752                         local_info.AddressTaken = true;
4753                 }
4754
4755                 public override Expression CreateExpressionTree (ResolveContext ec)
4756                 {
4757                         HoistedVariable hv = GetHoistedVariable (ec);
4758                         if (hv != null)
4759                                 return hv.CreateExpressionTree ();
4760
4761                         Arguments arg = new Arguments (1);
4762                         arg.Add (new Argument (this));
4763                         return CreateExpressionFactoryCall (ec, "Constant", arg);
4764                 }
4765
4766                 void DoResolveBase (ResolveContext ec)
4767                 {
4768                         VerifyAssigned (ec);
4769
4770                         //
4771                         // If we are referencing a variable from the external block
4772                         // flag it for capturing
4773                         //
4774                         if (ec.MustCaptureVariable (local_info)) {
4775                                 if (local_info.AddressTaken)
4776                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
4777
4778                                 if (ec.IsVariableCapturingRequired) {
4779                                         AnonymousMethodStorey storey = local_info.Block.Explicit.CreateAnonymousMethodStorey (ec);
4780                                         storey.CaptureLocalVariable (ec, local_info);
4781                                 }
4782                         }
4783
4784                         eclass = ExprClass.Variable;
4785                         type = local_info.Type;
4786                 }
4787
4788                 protected override Expression DoResolve (ResolveContext ec)
4789                 {
4790                         local_info.SetIsUsed ();
4791
4792                         DoResolveBase (ec);
4793                         return this;
4794                 }
4795
4796                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
4797                 {
4798                         // is out param
4799                         if (right_side == EmptyExpression.OutAccess.Instance)
4800                                 local_info.SetIsUsed ();
4801
4802                         if (local_info.IsReadonly && !ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.UsingInitializerScope)) {
4803                                 int code;
4804                                 string msg;
4805                                 if (right_side == EmptyExpression.OutAccess.Instance) {
4806                                         code = 1657; msg = "Cannot pass `{0}' as a ref or out argument because it is a `{1}'";
4807                                 } else if (right_side == EmptyExpression.LValueMemberAccess) {
4808                                         code = 1654; msg = "Cannot assign to members of `{0}' because it is a `{1}'";
4809                                 } else if (right_side == EmptyExpression.LValueMemberOutAccess) {
4810                                         code = 1655; msg = "Cannot pass members of `{0}' as ref or out arguments because it is a `{1}'";
4811                                 } else if (right_side == EmptyExpression.UnaryAddress) {
4812                                         code = 459; msg = "Cannot take the address of {1} `{0}'";
4813                                 } else {
4814                                         code = 1656; msg = "Cannot assign to `{0}' because it is a `{1}'";
4815                                 }
4816                                 ec.Report.Error (code, loc, msg, Name, local_info.GetReadOnlyContext ());
4817                         } else if (VariableInfo != null) {
4818                                 VariableInfo.SetAssigned (ec);
4819                         }
4820
4821                         DoResolveBase (ec);
4822
4823                         return base.DoResolveLValue (ec, right_side);
4824                 }
4825
4826                 public override int GetHashCode ()
4827                 {
4828                         return local_info.GetHashCode ();
4829                 }
4830
4831                 public override bool Equals (object obj)
4832                 {
4833                         LocalVariableReference lvr = obj as LocalVariableReference;
4834                         if (lvr == null)
4835                                 return false;
4836
4837                         return local_info == lvr.local_info;
4838                 }
4839
4840                 protected override ILocalVariable Variable {
4841                         get { return local_info; }
4842                 }
4843
4844                 public override string ToString ()
4845                 {
4846                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
4847                 }
4848
4849                 protected override void CloneTo (CloneContext clonectx, Expression t)
4850                 {
4851                         // Nothing
4852                 }
4853         }
4854
4855         /// <summary>
4856         ///   This represents a reference to a parameter in the intermediate
4857         ///   representation.
4858         /// </summary>
4859         public class ParameterReference : VariableReference
4860         {
4861                 protected ParametersBlock.ParameterInfo pi;
4862
4863                 public ParameterReference (ParametersBlock.ParameterInfo pi, Location loc)
4864                 {
4865                         this.pi = pi;
4866                         this.loc = loc;
4867                 }
4868
4869                 #region Properties
4870
4871                 public override bool IsLockedByStatement {
4872                         get {
4873                                 return pi.IsLocked;
4874                         }
4875                         set     {
4876                                 pi.IsLocked = value;
4877                         }
4878                 }
4879
4880                 public override bool IsRef {
4881                         get { return (pi.Parameter.ModFlags & Parameter.Modifier.ISBYREF) != 0; }
4882                 }
4883
4884                 bool HasOutModifier {
4885                         get { return pi.Parameter.ModFlags == Parameter.Modifier.OUT; }
4886                 }
4887
4888                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
4889                 {
4890                         return pi.Parameter.HoistedVariant;
4891                 }
4892
4893                 //
4894                 // A ref or out parameter is classified as a moveable variable, even
4895                 // if the argument given for the parameter is a fixed variable
4896                 //
4897                 public override bool IsFixed {
4898                         get { return !IsRef; }
4899                 }
4900
4901                 public override string Name {
4902                         get { return Parameter.Name; }
4903                 }
4904
4905                 public Parameter Parameter {
4906                         get { return pi.Parameter; }
4907                 }
4908
4909                 public override VariableInfo VariableInfo {
4910                         get { return pi.VariableInfo; }
4911                 }
4912
4913                 protected override ILocalVariable Variable {
4914                         get { return Parameter; }
4915                 }
4916
4917                 #endregion
4918
4919                 public bool IsAssigned (ResolveContext ec, Location loc)
4920                 {
4921                         // HACK: Variables are not captured in probing mode
4922                         if (ec.IsInProbingMode)
4923                                 return true;
4924
4925                         if (!ec.DoFlowAnalysis || !HasOutModifier || ec.CurrentBranching.IsAssigned (VariableInfo))
4926                                 return true;
4927
4928                         ec.Report.Error (269, loc, "Use of unassigned out parameter `{0}'", Name);
4929                         return false;
4930                 }
4931
4932                 public override void SetHasAddressTaken ()
4933                 {
4934                         Parameter.HasAddressTaken = true;
4935                 }
4936
4937                 void SetAssigned (ResolveContext ec)
4938                 {
4939                         if (HasOutModifier && ec.DoFlowAnalysis)
4940                                 ec.CurrentBranching.SetAssigned (VariableInfo);
4941                 }
4942
4943                 bool DoResolveBase (ResolveContext ec)
4944                 {
4945                         type = pi.ParameterType;
4946                         eclass = ExprClass.Variable;
4947
4948                         //
4949                         // If we are referencing a parameter from the external block
4950                         // flag it for capturing
4951                         //
4952                         if (ec.MustCaptureVariable (pi)) {
4953                                 if (Parameter.HasAddressTaken)
4954                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
4955
4956                                 if (IsRef) {
4957                                         ec.Report.Error (1628, loc,
4958                                                 "Parameter `{0}' cannot be used inside `{1}' when using `ref' or `out' modifier",
4959                                                 Name, ec.CurrentAnonymousMethod.ContainerType);
4960                                 }
4961
4962                                 if (ec.IsVariableCapturingRequired && !pi.Block.ParametersBlock.IsExpressionTree) {
4963                                         AnonymousMethodStorey storey = pi.Block.Explicit.CreateAnonymousMethodStorey (ec);
4964                                         storey.CaptureParameter (ec, this);
4965                                 }
4966                         }
4967
4968                         return true;
4969                 }
4970
4971                 public override int GetHashCode ()
4972                 {
4973                         return Name.GetHashCode ();
4974                 }
4975
4976                 public override bool Equals (object obj)
4977                 {
4978                         ParameterReference pr = obj as ParameterReference;
4979                         if (pr == null)
4980                                 return false;
4981
4982                         return Name == pr.Name;
4983                 }
4984
4985                 public override void AddressOf (EmitContext ec, AddressOp mode)
4986                 {
4987                         //
4988                         // ParameterReferences might already be a reference
4989                         //
4990                         if (IsRef) {
4991                                 EmitLoad (ec);
4992                                 return;
4993                         }
4994
4995                         base.AddressOf (ec, mode);
4996                 }
4997
4998                 protected override void CloneTo (CloneContext clonectx, Expression target)
4999                 {
5000                         // Nothing to clone
5001                         return;
5002                 }
5003
5004                 public override Expression CreateExpressionTree (ResolveContext ec)
5005                 {
5006                         HoistedVariable hv = GetHoistedVariable (ec);
5007                         if (hv != null)
5008                                 return hv.CreateExpressionTree ();
5009
5010                         return Parameter.ExpressionTreeVariableReference ();
5011                 }
5012
5013                 //
5014                 // Notice that for ref/out parameters, the type exposed is not the
5015                 // same type exposed externally.
5016                 //
5017                 // for "ref int a":
5018                 //   externally we expose "int&"
5019                 //   here we expose       "int".
5020                 //
5021                 // We record this in "is_ref".  This means that the type system can treat
5022                 // the type as it is expected, but when we generate the code, we generate
5023                 // the alternate kind of code.
5024                 //
5025                 protected override Expression DoResolve (ResolveContext ec)
5026                 {
5027                         if (!DoResolveBase (ec))
5028                                 return null;
5029
5030                         // HACK: Variables are not captured in probing mode
5031                         if (ec.IsInProbingMode)
5032                                 return this;
5033
5034                         if (HasOutModifier && ec.DoFlowAnalysis &&
5035                             (!ec.OmitStructFlowAnalysis || !VariableInfo.TypeInfo.IsStruct) && !IsAssigned (ec, loc))
5036                                 return null;
5037
5038                         return this;
5039                 }
5040
5041                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5042                 {
5043                         if (!DoResolveBase (ec))
5044                                 return null;
5045
5046                         SetAssigned (ec);
5047                         return base.DoResolveLValue (ec, right_side);
5048                 }
5049
5050                 static public void EmitLdArg (EmitContext ec, int x)
5051                 {
5052                         switch (x) {
5053                         case 0: ec.Emit (OpCodes.Ldarg_0); break;
5054                         case 1: ec.Emit (OpCodes.Ldarg_1); break;
5055                         case 2: ec.Emit (OpCodes.Ldarg_2); break;
5056                         case 3: ec.Emit (OpCodes.Ldarg_3); break;
5057                         default:
5058                                 if (x > byte.MaxValue)
5059                                         ec.Emit (OpCodes.Ldarg, x);
5060                                 else
5061                                         ec.Emit (OpCodes.Ldarg_S, (byte) x);
5062                                 break;
5063                         }
5064                 }
5065         }
5066
5067         /// <summary>
5068         ///   Invocation of methods or delegates.
5069         /// </summary>
5070         public class Invocation : ExpressionStatement
5071         {
5072                 protected Arguments arguments;
5073                 protected Expression expr;
5074                 protected MethodGroupExpr mg;
5075
5076                 public Invocation (Expression expr, Arguments arguments)
5077                 {
5078                         this.expr = expr;
5079                         this.arguments = arguments;
5080                         if (expr != null)
5081                                 loc = expr.Location;
5082                 }
5083
5084                 #region Properties
5085                 public Arguments Arguments {
5086                         get {
5087                                 return arguments;
5088                         }
5089                 }
5090
5091                 public Expression Expression {
5092                         get {
5093                                 return expr;
5094                         }
5095                 }
5096                 #endregion
5097
5098                 protected override void CloneTo (CloneContext clonectx, Expression t)
5099                 {
5100                         Invocation target = (Invocation) t;
5101
5102                         if (arguments != null)
5103                                 target.arguments = arguments.Clone (clonectx);
5104
5105                         target.expr = expr.Clone (clonectx);
5106                 }
5107
5108
5109                 public override Expression CreateExpressionTree (ResolveContext ec)
5110                 {
5111                         Expression instance = mg.IsInstance ?
5112                                 mg.InstanceExpression.CreateExpressionTree (ec) :
5113                                 new NullLiteral (loc);
5114
5115                         var args = Arguments.CreateForExpressionTree (ec, arguments,
5116                                 instance,
5117                                 mg.CreateExpressionTree (ec));
5118
5119                         return CreateExpressionFactoryCall (ec, "Call", args);
5120                 }
5121
5122                 protected override Expression DoResolve (ResolveContext ec)
5123                 {
5124                         Expression member_expr;
5125                         var atn = expr as ATypeNameExpression;
5126                         if (atn != null) {
5127                                 member_expr = atn.LookupNameExpression (ec, MemberLookupRestrictions.InvocableOnly | MemberLookupRestrictions.ReadAccess);
5128                                 if (member_expr != null)
5129                                         member_expr = member_expr.Resolve (ec);
5130                         } else {
5131                                 member_expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
5132                         }
5133
5134                         if (member_expr == null)
5135                                 return null;
5136
5137                         //
5138                         // Next, evaluate all the expressions in the argument list
5139                         //
5140                         bool dynamic_arg = false;
5141                         if (arguments != null)
5142                                 arguments.Resolve (ec, out dynamic_arg);
5143
5144                         TypeSpec expr_type = member_expr.Type;
5145                         if (expr_type == InternalType.Dynamic)
5146                                 return DoResolveDynamic (ec, member_expr);
5147
5148                         mg = member_expr as MethodGroupExpr;
5149                         Expression invoke = null;
5150
5151                         if (mg == null) {
5152                                 if (expr_type != null && TypeManager.IsDelegateType (expr_type)) {
5153                                         invoke = new DelegateInvocation (member_expr, arguments, loc);
5154                                         invoke = invoke.Resolve (ec);
5155                                         if (invoke == null || !dynamic_arg)
5156                                                 return invoke;
5157                                 } else {
5158                                         if (member_expr is RuntimeValueExpression) {
5159                                                 ec.Report.Error (Report.RuntimeErrorId, loc, "Cannot invoke a non-delegate type `{0}'",
5160                                                         member_expr.Type.GetSignatureForError ()); ;
5161                                                 return null;
5162                                         }
5163
5164                                         MemberExpr me = member_expr as MemberExpr;
5165                                         if (me == null) {
5166                                                 member_expr.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup, loc);
5167                                                 return null;
5168                                         }
5169
5170                                         ec.Report.Error (1955, loc, "The member `{0}' cannot be used as method or delegate",
5171                                                         member_expr.GetSignatureForError ());
5172                                         return null;
5173                                 }
5174                         }
5175
5176                         if (invoke == null) {
5177                                 mg = DoResolveOverload (ec);
5178                                 if (mg == null)
5179                                         return null;
5180                         }
5181
5182                         if (dynamic_arg)
5183                                 return DoResolveDynamic (ec, member_expr);
5184
5185                         var method = mg.BestCandidate;
5186                         type = mg.BestCandidateReturnType;
5187
5188                         if (arguments == null && method.DeclaringType == TypeManager.object_type && method.Name == Destructor.MetadataName) {
5189                                 if (mg.IsBase)
5190                                         ec.Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
5191                                 else
5192                                         ec.Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
5193                                 return null;
5194                         }
5195
5196                         IsSpecialMethodInvocation (ec, method, loc);
5197
5198                         eclass = ExprClass.Value;
5199                         return this;
5200                 }
5201
5202                 protected virtual Expression DoResolveDynamic (ResolveContext ec, Expression memberExpr)
5203                 {
5204                         Arguments args;
5205                         DynamicMemberBinder dmb = memberExpr as DynamicMemberBinder;
5206                         if (dmb != null) {
5207                                 args = dmb.Arguments;
5208                                 if (arguments != null)
5209                                         args.AddRange (arguments);
5210                         } else if (mg == null) {
5211                                 if (arguments == null)
5212                                         args = new Arguments (1);
5213                                 else
5214                                         args = arguments;
5215
5216                                 args.Insert (0, new Argument (memberExpr));
5217                                 this.expr = null;
5218                         } else {
5219                                 if (mg.IsBase) {
5220                                         ec.Report.Error (1971, loc,
5221                                                 "The base call to method `{0}' cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access",
5222                                                 mg.Name);
5223                                         return null;
5224                                 }
5225
5226                                 if (arguments == null)
5227                                         args = new Arguments (1);
5228                                 else
5229                                         args = arguments;
5230
5231                                 MemberAccess ma = expr as MemberAccess;
5232                                 if (ma != null) {
5233                                         var left_type = ma.LeftExpression as TypeExpr;
5234                                         if (left_type != null) {
5235                                                 args.Insert (0, new Argument (new TypeOf (left_type, loc).Resolve (ec), Argument.AType.DynamicTypeName));
5236                                         } else {
5237                                                 //
5238                                                 // Any value type has to be pass as by-ref to get back the same
5239                                                 // instance on which the member was called
5240                                                 //
5241                                                 var mod = TypeManager.IsValueType (ma.LeftExpression.Type) ? Argument.AType.Ref : Argument.AType.None;
5242                                                 args.Insert (0, new Argument (ma.LeftExpression.Resolve (ec), mod));
5243                                         }
5244                                 } else {        // is SimpleName
5245                                         if (ec.IsStatic) {
5246                                                 args.Insert (0, new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc).Resolve (ec), Argument.AType.DynamicTypeName));
5247                                         } else {
5248                                                 args.Insert (0, new Argument (new This (loc).Resolve (ec)));
5249                                         }
5250                                 }
5251                         }
5252
5253                         return new DynamicInvocation (expr as ATypeNameExpression, args, loc).Resolve (ec);
5254                 }
5255
5256                 protected virtual MethodGroupExpr DoResolveOverload (ResolveContext ec)
5257                 {
5258                         return mg.OverloadResolve (ec, ref arguments, null, OverloadResolver.Restrictions.None);
5259                 }
5260
5261                 static MetaType[] GetVarargsTypes (MethodSpec mb, Arguments arguments)
5262                 {
5263                         AParametersCollection pd = mb.Parameters;
5264
5265                         Argument a = arguments[pd.Count - 1];
5266                         Arglist list = (Arglist) a.Expr;
5267
5268                         return list.ArgumentTypes;
5269                 }
5270
5271                 //
5272                 // If a member is a method or event, or if it is a constant, field or property of either a delegate type
5273                 // or the type dynamic, then the member is invocable
5274                 //
5275                 public static bool IsMemberInvocable (MemberSpec member)
5276                 {
5277                         switch (member.Kind) {
5278                         case MemberKind.Event:
5279                                 return true;
5280                         case MemberKind.Field:
5281                         case MemberKind.Property:
5282                                 var m = member as IInterfaceMemberSpec;
5283                                 return m.MemberType.IsDelegate || m.MemberType == InternalType.Dynamic;
5284                         default:
5285                                 return false;
5286                         }
5287                 }
5288
5289                 public static bool IsSpecialMethodInvocation (ResolveContext ec, MethodSpec method, Location loc)
5290                 {
5291                         if (!method.IsReservedMethod)
5292                                 return false;
5293
5294                         if (ec.HasSet (ResolveContext.Options.InvokeSpecialName) || ec.CurrentMemberDefinition.IsCompilerGenerated)
5295                                 return false;
5296
5297                         ec.Report.SymbolRelatedToPreviousError (method);
5298                         ec.Report.Error (571, loc, "`{0}': cannot explicitly call operator or accessor",
5299                                 method.GetSignatureForError ());
5300
5301                         return true;
5302                 }
5303
5304                 //
5305                 // Used to decide whether call or callvirt is needed
5306                 //
5307                 static bool IsVirtualCallRequired (Expression instance, MethodSpec method)
5308                 {
5309                         //
5310                         // There are 2 scenarious where we emit callvirt
5311                         //
5312                         // Case 1: A method is virtual and it's not used to call base
5313                         // Case 2: A method instance expression can be null. In this casen callvirt ensures
5314                         // correct NRE exception when the method is called
5315                         //
5316                         var decl_type = method.DeclaringType;
5317                         if (decl_type.IsStruct || decl_type.IsEnum)
5318                                 return false;
5319
5320                         if (instance is BaseThis)
5321                                 return false;
5322
5323                         //
5324                         // It's non-virtual and will never be null
5325                         //
5326                         if (!method.IsVirtual && (instance is This || instance is New || instance is ArrayCreation || instance is DelegateCreation || instance is TypeOf))
5327                                 return false;
5328
5329                         return true;
5330                 }
5331
5332                 /// <remarks>
5333                 ///   is_base tells whether we want to force the use of the `call'
5334                 ///   opcode instead of using callvirt.  Call is required to call
5335                 ///   a specific method, while callvirt will always use the most
5336                 ///   recent method in the vtable.
5337                 ///
5338                 ///   is_static tells whether this is an invocation on a static method
5339                 ///
5340                 ///   instance_expr is an expression that represents the instance
5341                 ///   it must be non-null if is_static is false.
5342                 ///
5343                 ///   method is the method to invoke.
5344                 ///
5345                 ///   Arguments is the list of arguments to pass to the method or constructor.
5346                 /// </remarks>
5347                 public static void EmitCall (EmitContext ec, Expression instance_expr,
5348                                              MethodSpec method, Arguments Arguments, Location loc)
5349                 {
5350                         EmitCall (ec, instance_expr, method, Arguments, loc, false, false);
5351                 }
5352
5353                 // `dup_args' leaves an extra copy of the arguments on the stack
5354                 // `omit_args' does not leave any arguments at all.
5355                 // So, basically, you could make one call with `dup_args' set to true,
5356                 // and then another with `omit_args' set to true, and the two calls
5357                 // would have the same set of arguments. However, each argument would
5358                 // only have been evaluated once.
5359                 public static void EmitCall (EmitContext ec, Expression instance_expr,
5360                                              MethodSpec method, Arguments Arguments, Location loc,
5361                                              bool dup_args, bool omit_args)
5362                 {
5363                         LocalTemporary this_arg = null;
5364
5365                         // Speed up the check by not doing it on not allowed targets
5366                         if (method.ReturnType == TypeManager.void_type && method.IsConditionallyExcluded (loc))
5367                                 return;
5368
5369                         OpCode call_op;
5370                         TypeSpec iexpr_type;
5371
5372                         if (method.IsStatic) {
5373                                 iexpr_type = null;
5374                                 call_op = OpCodes.Call;
5375                         } else {
5376                                 iexpr_type = instance_expr.Type;
5377
5378                                 if (IsVirtualCallRequired (instance_expr, method)) {
5379                                         call_op = OpCodes.Callvirt;
5380                                 } else {
5381                                         call_op = OpCodes.Call;
5382                                 }
5383
5384                                 //
5385                                 // If this is ourselves, push "this"
5386                                 //
5387                                 if (!omit_args) {
5388                                         TypeSpec t = iexpr_type;
5389
5390                                         //
5391                                         // Push the instance expression
5392                                         //
5393                                         if ((iexpr_type.IsStruct && (call_op == OpCodes.Callvirt || (call_op == OpCodes.Call && method.DeclaringType == iexpr_type))) ||
5394                                                 iexpr_type.IsGenericParameter || TypeManager.IsNullableType (method.DeclaringType)) {
5395                                                 //
5396                                                 // If the expression implements IMemoryLocation, then
5397                                                 // we can optimize and use AddressOf on the
5398                                                 // return.
5399                                                 //
5400                                                 // If not we have to use some temporary storage for
5401                                                 // it.
5402                                                 var iml = instance_expr as IMemoryLocation;
5403                                                 if (iml != null) {
5404                                                         iml.AddressOf (ec, AddressOp.LoadStore);
5405                                                 } else {
5406                                                         LocalTemporary temp = new LocalTemporary (iexpr_type);
5407                                                         instance_expr.Emit (ec);
5408                                                         temp.Store (ec);
5409                                                         temp.AddressOf (ec, AddressOp.Load);
5410                                                 }
5411
5412                                                 // avoid the overhead of doing this all the time.
5413                                                 if (dup_args)
5414                                                         t = ReferenceContainer.MakeType (iexpr_type);
5415                                         } else if (iexpr_type.IsEnum || iexpr_type.IsStruct) {
5416                                                 instance_expr.Emit (ec);
5417                                                 ec.Emit (OpCodes.Box, iexpr_type);
5418                                                 t = iexpr_type = TypeManager.object_type;
5419                                         } else {
5420                                                 instance_expr.Emit (ec);
5421                                         }
5422
5423                                         if (dup_args) {
5424                                                 ec.Emit (OpCodes.Dup);
5425                                                 if (Arguments != null && Arguments.Count != 0) {
5426                                                         this_arg = new LocalTemporary (t);
5427                                                         this_arg.Store (ec);
5428                                                 }
5429                                         }
5430                                 }
5431                         }
5432
5433                         if (!omit_args && Arguments != null) {
5434                                 var dup_arg_exprs = Arguments.Emit (ec, dup_args);
5435                                 if (dup_args) {
5436                                         this_arg.Emit (ec);
5437                                         LocalTemporary lt;
5438                                         foreach (var dup in dup_arg_exprs) {
5439                                                 dup.Emit (ec);
5440                                                 lt = dup as LocalTemporary;
5441                                                 if (lt != null)
5442                                                         lt.Release (ec);
5443                                         }
5444                                 }
5445                         }
5446
5447                         if (call_op == OpCodes.Callvirt && (iexpr_type.IsGenericParameter || iexpr_type.IsStruct)) {
5448                                 ec.Emit (OpCodes.Constrained, iexpr_type);
5449                         }
5450
5451                         if (method.Parameters.HasArglist) {
5452                                 var varargs_types = GetVarargsTypes (method, Arguments);
5453                                 ec.Emit (call_op, method, varargs_types);
5454                                 return;
5455                         }
5456
5457                         //
5458                         // If you have:
5459                         // this.DoFoo ();
5460                         // and DoFoo is not virtual, you can omit the callvirt,
5461                         // because you don't need the null checking behavior.
5462                         //
5463                         ec.Emit (call_op, method);
5464                 }
5465
5466                 public override void Emit (EmitContext ec)
5467                 {
5468                         mg.EmitCall (ec, arguments);
5469                 }
5470
5471                 public override void EmitStatement (EmitContext ec)
5472                 {
5473                         Emit (ec);
5474
5475                         //
5476                         // Pop the return value if there is one
5477                         //
5478                         if (type != TypeManager.void_type)
5479                                 ec.Emit (OpCodes.Pop);
5480                 }
5481
5482                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5483                 {
5484                         return MakeExpression (ctx, mg.InstanceExpression, mg.BestCandidate, arguments);
5485                 }
5486
5487                 public static SLE.Expression MakeExpression (BuilderContext ctx, Expression instance, MethodSpec mi, Arguments args)
5488                 {
5489 #if STATIC
5490                         throw new NotSupportedException ();
5491 #else
5492                         var instance_expr = instance == null ? null : instance.MakeExpression (ctx);
5493                         return SLE.Expression.Call (instance_expr, (MethodInfo) mi.GetMetaInfo (), Arguments.MakeExpression (args, ctx));
5494 #endif
5495                 }
5496         }
5497
5498         //
5499         // Implements simple new expression
5500         //
5501         public class New : ExpressionStatement, IMemoryLocation
5502         {
5503                 protected Arguments arguments;
5504
5505                 //
5506                 // During bootstrap, it contains the RequestedType,
5507                 // but if `type' is not null, it *might* contain a NewDelegate
5508                 // (because of field multi-initialization)
5509                 //
5510                 protected Expression RequestedType;
5511
5512                 protected MethodSpec method;
5513
5514                 public New (Expression requested_type, Arguments arguments, Location l)
5515                 {
5516                         RequestedType = requested_type;
5517                         this.arguments = arguments;
5518                         loc = l;
5519                 }
5520
5521                 #region Properties
5522                 public Arguments Arguments {
5523                         get {
5524                                 return arguments;
5525                         }
5526                 }
5527
5528                 //
5529                 // Returns true for resolved `new S()'
5530                 //
5531                 public bool IsDefaultStruct {
5532                         get {
5533                                 return arguments == null && type.IsStruct && GetType () == typeof (New);
5534                         }
5535                 }
5536
5537                 #endregion
5538
5539                 /// <summary>
5540                 /// Converts complex core type syntax like 'new int ()' to simple constant
5541                 /// </summary>
5542                 public static Constant Constantify (TypeSpec t, Location loc)
5543                 {
5544                         if (t == TypeManager.int32_type)
5545                                 return new IntConstant (0, loc);
5546                         if (t == TypeManager.uint32_type)
5547                                 return new UIntConstant (0, loc);
5548                         if (t == TypeManager.int64_type)
5549                                 return new LongConstant (0, loc);
5550                         if (t == TypeManager.uint64_type)
5551                                 return new ULongConstant (0, loc);
5552                         if (t == TypeManager.float_type)
5553                                 return new FloatConstant (0, loc);
5554                         if (t == TypeManager.double_type)
5555                                 return new DoubleConstant (0, loc);
5556                         if (t == TypeManager.short_type)
5557                                 return new ShortConstant (0, loc);
5558                         if (t == TypeManager.ushort_type)
5559                                 return new UShortConstant (0, loc);
5560                         if (t == TypeManager.sbyte_type)
5561                                 return new SByteConstant (0, loc);
5562                         if (t == TypeManager.byte_type)
5563                                 return new ByteConstant (0, loc);
5564                         if (t == TypeManager.char_type)
5565                                 return new CharConstant ('\0', loc);
5566                         if (t == TypeManager.bool_type)
5567                                 return new BoolConstant (false, loc);
5568                         if (t == TypeManager.decimal_type)
5569                                 return new DecimalConstant (0, loc);
5570                         if (TypeManager.IsEnumType (t))
5571                                 return new EnumConstant (Constantify (EnumSpec.GetUnderlyingType (t), loc), t);
5572                         if (TypeManager.IsNullableType (t))
5573                                 return Nullable.LiftedNull.Create (t, loc);
5574
5575                         return null;
5576                 }
5577
5578                 //
5579                 // Checks whether the type is an interface that has the
5580                 // [ComImport, CoClass] attributes and must be treated
5581                 // specially
5582                 //
5583                 public Expression CheckComImport (ResolveContext ec)
5584                 {
5585                         if (!type.IsInterface)
5586                                 return null;
5587
5588                         //
5589                         // Turn the call into:
5590                         // (the-interface-stated) (new class-referenced-in-coclassattribute ())
5591                         //
5592                         var real_class = type.MemberDefinition.GetAttributeCoClass ();
5593                         if (real_class == null)
5594                                 return null;
5595
5596                         New proxy = new New (new TypeExpression (real_class, loc), arguments, loc);
5597                         Cast cast = new Cast (new TypeExpression (type, loc), proxy, loc);
5598                         return cast.Resolve (ec);
5599                 }
5600
5601                 public override Expression CreateExpressionTree (ResolveContext ec)
5602                 {
5603                         Arguments args;
5604                         if (method == null) {
5605                                 args = new Arguments (1);
5606                                 args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
5607                         } else {
5608                                 args = Arguments.CreateForExpressionTree (ec,
5609                                         arguments, new TypeOfMethod (method, loc));
5610                         }
5611
5612                         return CreateExpressionFactoryCall (ec, "New", args);
5613                 }
5614
5615                 protected override Expression DoResolve (ResolveContext ec)
5616                 {
5617                         TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec, false);
5618                         if (texpr == null)
5619                                 return null;
5620
5621                         type = texpr.Type;
5622                         eclass = ExprClass.Value;
5623
5624                         if (type.IsPointer) {
5625                                 ec.Report.Error (1919, loc, "Unsafe type `{0}' cannot be used in an object creation expression",
5626                                         TypeManager.CSharpName (type));
5627                                 return null;
5628                         }
5629
5630                         if (arguments == null) {
5631                                 Constant c = Constantify (type, RequestedType.Location);
5632                                 if (c != null)
5633                                         return ReducedExpression.Create (c.Resolve (ec), this);
5634                         }
5635
5636                         if (TypeManager.IsDelegateType (type)) {
5637                                 return (new NewDelegate (type, arguments, loc)).Resolve (ec);
5638                         }
5639
5640                         var tparam = type as TypeParameterSpec;
5641                         if (tparam != null) {
5642                                 //
5643                                 // Check whether the type of type parameter can be constructed. BaseType can be a struct for method overrides
5644                                 // where type parameter constraint is inflated to struct
5645                                 //
5646                                 if ((tparam.SpecialConstraint & (SpecialConstraint.Struct | SpecialConstraint.Constructor)) == 0 && !tparam.BaseType.IsStruct) {
5647                                         ec.Report.Error (304, loc,
5648                                                 "Cannot create an instance of the variable type `{0}' because it does not have the new() constraint",
5649                                                 TypeManager.CSharpName (type));
5650                                 }
5651
5652                                 if ((arguments != null) && (arguments.Count != 0)) {
5653                                         ec.Report.Error (417, loc,
5654                                                 "`{0}': cannot provide arguments when creating an instance of a variable type",
5655                                                 TypeManager.CSharpName (type));
5656                                 }
5657
5658                                 return this;
5659                         }
5660
5661                         if (type.IsStatic) {
5662                                 ec.Report.SymbolRelatedToPreviousError (type);
5663                                 ec.Report.Error (712, loc, "Cannot create an instance of the static class `{0}'", TypeManager.CSharpName (type));
5664                                 return null;
5665                         }
5666
5667                         if (type.IsInterface || type.IsAbstract){
5668                                 if (!TypeManager.IsGenericType (type)) {
5669                                         RequestedType = CheckComImport (ec);
5670                                         if (RequestedType != null)
5671                                                 return RequestedType;
5672                                 }
5673
5674                                 ec.Report.SymbolRelatedToPreviousError (type);
5675                                 ec.Report.Error (144, loc, "Cannot create an instance of the abstract class or interface `{0}'", TypeManager.CSharpName (type));
5676                                 return null;
5677                         }
5678
5679                         //
5680                         // Any struct always defines parameterless constructor
5681                         //
5682                         if (type.IsStruct && arguments == null)
5683                                 return this;
5684
5685                         bool dynamic;
5686                         if (arguments != null) {
5687                                 arguments.Resolve (ec, out dynamic);
5688                         } else {
5689                                 dynamic = false;
5690                         }
5691
5692                         method = ConstructorLookup (ec, type, ref arguments, loc);
5693
5694                         if (dynamic) {
5695                                 arguments.Insert (0, new Argument (new TypeOf (texpr, loc).Resolve (ec), Argument.AType.DynamicTypeName));
5696                                 return new DynamicConstructorBinder (type, arguments, loc).Resolve (ec);
5697                         }
5698
5699                         return this;
5700                 }
5701
5702                 bool DoEmitTypeParameter (EmitContext ec)
5703                 {
5704                         var activator = ec.MemberContext.Module.PredefinedTypes.Activator;
5705                         var t = activator.Resolve (loc);
5706                         if (t == null)
5707                                 return true;
5708
5709                         if (TypeManager.activator_create_instance == null) {
5710                                 TypeManager.activator_create_instance = TypeManager.GetPredefinedMethod (
5711                                         t, MemberFilter.Method ("CreateInstance", 1, ParametersCompiled.EmptyReadOnlyParameters, null), loc);
5712                         }
5713
5714                         var ctor_factory = TypeManager.activator_create_instance.MakeGenericMethod (type);
5715                         var tparam = (TypeParameterSpec) type;
5716
5717                         if (tparam.IsReferenceType) {
5718                                 ec.Emit (OpCodes.Call, ctor_factory);
5719                                 return true;
5720                         }
5721
5722                         // Allow DoEmit() to be called multiple times.
5723                         // We need to create a new LocalTemporary each time since
5724                         // you can't share LocalBuilders among ILGeneators.
5725                         LocalTemporary temp = new LocalTemporary (type);
5726
5727                         Label label_activator = ec.DefineLabel ();
5728                         Label label_end = ec.DefineLabel ();
5729
5730                         temp.AddressOf (ec, AddressOp.Store);
5731                         ec.Emit (OpCodes.Initobj, type);
5732
5733                         temp.Emit (ec);
5734                         ec.Emit (OpCodes.Box, type);
5735                         ec.Emit (OpCodes.Brfalse, label_activator);
5736
5737                         temp.AddressOf (ec, AddressOp.Store);
5738                         ec.Emit (OpCodes.Initobj, type);
5739                         temp.Emit (ec);
5740                         ec.Emit (OpCodes.Br_S, label_end);
5741
5742                         ec.MarkLabel (label_activator);
5743
5744                         ec.Emit (OpCodes.Call, ctor_factory);
5745                         ec.MarkLabel (label_end);
5746                         return true;
5747                 }
5748
5749                 //
5750                 // This Emit can be invoked in two contexts:
5751                 //    * As a mechanism that will leave a value on the stack (new object)
5752                 //    * As one that wont (init struct)
5753                 //
5754                 // If we are dealing with a ValueType, we have a few
5755                 // situations to deal with:
5756                 //
5757                 //    * The target is a ValueType, and we have been provided
5758                 //      the instance (this is easy, we are being assigned).
5759                 //
5760                 //    * The target of New is being passed as an argument,
5761                 //      to a boxing operation or a function that takes a
5762                 //      ValueType.
5763                 //
5764                 //      In this case, we need to create a temporary variable
5765                 //      that is the argument of New.
5766                 //
5767                 // Returns whether a value is left on the stack
5768                 //
5769                 // *** Implementation note ***
5770                 //
5771                 // To benefit from this optimization, each assignable expression
5772                 // has to manually cast to New and call this Emit.
5773                 //
5774                 // TODO: It's worth to implement it for arrays and fields
5775                 //
5776                 public virtual bool Emit (EmitContext ec, IMemoryLocation target)
5777                 {
5778                         bool is_value_type = TypeManager.IsValueType (type);
5779                         VariableReference vr = target as VariableReference;
5780
5781                         if (target != null && is_value_type && (vr != null || method == null)) {
5782                                 target.AddressOf (ec, AddressOp.Store);
5783                         } else if (vr != null && vr.IsRef) {
5784                                 vr.EmitLoad (ec);
5785                         }
5786
5787                         if (arguments != null)
5788                                 arguments.Emit (ec);
5789
5790                         if (is_value_type) {
5791                                 if (method == null) {
5792                                         ec.Emit (OpCodes.Initobj, type);
5793                                         return false;
5794                                 }
5795
5796                                 if (vr != null) {
5797                                         ec.Emit (OpCodes.Call, method);
5798                                         return false;
5799                                 }
5800                         }
5801
5802                         if (type is TypeParameterSpec)
5803                                 return DoEmitTypeParameter (ec);
5804
5805                         ec.Emit (OpCodes.Newobj, method);
5806                         return true;
5807                 }
5808
5809                 public override void Emit (EmitContext ec)
5810                 {
5811                         LocalTemporary v = null;
5812                         if (method == null && TypeManager.IsValueType (type)) {
5813                                 // TODO: Use temporary variable from pool
5814                                 v = new LocalTemporary (type);
5815                         }
5816
5817                         if (!Emit (ec, v))
5818                                 v.Emit (ec);
5819                 }
5820
5821                 public override void EmitStatement (EmitContext ec)
5822                 {
5823                         LocalTemporary v = null;
5824                         if (method == null && TypeManager.IsValueType (type)) {
5825                                 // TODO: Use temporary variable from pool
5826                                 v = new LocalTemporary (type);
5827                         }
5828
5829                         if (Emit (ec, v))
5830                                 ec.Emit (OpCodes.Pop);
5831                 }
5832
5833                 public void AddressOf (EmitContext ec, AddressOp mode)
5834                 {
5835                         EmitAddressOf (ec, mode);
5836                 }
5837
5838                 protected virtual IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp mode)
5839                 {
5840                         LocalTemporary value_target = new LocalTemporary (type);
5841
5842                         if (type is TypeParameterSpec) {
5843                                 DoEmitTypeParameter (ec);
5844                                 value_target.Store (ec);
5845                                 value_target.AddressOf (ec, mode);
5846                                 return value_target;
5847                         }
5848
5849                         if (!TypeManager.IsStruct (type)){
5850                                 //
5851                                 // We throw an exception.  So far, I believe we only need to support
5852                                 // value types:
5853                                 // foreach (int j in new StructType ())
5854                                 // see bug 42390
5855                                 //
5856                                 throw new Exception ("AddressOf should not be used for classes");
5857                         }
5858
5859                         value_target.AddressOf (ec, AddressOp.Store);
5860
5861                         if (method == null) {
5862                                 ec.Emit (OpCodes.Initobj, type);
5863                         } else {
5864                                 if (arguments != null)
5865                                         arguments.Emit (ec);
5866
5867                                 ec.Emit (OpCodes.Call, method);
5868                         }
5869
5870                         value_target.AddressOf (ec, mode);
5871                         return value_target;
5872                 }
5873
5874                 protected override void CloneTo (CloneContext clonectx, Expression t)
5875                 {
5876                         New target = (New) t;
5877
5878                         target.RequestedType = RequestedType.Clone (clonectx);
5879                         if (arguments != null){
5880                                 target.arguments = arguments.Clone (clonectx);
5881                         }
5882                 }
5883
5884                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5885                 {
5886 #if STATIC
5887                         return base.MakeExpression (ctx);
5888 #else
5889                         return SLE.Expression.New ((ConstructorInfo) method.GetMetaInfo (), Arguments.MakeExpression (arguments, ctx));
5890 #endif
5891                 }
5892         }
5893
5894         //
5895         // Array initializer expression, the expression is allowed in
5896         // variable or field initialization only which makes it tricky as
5897         // the type has to be infered based on the context either from field
5898         // type or variable type (think of multiple declarators)
5899         //
5900         public class ArrayInitializer : Expression
5901         {
5902                 List<Expression> elements;
5903                 BlockVariableDeclaration variable;
5904
5905                 public ArrayInitializer (List<Expression> init, Location loc)
5906                 {
5907                         elements = init;
5908                         this.loc = loc;
5909                 }
5910
5911                 public ArrayInitializer (int count, Location loc)
5912                         : this (new List<Expression> (count), loc)
5913                 {
5914                 }
5915
5916                 public ArrayInitializer (Location loc)
5917                         : this (4, loc)
5918                 {
5919                 }
5920
5921                 #region Properties
5922
5923                 public int Count {
5924                         get { return elements.Count; }
5925                 }
5926
5927                 public Expression this [int index] {
5928                         get {
5929                                 return elements [index];
5930                         }
5931                 }
5932
5933                 public BlockVariableDeclaration VariableDeclaration {
5934                         get {
5935                                 return variable;
5936                         }
5937                         set {
5938                                 variable = value;
5939                         }
5940                 }
5941
5942                 #endregion
5943
5944                 public void Add (Expression expr)
5945                 {
5946                         elements.Add (expr);
5947                 }
5948
5949                 public override Expression CreateExpressionTree (ResolveContext ec)
5950                 {
5951                         throw new NotSupportedException ("ET");
5952                 }
5953
5954                 protected override void CloneTo (CloneContext clonectx, Expression t)
5955                 {
5956                         var target = (ArrayInitializer) t;
5957
5958                         target.elements = new List<Expression> (elements.Count);
5959                         foreach (var element in elements)
5960                                 target.elements.Add (element.Clone (clonectx));
5961                 }
5962
5963                 protected override Expression DoResolve (ResolveContext rc)
5964                 {
5965                         var current_field = rc.CurrentMemberDefinition as FieldBase;
5966                         TypeExpression type;
5967                         if (current_field != null) {
5968                                 type = new TypeExpression (current_field.MemberType, current_field.Location);
5969                         } else if (variable != null) {
5970                                 if (variable.TypeExpression is VarExpr) {
5971                                         rc.Report.Error (820, loc, "An implicitly typed local variable declarator cannot use an array initializer");
5972                                         return EmptyExpression.Null;
5973                                 }
5974
5975                                 type = new TypeExpression (variable.Variable.Type, variable.Variable.Location);
5976                         } else {
5977                                 throw new NotImplementedException ("Unexpected array initializer context");
5978                         }
5979
5980                         return new ArrayCreation (type, this).Resolve (rc);
5981                 }
5982
5983                 public override void Emit (EmitContext ec)
5984                 {
5985                         throw new InternalErrorException ("Missing Resolve call");
5986                 }
5987         }
5988
5989         /// <summary>
5990         ///   14.5.10.2: Represents an array creation expression.
5991         /// </summary>
5992         ///
5993         /// <remarks>
5994         ///   There are two possible scenarios here: one is an array creation
5995         ///   expression that specifies the dimensions and optionally the
5996         ///   initialization data and the other which does not need dimensions
5997         ///   specified but where initialization data is mandatory.
5998         /// </remarks>
5999         public class ArrayCreation : Expression
6000         {
6001                 FullNamedExpression requested_base_type;
6002                 ArrayInitializer initializers;
6003
6004                 //
6005                 // The list of Argument types.
6006                 // This is used to construct the `newarray' or constructor signature
6007                 //
6008                 protected List<Expression> arguments;
6009
6010                 protected TypeSpec array_element_type;
6011                 int num_arguments = 0;
6012                 protected int dimensions;
6013                 protected readonly ComposedTypeSpecifier rank;
6014                 Expression first_emit;
6015                 LocalTemporary first_emit_temp;
6016
6017                 protected List<Expression> array_data;
6018
6019                 Dictionary<int, int> bounds;
6020
6021                 // The number of constants in array initializers
6022                 int const_initializers_count;
6023                 bool only_constant_initializers;
6024
6025                 public ArrayCreation (FullNamedExpression requested_base_type, List<Expression> exprs, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location l)
6026                         : this (requested_base_type, rank, initializers, l)
6027                 {
6028                         arguments = new List<Expression> (exprs);
6029                         num_arguments = arguments.Count;
6030                 }
6031
6032                 //
6033                 // For expressions like int[] foo = new int[] { 1, 2, 3 };
6034                 //
6035                 public ArrayCreation (FullNamedExpression requested_base_type, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
6036                 {
6037                         this.requested_base_type = requested_base_type;
6038                         this.rank = rank;
6039                         this.initializers = initializers;
6040                         this.loc = loc;
6041
6042                         if (rank != null)
6043                                 num_arguments = rank.Dimension;
6044                 }
6045
6046                 //
6047                 // For compiler generated single dimensional arrays only
6048                 //
6049                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers, Location loc)
6050                         : this (requested_base_type, ComposedTypeSpecifier.SingleDimension, initializers, loc)
6051                 {
6052                 }
6053
6054                 //
6055                 // For expressions like int[] foo = { 1, 2, 3 };
6056                 //
6057                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers)
6058                         : this (requested_base_type, null, initializers, initializers.Location)
6059                 {
6060                 }
6061
6062                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
6063                 {
6064                         ec.Report.Error (248, loc, "Cannot create an array with a negative size");
6065                 }
6066
6067                 bool CheckIndices (ResolveContext ec, ArrayInitializer probe, int idx, bool specified_dims, int child_bounds)
6068                 {
6069                         if (initializers != null && bounds == null) {
6070                                 //
6071                                 // We use this to store all the date values in the order in which we
6072                                 // will need to store them in the byte blob later
6073                                 //
6074                                 array_data = new List<Expression> ();
6075                                 bounds = new Dictionary<int, int> ();
6076                         }
6077
6078                         if (specified_dims) {
6079                                 Expression a = arguments [idx];
6080                                 a = a.Resolve (ec);
6081                                 if (a == null)
6082                                         return false;
6083
6084                                 a = ConvertExpressionToArrayIndex (ec, a);
6085                                 if (a == null)
6086                                         return false;
6087
6088                                 arguments[idx] = a;
6089
6090                                 if (initializers != null) {
6091                                         Constant c = a as Constant;
6092                                         if (c == null && a is ArrayIndexCast)
6093                                                 c = ((ArrayIndexCast) a).Child as Constant;
6094
6095                                         if (c == null) {
6096                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
6097                                                 return false;
6098                                         }
6099
6100                                         int value;
6101                                         try {
6102                                                 value = System.Convert.ToInt32 (c.GetValue ());
6103                                         } catch {
6104                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
6105                                                 return false;
6106                                         }
6107
6108                                         // TODO: probe.Count does not fit ulong in
6109                                         if (value != probe.Count) {
6110                                                 ec.Report.Error (847, loc, "An array initializer of length `{0}' was expected", value.ToString ());
6111                                                 return false;
6112                                         }
6113
6114                                         bounds[idx] = value;
6115                                 }
6116                         }
6117
6118                         if (initializers == null)
6119                                 return true;
6120
6121                         for (int i = 0; i < probe.Count; ++i) {
6122                                 var o = probe [i];
6123                                 if (o is ArrayInitializer) {
6124                                         var sub_probe = o as ArrayInitializer;
6125                                         if (idx + 1 >= dimensions){
6126                                                 ec.Report.Error (623, loc, "Array initializers can only be used in a variable or field initializer. Try using a new expression instead");
6127                                                 return false;
6128                                         }
6129
6130                                         bool ret = CheckIndices (ec, sub_probe, idx + 1, specified_dims, child_bounds - 1);
6131                                         if (!ret)
6132                                                 return false;
6133                                 } else if (child_bounds > 1) {
6134                                         ec.Report.Error (846, o.Location, "A nested array initializer was expected");
6135                                 } else {
6136                                         Expression element = ResolveArrayElement (ec, o);
6137                                         if (element == null)
6138                                                 continue;
6139
6140                                         // Initializers with the default values can be ignored
6141                                         Constant c = element as Constant;
6142                                         if (c != null) {
6143                                                 if (!c.IsDefaultInitializer (array_element_type)) {
6144                                                         ++const_initializers_count;
6145                                                 }
6146                                         } else {
6147                                                 only_constant_initializers = false;
6148                                         }
6149
6150                                         array_data.Add (element);
6151                                 }
6152                         }
6153
6154                         return true;
6155                 }
6156
6157                 public override Expression CreateExpressionTree (ResolveContext ec)
6158                 {
6159                         Arguments args;
6160
6161                         if (array_data == null) {
6162                                 args = new Arguments (arguments.Count + 1);
6163                                 args.Add (new Argument (new TypeOf (new TypeExpression (array_element_type, loc), loc)));
6164                                 foreach (Expression a in arguments)
6165                                         args.Add (new Argument (a.CreateExpressionTree (ec)));
6166
6167                                 return CreateExpressionFactoryCall (ec, "NewArrayBounds", args);
6168                         }
6169
6170                         if (dimensions > 1) {
6171                                 ec.Report.Error (838, loc, "An expression tree cannot contain a multidimensional array initializer");
6172                                 return null;
6173                         }
6174
6175                         args = new Arguments (array_data == null ? 1 : array_data.Count + 1);
6176                         args.Add (new Argument (new TypeOf (new TypeExpression (array_element_type, loc), loc)));
6177                         if (array_data != null) {
6178                                 for (int i = 0; i < array_data.Count; ++i) {
6179                                         Expression e = array_data [i];
6180                                         args.Add (new Argument (e.CreateExpressionTree (ec)));
6181                                 }
6182                         }
6183
6184                         return CreateExpressionFactoryCall (ec, "NewArrayInit", args);
6185                 }
6186
6187                 public void UpdateIndices ()
6188                 {
6189                         int i = 0;
6190                         for (var probe = initializers; probe != null;) {
6191                                 if (probe.Count > 0 && probe [0] is ArrayInitializer) {
6192                                         Expression e = new IntConstant (probe.Count, Location.Null);
6193                                         arguments.Add (e);
6194
6195                                         bounds [i++] = probe.Count;
6196
6197                                         probe = (ArrayInitializer) probe[0];
6198
6199                                 } else {
6200                                         Expression e = new IntConstant (probe.Count, Location.Null);
6201                                         arguments.Add (e);
6202
6203                                         bounds [i++] = probe.Count;
6204                                         return;
6205                                 }
6206                         }
6207                 }
6208
6209                 protected virtual Expression ResolveArrayElement (ResolveContext ec, Expression element)
6210                 {
6211                         element = element.Resolve (ec);
6212                         if (element == null)
6213                                 return null;
6214
6215                         if (element is CompoundAssign.TargetExpression) {
6216                                 if (first_emit != null)
6217                                         throw new InternalErrorException ("Can only handle one mutator at a time");
6218                                 first_emit = element;
6219                                 element = first_emit_temp = new LocalTemporary (element.Type);
6220                         }
6221
6222                         return Convert.ImplicitConversionRequired (
6223                                 ec, element, array_element_type, loc);
6224                 }
6225
6226                 protected bool ResolveInitializers (ResolveContext ec)
6227                 {
6228                         only_constant_initializers = true;
6229
6230                         if (arguments != null) {
6231                                 bool res = true;
6232                                 for (int i = 0; i < arguments.Count; ++i) {
6233                                         res &= CheckIndices (ec, initializers, i, true, dimensions);
6234                                         if (initializers != null)
6235                                                 break;
6236                                 }
6237
6238                                 return res;
6239                         }
6240
6241                         arguments = new List<Expression> ();
6242
6243                         if (!CheckIndices (ec, initializers, 0, false, dimensions))
6244                                 return false;
6245
6246                         UpdateIndices ();
6247
6248                         return true;
6249                 }
6250
6251                 //
6252                 // Resolved the type of the array
6253                 //
6254                 bool ResolveArrayType (ResolveContext ec)
6255                 {
6256                         //
6257                         // Lookup the type
6258                         //
6259                         FullNamedExpression array_type_expr;
6260                         if (num_arguments > 0) {
6261                                 array_type_expr = new ComposedCast (requested_base_type, rank);
6262                         } else {
6263                                 array_type_expr = requested_base_type;
6264                         }
6265
6266                         array_type_expr = array_type_expr.ResolveAsTypeTerminal (ec, false);
6267                         if (array_type_expr == null)
6268                                 return false;
6269
6270                         type = array_type_expr.Type;
6271                         var ac = type as ArrayContainer;
6272                         if (ac == null) {
6273                                 ec.Report.Error (622, loc, "Can only use array initializer expressions to assign to array types. Try using a new expression instead");
6274                                 return false;
6275                         }
6276
6277                         array_element_type = ac.Element;
6278                         dimensions = ac.Rank;
6279
6280                         return true;
6281                 }
6282
6283                 protected override Expression DoResolve (ResolveContext ec)
6284                 {
6285                         if (type != null)
6286                                 return this;
6287
6288                         if (!ResolveArrayType (ec))
6289                                 return null;
6290
6291                         //
6292                         // validate the initializers and fill in any missing bits
6293                         //
6294                         if (!ResolveInitializers (ec))
6295                                 return null;
6296
6297                         eclass = ExprClass.Value;
6298                         return this;
6299                 }
6300
6301                 byte [] MakeByteBlob ()
6302                 {
6303                         int factor;
6304                         byte [] data;
6305                         byte [] element;
6306                         int count = array_data.Count;
6307
6308                         TypeSpec element_type = array_element_type;
6309                         if (TypeManager.IsEnumType (element_type))
6310                                 element_type = EnumSpec.GetUnderlyingType (element_type);
6311
6312                         factor = GetTypeSize (element_type);
6313                         if (factor == 0)
6314                                 throw new Exception ("unrecognized type in MakeByteBlob: " + element_type);
6315
6316                         data = new byte [(count * factor + 3) & ~3];
6317                         int idx = 0;
6318
6319                         for (int i = 0; i < count; ++i) {
6320                                 object v = array_data [i];
6321
6322                                 if (v is EnumConstant)
6323                                         v = ((EnumConstant) v).Child;
6324
6325                                 if (v is Constant && !(v is StringConstant))
6326                                         v = ((Constant) v).GetValue ();
6327                                 else {
6328                                         idx += factor;
6329                                         continue;
6330                                 }
6331
6332                                 if (element_type == TypeManager.int64_type){
6333                                         if (!(v is Expression)){
6334                                                 long val = (long) v;
6335
6336                                                 for (int j = 0; j < factor; ++j) {
6337                                                         data [idx + j] = (byte) (val & 0xFF);
6338                                                         val = (val >> 8);
6339                                                 }
6340                                         }
6341                                 } else if (element_type == TypeManager.uint64_type){
6342                                         if (!(v is Expression)){
6343                                                 ulong val = (ulong) v;
6344
6345                                                 for (int j = 0; j < factor; ++j) {
6346                                                         data [idx + j] = (byte) (val & 0xFF);
6347                                                         val = (val >> 8);
6348                                                 }
6349                                         }
6350                                 } else if (element_type == TypeManager.float_type) {
6351                                         if (!(v is Expression)){
6352                                                 element = BitConverter.GetBytes ((float) v);
6353
6354                                                 for (int j = 0; j < factor; ++j)
6355                                                         data [idx + j] = element [j];
6356                                                 if (!BitConverter.IsLittleEndian)
6357                                                         System.Array.Reverse (data, idx, 4);
6358                                         }
6359                                 } else if (element_type == TypeManager.double_type) {
6360                                         if (!(v is Expression)){
6361                                                 element = BitConverter.GetBytes ((double) v);
6362
6363                                                 for (int j = 0; j < factor; ++j)
6364                                                         data [idx + j] = element [j];
6365
6366                                                 // FIXME: Handle the ARM float format.
6367                                                 if (!BitConverter.IsLittleEndian)
6368                                                         System.Array.Reverse (data, idx, 8);
6369                                         }
6370                                 } else if (element_type == TypeManager.char_type){
6371                                         if (!(v is Expression)){
6372                                                 int val = (int) ((char) v);
6373
6374                                                 data [idx] = (byte) (val & 0xff);
6375                                                 data [idx+1] = (byte) (val >> 8);
6376                                         }
6377                                 } else if (element_type == TypeManager.short_type){
6378                                         if (!(v is Expression)){
6379                                                 int val = (int) ((short) v);
6380
6381                                                 data [idx] = (byte) (val & 0xff);
6382                                                 data [idx+1] = (byte) (val >> 8);
6383                                         }
6384                                 } else if (element_type == TypeManager.ushort_type){
6385                                         if (!(v is Expression)){
6386                                                 int val = (int) ((ushort) v);
6387
6388                                                 data [idx] = (byte) (val & 0xff);
6389                                                 data [idx+1] = (byte) (val >> 8);
6390                                         }
6391                                 } else if (element_type == TypeManager.int32_type) {
6392                                         if (!(v is Expression)){
6393                                                 int val = (int) v;
6394
6395                                                 data [idx]   = (byte) (val & 0xff);
6396                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6397                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6398                                                 data [idx+3] = (byte) (val >> 24);
6399                                         }
6400                                 } else if (element_type == TypeManager.uint32_type) {
6401                                         if (!(v is Expression)){
6402                                                 uint val = (uint) v;
6403
6404                                                 data [idx]   = (byte) (val & 0xff);
6405                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6406                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6407                                                 data [idx+3] = (byte) (val >> 24);
6408                                         }
6409                                 } else if (element_type == TypeManager.sbyte_type) {
6410                                         if (!(v is Expression)){
6411                                                 sbyte val = (sbyte) v;
6412                                                 data [idx] = (byte) val;
6413                                         }
6414                                 } else if (element_type == TypeManager.byte_type) {
6415                                         if (!(v is Expression)){
6416                                                 byte val = (byte) v;
6417                                                 data [idx] = (byte) val;
6418                                         }
6419                                 } else if (element_type == TypeManager.bool_type) {
6420                                         if (!(v is Expression)){
6421                                                 bool val = (bool) v;
6422                                                 data [idx] = (byte) (val ? 1 : 0);
6423                                         }
6424                                 } else if (element_type == TypeManager.decimal_type){
6425                                         if (!(v is Expression)){
6426                                                 int [] bits = Decimal.GetBits ((decimal) v);
6427                                                 int p = idx;
6428
6429                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6430                                                 int [] nbits = new int [4];
6431                                                 nbits [0] = bits [3];
6432                                                 nbits [1] = bits [2];
6433                                                 nbits [2] = bits [0];
6434                                                 nbits [3] = bits [1];
6435
6436                                                 for (int j = 0; j < 4; j++){
6437                                                         data [p++] = (byte) (nbits [j] & 0xff);
6438                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6439                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6440                                                         data [p++] = (byte) (nbits [j] >> 24);
6441                                                 }
6442                                         }
6443                                 } else {
6444                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + element_type);
6445                                 }
6446
6447                                 idx += factor;
6448                         }
6449
6450                         return data;
6451                 }
6452
6453 #if NET_4_0
6454                 public override SLE.Expression MakeExpression (BuilderContext ctx)
6455                 {
6456 #if STATIC
6457                         return base.MakeExpression (ctx);
6458 #else
6459                         var initializers = new SLE.Expression [array_data.Count];
6460                         for (var i = 0; i < initializers.Length; i++) {
6461                                 if (array_data [i] == null)
6462                                         initializers [i] = SLE.Expression.Default (array_element_type.GetMetaInfo ());
6463                                 else
6464                                         initializers [i] = array_data [i].MakeExpression (ctx);
6465                         }
6466
6467                         return SLE.Expression.NewArrayInit (array_element_type.GetMetaInfo (), initializers);
6468 #endif
6469                 }
6470 #endif
6471                 //
6472                 // Emits the initializers for the array
6473                 //
6474                 void EmitStaticInitializers (EmitContext ec)
6475                 {
6476                         if (TypeManager.void_initializearray_array_fieldhandle == null) {
6477                                 var helper = ec.CurrentTypeDefinition.Module.PredefinedTypes.RuntimeHelpers.Resolve (loc);
6478                                 if (helper == null)
6479                                         return;
6480
6481                                 TypeManager.void_initializearray_array_fieldhandle = TypeManager.GetPredefinedMethod (
6482                                         helper, "InitializeArray", loc,
6483                                         TypeManager.array_type, TypeManager.runtime_field_handle_type);
6484                                 if (TypeManager.void_initializearray_array_fieldhandle == null)
6485                                         return;
6486                         }
6487
6488                         //
6489                         // First, the static data
6490                         //
6491                         byte [] data = MakeByteBlob ();
6492                         var fb = ec.CurrentTypeDefinition.Module.MakeStaticData (data, loc);
6493
6494                         ec.Emit (OpCodes.Dup);
6495                         ec.Emit (OpCodes.Ldtoken, fb);
6496                         ec.Emit (OpCodes.Call, TypeManager.void_initializearray_array_fieldhandle);
6497                 }
6498
6499                 //
6500                 // Emits pieces of the array that can not be computed at compile
6501                 // time (variables and string locations).
6502                 //
6503                 // This always expect the top value on the stack to be the array
6504                 //
6505                 void EmitDynamicInitializers (EmitContext ec, bool emitConstants)
6506                 {
6507                         int dims = bounds.Count;
6508                         var current_pos = new int [dims];
6509
6510                         for (int i = 0; i < array_data.Count; i++){
6511
6512                                 Expression e = array_data [i];
6513                                 var c = e as Constant;
6514
6515                                 // Constant can be initialized via StaticInitializer
6516                                 if (c == null || (c != null && emitConstants && !c.IsDefaultInitializer (array_element_type))) {
6517                                         TypeSpec etype = e.Type;
6518
6519                                         ec.Emit (OpCodes.Dup);
6520
6521                                         for (int idx = 0; idx < dims; idx++)
6522                                                 ec.EmitInt (current_pos [idx]);
6523
6524                                         //
6525                                         // If we are dealing with a struct, get the
6526                                         // address of it, so we can store it.
6527                                         //
6528                                         if ((dims == 1) && TypeManager.IsStruct (etype) &&
6529                                             (!TypeManager.IsBuiltinOrEnum (etype) ||
6530                                              etype == TypeManager.decimal_type)) {
6531
6532                                                 ec.Emit (OpCodes.Ldelema, etype);
6533                                         }
6534
6535                                         e.Emit (ec);
6536
6537                                         ec.EmitArrayStore ((ArrayContainer) type);
6538                                 }
6539
6540                                 //
6541                                 // Advance counter
6542                                 //
6543                                 for (int j = dims - 1; j >= 0; j--){
6544                                         current_pos [j]++;
6545                                         if (current_pos [j] < bounds [j])
6546                                                 break;
6547                                         current_pos [j] = 0;
6548                                 }
6549                         }
6550                 }
6551
6552                 public override void Emit (EmitContext ec)
6553                 {
6554                         if (first_emit != null) {
6555                                 first_emit.Emit (ec);
6556                                 first_emit_temp.Store (ec);
6557                         }
6558
6559                         foreach (Expression e in arguments)
6560                                 e.Emit (ec);
6561
6562                         ec.EmitArrayNew ((ArrayContainer) type);
6563
6564                         if (initializers == null)
6565                                 return;
6566
6567                         // Emit static initializer for arrays which have contain more than 2 items and
6568                         // the static initializer will initialize at least 25% of array values or there
6569                         // is more than 10 items to be initialized
6570                         // NOTE: const_initializers_count does not contain default constant values.
6571                         if (const_initializers_count > 2 && (array_data.Count > 10 || const_initializers_count * 4 > (array_data.Count)) &&
6572                                 (TypeManager.IsPrimitiveType (array_element_type) || TypeManager.IsEnumType (array_element_type))) {
6573                                 EmitStaticInitializers (ec);
6574
6575                                 if (!only_constant_initializers)
6576                                         EmitDynamicInitializers (ec, false);
6577                         } else {
6578                                 EmitDynamicInitializers (ec, true);
6579                         }
6580
6581                         if (first_emit_temp != null)
6582                                 first_emit_temp.Release (ec);
6583                 }
6584
6585                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
6586                 {
6587                         // no multi dimensional or jagged arrays
6588                         if (arguments.Count != 1 || array_element_type.IsArray) {
6589                                 base.EncodeAttributeValue (rc, enc, targetType);
6590                                 return;
6591                         }
6592
6593                         // No array covariance, except for array -> object
6594                         if (type != targetType) {
6595                                 if (targetType != TypeManager.object_type) {
6596                                         base.EncodeAttributeValue (rc, enc, targetType);
6597                                         return;
6598                                 }
6599
6600                                 if (enc.Encode (type) == AttributeEncoder.EncodedTypeProperties.DynamicType) {
6601                                         Attribute.Error_AttributeArgumentIsDynamic (rc, loc);
6602                                         return;
6603                                 }
6604                         }
6605
6606                         // Single dimensional array of 0 size
6607                         if (array_data == null) {
6608                                 IntConstant ic = arguments[0] as IntConstant;
6609                                 if (ic == null || !ic.IsDefaultValue) {
6610                                         base.EncodeAttributeValue (rc, enc, targetType);
6611                                 } else {
6612                                         enc.Stream.Write (0);
6613                                 }
6614
6615                                 return;
6616                         }
6617
6618                         enc.Stream.Write ((int) array_data.Count);
6619                         foreach (var element in array_data) {
6620                                 element.EncodeAttributeValue (rc, enc, array_element_type);
6621                         }
6622                 }
6623
6624                 protected override void CloneTo (CloneContext clonectx, Expression t)
6625                 {
6626                         ArrayCreation target = (ArrayCreation) t;
6627
6628                         if (requested_base_type != null)
6629                                 target.requested_base_type = (FullNamedExpression)requested_base_type.Clone (clonectx);
6630
6631                         if (arguments != null){
6632                                 target.arguments = new List<Expression> (arguments.Count);
6633                                 foreach (Expression e in arguments)
6634                                         target.arguments.Add (e.Clone (clonectx));
6635                         }
6636
6637                         if (initializers != null)
6638                                 target.initializers = (ArrayInitializer) initializers.Clone (clonectx);
6639                 }
6640         }
6641
6642         //
6643         // Represents an implicitly typed array epxression
6644         //
6645         class ImplicitlyTypedArrayCreation : ArrayCreation
6646         {
6647                 sealed class InferenceContext : TypeInferenceContext
6648                 {
6649                         class ExpressionBoundInfo : BoundInfo
6650                         {
6651                                 readonly Expression expr;
6652
6653                                 public ExpressionBoundInfo (Expression expr)
6654                                         : base (expr.Type, BoundKind.Lower)
6655                                 {
6656                                         this.expr = expr;
6657                                 }
6658
6659                                 public override bool Equals (BoundInfo other)
6660                                 {
6661                                         // We are using expression not type for conversion check
6662                                         // no optimization based on types is possible
6663                                         return false;
6664                                 }
6665
6666                                 public override Expression GetTypeExpression ()
6667                                 {
6668                                         return expr;
6669                                 }
6670                         }
6671
6672                         public void AddExpression (Expression expr)
6673                         {
6674                                 AddToBounds (new ExpressionBoundInfo (expr), 0);
6675                         }
6676                 }
6677
6678                 InferenceContext best_type_inference;
6679
6680                 public ImplicitlyTypedArrayCreation (ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
6681                         : base (null, rank, initializers, loc)
6682                 {
6683                 }
6684
6685                 public ImplicitlyTypedArrayCreation (ArrayInitializer initializers, Location loc)
6686                         : base (null, initializers, loc)
6687                 {
6688                 }
6689
6690                 protected override Expression DoResolve (ResolveContext ec)
6691                 {
6692                         if (type != null)
6693                                 return this;
6694
6695                         dimensions = rank.Dimension;
6696
6697                         best_type_inference = new InferenceContext ();
6698
6699                         if (!ResolveInitializers (ec))
6700                                 return null;
6701
6702                         best_type_inference.FixAllTypes (ec);
6703                         array_element_type = best_type_inference.InferredTypeArguments[0];
6704                         best_type_inference = null;
6705
6706                         if (array_element_type == null || array_element_type == InternalType.MethodGroup || array_element_type == InternalType.AnonymousMethod ||
6707                                 arguments.Count != rank.Dimension) {
6708                                 ec.Report.Error (826, loc,
6709                                         "The type of an implicitly typed array cannot be inferred from the initializer. Try specifying array type explicitly");
6710                                 return null;
6711                         }
6712
6713                         //
6714                         // At this point we found common base type for all initializer elements
6715                         // but we have to be sure that all static initializer elements are of
6716                         // same type
6717                         //
6718                         UnifyInitializerElement (ec);
6719
6720                         type = ArrayContainer.MakeType (array_element_type, dimensions);
6721                         eclass = ExprClass.Value;
6722                         return this;
6723                 }
6724
6725                 //
6726                 // Converts static initializer only
6727                 //
6728                 void UnifyInitializerElement (ResolveContext ec)
6729                 {
6730                         for (int i = 0; i < array_data.Count; ++i) {
6731                                 Expression e = array_data[i];
6732                                 if (e != null)
6733                                         array_data [i] = Convert.ImplicitConversion (ec, e, array_element_type, Location.Null);
6734                         }
6735                 }
6736
6737                 protected override Expression ResolveArrayElement (ResolveContext ec, Expression element)
6738                 {
6739                         element = element.Resolve (ec);
6740                         if (element != null)
6741                                 best_type_inference.AddExpression (element);
6742
6743                         return element;
6744                 }
6745         }
6746
6747         sealed class CompilerGeneratedThis : This
6748         {
6749                 public static This Instance = new CompilerGeneratedThis ();
6750
6751                 private CompilerGeneratedThis ()
6752                         : base (Location.Null)
6753                 {
6754                 }
6755
6756                 public CompilerGeneratedThis (TypeSpec type, Location loc)
6757                         : base (loc)
6758                 {
6759                         this.type = type;
6760                 }
6761
6762                 protected override Expression DoResolve (ResolveContext ec)
6763                 {
6764                         eclass = ExprClass.Variable;
6765                         if (type == null)
6766                                 type = ec.CurrentType;
6767
6768                         return this;
6769                 }
6770
6771                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6772                 {
6773                         return null;
6774                 }
6775         }
6776
6777         /// <summary>
6778         ///   Represents the `this' construct
6779         /// </summary>
6780
6781         public class This : VariableReference
6782         {
6783                 sealed class ThisVariable : ILocalVariable
6784                 {
6785                         public static readonly ILocalVariable Instance = new ThisVariable ();
6786
6787                         public void Emit (EmitContext ec)
6788                         {
6789                                 ec.Emit (OpCodes.Ldarg_0);
6790                         }
6791
6792                         public void EmitAssign (EmitContext ec)
6793                         {
6794                                 throw new InvalidOperationException ();
6795                         }
6796
6797                         public void EmitAddressOf (EmitContext ec)
6798                         {
6799                                 ec.Emit (OpCodes.Ldarg_0);
6800                         }
6801                 }
6802
6803                 VariableInfo variable_info;
6804
6805                 public This (Location loc)
6806                 {
6807                         this.loc = loc;
6808                 }
6809
6810                 #region Properties
6811
6812                 public override string Name {
6813                         get { return "this"; }
6814                 }
6815
6816                 public override bool IsLockedByStatement {
6817                         get {
6818                                 return false;
6819                         }
6820                         set {
6821                         }
6822                 }
6823
6824                 public override bool IsRef {
6825                         get { return type.IsStruct; }
6826                 }
6827
6828                 protected override ILocalVariable Variable {
6829                         get { return ThisVariable.Instance; }
6830                 }
6831
6832                 public override VariableInfo VariableInfo {
6833                         get { return variable_info; }
6834                 }
6835
6836                 public override bool IsFixed {
6837                         get { return false; }
6838                 }
6839
6840                 #endregion
6841
6842                 public void CheckStructThisDefiniteAssignment (ResolveContext rc)
6843                 {
6844                         if (variable_info != null && !variable_info.IsAssigned (rc)) {
6845                                 rc.Report.Error (188, loc,
6846                                         "The `this' object cannot be used before all of its fields are assigned to");
6847                         }
6848                 }
6849
6850                 protected virtual void Error_ThisNotAvailable (ResolveContext ec)
6851                 {
6852                         if (ec.IsStatic && !ec.HasSet (ResolveContext.Options.ConstantScope)) {
6853                                 ec.Report.Error (26, loc, "Keyword `this' is not valid in a static property, static method, or static field initializer");
6854                         } else if (ec.CurrentAnonymousMethod != null) {
6855                                 ec.Report.Error (1673, loc,
6856                                         "Anonymous methods inside structs cannot access instance members of `this'. " +
6857                                         "Consider copying `this' to a local variable outside the anonymous method and using the local instead");
6858                         } else {
6859                                 ec.Report.Error (27, loc, "Keyword `this' is not available in the current context");
6860                         }
6861                 }
6862
6863                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6864                 {
6865                         if (ae == null)
6866                                 return null;
6867
6868                         AnonymousMethodStorey storey = ae.Storey;
6869                         while (storey != null) {
6870                                 AnonymousMethodStorey temp = storey.Parent as AnonymousMethodStorey;
6871                                 if (temp == null)
6872                                         return storey.HoistedThis;
6873
6874                                 storey = temp;
6875                         }
6876
6877                         return null;
6878                 }
6879
6880                 public static bool IsThisAvailable (ResolveContext ec, bool ignoreAnonymous)
6881                 {
6882                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope))
6883                                 return false;
6884
6885                         if (ignoreAnonymous || ec.CurrentAnonymousMethod == null)
6886                                 return true;
6887
6888                         if (TypeManager.IsStruct (ec.CurrentType) && ec.CurrentIterator == null)
6889                                 return false;
6890
6891                         return true;
6892                 }
6893
6894                 public virtual void ResolveBase (ResolveContext ec)
6895                 {
6896                         eclass = ExprClass.Variable;
6897                         type = ec.CurrentType;
6898
6899                         if (!IsThisAvailable (ec, false)) {
6900                                 Error_ThisNotAvailable (ec);
6901                                 return;
6902                         }
6903
6904                         var block = ec.CurrentBlock;
6905                         if (block != null) {
6906                                 if (block.ParametersBlock.TopBlock.ThisVariable != null)
6907                                         variable_info = block.ParametersBlock.TopBlock.ThisVariable.VariableInfo;
6908
6909                                 AnonymousExpression am = ec.CurrentAnonymousMethod;
6910                                 if (am != null && ec.IsVariableCapturingRequired) {
6911                                         am.SetHasThisAccess ();
6912                                 }
6913                         }
6914                 }
6915
6916                 public override Expression CreateExpressionTree (ResolveContext ec)
6917                 {
6918                         Arguments args = new Arguments (1);
6919                         args.Add (new Argument (this));
6920
6921                         // Use typeless constant for ldarg.0 to save some
6922                         // space and avoid problems with anonymous stories
6923                         return CreateExpressionFactoryCall (ec, "Constant", args);
6924                 }
6925
6926                 protected override Expression DoResolve (ResolveContext ec)
6927                 {
6928                         ResolveBase (ec);
6929
6930                         if (variable_info != null && type.IsStruct) {
6931                                 CheckStructThisDefiniteAssignment (ec);
6932                         }
6933
6934                         return this;
6935                 }
6936
6937                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6938                 {
6939                         ResolveBase (ec);
6940
6941                         if (variable_info != null)
6942                                 variable_info.SetAssigned (ec);
6943
6944                         if (type.IsClass){
6945                                 if (right_side == EmptyExpression.UnaryAddress)
6946                                         ec.Report.Error (459, loc, "Cannot take the address of `this' because it is read-only");
6947                                 else if (right_side == EmptyExpression.OutAccess.Instance)
6948                                         ec.Report.Error (1605, loc, "Cannot pass `this' as a ref or out argument because it is read-only");
6949                                 else
6950                                         ec.Report.Error (1604, loc, "Cannot assign to `this' because it is read-only");
6951                         }
6952
6953                         return this;
6954                 }
6955
6956                 public override int GetHashCode()
6957                 {
6958                         throw new NotImplementedException ();
6959                 }
6960
6961                 public override bool Equals (object obj)
6962                 {
6963                         This t = obj as This;
6964                         if (t == null)
6965                                 return false;
6966
6967                         return true;
6968                 }
6969
6970                 protected override void CloneTo (CloneContext clonectx, Expression t)
6971                 {
6972                         // Nothing
6973                 }
6974
6975                 public override void SetHasAddressTaken ()
6976                 {
6977                         // Nothing
6978                 }
6979         }
6980
6981         /// <summary>
6982         ///   Represents the `__arglist' construct
6983         /// </summary>
6984         public class ArglistAccess : Expression
6985         {
6986                 public ArglistAccess (Location loc)
6987                 {
6988                         this.loc = loc;
6989                 }
6990
6991                 public override Expression CreateExpressionTree (ResolveContext ec)
6992                 {
6993                         throw new NotSupportedException ("ET");
6994                 }
6995
6996                 protected override Expression DoResolve (ResolveContext ec)
6997                 {
6998                         eclass = ExprClass.Variable;
6999                         type = ec.Module.PredefinedTypes.RuntimeArgumentHandle.Resolve (loc);
7000
7001                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope) || !ec.CurrentBlock.ParametersBlock.Parameters.HasArglist) {
7002                                 ec.Report.Error (190, loc,
7003                                         "The __arglist construct is valid only within a variable argument method");
7004                         }
7005
7006                         return this;
7007                 }
7008
7009                 public override void Emit (EmitContext ec)
7010                 {
7011                         ec.Emit (OpCodes.Arglist);
7012                 }
7013
7014                 protected override void CloneTo (CloneContext clonectx, Expression target)
7015                 {
7016                         // nothing.
7017                 }
7018         }
7019
7020         /// <summary>
7021         ///   Represents the `__arglist (....)' construct
7022         /// </summary>
7023         public class Arglist : Expression
7024         {
7025                 Arguments Arguments;
7026
7027                 public Arglist (Location loc)
7028                         : this (null, loc)
7029                 {
7030                 }
7031
7032                 public Arglist (Arguments args, Location l)
7033                 {
7034                         Arguments = args;
7035                         loc = l;
7036                 }
7037
7038                 public MetaType[] ArgumentTypes {
7039                     get {
7040                                 if (Arguments == null)
7041                                         return MetaType.EmptyTypes;
7042
7043                                 var retval = new MetaType[Arguments.Count];
7044                         for (int i = 0; i < retval.Length; i++)
7045                                         retval[i] = Arguments[i].Expr.Type.GetMetaInfo ();
7046
7047                         return retval;
7048                     }
7049                 }
7050
7051                 public override Expression CreateExpressionTree (ResolveContext ec)
7052                 {
7053                         ec.Report.Error (1952, loc, "An expression tree cannot contain a method with variable arguments");
7054                         return null;
7055                 }
7056
7057                 protected override Expression DoResolve (ResolveContext ec)
7058                 {
7059                         eclass = ExprClass.Variable;
7060                         type = InternalType.Arglist;
7061                         if (Arguments != null) {
7062                                 bool dynamic;   // Can be ignored as there is always only 1 overload
7063                                 Arguments.Resolve (ec, out dynamic);
7064                         }
7065
7066                         return this;
7067                 }
7068
7069                 public override void Emit (EmitContext ec)
7070                 {
7071                         if (Arguments != null)
7072                                 Arguments.Emit (ec);
7073                 }
7074
7075                 protected override void CloneTo (CloneContext clonectx, Expression t)
7076                 {
7077                         Arglist target = (Arglist) t;
7078
7079                         if (Arguments != null)
7080                                 target.Arguments = Arguments.Clone (clonectx);
7081                 }
7082         }
7083
7084         /// <summary>
7085         ///   Implements the typeof operator
7086         /// </summary>
7087         public class TypeOf : Expression {
7088                 FullNamedExpression QueriedType;
7089                 TypeSpec typearg;
7090
7091                 public TypeOf (FullNamedExpression queried_type, Location l)
7092                 {
7093                         QueriedType = queried_type;
7094                         loc = l;
7095                 }
7096
7097                 #region Properties
7098                 public TypeSpec TypeArgument {
7099                         get {
7100                                 return typearg;
7101                         }
7102                 }
7103
7104                 public FullNamedExpression TypeExpression {
7105                         get {
7106                                 return QueriedType;
7107                         }
7108                 }
7109
7110                 #endregion
7111
7112                 public override Expression CreateExpressionTree (ResolveContext ec)
7113                 {
7114                         Arguments args = new Arguments (2);
7115                         args.Add (new Argument (this));
7116                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
7117                         return CreateExpressionFactoryCall (ec, "Constant", args);
7118                 }
7119
7120                 protected override Expression DoResolve (ResolveContext ec)
7121                 {
7122                         TypeExpr texpr;
7123
7124                         //
7125                         // Pointer types are allowed without explicit unsafe, they are just tokens
7126                         //
7127                         using (ec.Set (ResolveContext.Options.UnsafeScope)) {
7128                                 texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
7129                         }
7130
7131                         if (texpr == null)
7132                                 return null;
7133
7134                         typearg = texpr.Type;
7135
7136                         if (typearg == TypeManager.void_type && !(QueriedType is TypeExpression)) {
7137                                 ec.Report.Error (673, loc, "System.Void cannot be used from C#. Use typeof (void) to get the void type object");
7138                         } else if (texpr is DynamicTypeExpr) {
7139                                 ec.Report.Error (1962, QueriedType.Location,
7140                                         "The typeof operator cannot be used on the dynamic type");
7141                         }
7142
7143                         type = TypeManager.type_type;
7144                         QueriedType = texpr;
7145
7146                         return DoResolveBase ();
7147                 }
7148
7149                 protected Expression DoResolveBase ()
7150                 {
7151                         if (TypeManager.system_type_get_type_from_handle == null) {
7152                                 TypeManager.system_type_get_type_from_handle = TypeManager.GetPredefinedMethod (
7153                                         TypeManager.type_type, "GetTypeFromHandle", loc, TypeManager.runtime_handle_type);
7154                         }
7155
7156                         // Even though what is returned is a type object, it's treated as a value by the compiler.
7157                         // In particular, 'typeof (Foo).X' is something totally different from 'Foo.X'.
7158                         eclass = ExprClass.Value;
7159                         return this;
7160                 }
7161
7162                 static bool ContainsDynamicType (TypeSpec type)
7163                 {
7164                         if (type == InternalType.Dynamic)
7165                                 return true;
7166
7167                         var element_container = type as ElementTypeSpec;
7168                         if (element_container != null)
7169                                 return ContainsDynamicType (element_container.Element);
7170
7171                         foreach (var t in type.TypeArguments) {
7172                                 if (ContainsDynamicType (t)) {
7173                                         return true;
7174                                 }
7175                         }
7176
7177                         return false;
7178                 }
7179
7180                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
7181                 {
7182                         // Target type is not System.Type therefore must be object
7183                         // and we need to use different encoding sequence
7184                         if (targetType != type)
7185                                 enc.Encode (type);
7186
7187                         if (!(QueriedType is GenericOpenTypeExpr)) {
7188                                 var gt = typearg;
7189                                 while (gt != null) {
7190                                         if (InflatedTypeSpec.ContainsTypeParameter (gt)) {
7191                                                 rc.Compiler.Report.Error (416, loc, "`{0}': an attribute argument cannot use type parameters",
7192                                                         typearg.GetSignatureForError ());
7193                                                 return;
7194                                         }
7195
7196                                         gt = gt.DeclaringType;
7197                                 }
7198
7199                                 if (ContainsDynamicType (typearg)) {
7200                                         Attribute.Error_AttributeArgumentIsDynamic (rc, loc);
7201                                         return;
7202                                 }
7203                         }
7204
7205                         enc.EncodeTypeName (typearg);
7206                 }
7207
7208                 public override void Emit (EmitContext ec)
7209                 {
7210                         ec.Emit (OpCodes.Ldtoken, typearg);
7211                         ec.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
7212                 }
7213
7214                 protected override void CloneTo (CloneContext clonectx, Expression t)
7215                 {
7216                         TypeOf target = (TypeOf) t;
7217                         if (QueriedType != null)
7218                                 target.QueriedType = (FullNamedExpression) QueriedType.Clone (clonectx);
7219                 }
7220         }
7221
7222         class TypeOfMethod : TypeOfMember<MethodSpec>
7223         {
7224                 public TypeOfMethod (MethodSpec method, Location loc)
7225                         : base (method, loc)
7226                 {
7227                 }
7228
7229                 protected override Expression DoResolve (ResolveContext ec)
7230                 {
7231                         if (member.IsConstructor) {
7232                                 type = ec.Module.PredefinedTypes.ConstructorInfo.Resolve (loc);
7233                         } else {
7234                                 type = ec.Module.PredefinedTypes.MethodInfo.Resolve (loc);
7235                         }
7236
7237                         if (type == null)
7238                                 return null;
7239
7240                         return base.DoResolve (ec);
7241                 }
7242
7243                 public override void Emit (EmitContext ec)
7244                 {
7245                         ec.Emit (OpCodes.Ldtoken, member);
7246
7247                         base.Emit (ec);
7248                         ec.Emit (OpCodes.Castclass, type);
7249                 }
7250
7251                 protected override string GetMethodName {
7252                         get { return "GetMethodFromHandle"; }
7253                 }
7254
7255                 protected override PredefinedType GetDeclaringType (PredefinedTypes types)
7256                 {
7257                         return types.MethodBase;
7258                 }
7259
7260                 protected override PredefinedType GetRuntimeHandle (PredefinedTypes types)
7261                 {
7262                         return types.RuntimeMethodHandle;
7263                 }
7264
7265                 protected override MethodSpec TypeFromHandle {
7266                         get {
7267                                 return TypeManager.methodbase_get_type_from_handle;
7268                         }
7269                         set {
7270                                 TypeManager.methodbase_get_type_from_handle = value;
7271                         }
7272                 }
7273
7274                 protected override MethodSpec TypeFromHandleGeneric {
7275                         get {
7276                                 return TypeManager.methodbase_get_type_from_handle_generic;
7277                         }
7278                         set {
7279                                 TypeManager.methodbase_get_type_from_handle_generic = value;
7280                         }
7281                 }
7282         }
7283
7284         abstract class TypeOfMember<T> : Expression where T : MemberSpec
7285         {
7286                 protected readonly T member;
7287
7288                 protected TypeOfMember (T member, Location loc)
7289                 {
7290                         this.member = member;
7291                         this.loc = loc;
7292                 }
7293
7294                 public override Expression CreateExpressionTree (ResolveContext ec)
7295                 {
7296                         Arguments args = new Arguments (2);
7297                         args.Add (new Argument (this));
7298                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
7299                         return CreateExpressionFactoryCall (ec, "Constant", args);
7300                 }
7301
7302                 protected override Expression DoResolve (ResolveContext ec)
7303                 {
7304                         bool is_generic = member.DeclaringType.IsGenericOrParentIsGeneric;
7305                         var mi = is_generic ? TypeFromHandleGeneric : TypeFromHandle;
7306
7307                         if (mi == null) {
7308                                 TypeSpec declaring_type = GetDeclaringType (ec.Module.PredefinedTypes).Resolve (loc);
7309                                 TypeSpec handle_type = GetRuntimeHandle (ec.Module.PredefinedTypes).Resolve (loc);
7310
7311                                 if (handle_type == null || declaring_type == null)
7312                                         return null;
7313
7314                                 mi = TypeManager.GetPredefinedMethod (declaring_type, GetMethodName, loc,
7315                                         is_generic ?
7316                                         new TypeSpec[] { handle_type, TypeManager.runtime_handle_type } :
7317                                         new TypeSpec[] { handle_type } );
7318
7319                                 if (is_generic)
7320                                         TypeFromHandleGeneric = mi;
7321                                 else
7322                                         TypeFromHandle = mi;
7323                         }
7324
7325                         eclass = ExprClass.Value;
7326                         return this;
7327                 }
7328
7329                 public override void Emit (EmitContext ec)
7330                 {
7331                         bool is_generic = member.DeclaringType.IsGenericOrParentIsGeneric;
7332                         MethodSpec mi;
7333                         if (is_generic) {
7334                                 mi = TypeFromHandleGeneric;
7335                                 ec.Emit (OpCodes.Ldtoken, member.DeclaringType);
7336                         } else {
7337                                 mi = TypeFromHandle;
7338                         }
7339
7340                         ec.Emit (OpCodes.Call, mi);
7341                 }
7342
7343                 protected abstract PredefinedType GetDeclaringType (PredefinedTypes types);
7344                 protected abstract string GetMethodName { get; }
7345                 protected abstract PredefinedType GetRuntimeHandle (PredefinedTypes types);
7346                 protected abstract MethodSpec TypeFromHandle { get; set; }
7347                 protected abstract MethodSpec TypeFromHandleGeneric { get; set; }
7348         }
7349
7350         class TypeOfField : TypeOfMember<FieldSpec>
7351         {
7352                 public TypeOfField (FieldSpec field, Location loc)
7353                         : base (field, loc)
7354                 {
7355                 }
7356
7357                 protected override Expression DoResolve (ResolveContext ec)
7358                 {
7359                         type = ec.Module.PredefinedTypes.FieldInfo.Resolve (loc);
7360                         if (type == null)
7361                                 return null;
7362
7363                         return base.DoResolve (ec);
7364                 }
7365
7366                 public override void Emit (EmitContext ec)
7367                 {
7368                         ec.Emit (OpCodes.Ldtoken, member);
7369                         base.Emit (ec);
7370                 }
7371
7372                 protected override PredefinedType GetDeclaringType (PredefinedTypes types)
7373                 {
7374                         return types.FieldInfo;
7375                 }
7376
7377                 protected override string GetMethodName {
7378                         get { return "GetFieldFromHandle"; }
7379                 }
7380
7381                 protected override PredefinedType GetRuntimeHandle (PredefinedTypes types)
7382                 {
7383                         return types.RuntimeFieldHandle;
7384                 }
7385
7386                 protected override MethodSpec TypeFromHandle {
7387                         get {
7388                                 return TypeManager.fieldinfo_get_field_from_handle;
7389                         }
7390                         set {
7391                                 TypeManager.fieldinfo_get_field_from_handle = value;
7392                         }
7393                 }
7394
7395                 protected override MethodSpec TypeFromHandleGeneric {
7396                         get {
7397                                 return TypeManager.fieldinfo_get_field_from_handle_generic;
7398                         }
7399                         set {
7400                                 TypeManager.fieldinfo_get_field_from_handle_generic = value;
7401                         }
7402                 }
7403         }
7404
7405         /// <summary>
7406         ///   Implements the sizeof expression
7407         /// </summary>
7408         public class SizeOf : Expression {
7409                 readonly Expression QueriedType;
7410                 TypeSpec type_queried;
7411
7412                 public SizeOf (Expression queried_type, Location l)
7413                 {
7414                         this.QueriedType = queried_type;
7415                         loc = l;
7416                 }
7417
7418                 public override Expression CreateExpressionTree (ResolveContext ec)
7419                 {
7420                         Error_PointerInsideExpressionTree (ec);
7421                         return null;
7422                 }
7423
7424                 protected override Expression DoResolve (ResolveContext ec)
7425                 {
7426                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
7427                         if (texpr == null)
7428                                 return null;
7429
7430                         type_queried = texpr.Type;
7431                         if (TypeManager.IsEnumType (type_queried))
7432                                 type_queried = EnumSpec.GetUnderlyingType (type_queried);
7433
7434                         int size_of = GetTypeSize (type_queried);
7435                         if (size_of > 0) {
7436                                 return new IntConstant (size_of, loc).Resolve (ec);
7437                         }
7438
7439                         if (!TypeManager.VerifyUnmanaged (ec.Compiler, type_queried, loc)){
7440                                 return null;
7441                         }
7442
7443                         if (!ec.IsUnsafe) {
7444                                 ec.Report.Error (233, loc,
7445                                         "`{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
7446                                         TypeManager.CSharpName (type_queried));
7447                         }
7448
7449                         type = TypeManager.int32_type;
7450                         eclass = ExprClass.Value;
7451                         return this;
7452                 }
7453
7454                 public override void Emit (EmitContext ec)
7455                 {
7456                         ec.Emit (OpCodes.Sizeof, type_queried);
7457                 }
7458
7459                 protected override void CloneTo (CloneContext clonectx, Expression t)
7460                 {
7461                 }
7462         }
7463
7464         /// <summary>
7465         ///   Implements the qualified-alias-member (::) expression.
7466         /// </summary>
7467         public class QualifiedAliasMember : MemberAccess
7468         {
7469                 readonly string alias;
7470                 public static readonly string GlobalAlias = "global";
7471
7472                 public QualifiedAliasMember (string alias, string identifier, Location l)
7473                         : base (null, identifier, l)
7474                 {
7475                         this.alias = alias;
7476                 }
7477
7478                 public QualifiedAliasMember (string alias, string identifier, TypeArguments targs, Location l)
7479                         : base (null, identifier, targs, l)
7480                 {
7481                         this.alias = alias;
7482                 }
7483
7484                 public QualifiedAliasMember (string alias, string identifier, int arity, Location l)
7485                         : base (null, identifier, arity, l)
7486                 {
7487                         this.alias = alias;
7488                 }
7489
7490                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
7491                 {
7492                         if (alias == GlobalAlias) {
7493                                 expr = ec.Module.GlobalRootNamespace;
7494                                 return base.ResolveAsTypeStep (ec, silent);
7495                         }
7496
7497                         int errors = ec.Compiler.Report.Errors;
7498                         expr = ec.LookupNamespaceAlias (alias);
7499                         if (expr == null) {
7500                                 if (errors == ec.Compiler.Report.Errors)
7501                                         ec.Compiler.Report.Error (432, loc, "Alias `{0}' not found", alias);
7502                                 return null;
7503                         }
7504
7505                         FullNamedExpression fne = base.ResolveAsTypeStep (ec, silent);
7506                         if (fne == null)
7507                                 return null;
7508
7509                         if (expr.eclass == ExprClass.Type) {
7510                                 if (!silent) {
7511                                         ec.Compiler.Report.Error (431, loc,
7512                                                 "Alias `{0}' cannot be used with '::' since it denotes a type. Consider replacing '::' with '.'", alias);
7513                                 }
7514                                 return null;
7515                         }
7516
7517                         return fne;
7518                 }
7519
7520                 protected override Expression DoResolve (ResolveContext ec)
7521                 {
7522                         return ResolveAsTypeStep (ec, false);
7523                 }
7524
7525                 protected override void Error_IdentifierNotFound (IMemberContext rc, TypeSpec expr_type, string identifier)
7526                 {
7527                         rc.Compiler.Report.Error (687, loc,
7528                                 "A namespace alias qualifier `{0}' did not resolve to a namespace or a type",
7529                                 GetSignatureForError ());
7530                 }
7531
7532                 public override string GetSignatureForError ()
7533                 {
7534                         string name = Name;
7535                         if (targs != null) {
7536                                 name = Name + "<" + targs.GetSignatureForError () + ">";
7537                         }
7538
7539                         return alias + "::" + name;
7540                 }
7541
7542                 public override Expression LookupNameExpression (ResolveContext rc, MemberLookupRestrictions restrictions)
7543                 {
7544                         return DoResolve (rc);
7545                 }
7546
7547                 protected override void CloneTo (CloneContext clonectx, Expression t)
7548                 {
7549                         // Nothing
7550                 }
7551         }
7552
7553         /// <summary>
7554         ///   Implements the member access expression
7555         /// </summary>
7556         public class MemberAccess : ATypeNameExpression
7557         {
7558                 protected Expression expr;
7559
7560                 public MemberAccess (Expression expr, string id)
7561                         : base (id, expr.Location)
7562                 {
7563                         this.expr = expr;
7564                 }
7565
7566                 public MemberAccess (Expression expr, string identifier, Location loc)
7567                         : base (identifier, loc)
7568                 {
7569                         this.expr = expr;
7570                 }
7571
7572                 public MemberAccess (Expression expr, string identifier, TypeArguments args, Location loc)
7573                         : base (identifier, args, loc)
7574                 {
7575                         this.expr = expr;
7576                 }
7577
7578                 public MemberAccess (Expression expr, string identifier, int arity, Location loc)
7579                         : base (identifier, arity, loc)
7580                 {
7581                         this.expr = expr;
7582                 }
7583
7584                 public Expression LeftExpression {
7585                         get {
7586                                 return expr;
7587                         }
7588                 }
7589
7590                 protected override Expression DoResolve (ResolveContext ec)
7591                 {
7592                         return DoResolveName (ec, null);
7593                 }
7594
7595                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
7596                 {
7597                         return DoResolveName (ec, right_side);
7598                 }
7599
7600                 Expression DoResolveName (ResolveContext rc, Expression right_side)
7601                 {
7602                         Expression e = LookupNameExpression (rc, right_side == null ? MemberLookupRestrictions.ReadAccess : MemberLookupRestrictions.None);
7603                         if (e == null)
7604                                 return null;
7605
7606                         if (right_side != null) {
7607                                 if (e is TypeExpr) {
7608                                         e.Error_UnexpectedKind (rc, ResolveFlags.VariableOrValue, loc);
7609                                         return null;
7610                                 }
7611
7612                                 e = e.ResolveLValue (rc, right_side);
7613                         } else {
7614                                 e = e.Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7615                         }
7616
7617                         return e;
7618                 }
7619
7620                 public override Expression LookupNameExpression (ResolveContext rc, MemberLookupRestrictions restrictions)
7621                 {
7622                         var sn = expr as SimpleName;
7623                         const ResolveFlags flags = ResolveFlags.VariableOrValue | ResolveFlags.Type;
7624
7625                         //
7626                         // Resolve the expression with flow analysis turned off, we'll do the definite
7627                         // assignment checks later.  This is because we don't know yet what the expression
7628                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7629                         // definite assignment check on the actual field and not on the whole struct.
7630                         //
7631                         using (rc.Set (ResolveContext.Options.OmitStructFlowAnalysis)) {
7632                                 if (sn != null) {
7633                                         expr = sn.LookupNameExpression (rc, MemberLookupRestrictions.ReadAccess | MemberLookupRestrictions.ExactArity);
7634
7635                                         // Call resolve on expression which does have type set as we need expression type
7636                                         // TODO: I should probably ensure that the type is always set and leave resolve for the final
7637                                         if (expr is VariableReference || expr is ConstantExpr || expr is Linq.TransparentMemberAccess) {
7638                                                 using (rc.With (ResolveContext.Options.DoFlowAnalysis, false)) {
7639                                                         expr = expr.Resolve (rc);
7640                                                 }
7641                                         } else if (expr is TypeParameterExpr) {
7642                                                 expr.Error_UnexpectedKind (rc, flags, sn.Location);
7643                                                 expr = null;
7644                                         }
7645                                 } else {
7646                                         expr = expr.Resolve (rc, flags);
7647                                 }
7648                         }
7649
7650                         if (expr == null)
7651                                 return null;
7652
7653                         Namespace ns = expr as Namespace;
7654                         if (ns != null) {
7655                                 FullNamedExpression retval = ns.Lookup (rc.Compiler, Name, Arity, loc);
7656
7657                                 if (retval == null) {
7658                                         ns.Error_NamespaceDoesNotExist (loc, Name, Arity, rc);
7659                                         return null;
7660                                 }
7661
7662                                 if (HasTypeArguments)
7663                                         return new GenericTypeExpr (retval.Type, targs, loc);
7664
7665                                 return retval;
7666                         }
7667
7668                         MemberExpr me;
7669                         TypeSpec expr_type = expr.Type;
7670                         if (expr_type == InternalType.Dynamic) {
7671                                 me = expr as MemberExpr;
7672                                 if (me != null)
7673                                         me.ResolveInstanceExpression (rc, null);
7674
7675                                 Arguments args = new Arguments (1);
7676                                 args.Add (new Argument (expr));
7677                                 return new DynamicMemberBinder (Name, args, loc);
7678                         }
7679
7680                         const MemberKind dot_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.Delegate | MemberKind.Enum |
7681                                 MemberKind.Interface | MemberKind.TypeParameter | MemberKind.ArrayType;
7682
7683                         if ((expr_type.Kind & dot_kinds) == 0 || expr_type == TypeManager.void_type) {
7684                                 if (expr_type == InternalType.Null && rc.Compiler.IsRuntimeBinder)
7685                                         rc.Report.Error (Report.RuntimeErrorId, loc, "Cannot perform member binding on `null' value");
7686                                 else
7687                                         Unary.Error_OperatorCannotBeApplied (rc, loc, ".", expr_type);
7688                                 return null;
7689                         }
7690
7691                         var current_type = rc.CurrentType;
7692                         var lookup_arity = Arity;
7693                         bool errorMode = false;
7694                         Expression member_lookup;
7695                         while (true) {
7696                                 member_lookup = MemberLookup (errorMode ? null : rc, current_type, expr_type, Name, lookup_arity, restrictions, loc);
7697                                 if (member_lookup == null) {
7698                                         //
7699                                         // Try to look for extension method when member lookup failed
7700                                         //
7701                                         if (MethodGroupExpr.IsExtensionMethodArgument (expr)) {
7702                                                 NamespaceEntry scope = null;
7703                                                 var methods = rc.LookupExtensionMethod (expr_type, Name, lookup_arity, ref scope);
7704                                                 if (methods != null) {
7705                                                         var emg = new ExtensionMethodGroupExpr (methods, scope, expr, loc);
7706                                                         if (HasTypeArguments) {
7707                                                                 if (!targs.Resolve (rc))
7708                                                                         return null;
7709
7710                                                                 emg.SetTypeArguments (rc, targs);
7711                                                         }
7712
7713                                                         // TODO: it should really skip the checks bellow
7714                                                         return emg.Resolve (rc);
7715                                                 }
7716                                         }
7717                                 }
7718
7719                                 if (errorMode) {
7720                                         if (member_lookup == null) {
7721                                                 if (expr is TypeExpr)
7722                                                         base.Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
7723                                                 else
7724                                                         Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
7725
7726                                                 return null;
7727                                         }
7728
7729                                         if (member_lookup is MethodGroupExpr) {
7730                                                 // Leave it to overload resolution to report correct error
7731                                         } else {
7732                                                 // TODO: rc.SymbolRelatedToPreviousError
7733                                                 ErrorIsInaccesible (rc, member_lookup.GetSignatureForError (), loc);
7734                                         }
7735                                         break;
7736                                 }
7737
7738                                 if (member_lookup != null)
7739                                         break;
7740
7741                                 current_type = null;
7742                                 lookup_arity = 0;
7743                                 restrictions &= ~MemberLookupRestrictions.InvocableOnly;
7744                                 errorMode = true;
7745                         }
7746
7747                         TypeExpr texpr = member_lookup as TypeExpr;
7748                         if (texpr != null) {
7749                                 if (!(expr is TypeExpr)) {
7750                                         me = expr as MemberExpr;
7751                                         if (me == null || me.ProbeIdenticalTypeName (rc, expr, sn) == expr) {
7752                                                 rc.Report.Error (572, loc, "`{0}': cannot reference a type through an expression; try `{1}' instead",
7753                                                         Name, member_lookup.GetSignatureForError ());
7754                                                 return null;
7755                                         }
7756                                 }
7757
7758                                 if (!texpr.Type.IsAccessible (rc.CurrentType)) {
7759                                         rc.Report.SymbolRelatedToPreviousError (member_lookup.Type);
7760                                         ErrorIsInaccesible (rc, member_lookup.Type.GetSignatureForError (), loc);
7761                                         return null;
7762                                 }
7763
7764                                 if (HasTypeArguments) {
7765                                         return new GenericTypeExpr (member_lookup.Type, targs, loc);
7766                                 }
7767
7768                                 return member_lookup;
7769                         }
7770
7771                         me = member_lookup as MemberExpr;
7772
7773                         if (sn != null && me.IsStatic)
7774                                 expr = me.ProbeIdenticalTypeName (rc, expr, sn);
7775
7776                         me = me.ResolveMemberAccess (rc, expr, sn);
7777
7778                         if (Arity > 0) {
7779                                 if (!targs.Resolve (rc))
7780                                         return null;
7781
7782                                 me.SetTypeArguments (rc, targs);
7783                         }
7784
7785                         if (sn != null && (!TypeManager.IsValueType (expr_type) || me is PropertyExpr)) {
7786                                 if (me.IsInstance) {
7787                                         LocalVariableReference var = expr as LocalVariableReference;
7788                                         if (var != null && !var.VerifyAssigned (rc))
7789                                                 return null;
7790                                 }
7791                         }
7792
7793                         return me;
7794                 }
7795
7796                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
7797                 {
7798                         return ResolveNamespaceOrType (ec, silent);
7799                 }
7800
7801                 public FullNamedExpression ResolveNamespaceOrType (IMemberContext rc, bool silent)
7802                 {
7803                         FullNamedExpression expr_resolved = expr.ResolveAsTypeStep (rc, silent);
7804
7805                         if (expr_resolved == null)
7806                                 return null;
7807
7808                         Namespace ns = expr_resolved as Namespace;
7809                         if (ns != null) {
7810                                 FullNamedExpression retval = ns.Lookup (rc.Compiler, Name, Arity, loc);
7811
7812                                 if (retval == null) {
7813                                         if (!silent)
7814                                                 ns.Error_NamespaceDoesNotExist (loc, Name, Arity, rc);
7815                                 } else if (HasTypeArguments) {
7816                                         retval = new GenericTypeExpr (retval.Type, targs, loc).ResolveAsTypeStep (rc, silent);
7817                                 }
7818
7819                                 return retval;
7820                         }
7821
7822                         TypeExpr tnew_expr = expr_resolved.ResolveAsTypeTerminal (rc, false);
7823                         if (tnew_expr == null)
7824                                 return null;
7825
7826                         TypeSpec expr_type = tnew_expr.Type;
7827                         if (TypeManager.IsGenericParameter (expr_type)) {
7828                                 rc.Compiler.Report.Error (704, loc, "A nested type cannot be specified through a type parameter `{0}'",
7829                                         tnew_expr.GetSignatureForError ());
7830                                 return null;
7831                         }
7832
7833                         TypeSpec nested = null;
7834                         while (expr_type != null) {
7835                                 nested = MemberCache.FindNestedType (expr_type, Name, Arity);
7836                                 if (nested == null) {
7837                                         if (silent)
7838                                                 return null;
7839
7840                                         if (expr_type == tnew_expr.Type) {
7841                                                 Error_IdentifierNotFound (rc, expr_type, Name);
7842                                                 return null;
7843                                         }
7844
7845                                         expr_type = tnew_expr.Type;
7846                                         nested = MemberCache.FindNestedType (expr_type, Name, Arity);
7847                                         ErrorIsInaccesible (rc, nested.GetSignatureForError (), loc);
7848                                         break;
7849                                 }
7850
7851                                 if (nested.IsAccessible (rc.CurrentType))
7852                                         break;
7853
7854                                 // Keep looking after inaccessible candidate
7855                                 expr_type = nested.DeclaringType.BaseType;
7856                         }
7857
7858                         TypeExpr texpr;
7859                         if (Arity > 0) {
7860                                 if (HasTypeArguments) {
7861                                         texpr = new GenericTypeExpr (nested, targs, loc);
7862                                 } else {
7863                                         texpr = new GenericOpenTypeExpr (nested, loc);
7864                                 }
7865                         } else {
7866                                 texpr = new TypeExpression (nested, loc);
7867                         }
7868
7869                         return texpr.ResolveAsTypeStep (rc, false);
7870                 }
7871
7872                 protected virtual void Error_IdentifierNotFound (IMemberContext rc, TypeSpec expr_type, string identifier)
7873                 {
7874                         var nested = MemberCache.FindNestedType (expr_type, Name, -System.Math.Max (1, Arity));
7875
7876                         if (nested != null) {
7877                                 Error_TypeArgumentsCannotBeUsed (rc.Compiler.Report, expr.Location, nested, Arity);
7878                                 return;
7879                         }
7880
7881                         var any_other_member = MemberLookup (null, rc.CurrentType, expr_type, Name, 0, MemberLookupRestrictions.None, loc);
7882                         if (any_other_member != null) {
7883                                 any_other_member.Error_UnexpectedKind (rc.Compiler.Report, null, "type", loc);
7884                                 return;
7885                         }
7886
7887                         rc.Compiler.Report.Error (426, loc, "The nested type `{0}' does not exist in the type `{1}'",
7888                                 Name, expr_type.GetSignatureForError ());
7889                 }
7890
7891                 protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
7892                 {
7893                         if (RootContext.Version > LanguageVersion.ISO_2 && !ec.Compiler.IsRuntimeBinder && MethodGroupExpr.IsExtensionMethodArgument (expr)) {
7894                                 ec.Report.SymbolRelatedToPreviousError (type);
7895                                 ec.Report.Error (1061, loc,
7896                                         "Type `{0}' does not contain a definition for `{1}' and no extension method `{1}' of type `{0}' could be found (are you missing a using directive or an assembly reference?)",
7897                                         type.GetSignatureForError (), name);
7898                                 return;
7899                         }
7900
7901                         base.Error_TypeDoesNotContainDefinition (ec, type, name);
7902                 }
7903
7904                 public override string GetSignatureForError ()
7905                 {
7906                         return expr.GetSignatureForError () + "." + base.GetSignatureForError ();
7907                 }
7908
7909                 protected override void CloneTo (CloneContext clonectx, Expression t)
7910                 {
7911                         MemberAccess target = (MemberAccess) t;
7912
7913                         target.expr = expr.Clone (clonectx);
7914                 }
7915         }
7916
7917         /// <summary>
7918         ///   Implements checked expressions
7919         /// </summary>
7920         public class CheckedExpr : Expression {
7921
7922                 public Expression Expr;
7923
7924                 public CheckedExpr (Expression e, Location l)
7925                 {
7926                         Expr = e;
7927                         loc = l;
7928                 }
7929
7930                 public override Expression CreateExpressionTree (ResolveContext ec)
7931                 {
7932                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
7933                                 return Expr.CreateExpressionTree (ec);
7934                 }
7935
7936                 protected override Expression DoResolve (ResolveContext ec)
7937                 {
7938                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
7939                                 Expr = Expr.Resolve (ec);
7940
7941                         if (Expr == null)
7942                                 return null;
7943
7944                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
7945                                 return Expr;
7946
7947                         eclass = Expr.eclass;
7948                         type = Expr.Type;
7949                         return this;
7950                 }
7951
7952                 public override void Emit (EmitContext ec)
7953                 {
7954                         using (ec.With (EmitContext.Options.AllCheckStateFlags, true))
7955                                 Expr.Emit (ec);
7956                 }
7957
7958                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
7959                 {
7960                         using (ec.With (EmitContext.Options.AllCheckStateFlags, true))
7961                                 Expr.EmitBranchable (ec, target, on_true);
7962                 }
7963
7964                 public override SLE.Expression MakeExpression (BuilderContext ctx)
7965                 {
7966                         using (ctx.With (BuilderContext.Options.AllCheckStateFlags, true)) {
7967                                 return Expr.MakeExpression (ctx);
7968                         }
7969                 }
7970
7971                 protected override void CloneTo (CloneContext clonectx, Expression t)
7972                 {
7973                         CheckedExpr target = (CheckedExpr) t;
7974
7975                         target.Expr = Expr.Clone (clonectx);
7976                 }
7977         }
7978
7979         /// <summary>
7980         ///   Implements the unchecked expression
7981         /// </summary>
7982         public class UnCheckedExpr : Expression {
7983
7984                 public Expression Expr;
7985
7986                 public UnCheckedExpr (Expression e, Location l)
7987                 {
7988                         Expr = e;
7989                         loc = l;
7990                 }
7991
7992                 public override Expression CreateExpressionTree (ResolveContext ec)
7993                 {
7994                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
7995                                 return Expr.CreateExpressionTree (ec);
7996                 }
7997
7998                 protected override Expression DoResolve (ResolveContext ec)
7999                 {
8000                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
8001                                 Expr = Expr.Resolve (ec);
8002
8003                         if (Expr == null)
8004                                 return null;
8005
8006                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
8007                                 return Expr;
8008
8009                         eclass = Expr.eclass;
8010                         type = Expr.Type;
8011                         return this;
8012                 }
8013
8014                 public override void Emit (EmitContext ec)
8015                 {
8016                         using (ec.With (EmitContext.Options.AllCheckStateFlags, false))
8017                                 Expr.Emit (ec);
8018                 }
8019
8020                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
8021                 {
8022                         using (ec.With (EmitContext.Options.AllCheckStateFlags, false))
8023                                 Expr.EmitBranchable (ec, target, on_true);
8024                 }
8025
8026                 protected override void CloneTo (CloneContext clonectx, Expression t)
8027                 {
8028                         UnCheckedExpr target = (UnCheckedExpr) t;
8029
8030                         target.Expr = Expr.Clone (clonectx);
8031                 }
8032         }
8033
8034         /// <summary>
8035         ///   An Element Access expression.
8036         ///
8037         ///   During semantic analysis these are transformed into
8038         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
8039         /// </summary>
8040         public class ElementAccess : Expression {
8041                 public Arguments Arguments;
8042                 public Expression Expr;
8043
8044                 public ElementAccess (Expression e, Arguments args, Location loc)
8045                 {
8046                         Expr = e;
8047                         this.loc = loc;
8048                         this.Arguments = args;
8049                 }
8050
8051                 //
8052                 // We perform some simple tests, and then to "split" the emit and store
8053                 // code we create an instance of a different class, and return that.
8054                 //
8055                 Expression CreateAccessExpression (ResolveContext ec)
8056                 {
8057                         if (type.IsArray)
8058                                 return (new ArrayAccess (this, loc));
8059
8060                         if (type.IsPointer)
8061                                 return MakePointerAccess (ec, type);
8062
8063                         FieldExpr fe = Expr as FieldExpr;
8064                         if (fe != null) {
8065                                 var ff = fe.Spec as FixedFieldSpec;
8066                                 if (ff != null) {
8067                                         return MakePointerAccess (ec, ff.ElementType);
8068                                 }
8069                         }
8070
8071                         var indexers = MemberCache.FindMembers (type, MemberCache.IndexerNameAlias, false);
8072                         if (indexers != null || type == InternalType.Dynamic) {
8073                                 return new IndexerExpr (indexers, type, this);
8074                         }
8075
8076                         ec.Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
8077                                 type.GetSignatureForError ());
8078                         return null;
8079                 }
8080
8081                 public override Expression CreateExpressionTree (ResolveContext ec)
8082                 {
8083                         Arguments args = Arguments.CreateForExpressionTree (ec, Arguments,
8084                                 Expr.CreateExpressionTree (ec));
8085
8086                         return CreateExpressionFactoryCall (ec, "ArrayIndex", args);
8087                 }
8088
8089                 Expression MakePointerAccess (ResolveContext ec, TypeSpec type)
8090                 {
8091                         if (Arguments.Count != 1){
8092                                 ec.Report.Error (196, loc, "A pointer must be indexed by only one value");
8093                                 return null;
8094                         }
8095
8096                         if (Arguments [0] is NamedArgument)
8097                                 Error_NamedArgument ((NamedArgument) Arguments[0], ec.Report);
8098
8099                         Expression p = new PointerArithmetic (Binary.Operator.Addition, Expr, Arguments [0].Expr.Resolve (ec), type, loc);
8100                         return new Indirection (p, loc);
8101                 }
8102
8103                 protected override Expression DoResolve (ResolveContext ec)
8104                 {
8105                         Expr = Expr.Resolve (ec);
8106                         if (Expr == null)
8107                                 return null;
8108
8109                         type = Expr.Type;
8110
8111                         // TODO: Create 1 result for Resolve and ResolveLValue ?
8112                         var res = CreateAccessExpression (ec);
8113                         if (res == null)
8114                                 return null;
8115
8116                         return res.Resolve (ec);
8117                 }
8118
8119                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
8120                 {
8121                         Expr = Expr.Resolve (ec);
8122                         if (Expr == null)
8123                                 return null;
8124
8125                         type = Expr.Type;
8126
8127                         var res = CreateAccessExpression (ec);
8128                         if (res == null)
8129                                 return null;
8130
8131                         return res.ResolveLValue (ec, right_side);
8132                 }
8133
8134                 public override void Emit (EmitContext ec)
8135                 {
8136                         throw new Exception ("Should never be reached");
8137                 }
8138
8139                 public static void Error_NamedArgument (NamedArgument na, Report Report)
8140                 {
8141                         Report.Error (1742, na.Location, "An element access expression cannot use named argument");
8142                 }
8143
8144                 public override string GetSignatureForError ()
8145                 {
8146                         return Expr.GetSignatureForError ();
8147                 }
8148
8149                 protected override void CloneTo (CloneContext clonectx, Expression t)
8150                 {
8151                         ElementAccess target = (ElementAccess) t;
8152
8153                         target.Expr = Expr.Clone (clonectx);
8154                         if (Arguments != null)
8155                                 target.Arguments = Arguments.Clone (clonectx);
8156                 }
8157         }
8158
8159         /// <summary>
8160         ///   Implements array access
8161         /// </summary>
8162         public class ArrayAccess : Expression, IDynamicAssign, IMemoryLocation {
8163                 //
8164                 // Points to our "data" repository
8165                 //
8166                 ElementAccess ea;
8167
8168                 LocalTemporary temp, expr_copy;
8169                 Expression[] prepared_arguments;
8170                 bool prepared;
8171
8172                 public ArrayAccess (ElementAccess ea_data, Location l)
8173                 {
8174                         ea = ea_data;
8175                         loc = l;
8176                 }
8177
8178                 public override Expression CreateExpressionTree (ResolveContext ec)
8179                 {
8180                         return ea.CreateExpressionTree (ec);
8181                 }
8182
8183                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
8184                 {
8185                         return DoResolve (ec);
8186                 }
8187
8188                 protected override Expression DoResolve (ResolveContext ec)
8189                 {
8190                         // dynamic is used per argument in ConvertExpressionToArrayIndex case
8191                         bool dynamic;
8192                         ea.Arguments.Resolve (ec, out dynamic);
8193
8194                         var ac = ea.Expr.Type as ArrayContainer;
8195                         int rank = ea.Arguments.Count;
8196                         if (ac.Rank != rank) {
8197                                 ec.Report.Error (22, ea.Location, "Wrong number of indexes `{0}' inside [], expected `{1}'",
8198                                           rank.ToString (), ac.Rank.ToString ());
8199                                 return null;
8200                         }
8201
8202                         type = ac.Element;
8203                         if (type.IsPointer && !ec.IsUnsafe) {
8204                                 UnsafeError (ec, ea.Location);
8205                         }
8206
8207                         foreach (Argument a in ea.Arguments) {
8208                                 if (a is NamedArgument)
8209                                         ElementAccess.Error_NamedArgument ((NamedArgument) a, ec.Report);
8210
8211                                 a.Expr = ConvertExpressionToArrayIndex (ec, a.Expr);
8212                         }
8213
8214                         eclass = ExprClass.Variable;
8215
8216                         return this;
8217                 }
8218
8219                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
8220                 {
8221                         ec.Report.Warning (251, 2, loc, "Indexing an array with a negative index (array indices always start at zero)");
8222                 }
8223
8224                 //
8225                 // Load the array arguments into the stack.
8226                 //
8227                 void LoadArrayAndArguments (EmitContext ec)
8228                 {
8229                         ea.Expr.Emit (ec);
8230                         ea.Arguments.Emit (ec);
8231                 }
8232
8233                 public void Emit (EmitContext ec, bool leave_copy)
8234                 {
8235                         var ac = ea.Expr.Type as ArrayContainer;
8236
8237                         if (prepared) {
8238                                 ec.EmitLoadFromPtr (type);
8239                         } else {
8240                                 if (prepared_arguments == null) {
8241                                         LoadArrayAndArguments (ec);
8242                                 } else {
8243                                         expr_copy.Emit (ec);
8244                                         LocalTemporary lt;
8245                                         foreach (var expr in prepared_arguments) {
8246                                                 expr.Emit (ec);
8247                                                 lt = expr as LocalTemporary;
8248                                                 if (lt != null)
8249                                                         lt.Release (ec);
8250                                         }
8251                                 }
8252
8253                                 ec.EmitArrayLoad (ac);
8254                         }
8255
8256                         if (leave_copy) {
8257                                 ec.Emit (OpCodes.Dup);
8258                                 temp = new LocalTemporary (this.type);
8259                                 temp.Store (ec);
8260                         }
8261                 }
8262
8263                 public override void Emit (EmitContext ec)
8264                 {
8265                         Emit (ec, false);
8266                 }
8267
8268                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8269                 {
8270                         var ac = (ArrayContainer) ea.Expr.Type;
8271                         TypeSpec t = source.Type;
8272
8273                         //
8274                         // When we are dealing with a struct, get the address of it to avoid value copy
8275                         // Same cannot be done for reference type because array covariance and the
8276                         // check in ldelema requires to specify the type of array element stored at the index
8277                         //
8278                         if (t.IsStruct && ((prepare_for_load && !(source is DynamicExpressionStatement)) || !TypeManager.IsPrimitiveType (t))) {
8279                                 LoadArrayAndArguments (ec);
8280                                 ec.EmitArrayAddress (ac);
8281
8282                                 if (prepare_for_load) {
8283                                         ec.Emit (OpCodes.Dup);
8284                                 }
8285
8286                                 prepared = true;
8287                         } else if (prepare_for_load) {
8288                                 ea.Expr.Emit (ec);
8289                                 ec.Emit (OpCodes.Dup);
8290
8291                                 expr_copy = new LocalTemporary (ea.Expr.Type);
8292                                 expr_copy.Store (ec);
8293                                 prepared_arguments = ea.Arguments.Emit (ec, true);
8294                         } else {
8295                                 LoadArrayAndArguments (ec);
8296                         }
8297
8298                         source.Emit (ec);
8299
8300                         if (expr_copy != null) {
8301                                 expr_copy.Release (ec);
8302                         }
8303
8304                         if (leave_copy) {
8305                                 ec.Emit (OpCodes.Dup);
8306                                 temp = new LocalTemporary (this.type);
8307                                 temp.Store (ec);
8308                         }
8309
8310                         if (prepared) {
8311                                 ec.EmitStoreFromPtr (t);
8312                         } else {
8313                                 ec.EmitArrayStore (ac);
8314                         }
8315
8316                         if (temp != null) {
8317                                 temp.Emit (ec);
8318                                 temp.Release (ec);
8319                         }
8320                 }
8321
8322                 public void EmitNew (EmitContext ec, New source, bool leave_copy)
8323                 {
8324                         if (!source.Emit (ec, this)) {
8325                                 if (leave_copy)
8326                                         throw new NotImplementedException ();
8327
8328                                 return;
8329                         }
8330
8331                         throw new NotImplementedException ();
8332                 }
8333
8334                 public void AddressOf (EmitContext ec, AddressOp mode)
8335                 {
8336                         var ac = (ArrayContainer) ea.Expr.Type;
8337
8338                         LoadArrayAndArguments (ec);
8339                         ec.EmitArrayAddress (ac);
8340                 }
8341
8342                 public SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
8343                 {
8344 #if NET_4_0
8345                         return SLE.Expression.ArrayAccess (ea.Expr.MakeExpression (ctx), MakeExpressionArguments (ctx));
8346 #else
8347                         throw new NotImplementedException ();
8348 #endif
8349                 }
8350
8351                 public override SLE.Expression MakeExpression (BuilderContext ctx)
8352                 {
8353                         return SLE.Expression.ArrayIndex (ea.Expr.MakeExpression (ctx), MakeExpressionArguments (ctx));
8354                 }
8355
8356                 SLE.Expression[] MakeExpressionArguments (BuilderContext ctx)
8357                 {
8358                         using (ctx.With (BuilderContext.Options.AllCheckStateFlags, true)) {
8359                                 return Arguments.MakeExpression (ea.Arguments, ctx);
8360                         }
8361                 }
8362         }
8363
8364         //
8365         // Indexer access expression
8366         //
8367         class IndexerExpr : PropertyOrIndexerExpr<IndexerSpec>, OverloadResolver.IBaseMembersProvider
8368         {
8369                 LocalTemporary prepared_value;
8370                 IList<MemberSpec> indexers;
8371                 Arguments arguments;
8372                 TypeSpec queried_type;
8373
8374                 public IndexerExpr (IList<MemberSpec> indexers, TypeSpec queriedType, ElementAccess ea)
8375                         : base (ea.Location)
8376                 {
8377                         this.indexers = indexers;
8378                         this.queried_type = queriedType;
8379                         this.InstanceExpression = ea.Expr;
8380                         this.arguments = ea.Arguments;
8381                 }
8382
8383                 #region Properties
8384                 protected override TypeSpec DeclaringType {
8385                         get {
8386                                 return best_candidate.DeclaringType;
8387                         }
8388                 }
8389
8390                 public override bool IsInstance {
8391                         get {
8392                                 return true;
8393                         }
8394                 }
8395
8396                 public override bool IsStatic {
8397                         get {
8398                                 return false;
8399                         }
8400                 }
8401
8402                 public override string Name {
8403                         get {
8404                                 return "this";
8405                         }
8406                 }
8407
8408                 #endregion
8409
8410                 public override Expression CreateExpressionTree (ResolveContext ec)
8411                 {
8412                         Arguments args = Arguments.CreateForExpressionTree (ec, arguments,
8413                                 InstanceExpression.CreateExpressionTree (ec),
8414                                 new TypeOfMethod (Getter, loc));
8415
8416                         return CreateExpressionFactoryCall (ec, "Call", args);
8417                 }
8418
8419                 public override void Emit (EmitContext ec, bool leave_copy)
8420                 {
8421                         if (prepared) {
8422                                 prepared_value.Emit (ec);
8423                         } else {
8424                                 Invocation.EmitCall (ec, InstanceExpression, Getter, arguments, loc);
8425                         }
8426
8427                         if (leave_copy) {
8428                                 ec.Emit (OpCodes.Dup);
8429                                 temp = new LocalTemporary (Type);
8430                                 temp.Store (ec);
8431                         }
8432                 }
8433
8434                 public override void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8435                 {
8436                         prepared = prepare_for_load;
8437                         Expression value = source;
8438
8439                         if (prepared) {
8440                                 Invocation.EmitCall (ec, InstanceExpression, Getter, arguments, loc, true, false);
8441
8442                                 prepared_value = new LocalTemporary (type);
8443                                 prepared_value.Store (ec);
8444                                 source.Emit (ec);
8445                                 prepared_value.Release (ec);
8446
8447                                 if (leave_copy) {
8448                                         ec.Emit (OpCodes.Dup);
8449                                         temp = new LocalTemporary (Type);
8450                                         temp.Store (ec);
8451                                 }
8452                         } else if (leave_copy) {
8453                                 temp = new LocalTemporary (Type);
8454                                 source.Emit (ec);
8455                                 temp.Store (ec);
8456                                 value = temp;
8457                         }
8458
8459                         if (!prepared)
8460                                 arguments.Add (new Argument (value));
8461
8462                         Invocation.EmitCall (ec, InstanceExpression, Setter, arguments, loc, false, prepared);
8463
8464                         if (temp != null) {
8465                                 temp.Emit (ec);
8466                                 temp.Release (ec);
8467                         }
8468                 }
8469
8470                 public override string GetSignatureForError ()
8471                 {
8472                         return best_candidate.GetSignatureForError ();
8473                 }
8474
8475                 public override SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
8476                 {
8477 #if STATIC
8478                         throw new NotSupportedException ();
8479 #else
8480                         var value = new[] { source.MakeExpression (ctx) };
8481                         var args = Arguments.MakeExpression (arguments, ctx).Concat (value);
8482 #if NET_4_0
8483                         return SLE.Expression.Block (
8484                                         SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Setter.GetMetaInfo (), args),
8485                                         value [0]);
8486 #else
8487                         return args.First ();
8488 #endif
8489 #endif
8490                 }
8491
8492                 public override SLE.Expression MakeExpression (BuilderContext ctx)
8493                 {
8494 #if STATIC
8495                         return base.MakeExpression (ctx);
8496 #else
8497                         var args = Arguments.MakeExpression (arguments, ctx);
8498                         return SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Getter.GetMetaInfo (), args);
8499 #endif
8500                 }
8501
8502                 protected override Expression OverloadResolve (ResolveContext rc, Expression right_side)
8503                 {
8504                         if (best_candidate != null)
8505                                 return this;
8506
8507                         eclass = ExprClass.IndexerAccess;
8508
8509                         bool dynamic;
8510                         arguments.Resolve (rc, out dynamic);
8511
8512                         if (indexers == null && InstanceExpression.Type == InternalType.Dynamic) {
8513                                 dynamic = true;
8514                         } else {
8515                                 var res = new OverloadResolver (indexers, OverloadResolver.Restrictions.None, loc);
8516                                 res.BaseMembersProvider = this;
8517
8518                                 // TODO: Do I need 2 argument sets?
8519                                 best_candidate = res.ResolveMember<IndexerSpec> (rc, ref arguments);
8520                                 if (best_candidate != null)
8521                                         type = res.BestCandidateReturnType;
8522                                 else if (!res.BestCandidateIsDynamic)
8523                                         return null;
8524                         }
8525
8526                         //
8527                         // It has dynamic arguments
8528                         //
8529                         if (dynamic) {
8530                                 Arguments args = new Arguments (arguments.Count + 1);
8531                                 if (IsBase) {
8532                                         rc.Report.Error (1972, loc,
8533                                                 "The indexer base access cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access");
8534                                 } else {
8535                                         args.Add (new Argument (InstanceExpression));
8536                                 }
8537                                 args.AddRange (arguments);
8538
8539                                 best_candidate = null;
8540                                 return new DynamicIndexBinder (args, loc);
8541                         }
8542
8543                         ResolveInstanceExpression (rc, right_side);
8544                         CheckProtectedMemberAccess (rc, best_candidate);
8545                         return this;
8546                 }
8547
8548                 protected override void CloneTo (CloneContext clonectx, Expression t)
8549                 {
8550                         IndexerExpr target = (IndexerExpr) t;
8551
8552                         if (arguments != null)
8553                                 target.arguments = arguments.Clone (clonectx);
8554                 }
8555
8556                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
8557                 {
8558                         Error_TypeArgumentsCannotBeUsed (ec.Report, "indexer", GetSignatureForError (), loc);
8559                 }
8560
8561                 #region IBaseMembersProvider Members
8562
8563                 IList<MemberSpec> OverloadResolver.IBaseMembersProvider.GetBaseMembers (TypeSpec baseType)
8564                 {
8565                         return baseType == null ? null : MemberCache.FindMembers (baseType, MemberCache.IndexerNameAlias, false);
8566                 }
8567
8568                 IParametersMember OverloadResolver.IBaseMembersProvider.GetOverrideMemberParameters (MemberSpec member)
8569                 {
8570                         if (queried_type == member.DeclaringType)
8571                                 return null;
8572
8573                         var filter = new MemberFilter (MemberCache.IndexerNameAlias, 0, MemberKind.Indexer, ((IndexerSpec) member).Parameters, null);
8574                         return MemberCache.FindMember (queried_type, filter, BindingRestriction.InstanceOnly | BindingRestriction.OverrideOnly) as IParametersMember;
8575                 }
8576
8577                 MethodGroupExpr OverloadResolver.IBaseMembersProvider.LookupExtensionMethod (ResolveContext rc)
8578                 {
8579                         return null;
8580                 }
8581
8582                 #endregion
8583         }
8584
8585         //
8586         // A base access expression
8587         //
8588         public class BaseThis : This
8589         {
8590                 public BaseThis (Location loc)
8591                         : base (loc)
8592                 {
8593                 }
8594
8595                 public BaseThis (TypeSpec type, Location loc)
8596                         : base (loc)
8597                 {
8598                         this.type = type;
8599                         eclass = ExprClass.Variable;
8600                 }
8601
8602                 #region Properties
8603
8604                 public override string Name {
8605                         get {
8606                                 return "base";
8607                         }
8608                 }
8609
8610                 #endregion
8611
8612                 public override Expression CreateExpressionTree (ResolveContext ec)
8613                 {
8614                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
8615                         return base.CreateExpressionTree (ec);
8616                 }
8617
8618                 public override void Emit (EmitContext ec)
8619                 {
8620                         base.Emit (ec);
8621
8622                         if (ec.CurrentType.IsStruct) {
8623                                 ec.Emit (OpCodes.Ldobj, ec.CurrentType);
8624                                 ec.Emit (OpCodes.Box, ec.CurrentType);
8625                         }
8626                 }
8627
8628                 protected override void Error_ThisNotAvailable (ResolveContext ec)
8629                 {
8630                         if (ec.IsStatic) {
8631                                 ec.Report.Error (1511, loc, "Keyword `base' is not available in a static method");
8632                         } else {
8633                                 ec.Report.Error (1512, loc, "Keyword `base' is not available in the current context");
8634                         }
8635                 }
8636
8637                 public override void ResolveBase (ResolveContext ec)
8638                 {
8639                         base.ResolveBase (ec);
8640                         type = ec.CurrentType.BaseType;
8641                 }
8642         }
8643
8644         /// <summary>
8645         ///   This class exists solely to pass the Type around and to be a dummy
8646         ///   that can be passed to the conversion functions (this is used by
8647         ///   foreach implementation to typecast the object return value from
8648         ///   get_Current into the proper type.  All code has been generated and
8649         ///   we only care about the side effect conversions to be performed
8650         ///
8651         ///   This is also now used as a placeholder where a no-action expression
8652         ///   is needed (the `New' class).
8653         /// </summary>
8654         public class EmptyExpression : Expression {
8655                 public static readonly Expression Null = new EmptyExpression ();
8656
8657                 public class OutAccess : EmptyExpression
8658                 {
8659                         public static readonly OutAccess Instance = new OutAccess ();
8660
8661                         public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
8662                         {
8663                                 rc.Report.Error (206, right_side.Location,
8664                                         "A property, indexer or dynamic member access may not be passed as `ref' or `out' parameter");
8665
8666                                 return null;
8667                         }
8668                 }
8669
8670                 public static readonly EmptyExpression LValueMemberAccess = new EmptyExpression ();
8671                 public static readonly EmptyExpression LValueMemberOutAccess = new EmptyExpression ();
8672                 public static readonly EmptyExpression UnaryAddress = new EmptyExpression ();
8673                 public static readonly EmptyExpression EventAddition = new EmptyExpression ();
8674                 public static readonly EmptyExpression EventSubtraction = new EmptyExpression ();
8675                 public static readonly EmptyExpression MissingValue = new EmptyExpression (InternalType.FakeInternalType);
8676
8677                 static EmptyExpression temp = new EmptyExpression ();
8678                 public static EmptyExpression Grab ()
8679                 {
8680                         EmptyExpression retval = temp == null ? new EmptyExpression () : temp;
8681                         temp = null;
8682                         return retval;
8683                 }
8684
8685                 public static void Release (EmptyExpression e)
8686                 {
8687                         temp = e;
8688                 }
8689
8690                 EmptyExpression ()
8691                 {
8692                         // FIXME: Don't set to object
8693                         type = TypeManager.object_type;
8694                         eclass = ExprClass.Value;
8695                         loc = Location.Null;
8696                 }
8697
8698                 public EmptyExpression (TypeSpec t)
8699                 {
8700                         type = t;
8701                         eclass = ExprClass.Value;
8702                         loc = Location.Null;
8703                 }
8704
8705                 public override Expression CreateExpressionTree (ResolveContext ec)
8706                 {
8707                         throw new NotSupportedException ("ET");
8708                 }
8709
8710                 protected override Expression DoResolve (ResolveContext ec)
8711                 {
8712                         return this;
8713                 }
8714
8715                 public override void Emit (EmitContext ec)
8716                 {
8717                         // nothing, as we only exist to not do anything.
8718                 }
8719
8720                 public override void EmitSideEffect (EmitContext ec)
8721                 {
8722                 }
8723
8724                 //
8725                 // This is just because we might want to reuse this bad boy
8726                 // instead of creating gazillions of EmptyExpressions.
8727                 // (CanImplicitConversion uses it)
8728                 //
8729                 public void SetType (TypeSpec t)
8730                 {
8731                         type = t;
8732                 }
8733         }
8734
8735         //
8736         // Empty statement expression
8737         //
8738         public sealed class EmptyExpressionStatement : ExpressionStatement
8739         {
8740                 public static readonly EmptyExpressionStatement Instance = new EmptyExpressionStatement ();
8741
8742                 private EmptyExpressionStatement ()
8743                 {
8744                         loc = Location.Null;
8745                 }
8746
8747                 public override Expression CreateExpressionTree (ResolveContext ec)
8748                 {
8749                         return null;
8750                 }
8751
8752                 public override void EmitStatement (EmitContext ec)
8753                 {
8754                         // Do nothing
8755                 }
8756
8757                 protected override Expression DoResolve (ResolveContext ec)
8758                 {
8759                         eclass = ExprClass.Value;
8760                         type = TypeManager.object_type;
8761                         return this;
8762                 }
8763
8764                 public override void Emit (EmitContext ec)
8765                 {
8766                         // Do nothing
8767                 }
8768         }
8769
8770         public class UserCast : Expression {
8771                 MethodSpec method;
8772                 Expression source;
8773
8774                 public UserCast (MethodSpec method, Expression source, Location l)
8775                 {
8776                         this.method = method;
8777                         this.source = source;
8778                         type = method.ReturnType;
8779                         loc = l;
8780                 }
8781
8782                 public Expression Source {
8783                         get {
8784                                 return source;
8785                         }
8786                 }
8787
8788                 public override Expression CreateExpressionTree (ResolveContext ec)
8789                 {
8790                         Arguments args = new Arguments (3);
8791                         args.Add (new Argument (source.CreateExpressionTree (ec)));
8792                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
8793                         args.Add (new Argument (new TypeOfMethod (method, loc)));
8794                         return CreateExpressionFactoryCall (ec, "Convert", args);
8795                 }
8796
8797                 protected override Expression DoResolve (ResolveContext ec)
8798                 {
8799                         ObsoleteAttribute oa = method.GetAttributeObsolete ();
8800                         if (oa != null)
8801                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
8802
8803                         eclass = ExprClass.Value;
8804                         return this;
8805                 }
8806
8807                 public override void Emit (EmitContext ec)
8808                 {
8809                         source.Emit (ec);
8810                         ec.Emit (OpCodes.Call, method);
8811                 }
8812
8813                 public override string GetSignatureForError ()
8814                 {
8815                         return TypeManager.CSharpSignature (method);
8816                 }
8817
8818                 public override SLE.Expression MakeExpression (BuilderContext ctx)
8819                 {
8820 #if STATIC
8821                         return base.MakeExpression (ctx);
8822 #else
8823                         return SLE.Expression.Convert (source.MakeExpression (ctx), type.GetMetaInfo (), (MethodInfo) method.GetMetaInfo ());
8824 #endif
8825                 }
8826         }
8827
8828         //
8829         // Holds additional type specifiers like ?, *, []
8830         //
8831         public class ComposedTypeSpecifier
8832         {
8833                 public static readonly ComposedTypeSpecifier SingleDimension = new ComposedTypeSpecifier (1, Location.Null);
8834
8835                 public readonly int Dimension;
8836                 public readonly Location Location;
8837
8838                 public ComposedTypeSpecifier (int specifier, Location loc)
8839                 {
8840                         this.Dimension = specifier;
8841                         this.Location = loc;
8842                 }
8843
8844                 #region Properties
8845                 public bool IsNullable {
8846                         get {
8847                                 return Dimension == -1;
8848                         }
8849                 }
8850
8851                 public bool IsPointer {
8852                         get {
8853                                 return Dimension == -2;
8854                         }
8855                 }
8856
8857                 public ComposedTypeSpecifier Next { get; set; }
8858
8859                 #endregion
8860
8861                 public static ComposedTypeSpecifier CreateArrayDimension (int dimension, Location loc)
8862                 {
8863                         return new ComposedTypeSpecifier (dimension, loc);
8864                 }
8865
8866                 public static ComposedTypeSpecifier CreateNullable (Location loc)
8867                 {
8868                         return new ComposedTypeSpecifier (-1, loc);
8869                 }
8870
8871                 public static ComposedTypeSpecifier CreatePointer (Location loc)
8872                 {
8873                         return new ComposedTypeSpecifier (-2, loc);
8874                 }
8875
8876                 public string GetSignatureForError ()
8877                 {
8878                         string s =
8879                                 IsPointer ? "*" :
8880                                 IsNullable ? "?" :
8881                                 ArrayContainer.GetPostfixSignature (Dimension);
8882
8883                         return Next != null ? s + Next.GetSignatureForError () : s;
8884                 }
8885         }
8886
8887         // <summary>
8888         //   This class is used to "construct" the type during a typecast
8889         //   operation.  Since the Type.GetType class in .NET can parse
8890         //   the type specification, we just use this to construct the type
8891         //   one bit at a time.
8892         // </summary>
8893         public class ComposedCast : TypeExpr {
8894                 FullNamedExpression left;
8895                 ComposedTypeSpecifier spec;
8896
8897                 public ComposedCast (FullNamedExpression left, ComposedTypeSpecifier spec)
8898                 {
8899                         if (spec == null)
8900                                 throw new ArgumentNullException ("spec");
8901
8902                         this.left = left;
8903                         this.spec = spec;
8904                         this.loc = spec.Location;
8905                 }
8906
8907                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
8908                 {
8909                         TypeExpr lexpr = left.ResolveAsTypeTerminal (ec, false);
8910                         if (lexpr == null)
8911                                 return null;
8912
8913                         type = lexpr.Type;
8914                         eclass = ExprClass.Type;
8915
8916                         var single_spec = spec;
8917
8918                         if (single_spec.IsNullable) {
8919                                 lexpr = new Nullable.NullableType (lexpr, loc);
8920                                 lexpr = lexpr.ResolveAsTypeTerminal (ec, false);
8921                                 if (lexpr != null)
8922                                         type = lexpr.Type;
8923
8924                                 single_spec = single_spec.Next;
8925                         } else if (single_spec.IsPointer) {
8926                                 if (!TypeManager.VerifyUnmanaged (ec.Compiler, type, loc))
8927                                         return null;
8928
8929                                 if (!ec.IsUnsafe) {
8930                                         UnsafeError (ec.Compiler.Report, loc);
8931                                 }
8932
8933                                 do {
8934                                         type = PointerContainer.MakeType (type);
8935                                         single_spec = single_spec.Next;
8936                                 } while (single_spec != null && single_spec.IsPointer);
8937                         }
8938
8939                         if (single_spec != null && single_spec.Dimension > 0) {
8940                                 if (TypeManager.IsSpecialType (type)) {
8941                                         ec.Compiler.Report.Error (611, loc, "Array elements cannot be of type `{0}'", type.GetSignatureForError ());
8942                                 } else if (type.IsStatic) {
8943                                         ec.Compiler.Report.SymbolRelatedToPreviousError (type);
8944                                         ec.Compiler.Report.Error (719, loc, "Array elements cannot be of static type `{0}'",
8945                                                 type.GetSignatureForError ());
8946                                 } else {
8947                                         MakeArray (single_spec);
8948                                 }
8949                         }
8950
8951                         return this;
8952                 }
8953
8954                 void MakeArray (ComposedTypeSpecifier spec)
8955                 {
8956                         if (spec.Next != null)
8957                                 MakeArray (spec.Next);
8958
8959                         type = ArrayContainer.MakeType (type, spec.Dimension);
8960                 }
8961
8962                 public override string GetSignatureForError ()
8963                 {
8964                         return left.GetSignatureForError () + spec.GetSignatureForError ();
8965                 }
8966         }
8967
8968         public class FixedBufferPtr : Expression {
8969                 Expression array;
8970
8971                 public FixedBufferPtr (Expression array, TypeSpec array_type, Location l)
8972                 {
8973                         this.array = array;
8974                         this.loc = l;
8975
8976                         type = PointerContainer.MakeType (array_type);
8977                         eclass = ExprClass.Value;
8978                 }
8979
8980                 public override Expression CreateExpressionTree (ResolveContext ec)
8981                 {
8982                         Error_PointerInsideExpressionTree (ec);
8983                         return null;
8984                 }
8985
8986                 public override void Emit(EmitContext ec)
8987                 {
8988                         array.Emit (ec);
8989                 }
8990
8991                 protected override Expression DoResolve (ResolveContext ec)
8992                 {
8993                         //
8994                         // We are born fully resolved
8995                         //
8996                         return this;
8997                 }
8998         }
8999
9000
9001         //
9002         // This class is used to represent the address of an array, used
9003         // only by the Fixed statement, this generates "&a [0]" construct
9004         // for fixed (char *pa = a)
9005         //
9006         public class ArrayPtr : FixedBufferPtr {
9007                 TypeSpec array_type;
9008
9009                 public ArrayPtr (Expression array, TypeSpec array_type, Location l):
9010                         base (array, array_type, l)
9011                 {
9012                         this.array_type = array_type;
9013                 }
9014
9015                 public override void Emit (EmitContext ec)
9016                 {
9017                         base.Emit (ec);
9018
9019                         ec.EmitInt (0);
9020                         ec.Emit (OpCodes.Ldelema, array_type);
9021                 }
9022         }
9023
9024         //
9025         // Encapsulates a conversion rules required for array indexes
9026         //
9027         public class ArrayIndexCast : TypeCast
9028         {
9029                 public ArrayIndexCast (Expression expr)
9030                         : base (expr, TypeManager.int32_type)
9031                 {
9032                         if (expr.Type == TypeManager.int32_type)
9033                                 throw new ArgumentException ("unnecessary array index conversion");
9034                 }
9035
9036                 public override Expression CreateExpressionTree (ResolveContext ec)
9037                 {
9038                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
9039                                 return base.CreateExpressionTree (ec);
9040                         }
9041                 }
9042
9043                 public override void Emit (EmitContext ec)
9044                 {
9045                         child.Emit (ec);
9046
9047                         var expr_type = child.Type;
9048
9049                         if (expr_type == TypeManager.uint32_type)
9050                                 ec.Emit (OpCodes.Conv_U);
9051                         else if (expr_type == TypeManager.int64_type)
9052                                 ec.Emit (OpCodes.Conv_Ovf_I);
9053                         else if (expr_type == TypeManager.uint64_type)
9054                                 ec.Emit (OpCodes.Conv_Ovf_I_Un);
9055                         else
9056                                 throw new InternalErrorException ("Cannot emit cast to unknown array element type", type);
9057                 }
9058         }
9059
9060         //
9061         // Implements the `stackalloc' keyword
9062         //
9063         public class StackAlloc : Expression {
9064                 TypeSpec otype;
9065                 Expression t;
9066                 Expression count;
9067
9068                 public StackAlloc (Expression type, Expression count, Location l)
9069                 {
9070                         t = type;
9071                         this.count = count;
9072                         loc = l;
9073                 }
9074
9075                 public override Expression CreateExpressionTree (ResolveContext ec)
9076                 {
9077                         throw new NotSupportedException ("ET");
9078                 }
9079
9080                 protected override Expression DoResolve (ResolveContext ec)
9081                 {
9082                         count = count.Resolve (ec);
9083                         if (count == null)
9084                                 return null;
9085
9086                         if (count.Type != TypeManager.uint32_type){
9087                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
9088                                 if (count == null)
9089                                         return null;
9090                         }
9091
9092                         Constant c = count as Constant;
9093                         if (c != null && c.IsNegative) {
9094                                 ec.Report.Error (247, loc, "Cannot use a negative size with stackalloc");
9095                         }
9096
9097                         if (ec.HasAny (ResolveContext.Options.CatchScope | ResolveContext.Options.FinallyScope)) {
9098                                 ec.Report.Error (255, loc, "Cannot use stackalloc in finally or catch");
9099                         }
9100
9101                         TypeExpr texpr = t.ResolveAsTypeTerminal (ec, false);
9102                         if (texpr == null)
9103                                 return null;
9104
9105                         otype = texpr.Type;
9106
9107                         if (!TypeManager.VerifyUnmanaged (ec.Compiler, otype, loc))
9108                                 return null;
9109
9110                         type = PointerContainer.MakeType (otype);
9111                         eclass = ExprClass.Value;
9112
9113                         return this;
9114                 }
9115
9116                 public override void Emit (EmitContext ec)
9117                 {
9118                         int size = GetTypeSize (otype);
9119
9120                         count.Emit (ec);
9121
9122                         if (size == 0)
9123                                 ec.Emit (OpCodes.Sizeof, otype);
9124                         else
9125                                 ec.EmitInt (size);
9126
9127                         ec.Emit (OpCodes.Mul_Ovf_Un);
9128                         ec.Emit (OpCodes.Localloc);
9129                 }
9130
9131                 protected override void CloneTo (CloneContext clonectx, Expression t)
9132                 {
9133                         StackAlloc target = (StackAlloc) t;
9134                         target.count = count.Clone (clonectx);
9135                         target.t = t.Clone (clonectx);
9136                 }
9137         }
9138
9139         //
9140         // An object initializer expression
9141         //
9142         public class ElementInitializer : Assign
9143         {
9144                 public readonly string Name;
9145
9146                 public ElementInitializer (string name, Expression initializer, Location loc)
9147                         : base (null, initializer, loc)
9148                 {
9149                         this.Name = name;
9150                 }
9151
9152                 protected override void CloneTo (CloneContext clonectx, Expression t)
9153                 {
9154                         ElementInitializer target = (ElementInitializer) t;
9155                         target.source = source.Clone (clonectx);
9156                 }
9157
9158                 public override Expression CreateExpressionTree (ResolveContext ec)
9159                 {
9160                         Arguments args = new Arguments (2);
9161                         FieldExpr fe = target as FieldExpr;
9162                         if (fe != null)
9163                                 args.Add (new Argument (fe.CreateTypeOfExpression ()));
9164                         else
9165                                 args.Add (new Argument (((PropertyExpr)target).CreateSetterTypeOfExpression ()));
9166
9167                         args.Add (new Argument (source.CreateExpressionTree (ec)));
9168                         return CreateExpressionFactoryCall (ec,
9169                                 source is CollectionOrObjectInitializers ? "ListBind" : "Bind",
9170                                 args);
9171                 }
9172
9173                 protected override Expression DoResolve (ResolveContext ec)
9174                 {
9175                         if (source == null)
9176                                 return EmptyExpressionStatement.Instance;
9177
9178                         var t = ec.CurrentInitializerVariable.Type;
9179                         if (t == InternalType.Dynamic) {
9180                                 Arguments args = new Arguments (1);
9181                                 args.Add (new Argument (ec.CurrentInitializerVariable));
9182                                 target = new DynamicMemberBinder (Name, args, loc);
9183                         } else {
9184
9185                                 var member = MemberLookup (ec, ec.CurrentType, t, Name, 0, MemberLookupRestrictions.ExactArity, loc);
9186                                 if (member == null) {
9187                                         member = Expression.MemberLookup (null, ec.CurrentType, t, Name, 0, MemberLookupRestrictions.ExactArity, loc);
9188
9189                                         if (member != null) {
9190                                                 // TODO: ec.Report.SymbolRelatedToPreviousError (member);
9191                                                 ErrorIsInaccesible (ec, member.GetSignatureForError (), loc);
9192                                                 return null;
9193                                         }
9194                                 }
9195
9196                                 if (member == null) {
9197                                         Error_TypeDoesNotContainDefinition (ec, loc, t, Name);
9198                                         return null;
9199                                 }
9200
9201                                 if (!(member is PropertyExpr || member is FieldExpr)) {
9202                                         ec.Report.Error (1913, loc,
9203                                                 "Member `{0}' cannot be initialized. An object initializer may only be used for fields, or properties",
9204                                                 member.GetSignatureForError ());
9205
9206                                         return null;
9207                                 }
9208
9209                                 var me = member as MemberExpr;
9210                                 if (me.IsStatic) {
9211                                         ec.Report.Error (1914, loc,
9212                                                 "Static field or property `{0}' cannot be assigned in an object initializer",
9213                                                 me.GetSignatureForError ());
9214                                 }
9215
9216                                 target = me;
9217                                 me.InstanceExpression = ec.CurrentInitializerVariable;
9218                         }
9219
9220                         if (source is CollectionOrObjectInitializers) {
9221                                 Expression previous = ec.CurrentInitializerVariable;
9222                                 ec.CurrentInitializerVariable = target;
9223                                 source = source.Resolve (ec);
9224                                 ec.CurrentInitializerVariable = previous;
9225                                 if (source == null)
9226                                         return null;
9227
9228                                 eclass = source.eclass;
9229                                 type = source.Type;
9230                                 return this;
9231                         }
9232
9233                         return base.DoResolve (ec);
9234                 }
9235
9236                 public override void EmitStatement (EmitContext ec)
9237                 {
9238                         if (source is CollectionOrObjectInitializers)
9239                                 source.Emit (ec);
9240                         else
9241                                 base.EmitStatement (ec);
9242                 }
9243         }
9244
9245         //
9246         // A collection initializer expression
9247         //
9248         class CollectionElementInitializer : Invocation
9249         {
9250                 public class ElementInitializerArgument : Argument
9251                 {
9252                         public ElementInitializerArgument (Expression e)
9253                                 : base (e)
9254                         {
9255                         }
9256                 }
9257
9258                 sealed class AddMemberAccess : MemberAccess
9259                 {
9260                         public AddMemberAccess (Expression expr, Location loc)
9261                                 : base (expr, "Add", loc)
9262                         {
9263                         }
9264
9265                         protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
9266                         {
9267                                 if (TypeManager.HasElementType (type))
9268                                         return;
9269
9270                                 base.Error_TypeDoesNotContainDefinition (ec, type, name);
9271                         }
9272                 }
9273
9274                 public CollectionElementInitializer (Expression argument)
9275                         : base (null, new Arguments (1))
9276                 {
9277                         base.arguments.Add (new ElementInitializerArgument (argument));
9278                         this.loc = argument.Location;
9279                 }
9280
9281                 public CollectionElementInitializer (List<Expression> arguments, Location loc)
9282                         : base (null, new Arguments (arguments.Count))
9283                 {
9284                         foreach (Expression e in arguments)
9285                                 base.arguments.Add (new ElementInitializerArgument (e));
9286
9287                         this.loc = loc;
9288                 }
9289
9290                 public override Expression CreateExpressionTree (ResolveContext ec)
9291                 {
9292                         Arguments args = new Arguments (2);
9293                         args.Add (new Argument (mg.CreateExpressionTree (ec)));
9294
9295                         var expr_initializers = new ArrayInitializer (arguments.Count, loc);
9296                         foreach (Argument a in arguments)
9297                                 expr_initializers.Add (a.CreateExpressionTree (ec));
9298
9299                         args.Add (new Argument (new ArrayCreation (
9300                                 CreateExpressionTypeExpression (ec, loc), expr_initializers, loc)));
9301                         return CreateExpressionFactoryCall (ec, "ElementInit", args);
9302                 }
9303
9304                 protected override void CloneTo (CloneContext clonectx, Expression t)
9305                 {
9306                         CollectionElementInitializer target = (CollectionElementInitializer) t;
9307                         if (arguments != null)
9308                                 target.arguments = arguments.Clone (clonectx);
9309                 }
9310
9311                 protected override Expression DoResolve (ResolveContext ec)
9312                 {
9313                         base.expr = new AddMemberAccess (ec.CurrentInitializerVariable, loc);
9314
9315                         return base.DoResolve (ec);
9316                 }
9317         }
9318
9319         //
9320         // A block of object or collection initializers
9321         //
9322         public class CollectionOrObjectInitializers : ExpressionStatement
9323         {
9324                 IList<Expression> initializers;
9325                 bool is_collection_initialization;
9326
9327                 public static readonly CollectionOrObjectInitializers Empty =
9328                         new CollectionOrObjectInitializers (Array.AsReadOnly (new Expression [0]), Location.Null);
9329
9330                 public CollectionOrObjectInitializers (IList<Expression> initializers, Location loc)
9331                 {
9332                         this.initializers = initializers;
9333                         this.loc = loc;
9334                 }
9335
9336                 public bool IsEmpty {
9337                         get {
9338                                 return initializers.Count == 0;
9339                         }
9340                 }
9341
9342                 public bool IsCollectionInitializer {
9343                         get {
9344                                 return is_collection_initialization;
9345                         }
9346                 }
9347
9348                 protected override void CloneTo (CloneContext clonectx, Expression target)
9349                 {
9350                         CollectionOrObjectInitializers t = (CollectionOrObjectInitializers) target;
9351
9352                         t.initializers = new List<Expression> (initializers.Count);
9353                         foreach (var e in initializers)
9354                                 t.initializers.Add (e.Clone (clonectx));
9355                 }
9356
9357                 public override Expression CreateExpressionTree (ResolveContext ec)
9358                 {
9359                         var expr_initializers = new ArrayInitializer (initializers.Count, loc);
9360                         foreach (Expression e in initializers) {
9361                                 Expression expr = e.CreateExpressionTree (ec);
9362                                 if (expr != null)
9363                                         expr_initializers.Add (expr);
9364                         }
9365
9366                         return new ImplicitlyTypedArrayCreation (expr_initializers, loc);
9367                 }
9368
9369                 protected override Expression DoResolve (ResolveContext ec)
9370                 {
9371                         List<string> element_names = null;
9372                         for (int i = 0; i < initializers.Count; ++i) {
9373                                 Expression initializer = initializers [i];
9374                                 ElementInitializer element_initializer = initializer as ElementInitializer;
9375
9376                                 if (i == 0) {
9377                                         if (element_initializer != null) {
9378                                                 element_names = new List<string> (initializers.Count);
9379                                                 element_names.Add (element_initializer.Name);
9380                                         } else if (initializer is CompletingExpression){
9381                                                 initializer.Resolve (ec);
9382                                                 throw new InternalErrorException ("This line should never be reached");
9383                                         } else {
9384                                                 var t = ec.CurrentInitializerVariable.Type;
9385                                                 // LAMESPEC: The collection must implement IEnumerable only, no dynamic support
9386                                                 if (!t.ImplementsInterface (TypeManager.ienumerable_type, false) && t != InternalType.Dynamic) {
9387                                                         ec.Report.Error (1922, loc, "A field or property `{0}' cannot be initialized with a collection " +
9388                                                                 "object initializer because type `{1}' does not implement `{2}' interface",
9389                                                                 ec.CurrentInitializerVariable.GetSignatureForError (),
9390                                                                 TypeManager.CSharpName (ec.CurrentInitializerVariable.Type),
9391                                                                 TypeManager.CSharpName (TypeManager.ienumerable_type));
9392                                                         return null;
9393                                                 }
9394                                                 is_collection_initialization = true;
9395                                         }
9396                                 } else {
9397                                         if (is_collection_initialization != (element_initializer == null)) {
9398                                                 ec.Report.Error (747, initializer.Location, "Inconsistent `{0}' member declaration",
9399                                                         is_collection_initialization ? "collection initializer" : "object initializer");
9400                                                 continue;
9401                                         }
9402
9403                                         if (!is_collection_initialization) {
9404                                                 if (element_names.Contains (element_initializer.Name)) {
9405                                                         ec.Report.Error (1912, element_initializer.Location,
9406                                                                 "An object initializer includes more than one member `{0}' initialization",
9407                                                                 element_initializer.Name);
9408                                                 } else {
9409                                                         element_names.Add (element_initializer.Name);
9410                                                 }
9411                                         }
9412                                 }
9413
9414                                 Expression e = initializer.Resolve (ec);
9415                                 if (e == EmptyExpressionStatement.Instance)
9416                                         initializers.RemoveAt (i--);
9417                                 else
9418                                         initializers [i] = e;
9419                         }
9420
9421                         type = ec.CurrentInitializerVariable.Type;
9422                         if (is_collection_initialization) {
9423                                 if (TypeManager.HasElementType (type)) {
9424                                         ec.Report.Error (1925, loc, "Cannot initialize object of type `{0}' with a collection initializer",
9425                                                 TypeManager.CSharpName (type));
9426                                 }
9427                         }
9428
9429                         eclass = ExprClass.Variable;
9430                         return this;
9431                 }
9432
9433                 public override void Emit (EmitContext ec)
9434                 {
9435                         EmitStatement (ec);
9436                 }
9437
9438                 public override void EmitStatement (EmitContext ec)
9439                 {
9440                         foreach (ExpressionStatement e in initializers)
9441                                 e.EmitStatement (ec);
9442                 }
9443         }
9444
9445         //
9446         // New expression with element/object initializers
9447         //
9448         public class NewInitialize : New
9449         {
9450                 //
9451                 // This class serves as a proxy for variable initializer target instances.
9452                 // A real variable is assigned later when we resolve left side of an
9453                 // assignment
9454                 //
9455                 sealed class InitializerTargetExpression : Expression, IMemoryLocation
9456                 {
9457                         NewInitialize new_instance;
9458
9459                         public InitializerTargetExpression (NewInitialize newInstance)
9460                         {
9461                                 this.type = newInstance.type;
9462                                 this.loc = newInstance.loc;
9463                                 this.eclass = newInstance.eclass;
9464                                 this.new_instance = newInstance;
9465                         }
9466
9467                         public override Expression CreateExpressionTree (ResolveContext ec)
9468                         {
9469                                 // Should not be reached
9470                                 throw new NotSupportedException ("ET");
9471                         }
9472
9473                         protected override Expression DoResolve (ResolveContext ec)
9474                         {
9475                                 return this;
9476                         }
9477
9478                         public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
9479                         {
9480                                 return this;
9481                         }
9482
9483                         public override void Emit (EmitContext ec)
9484                         {
9485                                 Expression e = (Expression) new_instance.instance;
9486                                 e.Emit (ec);
9487                         }
9488
9489                         #region IMemoryLocation Members
9490
9491                         public void AddressOf (EmitContext ec, AddressOp mode)
9492                         {
9493                                 new_instance.instance.AddressOf (ec, mode);
9494                         }
9495
9496                         #endregion
9497                 }
9498
9499                 CollectionOrObjectInitializers initializers;
9500                 IMemoryLocation instance;
9501
9502                 public NewInitialize (FullNamedExpression requested_type, Arguments arguments, CollectionOrObjectInitializers initializers, Location l)
9503                         : base (requested_type, arguments, l)
9504                 {
9505                         this.initializers = initializers;
9506                 }
9507
9508                 protected override IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp Mode)
9509                 {
9510                         instance = base.EmitAddressOf (ec, Mode);
9511
9512                         if (!initializers.IsEmpty)
9513                                 initializers.Emit (ec);
9514
9515                         return instance;
9516                 }
9517
9518                 protected override void CloneTo (CloneContext clonectx, Expression t)
9519                 {
9520                         base.CloneTo (clonectx, t);
9521
9522                         NewInitialize target = (NewInitialize) t;
9523                         target.initializers = (CollectionOrObjectInitializers) initializers.Clone (clonectx);
9524                 }
9525
9526                 public override Expression CreateExpressionTree (ResolveContext ec)
9527                 {
9528                         Arguments args = new Arguments (2);
9529                         args.Add (new Argument (base.CreateExpressionTree (ec)));
9530                         if (!initializers.IsEmpty)
9531                                 args.Add (new Argument (initializers.CreateExpressionTree (ec)));
9532
9533                         return CreateExpressionFactoryCall (ec,
9534                                 initializers.IsCollectionInitializer ? "ListInit" : "MemberInit",
9535                                 args);
9536                 }
9537
9538                 protected override Expression DoResolve (ResolveContext ec)
9539                 {
9540                         Expression e = base.DoResolve (ec);
9541                         if (type == null)
9542                                 return null;
9543
9544                         Expression previous = ec.CurrentInitializerVariable;
9545                         ec.CurrentInitializerVariable = new InitializerTargetExpression (this);
9546                         initializers.Resolve (ec);
9547                         ec.CurrentInitializerVariable = previous;
9548                         return e;
9549                 }
9550
9551                 public override bool Emit (EmitContext ec, IMemoryLocation target)
9552                 {
9553                         bool left_on_stack = base.Emit (ec, target);
9554
9555                         if (initializers.IsEmpty)
9556                                 return left_on_stack;
9557
9558                         LocalTemporary temp = target as LocalTemporary;
9559                         if (temp == null) {
9560                                 if (!left_on_stack) {
9561                                         VariableReference vr = target as VariableReference;
9562
9563                                         // FIXME: This still does not work correctly for pre-set variables
9564                                         if (vr != null && vr.IsRef)
9565                                                 target.AddressOf (ec, AddressOp.Load);
9566
9567                                         ((Expression) target).Emit (ec);
9568                                         left_on_stack = true;
9569                                 }
9570
9571                                 temp = new LocalTemporary (type);
9572                         }
9573
9574                         instance = temp;
9575                         if (left_on_stack)
9576                                 temp.Store (ec);
9577
9578                         initializers.Emit (ec);
9579
9580                         if (left_on_stack) {
9581                                 temp.Emit (ec);
9582                                 temp.Release (ec);
9583                         }
9584
9585                         return left_on_stack;
9586                 }
9587         }
9588
9589         public class NewAnonymousType : New
9590         {
9591                 static readonly AnonymousTypeParameter[] EmptyParameters = new AnonymousTypeParameter[0];
9592
9593                 List<AnonymousTypeParameter> parameters;
9594                 readonly TypeContainer parent;
9595                 AnonymousTypeClass anonymous_type;
9596
9597                 public NewAnonymousType (List<AnonymousTypeParameter> parameters, TypeContainer parent, Location loc)
9598                          : base (null, null, loc)
9599                 {
9600                         this.parameters = parameters;
9601                         this.parent = parent;
9602                 }
9603
9604                 protected override void CloneTo (CloneContext clonectx, Expression target)
9605                 {
9606                         if (parameters == null)
9607                                 return;
9608
9609                         NewAnonymousType t = (NewAnonymousType) target;
9610                         t.parameters = new List<AnonymousTypeParameter> (parameters.Count);
9611                         foreach (AnonymousTypeParameter atp in parameters)
9612                                 t.parameters.Add ((AnonymousTypeParameter) atp.Clone (clonectx));
9613                 }
9614
9615                 AnonymousTypeClass CreateAnonymousType (ResolveContext ec, IList<AnonymousTypeParameter> parameters)
9616                 {
9617                         AnonymousTypeClass type = parent.Module.GetAnonymousType (parameters);
9618                         if (type != null)
9619                                 return type;
9620
9621                         type = AnonymousTypeClass.Create (ec.Compiler, parent, parameters, loc);
9622                         if (type == null)
9623                                 return null;
9624
9625                         type.CreateType ();
9626                         type.DefineType ();
9627                         type.ResolveTypeParameters ();
9628                         type.Define ();
9629                         type.EmitType ();
9630                         if (ec.Report.Errors == 0)
9631                                 type.CloseType ();
9632
9633                         parent.Module.AddAnonymousType (type);
9634                         return type;
9635                 }
9636
9637                 public override Expression CreateExpressionTree (ResolveContext ec)
9638                 {
9639                         if (parameters == null)
9640                                 return base.CreateExpressionTree (ec);
9641
9642                         var init = new ArrayInitializer (parameters.Count, loc);
9643                         foreach (Property p in anonymous_type.Properties)
9644                                 init.Add (new TypeOfMethod (MemberCache.GetMember (type, p.Get.Spec), loc));
9645
9646                         var ctor_args = new ArrayInitializer (arguments.Count, loc);
9647                         foreach (Argument a in arguments)
9648                                 ctor_args.Add (a.CreateExpressionTree (ec));
9649
9650                         Arguments args = new Arguments (3);
9651                         args.Add (new Argument (new TypeOfMethod (method, loc)));
9652                         args.Add (new Argument (new ArrayCreation (CreateExpressionTypeExpression (ec, loc), ctor_args, loc)));
9653                         args.Add (new Argument (new ImplicitlyTypedArrayCreation (init, loc)));
9654
9655                         return CreateExpressionFactoryCall (ec, "New", args);
9656                 }
9657
9658                 protected override Expression DoResolve (ResolveContext ec)
9659                 {
9660                         if (ec.HasSet (ResolveContext.Options.ConstantScope)) {
9661                                 ec.Report.Error (836, loc, "Anonymous types cannot be used in this expression");
9662                                 return null;
9663                         }
9664
9665                         if (parameters == null) {
9666                                 anonymous_type = CreateAnonymousType (ec, EmptyParameters);
9667                                 RequestedType = new TypeExpression (anonymous_type.Definition, loc);
9668                                 return base.DoResolve (ec);
9669                         }
9670
9671                         bool error = false;
9672                         arguments = new Arguments (parameters.Count);
9673                         TypeExpression [] t_args = new TypeExpression [parameters.Count];
9674                         for (int i = 0; i < parameters.Count; ++i) {
9675                                 Expression e = ((AnonymousTypeParameter) parameters [i]).Resolve (ec);
9676                                 if (e == null) {
9677                                         error = true;
9678                                         continue;
9679                                 }
9680
9681                                 arguments.Add (new Argument (e));
9682                                 t_args [i] = new TypeExpression (e.Type, e.Location);
9683                         }
9684
9685                         if (error)
9686                                 return null;
9687
9688                         anonymous_type = CreateAnonymousType (ec, parameters);
9689                         if (anonymous_type == null)
9690                                 return null;
9691
9692                         RequestedType = new GenericTypeExpr (anonymous_type.Definition, new TypeArguments (t_args), loc);
9693                         return base.DoResolve (ec);
9694                 }
9695         }
9696
9697         public class AnonymousTypeParameter : ShimExpression
9698         {
9699                 public readonly string Name;
9700
9701                 public AnonymousTypeParameter (Expression initializer, string name, Location loc)
9702                         : base (initializer)
9703                 {
9704                         this.Name = name;
9705                         this.loc = loc;
9706                 }
9707
9708                 public AnonymousTypeParameter (Parameter parameter)
9709                         : base (new SimpleName (parameter.Name, parameter.Location))
9710                 {
9711                         this.Name = parameter.Name;
9712                         this.loc = parameter.Location;
9713                 }
9714
9715                 public override bool Equals (object o)
9716                 {
9717                         AnonymousTypeParameter other = o as AnonymousTypeParameter;
9718                         return other != null && Name == other.Name;
9719                 }
9720
9721                 public override int GetHashCode ()
9722                 {
9723                         return Name.GetHashCode ();
9724                 }
9725
9726                 protected override Expression DoResolve (ResolveContext ec)
9727                 {
9728                         Expression e = expr.Resolve (ec);
9729                         if (e == null)
9730                                 return null;
9731
9732                         if (e.eclass == ExprClass.MethodGroup) {
9733                                 Error_InvalidInitializer (ec, e.ExprClassName);
9734                                 return null;
9735                         }
9736
9737                         type = e.Type;
9738                         if (type == TypeManager.void_type || type == InternalType.Null ||
9739                                 type == InternalType.AnonymousMethod || type.IsPointer) {
9740                                 Error_InvalidInitializer (ec, e.GetSignatureForError ());
9741                                 return null;
9742                         }
9743
9744                         return e;
9745                 }
9746
9747                 protected virtual void Error_InvalidInitializer (ResolveContext ec, string initializer)
9748                 {
9749                         ec.Report.Error (828, loc, "An anonymous type property `{0}' cannot be initialized with `{1}'",
9750                                 Name, initializer);
9751                 }
9752         }
9753 }