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