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                         Expression e = Convert.ImplicitConversion (ec, expr, type, loc);
1450                         if (e != null){
1451                                 expr = e;
1452                                 return this;
1453                         }
1454
1455                         if (Convert.ExplicitReferenceConversionExists (etype, type)){
1456                                 if (TypeManager.IsGenericParameter (etype))
1457                                         expr = new BoxedCast (expr, etype);
1458
1459                                 do_isinst = true;
1460                                 return this;
1461                         }
1462
1463                         if (TypeManager.ContainsGenericParameters (etype) ||
1464                             TypeManager.ContainsGenericParameters (type)) {
1465                                 expr = new BoxedCast (expr, etype);
1466                                 do_isinst = true;
1467                                 return this;
1468                         }
1469
1470                         // If the compile-time type of E is dynamic, unlike the cast operator the as operator is not dynamically bound
1471                         if (etype == InternalType.Dynamic) {
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                                 if (TypeManager.IsEqual (left, lexpr.Type) &&
1729                                         TypeManager.IsEqual (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 (!TypeManager.IsEqual (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 (TypeManager.IsEqual (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 (!TypeManager.IsEqual (type, type) || !TypeManager.IsEqual (type, pd.Types [0]) || !TypeManager.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 (!TypeManager.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 (Convert.ImplicitConversion (ec, false_expr, true_type, loc) != null) {
4225                                                 ec.Report.Error (172, true_expr.Location,
4226                                                         "Type of conditional expression cannot be determined as `{0}' and `{1}' convert implicitly to each other",
4227                                                         TypeManager.CSharpName (true_type), TypeManager.CSharpName (false_type));
4228                                                 return null;
4229                                         }
4230                                         type = false_type;
4231                                         true_expr = conv;
4232                                 } else if ((conv = Convert.ImplicitConversion (ec, false_expr, true_type, loc)) != null) {
4233                                         false_expr = conv;
4234                                 } else {
4235                                         ec.Report.Error (173, true_expr.Location,
4236                                                 "Type of conditional expression cannot be determined because there is no implicit conversion between `{0}' and `{1}'",
4237                                                 TypeManager.CSharpName (true_type), TypeManager.CSharpName (false_type));
4238                                         return null;
4239                                 }
4240                         }
4241
4242                         // Dead code optimalization
4243                         Constant c = expr as Constant;
4244                         if (c != null){
4245                                 bool is_false = c.IsDefaultValue;
4246                                 ec.Report.Warning (429, 4, is_false ? true_expr.Location : false_expr.Location, "Unreachable expression code detected");
4247                                 return ReducedExpression.Create (is_false ? false_expr : true_expr, this).Resolve (ec);
4248                         }
4249
4250                         return this;
4251                 }
4252
4253                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
4254                 {
4255                         return null;
4256                 }
4257
4258                 public override void Emit (EmitContext ec)
4259                 {
4260                         Label false_target = ec.DefineLabel ();
4261                         Label end_target = ec.DefineLabel ();
4262
4263                         expr.EmitBranchable (ec, false_target, false);
4264                         true_expr.Emit (ec);
4265
4266                         if (type.IsInterface) {
4267                                 LocalBuilder temp = ec.GetTemporaryLocal (type);
4268                                 ec.Emit (OpCodes.Stloc, temp);
4269                                 ec.Emit (OpCodes.Ldloc, temp);
4270                                 ec.FreeTemporaryLocal (temp, type);
4271                         }
4272
4273                         ec.Emit (OpCodes.Br, end_target);
4274                         ec.MarkLabel (false_target);
4275                         false_expr.Emit (ec);
4276                         ec.MarkLabel (end_target);
4277                 }
4278
4279                 protected override void CloneTo (CloneContext clonectx, Expression t)
4280                 {
4281                         Conditional target = (Conditional) t;
4282
4283                         target.expr = expr.Clone (clonectx);
4284                         target.true_expr = true_expr.Clone (clonectx);
4285                         target.false_expr = false_expr.Clone (clonectx);
4286                 }
4287         }
4288
4289         public abstract class VariableReference : Expression, IAssignMethod, IMemoryLocation, IVariableReference {
4290                 LocalTemporary temp;
4291
4292                 #region Abstract
4293                 public abstract HoistedVariable GetHoistedVariable (AnonymousExpression ae);
4294                 public abstract bool IsFixed { get; }
4295                 public abstract bool IsRef { get; }
4296                 public abstract string Name { get; }
4297                 public abstract void SetHasAddressTaken ();
4298
4299                 //
4300                 // Variable IL data, it has to be protected to encapsulate hoisted variables
4301                 //
4302                 protected abstract ILocalVariable Variable { get; }
4303
4304                 //
4305                 // Variable flow-analysis data
4306                 //
4307                 public abstract VariableInfo VariableInfo { get; }
4308                 #endregion
4309
4310                 public virtual void AddressOf (EmitContext ec, AddressOp mode)
4311                 {
4312                         HoistedVariable hv = GetHoistedVariable (ec);
4313                         if (hv != null) {
4314                                 hv.AddressOf (ec, mode);
4315                                 return;
4316                         }
4317
4318                         Variable.EmitAddressOf (ec);
4319                 }
4320
4321                 public HoistedVariable GetHoistedVariable (ResolveContext rc)
4322                 {
4323                         return GetHoistedVariable (rc.CurrentAnonymousMethod);
4324                 }
4325
4326                 public HoistedVariable GetHoistedVariable (EmitContext ec)
4327                 {
4328                         return GetHoistedVariable (ec.CurrentAnonymousMethod);
4329                 }
4330
4331                 public override string GetSignatureForError ()
4332                 {
4333                         return Name;
4334                 }
4335
4336                 public override void Emit (EmitContext ec)
4337                 {
4338                         Emit (ec, false);
4339                 }
4340
4341                 public override void EmitSideEffect (EmitContext ec)
4342                 {
4343                         // do nothing
4344                 }
4345
4346                 //
4347                 // This method is used by parameters that are references, that are
4348                 // being passed as references:  we only want to pass the pointer (that
4349                 // is already stored in the parameter, not the address of the pointer,
4350                 // and not the value of the variable).
4351                 //
4352                 public void EmitLoad (EmitContext ec)
4353                 {
4354                         Variable.Emit (ec);
4355                 }
4356
4357                 public void Emit (EmitContext ec, bool leave_copy)
4358                 {
4359                         Report.Debug (64, "VARIABLE EMIT", this, Variable, type, IsRef, loc);
4360
4361                         HoistedVariable hv = GetHoistedVariable (ec);
4362                         if (hv != null) {
4363                                 hv.Emit (ec, leave_copy);
4364                                 return;
4365                         }
4366
4367                         EmitLoad (ec);
4368
4369                         if (IsRef) {
4370                                 //
4371                                 // If we are a reference, we loaded on the stack a pointer
4372                                 // Now lets load the real value
4373                                 //
4374                                 ec.EmitLoadFromPtr (type);
4375                         }
4376
4377                         if (leave_copy) {
4378                                 ec.Emit (OpCodes.Dup);
4379
4380                                 if (IsRef) {
4381                                         temp = new LocalTemporary (Type);
4382                                         temp.Store (ec);
4383                                 }
4384                         }
4385                 }
4386
4387                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy,
4388                                         bool prepare_for_load)
4389                 {
4390                         HoistedVariable hv = GetHoistedVariable (ec);
4391                         if (hv != null) {
4392                                 hv.EmitAssign (ec, source, leave_copy, prepare_for_load);
4393                                 return;
4394                         }
4395
4396                         New n_source = source as New;
4397                         if (n_source != null) {
4398                                 if (!n_source.Emit (ec, this)) {
4399                                         if (leave_copy) {
4400                                                 EmitLoad (ec);
4401                                                 if (IsRef)
4402                                                         ec.EmitLoadFromPtr (type);
4403                                         }
4404                                         return;
4405                                 }
4406                         } else {
4407                                 if (IsRef)
4408                                         EmitLoad (ec);
4409
4410                                 source.Emit (ec);
4411                         }
4412
4413                         if (leave_copy) {
4414                                 ec.Emit (OpCodes.Dup);
4415                                 if (IsRef) {
4416                                         temp = new LocalTemporary (Type);
4417                                         temp.Store (ec);
4418                                 }
4419                         }
4420
4421                         if (IsRef)
4422                                 ec.EmitStoreFromPtr (type);
4423                         else
4424                                 Variable.EmitAssign (ec);
4425
4426                         if (temp != null) {
4427                                 temp.Emit (ec);
4428                                 temp.Release (ec);
4429                         }
4430                 }
4431
4432                 public bool IsHoisted {
4433                         get { return GetHoistedVariable ((AnonymousExpression) null) != null; }
4434                 }
4435         }
4436
4437         /// <summary>
4438         ///   Local variables
4439         /// </summary>
4440         public class LocalVariableReference : VariableReference {
4441                 readonly string name;
4442                 public Block Block;
4443                 public LocalInfo local_info;
4444                 bool is_readonly;
4445
4446                 public LocalVariableReference (Block block, string name, Location l)
4447                 {
4448                         Block = block;
4449                         this.name = name;
4450                         loc = l;
4451                 }
4452
4453                 //
4454                 // Setting `is_readonly' to false will allow you to create a writable
4455                 // reference to a read-only variable.  This is used by foreach and using.
4456                 //
4457                 public LocalVariableReference (Block block, string name, Location l,
4458                                                LocalInfo local_info, bool is_readonly)
4459                         : this (block, name, l)
4460                 {
4461                         this.local_info = local_info;
4462                         this.is_readonly = is_readonly;
4463                 }
4464
4465                 public override VariableInfo VariableInfo {
4466                         get { return local_info.VariableInfo; }
4467                 }
4468
4469                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
4470                 {
4471                         return local_info.HoistedVariant;
4472                 }
4473
4474                 //
4475                 // A local variable is always fixed
4476                 //
4477                 public override bool IsFixed {
4478                         get { return true; }
4479                 }
4480
4481                 public override bool IsRef {
4482                         get { return false; }
4483                 }
4484
4485                 public bool IsReadOnly {
4486                         get { return is_readonly; }
4487                 }
4488
4489                 public override string Name {
4490                         get { return name; }
4491                 }
4492
4493                 public bool VerifyAssigned (ResolveContext ec)
4494                 {
4495                         VariableInfo variable_info = local_info.VariableInfo;
4496                         return variable_info == null || variable_info.IsAssigned (ec, loc);
4497                 }
4498
4499                 void ResolveLocalInfo ()
4500                 {
4501                         if (local_info == null) {
4502                                 local_info = Block.GetLocalInfo (Name);
4503                                 type = local_info.VariableType;
4504                                 is_readonly = local_info.ReadOnly;
4505                         }
4506                 }
4507
4508                 public override void SetHasAddressTaken ()
4509                 {
4510                         local_info.AddressTaken = true;
4511                 }
4512
4513                 public override Expression CreateExpressionTree (ResolveContext ec)
4514                 {
4515                         HoistedVariable hv = GetHoistedVariable (ec);
4516                         if (hv != null)
4517                                 return hv.CreateExpressionTree ();
4518
4519                         Arguments arg = new Arguments (1);
4520                         arg.Add (new Argument (this));
4521                         return CreateExpressionFactoryCall (ec, "Constant", arg);
4522                 }
4523
4524                 Expression DoResolveBase (ResolveContext ec)
4525                 {
4526                         Expression e = Block.GetConstantExpression (Name);
4527                         if (e != null)
4528                                 return e.Resolve (ec);
4529
4530                         VerifyAssigned (ec);
4531
4532                         //
4533                         // If we are referencing a variable from the external block
4534                         // flag it for capturing
4535                         //
4536                         if (ec.MustCaptureVariable (local_info)) {
4537                                 if (local_info.AddressTaken)
4538                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
4539
4540                                 if (ec.IsVariableCapturingRequired) {
4541                                         AnonymousMethodStorey storey = local_info.Block.Explicit.CreateAnonymousMethodStorey (ec);
4542                                         storey.CaptureLocalVariable (ec, local_info);
4543                                 }
4544                         }
4545
4546                         eclass = ExprClass.Variable;
4547                         type = local_info.VariableType;
4548                         return this;
4549                 }
4550
4551                 protected override Expression DoResolve (ResolveContext ec)
4552                 {
4553                         ResolveLocalInfo ();
4554                         local_info.Used = true;
4555
4556                         if (type == null && local_info.Type is VarExpr) {
4557                             local_info.VariableType = TypeManager.object_type;
4558                                 Error_VariableIsUsedBeforeItIsDeclared (ec.Report, Name);
4559                             return null;
4560                         }
4561
4562                         return DoResolveBase (ec);
4563                 }
4564
4565                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
4566                 {
4567                         ResolveLocalInfo ();
4568
4569                         // is out param
4570                         if (right_side == EmptyExpression.OutAccess.Instance)
4571                                 local_info.Used = true;
4572
4573                         // Infer implicitly typed local variable
4574                         if (type == null) {
4575                                 VarExpr ve = local_info.Type as VarExpr;
4576                                 if (ve != null) {
4577                                         if (!ve.InferType (ec, right_side))
4578                                                 return null;
4579                                         type = local_info.VariableType = ve.Type;
4580                                 }
4581                         }
4582
4583                         if (is_readonly) {
4584                                 int code;
4585                                 string msg;
4586                                 if (right_side == EmptyExpression.OutAccess.Instance) {
4587                                         code = 1657; msg = "Cannot pass `{0}' as a ref or out argument because it is a `{1}'";
4588                                 } else if (right_side == EmptyExpression.LValueMemberAccess) {
4589                                         code = 1654; msg = "Cannot assign to members of `{0}' because it is a `{1}'";
4590                                 } else if (right_side == EmptyExpression.LValueMemberOutAccess) {
4591                                         code = 1655; msg = "Cannot pass members of `{0}' as ref or out arguments because it is a `{1}'";
4592                                 } else if (right_side == EmptyExpression.UnaryAddress) {
4593                                         code = 459; msg = "Cannot take the address of {1} `{0}'";
4594                                 } else {
4595                                         code = 1656; msg = "Cannot assign to `{0}' because it is a `{1}'";
4596                                 }
4597                                 ec.Report.Error (code, loc, msg, Name, local_info.GetReadOnlyContext ());
4598                         } else if (VariableInfo != null) {
4599                                 VariableInfo.SetAssigned (ec);
4600                         }
4601
4602                         return DoResolveBase (ec);
4603                 }
4604
4605                 public override int GetHashCode ()
4606                 {
4607                         return Name.GetHashCode ();
4608                 }
4609
4610                 public override bool Equals (object obj)
4611                 {
4612                         LocalVariableReference lvr = obj as LocalVariableReference;
4613                         if (lvr == null)
4614                                 return false;
4615
4616                         return Name == lvr.Name && Block == lvr.Block;
4617                 }
4618
4619                 protected override ILocalVariable Variable {
4620                         get { return local_info; }
4621                 }
4622
4623                 public override string ToString ()
4624                 {
4625                         return String.Format ("{0} ({1}:{2})", GetType (), Name, loc);
4626                 }
4627
4628                 protected override void CloneTo (CloneContext clonectx, Expression t)
4629                 {
4630                         LocalVariableReference target = (LocalVariableReference) t;
4631
4632                         target.Block = clonectx.LookupBlock (Block);
4633                         if (local_info != null)
4634                                 target.local_info = clonectx.LookupVariable (local_info);
4635                 }
4636         }
4637
4638         /// <summary>
4639         ///   This represents a reference to a parameter in the intermediate
4640         ///   representation.
4641         /// </summary>
4642         public class ParameterReference : VariableReference {
4643                 readonly ToplevelParameterInfo pi;
4644
4645                 public ParameterReference (ToplevelParameterInfo pi, Location loc)
4646                 {
4647                         this.pi = pi;
4648                         this.loc = loc;
4649                 }
4650
4651                 public override bool IsRef {
4652                         get { return (pi.Parameter.ModFlags & Parameter.Modifier.ISBYREF) != 0; }
4653                 }
4654
4655                 bool HasOutModifier {
4656                         get { return pi.Parameter.ModFlags == Parameter.Modifier.OUT; }
4657                 }
4658
4659                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
4660                 {
4661                         return pi.Parameter.HoistedVariant;
4662                 }
4663
4664                 //
4665                 // A ref or out parameter is classified as a moveable variable, even
4666                 // if the argument given for the parameter is a fixed variable
4667                 //
4668                 public override bool IsFixed {
4669                         get { return !IsRef; }
4670                 }
4671
4672                 public override string Name {
4673                         get { return Parameter.Name; }
4674                 }
4675
4676                 public Parameter Parameter {
4677                         get { return pi.Parameter; }
4678                 }
4679
4680                 public override VariableInfo VariableInfo {
4681                         get { return pi.VariableInfo; }
4682                 }
4683
4684                 protected override ILocalVariable Variable {
4685                         get { return Parameter; }
4686                 }
4687
4688                 public bool IsAssigned (ResolveContext ec, Location loc)
4689                 {
4690                         // HACK: Variables are not captured in probing mode
4691                         if (ec.IsInProbingMode)
4692                                 return true;
4693
4694                         if (!ec.DoFlowAnalysis || !HasOutModifier || ec.CurrentBranching.IsAssigned (VariableInfo))
4695                                 return true;
4696
4697                         ec.Report.Error (269, loc, "Use of unassigned out parameter `{0}'", Name);
4698                         return false;
4699                 }
4700
4701                 public override void SetHasAddressTaken ()
4702                 {
4703                         Parameter.HasAddressTaken = true;
4704                 }
4705
4706                 void SetAssigned (ResolveContext ec)
4707                 {
4708                         if (HasOutModifier && ec.DoFlowAnalysis)
4709                                 ec.CurrentBranching.SetAssigned (VariableInfo);
4710                 }
4711
4712                 bool DoResolveBase (ResolveContext ec)
4713                 {
4714                         type = pi.ParameterType;
4715                         eclass = ExprClass.Variable;
4716
4717                         AnonymousExpression am = ec.CurrentAnonymousMethod;
4718                         if (am == null)
4719                                 return true;
4720
4721                         Block b = ec.CurrentBlock;
4722                         while (b != null) {
4723                                 b = b.Toplevel;
4724                                 IParameterData[] p = b.Toplevel.Parameters.FixedParameters;
4725                                 for (int i = 0; i < p.Length; ++i) {
4726                                         if (p [i] != Parameter)
4727                                                 continue;
4728
4729                                         //
4730                                         // Don't capture local parameters
4731                                         //
4732                                         if (b == ec.CurrentBlock.Toplevel && !am.IsIterator)
4733                                                 return true;
4734
4735                                         if (IsRef) {
4736                                                 ec.Report.Error (1628, loc,
4737                                                         "Parameter `{0}' cannot be used inside `{1}' when using `ref' or `out' modifier",
4738                                                         Name, am.ContainerType);
4739                                         }
4740
4741                                         if (pi.Parameter.HasAddressTaken)
4742                                                 AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, this, loc);
4743
4744                                         if (ec.IsVariableCapturingRequired && !b.Toplevel.IsExpressionTree) {
4745                                                 AnonymousMethodStorey storey = pi.Block.CreateAnonymousMethodStorey (ec);
4746                                                 storey.CaptureParameter (ec, this);
4747                                         }
4748
4749                                         return true;
4750                                 }
4751
4752                                 b = b.Parent;
4753                         }
4754
4755                         return true;
4756                 }
4757
4758                 public override int GetHashCode ()
4759                 {
4760                         return Name.GetHashCode ();
4761                 }
4762
4763                 public override bool Equals (object obj)
4764                 {
4765                         ParameterReference pr = obj as ParameterReference;
4766                         if (pr == null)
4767                                 return false;
4768
4769                         return Name == pr.Name;
4770                 }
4771
4772                 public override void AddressOf (EmitContext ec, AddressOp mode)
4773                 {
4774                         //
4775                         // ParameterReferences might already be a reference
4776                         //
4777                         if (IsRef) {
4778                                 EmitLoad (ec);
4779                                 return;
4780                         }
4781
4782                         base.AddressOf (ec, mode);
4783                 }
4784
4785                 protected override void CloneTo (CloneContext clonectx, Expression target)
4786                 {
4787                         // Nothing to clone
4788                 }
4789
4790                 public override Expression CreateExpressionTree (ResolveContext ec)
4791                 {
4792                         HoistedVariable hv = GetHoistedVariable (ec);
4793                         if (hv != null)
4794                                 return hv.CreateExpressionTree ();
4795
4796                         return Parameter.ExpressionTreeVariableReference ();
4797                 }
4798
4799                 //
4800                 // Notice that for ref/out parameters, the type exposed is not the
4801                 // same type exposed externally.
4802                 //
4803                 // for "ref int a":
4804                 //   externally we expose "int&"
4805                 //   here we expose       "int".
4806                 //
4807                 // We record this in "is_ref".  This means that the type system can treat
4808                 // the type as it is expected, but when we generate the code, we generate
4809                 // the alternate kind of code.
4810                 //
4811                 protected override Expression DoResolve (ResolveContext ec)
4812                 {
4813                         if (!DoResolveBase (ec))
4814                                 return null;
4815
4816                         // HACK: Variables are not captured in probing mode
4817                         if (ec.IsInProbingMode)
4818                                 return this;
4819
4820                         if (HasOutModifier && ec.DoFlowAnalysis &&
4821                             (!ec.OmitStructFlowAnalysis || !VariableInfo.TypeInfo.IsStruct) && !IsAssigned (ec, loc))
4822                                 return null;
4823
4824                         return this;
4825                 }
4826
4827                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
4828                 {
4829                         if (!DoResolveBase (ec))
4830                                 return null;
4831
4832                         SetAssigned (ec);
4833                         return this;
4834                 }
4835
4836                 static public void EmitLdArg (EmitContext ec, int x)
4837                 {
4838                         switch (x) {
4839                         case 0: ec.Emit (OpCodes.Ldarg_0); break;
4840                         case 1: ec.Emit (OpCodes.Ldarg_1); break;
4841                         case 2: ec.Emit (OpCodes.Ldarg_2); break;
4842                         case 3: ec.Emit (OpCodes.Ldarg_3); break;
4843                         default:
4844                                 if (x > byte.MaxValue)
4845                                         ec.Emit (OpCodes.Ldarg, x);
4846                                 else
4847                                         ec.Emit (OpCodes.Ldarg_S, (byte) x);
4848                                 break;
4849                         }
4850                 }
4851         }
4852
4853         /// <summary>
4854         ///   Invocation of methods or delegates.
4855         /// </summary>
4856         public class Invocation : ExpressionStatement
4857         {
4858                 protected Arguments arguments;
4859                 protected Expression expr;
4860                 protected MethodGroupExpr mg;
4861
4862                 public Invocation (Expression expr, Arguments arguments)
4863                 {
4864                         this.expr = expr;
4865                         this.arguments = arguments;
4866                         if (expr != null)
4867                                 loc = expr.Location;
4868                 }
4869
4870                 #region Properties
4871                 public Arguments Arguments {
4872                         get {
4873                                 return arguments;
4874                         }
4875                 }
4876
4877                 public Expression Expression {
4878                         get {
4879                                 return expr;
4880                         }
4881                 }
4882                 #endregion
4883
4884                 public override Expression CreateExpressionTree (ResolveContext ec)
4885                 {
4886                         Expression instance = mg.IsInstance ?
4887                                 mg.InstanceExpression.CreateExpressionTree (ec) :
4888                                 new NullLiteral (loc);
4889
4890                         var args = Arguments.CreateForExpressionTree (ec, arguments,
4891                                 instance,
4892                                 mg.CreateExpressionTree (ec));
4893
4894                         return CreateExpressionFactoryCall (ec, "Call", args);
4895                 }
4896
4897                 protected override Expression DoResolve (ResolveContext ec)
4898                 {
4899                         Expression member_expr;
4900                         var atn = expr as ATypeNameExpression;
4901                         if (atn != null) {
4902                                 member_expr = atn.LookupNameExpression (ec, true, true);
4903                                 if (member_expr != null)
4904                                         member_expr = member_expr.Resolve (ec);
4905                         } else {
4906                                 member_expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
4907                         }
4908
4909                         if (member_expr == null)
4910                                 return null;
4911
4912                         //
4913                         // Next, evaluate all the expressions in the argument list
4914                         //
4915                         bool dynamic_arg = false;
4916                         if (arguments != null)
4917                                 arguments.Resolve (ec, out dynamic_arg);
4918
4919                         TypeSpec expr_type = member_expr.Type;
4920                         mg = member_expr as MethodGroupExpr;
4921
4922                         bool dynamic_member = expr_type == InternalType.Dynamic;
4923
4924                         if (!dynamic_member) {
4925                                 Expression invoke = null;
4926
4927                                 if (mg == null) {
4928                                         if (expr_type != null && TypeManager.IsDelegateType (expr_type)) {
4929                                                 invoke = new DelegateInvocation (member_expr, arguments, loc);
4930                                                 invoke = invoke.Resolve (ec);
4931                                                 if (invoke == null || !dynamic_arg)
4932                                                         return invoke;
4933                                         } else {
4934                                                 MemberExpr me = member_expr as MemberExpr;
4935                                                 if (me == null) {
4936                                                         member_expr.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup, loc);
4937                                                         return null;
4938                                                 }
4939
4940                                                 ec.Report.Error (1955, loc, "The member `{0}' cannot be used as method or delegate",
4941                                                                 member_expr.GetSignatureForError ());
4942                                                 return null;
4943                                         }
4944                                 }
4945
4946                                 if (invoke == null) {
4947                                         mg = DoResolveOverload (ec);
4948                                         if (mg == null)
4949                                                 return null;
4950                                 }
4951                         }
4952
4953                         if (dynamic_arg || dynamic_member)
4954                                 return DoResolveDynamic (ec, member_expr);
4955
4956                         var method = mg.BestCandidate;
4957                         if (method != null) {
4958                                 type = method.ReturnType;
4959                         }
4960
4961                         if (arguments == null && method.DeclaringType == TypeManager.object_type && method.Name == Destructor.MetadataName) {
4962                                 if (mg.IsBase)
4963                                         ec.Report.Error (250, loc, "Do not directly call your base class Finalize method. It is called automatically from your destructor");
4964                                 else
4965                                         ec.Report.Error (245, loc, "Destructors and object.Finalize cannot be called directly. Consider calling IDisposable.Dispose if available");
4966                                 return null;
4967                         }
4968
4969                         IsSpecialMethodInvocation (ec, method, loc);
4970
4971                         if (mg.InstanceExpression != null)
4972                                 mg.InstanceExpression.CheckMarshalByRefAccess (ec);
4973
4974                         eclass = ExprClass.Value;
4975                         return this;
4976                 }
4977
4978                 Expression DoResolveDynamic (ResolveContext ec, Expression memberExpr)
4979                 {
4980                         Arguments args;
4981                         DynamicMemberBinder dmb = memberExpr as DynamicMemberBinder;
4982                         if (dmb != null) {
4983                                 args = dmb.Arguments;
4984                                 if (arguments != null)
4985                                         args.AddRange (arguments);
4986                         } else if (mg == null) {
4987                                 if (arguments == null)
4988                                         args = new Arguments (1);
4989                                 else
4990                                         args = arguments;
4991
4992                                 args.Insert (0, new Argument (memberExpr));
4993                                 this.expr = null;
4994                         } else {
4995                                 if (mg.IsBase) {
4996                                         ec.Report.Error (1971, loc,
4997                                                 "The base call to method `{0}' cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access",
4998                                                 mg.Name);
4999                                         return null;
5000                                 }
5001
5002                                 if (arguments == null)
5003                                         args = new Arguments (1);
5004                                 else
5005                                         args = arguments;
5006
5007                                 MemberAccess ma = expr as MemberAccess;
5008                                 if (ma != null) {
5009                                         var left_type = ma.LeftExpression as TypeExpr;
5010                                         if (left_type != null) {
5011                                                 args.Insert (0, new Argument (new TypeOf (left_type, loc).Resolve (ec), Argument.AType.DynamicTypeName));
5012                                         } else {
5013                                                 args.Insert (0, new Argument (ma.LeftExpression.Resolve (ec)));
5014                                         }
5015                                 } else {        // is SimpleName
5016                                         if (ec.IsStatic) {
5017                                                 args.Insert (0, new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc).Resolve (ec), Argument.AType.DynamicTypeName));
5018                                         } else {
5019                                                 args.Insert (0, new Argument (new This (loc).Resolve (ec)));
5020                                         }
5021                                 }
5022                         }
5023
5024                         return new DynamicInvocation (expr as ATypeNameExpression, args, loc).Resolve (ec);
5025                 }
5026
5027                 protected virtual MethodGroupExpr DoResolveOverload (ResolveContext ec)
5028                 {
5029                         return mg.OverloadResolve (ec, ref arguments, null, OverloadResolver.Restrictions.None);
5030                 }
5031
5032                 //
5033                 // If a member is a method or event, or if it is a constant, field or property of either a delegate type
5034                 // or the type dynamic, then the member is invocable
5035                 //
5036                 public static bool IsMemberInvocable (MemberSpec member)
5037                 {
5038                         switch (member.Kind) {
5039                         case MemberKind.Event:
5040                                 return true;
5041                         case MemberKind.Field:
5042                         case MemberKind.Property:
5043                                 var m = member as IInterfaceMemberSpec;
5044                                 return m.MemberType.IsDelegate || m.MemberType == InternalType.Dynamic;
5045                         default:
5046                                 return false;
5047                         }
5048                 }
5049
5050                 public static bool IsSpecialMethodInvocation (ResolveContext ec, MethodSpec method, Location loc)
5051                 {
5052                         if (!method.IsReservedMethod)
5053                                 return false;
5054
5055                         if (ec.HasSet (ResolveContext.Options.InvokeSpecialName) || ec.CurrentMemberDefinition.IsCompilerGenerated)
5056                                 return false;
5057
5058                         ec.Report.SymbolRelatedToPreviousError (method);
5059                         ec.Report.Error (571, loc, "`{0}': cannot explicitly call operator or accessor",
5060                                 method.GetSignatureForError ());
5061
5062                         return true;
5063                 }
5064
5065                 static Type[] GetVarargsTypes (MethodSpec mb, Arguments arguments)
5066                 {
5067                         AParametersCollection pd = mb.Parameters;
5068
5069                         Argument a = arguments [pd.Count - 1];
5070                         Arglist list = (Arglist) a.Expr;
5071
5072                         return list.ArgumentTypes;
5073                 }
5074
5075                 /// <remarks>
5076                 ///   is_base tells whether we want to force the use of the `call'
5077                 ///   opcode instead of using callvirt.  Call is required to call
5078                 ///   a specific method, while callvirt will always use the most
5079                 ///   recent method in the vtable.
5080                 ///
5081                 ///   is_static tells whether this is an invocation on a static method
5082                 ///
5083                 ///   instance_expr is an expression that represents the instance
5084                 ///   it must be non-null if is_static is false.
5085                 ///
5086                 ///   method is the method to invoke.
5087                 ///
5088                 ///   Arguments is the list of arguments to pass to the method or constructor.
5089                 /// </remarks>
5090                 public static void EmitCall (EmitContext ec, Expression instance_expr,
5091                                              MethodSpec method, Arguments Arguments, Location loc)
5092                 {
5093                         EmitCall (ec, instance_expr, method, Arguments, loc, false, false);
5094                 }
5095
5096                 // `dup_args' leaves an extra copy of the arguments on the stack
5097                 // `omit_args' does not leave any arguments at all.
5098                 // So, basically, you could make one call with `dup_args' set to true,
5099                 // and then another with `omit_args' set to true, and the two calls
5100                 // would have the same set of arguments. However, each argument would
5101                 // only have been evaluated once.
5102                 public static void EmitCall (EmitContext ec, Expression instance_expr,
5103                                              MethodSpec method, Arguments Arguments, Location loc,
5104                                              bool dup_args, bool omit_args)
5105                 {
5106                         LocalTemporary this_arg = null;
5107
5108                         TypeSpec decl_type = method.DeclaringType;
5109
5110                         // Speed up the check by not doing it on not allowed targets
5111                         if (method.ReturnType == TypeManager.void_type && method.IsConditionallyExcluded (loc))
5112                                 return;
5113
5114                         OpCode call_op;
5115                         TypeSpec iexpr_type;
5116
5117                         if (method.IsStatic) {
5118                                 iexpr_type = null;
5119                                 call_op = OpCodes.Call;
5120                         } else {
5121                                 iexpr_type = instance_expr.Type;
5122
5123                                 if (decl_type.IsStruct || decl_type.IsEnum || (instance_expr is This && !method.IsVirtual) || (instance_expr is BaseThis)) {
5124                                         call_op = OpCodes.Call;
5125                                 } else {
5126                                         call_op = OpCodes.Callvirt;
5127                                 }
5128
5129                                 //
5130                                 // If this is ourselves, push "this"
5131                                 //
5132                                 if (!omit_args) {
5133                                         TypeSpec t = iexpr_type;
5134
5135                                         //
5136                                         // Push the instance expression
5137                                         //
5138                                         if ((iexpr_type.IsStruct && (call_op == OpCodes.Callvirt || (call_op == OpCodes.Call && decl_type == iexpr_type))) ||
5139                                                 iexpr_type.IsGenericParameter || TypeManager.IsNullableType (decl_type)) {
5140                                                 //
5141                                                 // If the expression implements IMemoryLocation, then
5142                                                 // we can optimize and use AddressOf on the
5143                                                 // return.
5144                                                 //
5145                                                 // If not we have to use some temporary storage for
5146                                                 // it.
5147                                                 var iml = instance_expr as IMemoryLocation;
5148                                                 if (iml != null) {
5149                                                         iml.AddressOf (ec, AddressOp.LoadStore);
5150                                                 } else {
5151                                                         LocalTemporary temp = new LocalTemporary (iexpr_type);
5152                                                         instance_expr.Emit (ec);
5153                                                         temp.Store (ec);
5154                                                         temp.AddressOf (ec, AddressOp.Load);
5155                                                 }
5156
5157                                                 // avoid the overhead of doing this all the time.
5158                                                 if (dup_args)
5159                                                         t = ReferenceContainer.MakeType (iexpr_type);
5160                                         } else if (iexpr_type.IsEnum || iexpr_type.IsStruct) {
5161                                                 instance_expr.Emit (ec);
5162                                                 ec.Emit (OpCodes.Box, iexpr_type);
5163                                                 t = iexpr_type = TypeManager.object_type;
5164                                         } else {
5165                                                 instance_expr.Emit (ec);
5166                                         }
5167
5168                                         if (dup_args) {
5169                                                 ec.Emit (OpCodes.Dup);
5170                                                 if (Arguments != null && Arguments.Count != 0) {
5171                                                         this_arg = new LocalTemporary (t);
5172                                                         this_arg.Store (ec);
5173                                                 }
5174                                         }
5175                                 }
5176                         }
5177
5178                         if (!omit_args && Arguments != null)
5179                                 Arguments.Emit (ec, dup_args, this_arg);
5180
5181                         if (call_op == OpCodes.Callvirt && (iexpr_type.IsGenericParameter || iexpr_type.IsStruct)) {
5182                                 ec.Emit (OpCodes.Constrained, iexpr_type);
5183                         }
5184
5185                         if (method.Parameters.HasArglist) {
5186                                 Type[] varargs_types = GetVarargsTypes (method, Arguments);
5187                                 ec.Emit (call_op, method, varargs_types);
5188                                 return;
5189                         }
5190
5191                         //
5192                         // If you have:
5193                         // this.DoFoo ();
5194                         // and DoFoo is not virtual, you can omit the callvirt,
5195                         // because you don't need the null checking behavior.
5196                         //
5197                         ec.Emit (call_op, method);
5198                 }
5199
5200                 public override void Emit (EmitContext ec)
5201                 {
5202                         mg.EmitCall (ec, arguments);
5203                 }
5204
5205                 public override void EmitStatement (EmitContext ec)
5206                 {
5207                         Emit (ec);
5208
5209                         //
5210                         // Pop the return value if there is one
5211                         //
5212                         if (type != TypeManager.void_type)
5213                                 ec.Emit (OpCodes.Pop);
5214                 }
5215
5216                 protected override void CloneTo (CloneContext clonectx, Expression t)
5217                 {
5218                         Invocation target = (Invocation) t;
5219
5220                         if (arguments != null)
5221                                 target.arguments = arguments.Clone (clonectx);
5222
5223                         target.expr = expr.Clone (clonectx);
5224                 }
5225
5226                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5227                 {
5228                         return MakeExpression (ctx, mg.InstanceExpression, mg.BestCandidate, arguments);
5229                 }
5230
5231                 public static SLE.Expression MakeExpression (BuilderContext ctx, Expression instance, MethodSpec mi, Arguments args)
5232                 {
5233                         var instance_expr = instance == null ? null : instance.MakeExpression (ctx);
5234                         return SLE.Expression.Call (instance_expr, (MethodInfo) mi.GetMetaInfo (), Arguments.MakeExpression (args, ctx));
5235                 }
5236         }
5237
5238         /// <summary>
5239         ///    Implements the new expression
5240         /// </summary>
5241         public class New : ExpressionStatement, IMemoryLocation {
5242                 protected Arguments Arguments;
5243
5244                 //
5245                 // During bootstrap, it contains the RequestedType,
5246                 // but if `type' is not null, it *might* contain a NewDelegate
5247                 // (because of field multi-initialization)
5248                 //
5249                 protected Expression RequestedType;
5250
5251                 protected MethodSpec method;
5252
5253                 public New (Expression requested_type, Arguments arguments, Location l)
5254                 {
5255                         RequestedType = requested_type;
5256                         Arguments = arguments;
5257                         loc = l;
5258                 }
5259
5260                 /// <summary>
5261                 /// Converts complex core type syntax like 'new int ()' to simple constant
5262                 /// </summary>
5263                 public static Constant Constantify (TypeSpec t)
5264                 {
5265                         if (t == TypeManager.int32_type)
5266                                 return new IntConstant (0, Location.Null);
5267                         if (t == TypeManager.uint32_type)
5268                                 return new UIntConstant (0, Location.Null);
5269                         if (t == TypeManager.int64_type)
5270                                 return new LongConstant (0, Location.Null);
5271                         if (t == TypeManager.uint64_type)
5272                                 return new ULongConstant (0, Location.Null);
5273                         if (t == TypeManager.float_type)
5274                                 return new FloatConstant (0, Location.Null);
5275                         if (t == TypeManager.double_type)
5276                                 return new DoubleConstant (0, Location.Null);
5277                         if (t == TypeManager.short_type)
5278                                 return new ShortConstant (0, Location.Null);
5279                         if (t == TypeManager.ushort_type)
5280                                 return new UShortConstant (0, Location.Null);
5281                         if (t == TypeManager.sbyte_type)
5282                                 return new SByteConstant (0, Location.Null);
5283                         if (t == TypeManager.byte_type)
5284                                 return new ByteConstant (0, Location.Null);
5285                         if (t == TypeManager.char_type)
5286                                 return new CharConstant ('\0', Location.Null);
5287                         if (t == TypeManager.bool_type)
5288                                 return new BoolConstant (false, Location.Null);
5289                         if (t == TypeManager.decimal_type)
5290                                 return new DecimalConstant (0, Location.Null);
5291                         if (TypeManager.IsEnumType (t))
5292                                 return new EnumConstant (Constantify (EnumSpec.GetUnderlyingType (t)), t);
5293                         if (TypeManager.IsNullableType (t))
5294                                 return Nullable.LiftedNull.Create (t, Location.Null);
5295
5296                         return null;
5297                 }
5298
5299                 //
5300                 // Checks whether the type is an interface that has the
5301                 // [ComImport, CoClass] attributes and must be treated
5302                 // specially
5303                 //
5304                 public Expression CheckComImport (ResolveContext ec)
5305                 {
5306                         if (!type.IsInterface)
5307                                 return null;
5308
5309                         //
5310                         // Turn the call into:
5311                         // (the-interface-stated) (new class-referenced-in-coclassattribute ())
5312                         //
5313                         var real_class = type.MemberDefinition.GetAttributeCoClass ();
5314                         if (real_class == null)
5315                                 return null;
5316
5317                         New proxy = new New (new TypeExpression (real_class, loc), Arguments, loc);
5318                         Cast cast = new Cast (new TypeExpression (type, loc), proxy, loc);
5319                         return cast.Resolve (ec);
5320                 }
5321
5322                 public override Expression CreateExpressionTree (ResolveContext ec)
5323                 {
5324                         Arguments args;
5325                         if (method == null) {
5326                                 args = new Arguments (1);
5327                                 args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
5328                         } else {
5329                                 args = Arguments.CreateForExpressionTree (ec,
5330                                         Arguments, new TypeOfMethod (method, loc));
5331                         }
5332
5333                         return CreateExpressionFactoryCall (ec, "New", args);
5334                 }
5335
5336                 protected override Expression DoResolve (ResolveContext ec)
5337                 {
5338                         TypeExpr texpr = RequestedType.ResolveAsTypeTerminal (ec, false);
5339                         if (texpr == null)
5340                                 return null;
5341
5342                         type = texpr.Type;
5343                         eclass = ExprClass.Value;
5344
5345                         if (type.IsPointer) {
5346                                 ec.Report.Error (1919, loc, "Unsafe type `{0}' cannot be used in an object creation expression",
5347                                         TypeManager.CSharpName (type));
5348                                 return null;
5349                         }
5350
5351                         if (Arguments == null) {
5352                                 Constant c = Constantify (type);
5353                                 if (c != null)
5354                                         return ReducedExpression.Create (c.Resolve (ec), this);
5355                         }
5356
5357                         if (TypeManager.IsDelegateType (type)) {
5358                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
5359                         }
5360
5361                         var tparam = type as TypeParameterSpec;
5362                         if (tparam != null) {
5363                                 if (!tparam.HasSpecialConstructor && !tparam.HasSpecialStruct) {
5364                                         ec.Report.Error (304, loc,
5365                                                 "Cannot create an instance of the variable type `{0}' because it does not have the new() constraint",
5366                                                 TypeManager.CSharpName (type));
5367                                 }
5368
5369                                 if ((Arguments != null) && (Arguments.Count != 0)) {
5370                                         ec.Report.Error (417, loc,
5371                                                 "`{0}': cannot provide arguments when creating an instance of a variable type",
5372                                                 TypeManager.CSharpName (type));
5373                                 }
5374
5375                                 if (TypeManager.activator_create_instance == null) {
5376                                         TypeSpec activator_type = TypeManager.CoreLookupType (ec.Compiler, "System", "Activator", MemberKind.Class, true);
5377                                         if (activator_type != null) {
5378                                                 TypeManager.activator_create_instance = TypeManager.GetPredefinedMethod (
5379                                                         activator_type, MemberFilter.Method ("CreateInstance", 1, ParametersCompiled.EmptyReadOnlyParameters, null), loc);
5380                                         }
5381                                 }
5382
5383                                 return this;
5384                         }
5385
5386                         if (type.IsStatic) {
5387                                 ec.Report.SymbolRelatedToPreviousError (type);
5388                                 ec.Report.Error (712, loc, "Cannot create an instance of the static class `{0}'", TypeManager.CSharpName (type));
5389                                 return null;
5390                         }
5391
5392                         if (type.IsInterface || type.IsAbstract){
5393                                 if (!TypeManager.IsGenericType (type)) {
5394                                         RequestedType = CheckComImport (ec);
5395                                         if (RequestedType != null)
5396                                                 return RequestedType;
5397                                 }
5398
5399                                 ec.Report.SymbolRelatedToPreviousError (type);
5400                                 ec.Report.Error (144, loc, "Cannot create an instance of the abstract class or interface `{0}'", TypeManager.CSharpName (type));
5401                                 return null;
5402                         }
5403
5404                         //
5405                         // Any struct always defines parameterless constructor
5406                         //
5407                         if (type.IsStruct && Arguments == null)
5408                                 return this;
5409
5410                         bool dynamic;
5411                         if (Arguments != null) {
5412                                 Arguments.Resolve (ec, out dynamic);
5413                         } else {
5414                                 dynamic = false;
5415                         }
5416
5417                         method = ConstructorLookup (ec, type, ref Arguments, loc);
5418
5419                         if (dynamic) {
5420                                 Arguments.Insert (0, new Argument (new TypeOf (texpr, loc).Resolve (ec), Argument.AType.DynamicTypeName));
5421                                 return new DynamicConstructorBinder (type, Arguments, loc).Resolve (ec);
5422                         }
5423
5424                         return this;
5425                 }
5426
5427                 bool DoEmitTypeParameter (EmitContext ec)
5428                 {
5429                         var ctor_factory = TypeManager.activator_create_instance.MakeGenericMethod (type);
5430                         var tparam = (TypeParameterSpec) type;
5431
5432                         if (tparam.IsReferenceType) {
5433                                 ec.Emit (OpCodes.Call, ctor_factory);
5434                                 return true;
5435                         }
5436
5437                         // Allow DoEmit() to be called multiple times.
5438                         // We need to create a new LocalTemporary each time since
5439                         // you can't share LocalBuilders among ILGeneators.
5440                         LocalTemporary temp = new LocalTemporary (type);
5441
5442                         Label label_activator = ec.DefineLabel ();
5443                         Label label_end = ec.DefineLabel ();
5444
5445                         temp.AddressOf (ec, AddressOp.Store);
5446                         ec.Emit (OpCodes.Initobj, type);
5447
5448                         temp.Emit (ec);
5449                         ec.Emit (OpCodes.Box, type);
5450                         ec.Emit (OpCodes.Brfalse, label_activator);
5451
5452                         temp.AddressOf (ec, AddressOp.Store);
5453                         ec.Emit (OpCodes.Initobj, type);
5454                         temp.Emit (ec);
5455                         ec.Emit (OpCodes.Br_S, label_end);
5456
5457                         ec.MarkLabel (label_activator);
5458
5459                         ec.Emit (OpCodes.Call, ctor_factory);
5460                         ec.MarkLabel (label_end);
5461                         return true;
5462                 }
5463
5464                 //
5465                 // This Emit can be invoked in two contexts:
5466                 //    * As a mechanism that will leave a value on the stack (new object)
5467                 //    * As one that wont (init struct)
5468                 //
5469                 // If we are dealing with a ValueType, we have a few
5470                 // situations to deal with:
5471                 //
5472                 //    * The target is a ValueType, and we have been provided
5473                 //      the instance (this is easy, we are being assigned).
5474                 //
5475                 //    * The target of New is being passed as an argument,
5476                 //      to a boxing operation or a function that takes a
5477                 //      ValueType.
5478                 //
5479                 //      In this case, we need to create a temporary variable
5480                 //      that is the argument of New.
5481                 //
5482                 // Returns whether a value is left on the stack
5483                 //
5484                 // *** Implementation note ***
5485                 //
5486                 // To benefit from this optimization, each assignable expression
5487                 // has to manually cast to New and call this Emit.
5488                 //
5489                 // TODO: It's worth to implement it for arrays and fields
5490                 //
5491                 public virtual bool Emit (EmitContext ec, IMemoryLocation target)
5492                 {
5493                         bool is_value_type = TypeManager.IsValueType (type);
5494                         VariableReference vr = target as VariableReference;
5495
5496                         if (target != null && is_value_type && (vr != null || method == null)) {
5497                                 target.AddressOf (ec, AddressOp.Store);
5498                         } else if (vr != null && vr.IsRef) {
5499                                 vr.EmitLoad (ec);
5500                         }
5501
5502                         if (Arguments != null)
5503                                 Arguments.Emit (ec);
5504
5505                         if (is_value_type) {
5506                                 if (method == null) {
5507                                         ec.Emit (OpCodes.Initobj, type);
5508                                         return false;
5509                                 }
5510
5511                                 if (vr != null) {
5512                                         ec.Emit (OpCodes.Call, method);
5513                                         return false;
5514                                 }
5515                         }
5516
5517                         if (type is TypeParameterSpec)
5518                                 return DoEmitTypeParameter (ec);
5519
5520                         ec.Emit (OpCodes.Newobj, method);
5521                         return true;
5522                 }
5523
5524                 public override void Emit (EmitContext ec)
5525                 {
5526                         LocalTemporary v = null;
5527                         if (method == null && TypeManager.IsValueType (type)) {
5528                                 // TODO: Use temporary variable from pool
5529                                 v = new LocalTemporary (type);
5530                         }
5531
5532                         if (!Emit (ec, v))
5533                                 v.Emit (ec);
5534                 }
5535
5536                 public override void EmitStatement (EmitContext ec)
5537                 {
5538                         LocalTemporary v = null;
5539                         if (method == null && TypeManager.IsValueType (type)) {
5540                                 // TODO: Use temporary variable from pool
5541                                 v = new LocalTemporary (type);
5542                         }
5543
5544                         if (Emit (ec, v))
5545                                 ec.Emit (OpCodes.Pop);
5546                 }
5547
5548                 public virtual bool HasInitializer {
5549                         get {
5550                                 return false;
5551                         }
5552                 }
5553
5554                 public void AddressOf (EmitContext ec, AddressOp mode)
5555                 {
5556                         EmitAddressOf (ec, mode);
5557                 }
5558
5559                 protected virtual IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp mode)
5560                 {
5561                         LocalTemporary value_target = new LocalTemporary (type);
5562
5563                         if (type is TypeParameterSpec) {
5564                                 DoEmitTypeParameter (ec);
5565                                 value_target.Store (ec);
5566                                 value_target.AddressOf (ec, mode);
5567                                 return value_target;
5568                         }
5569
5570                         if (!TypeManager.IsStruct (type)){
5571                                 //
5572                                 // We throw an exception.  So far, I believe we only need to support
5573                                 // value types:
5574                                 // foreach (int j in new StructType ())
5575                                 // see bug 42390
5576                                 //
5577                                 throw new Exception ("AddressOf should not be used for classes");
5578                         }
5579
5580                         value_target.AddressOf (ec, AddressOp.Store);
5581
5582                         if (method == null) {
5583                                 ec.Emit (OpCodes.Initobj, type);
5584                         } else {
5585                                 if (Arguments != null)
5586                                         Arguments.Emit (ec);
5587
5588                                 ec.Emit (OpCodes.Call, method);
5589                         }
5590
5591                         value_target.AddressOf (ec, mode);
5592                         return value_target;
5593                 }
5594
5595                 protected override void CloneTo (CloneContext clonectx, Expression t)
5596                 {
5597                         New target = (New) t;
5598
5599                         target.RequestedType = RequestedType.Clone (clonectx);
5600                         if (Arguments != null){
5601                                 target.Arguments = Arguments.Clone (clonectx);
5602                         }
5603                 }
5604
5605                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5606                 {
5607                         return SLE.Expression.New ((ConstructorInfo) method.GetMetaInfo (), Arguments.MakeExpression (Arguments, ctx));
5608                 }
5609         }
5610
5611         public class ArrayInitializer : Expression
5612         {
5613                 List<Expression> elements;
5614
5615                 public ArrayInitializer (List<Expression> init, Location loc)
5616                 {
5617                         elements = init;
5618                         this.loc = loc;
5619                 }
5620
5621                 public ArrayInitializer (int count, Location loc)
5622                 {
5623                         elements = new List<Expression> (count);
5624                         this.loc = loc;
5625                 }
5626
5627                 public ArrayInitializer (Location loc)
5628                         : this (4, loc)
5629                 {
5630                 }
5631
5632                 public void Add (Expression expr)
5633                 {
5634                         elements.Add (expr);
5635                 }
5636
5637                 public override Expression CreateExpressionTree (ResolveContext ec)
5638                 {
5639                         throw new NotSupportedException ("ET");
5640                 }
5641
5642                 protected override void CloneTo (CloneContext clonectx, Expression t)
5643                 {
5644                         var target = (ArrayInitializer) t;
5645
5646                         target.elements = new List<Expression> (elements.Count);
5647                         foreach (var element in elements)
5648                                 target.elements.Add (element.Clone (clonectx));
5649                 }
5650
5651                 public int Count {
5652                         get { return elements.Count; }
5653                 }
5654
5655                 protected override Expression DoResolve (ResolveContext rc)
5656                 {
5657                         var current_field = rc.CurrentMemberDefinition as FieldBase;
5658                         return new ArrayCreation (new TypeExpression (current_field.MemberType, current_field.Location), this).Resolve (rc);
5659                 }
5660
5661                 public override void Emit (EmitContext ec)
5662                 {
5663                         throw new InternalErrorException ("Missing Resolve call");
5664                 }
5665
5666                 public Expression this [int index] {
5667                         get { return elements [index]; }
5668                 }
5669         }
5670
5671         /// <summary>
5672         ///   14.5.10.2: Represents an array creation expression.
5673         /// </summary>
5674         ///
5675         /// <remarks>
5676         ///   There are two possible scenarios here: one is an array creation
5677         ///   expression that specifies the dimensions and optionally the
5678         ///   initialization data and the other which does not need dimensions
5679         ///   specified but where initialization data is mandatory.
5680         /// </remarks>
5681         public class ArrayCreation : Expression
5682         {
5683                 FullNamedExpression requested_base_type;
5684                 ArrayInitializer initializers;
5685
5686                 //
5687                 // The list of Argument types.
5688                 // This is used to construct the `newarray' or constructor signature
5689                 //
5690                 protected List<Expression> arguments;
5691
5692                 protected TypeSpec array_element_type;
5693                 int num_arguments = 0;
5694                 protected int dimensions;
5695                 protected readonly ComposedTypeSpecifier rank;
5696                 Expression first_emit;
5697                 LocalTemporary first_emit_temp;
5698
5699                 protected List<Expression> array_data;
5700
5701                 Dictionary<int, int> bounds;
5702
5703                 // The number of constants in array initializers
5704                 int const_initializers_count;
5705                 bool only_constant_initializers;
5706
5707                 public ArrayCreation (FullNamedExpression requested_base_type, List<Expression> exprs, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location l)
5708                         : this (requested_base_type, rank, initializers, l)
5709                 {
5710                         arguments = new List<Expression> (exprs);
5711                         num_arguments = arguments.Count;
5712                 }
5713
5714                 //
5715                 // For expressions like int[] foo = new int[] { 1, 2, 3 };
5716                 //
5717                 public ArrayCreation (FullNamedExpression requested_base_type, ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
5718                 {
5719                         this.requested_base_type = requested_base_type;
5720                         this.rank = rank;
5721                         this.initializers = initializers;
5722                         this.loc = loc;
5723
5724                         if (rank != null)
5725                                 num_arguments = rank.Dimension;
5726                 }
5727
5728                 //
5729                 // For compiler generated single dimensional arrays only
5730                 //
5731                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers, Location loc)
5732                         : this (requested_base_type, ComposedTypeSpecifier.SingleDimension, initializers, loc)
5733                 {
5734                 }
5735
5736                 //
5737                 // For expressions like int[] foo = { 1, 2, 3 };
5738                 //
5739                 public ArrayCreation (FullNamedExpression requested_base_type, ArrayInitializer initializers)
5740                         : this (requested_base_type, null, initializers, initializers.Location)
5741                 {
5742                 }
5743
5744                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
5745                 {
5746                         ec.Report.Error (248, loc, "Cannot create an array with a negative size");
5747                 }
5748
5749                 bool CheckIndices (ResolveContext ec, ArrayInitializer probe, int idx, bool specified_dims, int child_bounds)
5750                 {
5751                         if (initializers != null && bounds == null) {
5752                                 //
5753                                 // We use this to store all the date values in the order in which we
5754                                 // will need to store them in the byte blob later
5755                                 //
5756                                 array_data = new List<Expression> ();
5757                                 bounds = new Dictionary<int, int> ();
5758                         }
5759
5760                         if (specified_dims) {
5761                                 Expression a = arguments [idx];
5762                                 a = a.Resolve (ec);
5763                                 if (a == null)
5764                                         return false;
5765
5766                                 a = ConvertExpressionToArrayIndex (ec, a);
5767                                 if (a == null)
5768                                         return false;
5769
5770                                 arguments[idx] = a;
5771
5772                                 if (initializers != null) {
5773                                         Constant c = a as Constant;
5774                                         if (c == null && a is ArrayIndexCast)
5775                                                 c = ((ArrayIndexCast) a).Child as Constant;
5776
5777                                         if (c == null) {
5778                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
5779                                                 return false;
5780                                         }
5781
5782                                         int value;
5783                                         try {
5784                                                 value = System.Convert.ToInt32 (c.GetValue ());
5785                                         } catch {
5786                                                 ec.Report.Error (150, a.Location, "A constant value is expected");
5787                                                 return false;
5788                                         }
5789
5790                                         // TODO: probe.Count does not fit ulong in
5791                                         if (value != probe.Count) {
5792                                                 ec.Report.Error (847, loc, "An array initializer of length `{0}' was expected", value.ToString ());
5793                                                 return false;
5794                                         }
5795
5796                                         bounds[idx] = value;
5797                                 }
5798                         }
5799
5800                         if (initializers == null)
5801                                 return true;
5802
5803                         only_constant_initializers = true;
5804                         for (int i = 0; i < probe.Count; ++i) {
5805                                 var o = probe [i];
5806                                 if (o is ArrayInitializer) {
5807                                         var sub_probe = o as ArrayInitializer;
5808                                         if (idx + 1 >= dimensions){
5809                                                 ec.Report.Error (623, loc, "Array initializers can only be used in a variable or field initializer. Try using a new expression instead");
5810                                                 return false;
5811                                         }
5812
5813                                         bool ret = CheckIndices (ec, sub_probe, idx + 1, specified_dims, child_bounds - 1);
5814                                         if (!ret)
5815                                                 return false;
5816                                 } else if (child_bounds > 1) {
5817                                         ec.Report.Error (846, o.Location, "A nested array initializer was expected");
5818                                 } else {
5819                                         Expression element = ResolveArrayElement (ec, o);
5820                                         if (element == null)
5821                                                 continue;
5822
5823                                         // Initializers with the default values can be ignored
5824                                         Constant c = element as Constant;
5825                                         if (c != null) {
5826                                                 if (!c.IsDefaultInitializer (array_element_type)) {
5827                                                         ++const_initializers_count;
5828                                                 }
5829                                         } else {
5830                                                 only_constant_initializers = false;
5831                                         }
5832
5833                                         array_data.Add (element);
5834                                 }
5835                         }
5836
5837                         return true;
5838                 }
5839
5840                 public override Expression CreateExpressionTree (ResolveContext ec)
5841                 {
5842                         Arguments args;
5843
5844                         if (array_data == null) {
5845                                 args = new Arguments (arguments.Count + 1);
5846                                 args.Add (new Argument (new TypeOf (new TypeExpression (array_element_type, loc), loc)));
5847                                 foreach (Expression a in arguments)
5848                                         args.Add (new Argument (a.CreateExpressionTree (ec)));
5849
5850                                 return CreateExpressionFactoryCall (ec, "NewArrayBounds", args);
5851                         }
5852
5853                         if (dimensions > 1) {
5854                                 ec.Report.Error (838, loc, "An expression tree cannot contain a multidimensional array initializer");
5855                                 return null;
5856                         }
5857
5858                         args = new Arguments (array_data == null ? 1 : array_data.Count + 1);
5859                         args.Add (new Argument (new TypeOf (new TypeExpression (array_element_type, loc), loc)));
5860                         if (array_data != null) {
5861                                 for (int i = 0; i < array_data.Count; ++i) {
5862                                         Expression e = array_data [i];
5863                                         args.Add (new Argument (e.CreateExpressionTree (ec)));
5864                                 }
5865                         }
5866
5867                         return CreateExpressionFactoryCall (ec, "NewArrayInit", args);
5868                 }
5869
5870                 public void UpdateIndices ()
5871                 {
5872                         int i = 0;
5873                         for (var probe = initializers; probe != null;) {
5874                                 if (probe.Count > 0 && probe [0] is ArrayInitializer) {
5875                                         Expression e = new IntConstant (probe.Count, Location.Null);
5876                                         arguments.Add (e);
5877
5878                                         bounds [i++] = probe.Count;
5879
5880                                         probe = (ArrayInitializer) probe[0];
5881
5882                                 } else {
5883                                         Expression e = new IntConstant (probe.Count, Location.Null);
5884                                         arguments.Add (e);
5885
5886                                         bounds [i++] = probe.Count;
5887                                         return;
5888                                 }
5889                         }
5890                 }
5891
5892                 protected virtual Expression ResolveArrayElement (ResolveContext ec, Expression element)
5893                 {
5894                         element = element.Resolve (ec);
5895                         if (element == null)
5896                                 return null;
5897
5898                         if (element is CompoundAssign.TargetExpression) {
5899                                 if (first_emit != null)
5900                                         throw new InternalErrorException ("Can only handle one mutator at a time");
5901                                 first_emit = element;
5902                                 element = first_emit_temp = new LocalTemporary (element.Type);
5903                         }
5904
5905                         return Convert.ImplicitConversionRequired (
5906                                 ec, element, array_element_type, loc);
5907                 }
5908
5909                 protected bool ResolveInitializers (ResolveContext ec)
5910                 {
5911                         if (arguments != null) {
5912                                 bool res = true;
5913                                 for (int i = 0; i < arguments.Count; ++i) {
5914                                         res &= CheckIndices (ec, initializers, i, true, dimensions);
5915                                         if (initializers != null)
5916                                                 break;
5917                                 }
5918
5919                                 return res;
5920                         }
5921
5922                         arguments = new List<Expression> ();
5923
5924                         if (!CheckIndices (ec, initializers, 0, false, dimensions))
5925                                 return false;
5926
5927                         UpdateIndices ();
5928
5929                         return true;
5930                 }
5931
5932                 //
5933                 // Resolved the type of the array
5934                 //
5935                 bool ResolveArrayType (ResolveContext ec)
5936                 {
5937                         if (requested_base_type is VarExpr) {
5938                                 ec.Report.Error (820, loc, "An implicitly typed local variable declarator cannot use an array initializer");
5939                                 return false;
5940                         }
5941
5942                         //
5943                         // Lookup the type
5944                         //
5945                         FullNamedExpression array_type_expr;
5946                         if (num_arguments > 0) {
5947                                 array_type_expr = new ComposedCast (requested_base_type, rank);
5948                         } else {
5949                                 array_type_expr = requested_base_type;
5950                         }
5951
5952                         array_type_expr = array_type_expr.ResolveAsTypeTerminal (ec, false);
5953                         if (array_type_expr == null)
5954                                 return false;
5955
5956                         type = array_type_expr.Type;
5957                         var ac = type as ArrayContainer;
5958                         if (ac == null) {
5959                                 ec.Report.Error (622, loc, "Can only use array initializer expressions to assign to array types. Try using a new expression instead");
5960                                 return false;
5961                         }
5962
5963                         array_element_type = ac.Element;
5964                         dimensions = ac.Rank;
5965
5966                         return true;
5967                 }
5968
5969                 protected override Expression DoResolve (ResolveContext ec)
5970                 {
5971                         if (type != null)
5972                                 return this;
5973
5974                         if (!ResolveArrayType (ec))
5975                                 return null;
5976
5977                         //
5978                         // validate the initializers and fill in any missing bits
5979                         //
5980                         if (!ResolveInitializers (ec))
5981                                 return null;
5982
5983                         eclass = ExprClass.Value;
5984                         return this;
5985                 }
5986
5987                 byte [] MakeByteBlob ()
5988                 {
5989                         int factor;
5990                         byte [] data;
5991                         byte [] element;
5992                         int count = array_data.Count;
5993
5994                         TypeSpec element_type = array_element_type;
5995                         if (TypeManager.IsEnumType (element_type))
5996                                 element_type = EnumSpec.GetUnderlyingType (element_type);
5997
5998                         factor = GetTypeSize (element_type);
5999                         if (factor == 0)
6000                                 throw new Exception ("unrecognized type in MakeByteBlob: " + element_type);
6001
6002                         data = new byte [(count * factor + 3) & ~3];
6003                         int idx = 0;
6004
6005                         for (int i = 0; i < count; ++i) {
6006                                 object v = array_data [i];
6007
6008                                 if (v is EnumConstant)
6009                                         v = ((EnumConstant) v).Child;
6010
6011                                 if (v is Constant && !(v is StringConstant))
6012                                         v = ((Constant) v).GetValue ();
6013                                 else {
6014                                         idx += factor;
6015                                         continue;
6016                                 }
6017
6018                                 if (element_type == TypeManager.int64_type){
6019                                         if (!(v is Expression)){
6020                                                 long val = (long) v;
6021
6022                                                 for (int j = 0; j < factor; ++j) {
6023                                                         data [idx + j] = (byte) (val & 0xFF);
6024                                                         val = (val >> 8);
6025                                                 }
6026                                         }
6027                                 } else if (element_type == TypeManager.uint64_type){
6028                                         if (!(v is Expression)){
6029                                                 ulong val = (ulong) v;
6030
6031                                                 for (int j = 0; j < factor; ++j) {
6032                                                         data [idx + j] = (byte) (val & 0xFF);
6033                                                         val = (val >> 8);
6034                                                 }
6035                                         }
6036                                 } else if (element_type == TypeManager.float_type) {
6037                                         if (!(v is Expression)){
6038                                                 element = BitConverter.GetBytes ((float) v);
6039
6040                                                 for (int j = 0; j < factor; ++j)
6041                                                         data [idx + j] = element [j];
6042                                                 if (!BitConverter.IsLittleEndian)
6043                                                         System.Array.Reverse (data, idx, 4);
6044                                         }
6045                                 } else if (element_type == TypeManager.double_type) {
6046                                         if (!(v is Expression)){
6047                                                 element = BitConverter.GetBytes ((double) v);
6048
6049                                                 for (int j = 0; j < factor; ++j)
6050                                                         data [idx + j] = element [j];
6051
6052                                                 // FIXME: Handle the ARM float format.
6053                                                 if (!BitConverter.IsLittleEndian)
6054                                                         System.Array.Reverse (data, idx, 8);
6055                                         }
6056                                 } else if (element_type == TypeManager.char_type){
6057                                         if (!(v is Expression)){
6058                                                 int val = (int) ((char) v);
6059
6060                                                 data [idx] = (byte) (val & 0xff);
6061                                                 data [idx+1] = (byte) (val >> 8);
6062                                         }
6063                                 } else if (element_type == TypeManager.short_type){
6064                                         if (!(v is Expression)){
6065                                                 int val = (int) ((short) v);
6066
6067                                                 data [idx] = (byte) (val & 0xff);
6068                                                 data [idx+1] = (byte) (val >> 8);
6069                                         }
6070                                 } else if (element_type == TypeManager.ushort_type){
6071                                         if (!(v is Expression)){
6072                                                 int val = (int) ((ushort) v);
6073
6074                                                 data [idx] = (byte) (val & 0xff);
6075                                                 data [idx+1] = (byte) (val >> 8);
6076                                         }
6077                                 } else if (element_type == TypeManager.int32_type) {
6078                                         if (!(v is Expression)){
6079                                                 int val = (int) v;
6080
6081                                                 data [idx]   = (byte) (val & 0xff);
6082                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6083                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6084                                                 data [idx+3] = (byte) (val >> 24);
6085                                         }
6086                                 } else if (element_type == TypeManager.uint32_type) {
6087                                         if (!(v is Expression)){
6088                                                 uint val = (uint) v;
6089
6090                                                 data [idx]   = (byte) (val & 0xff);
6091                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
6092                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
6093                                                 data [idx+3] = (byte) (val >> 24);
6094                                         }
6095                                 } else if (element_type == TypeManager.sbyte_type) {
6096                                         if (!(v is Expression)){
6097                                                 sbyte val = (sbyte) v;
6098                                                 data [idx] = (byte) val;
6099                                         }
6100                                 } else if (element_type == TypeManager.byte_type) {
6101                                         if (!(v is Expression)){
6102                                                 byte val = (byte) v;
6103                                                 data [idx] = (byte) val;
6104                                         }
6105                                 } else if (element_type == TypeManager.bool_type) {
6106                                         if (!(v is Expression)){
6107                                                 bool val = (bool) v;
6108                                                 data [idx] = (byte) (val ? 1 : 0);
6109                                         }
6110                                 } else if (element_type == TypeManager.decimal_type){
6111                                         if (!(v is Expression)){
6112                                                 int [] bits = Decimal.GetBits ((decimal) v);
6113                                                 int p = idx;
6114
6115                                                 // FIXME: For some reason, this doesn't work on the MS runtime.
6116                                                 int [] nbits = new int [4];
6117                                                 nbits [0] = bits [3];
6118                                                 nbits [1] = bits [2];
6119                                                 nbits [2] = bits [0];
6120                                                 nbits [3] = bits [1];
6121
6122                                                 for (int j = 0; j < 4; j++){
6123                                                         data [p++] = (byte) (nbits [j] & 0xff);
6124                                                         data [p++] = (byte) ((nbits [j] >> 8) & 0xff);
6125                                                         data [p++] = (byte) ((nbits [j] >> 16) & 0xff);
6126                                                         data [p++] = (byte) (nbits [j] >> 24);
6127                                                 }
6128                                         }
6129                                 } else {
6130                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + element_type);
6131                                 }
6132
6133                                 idx += factor;
6134                         }
6135
6136                         return data;
6137                 }
6138
6139 #if NET_4_0
6140                 public override SLE.Expression MakeExpression (BuilderContext ctx)
6141                 {
6142                         var initializers = new SLE.Expression [array_data.Count];
6143                         for (var i = 0; i < initializers.Length; i++) {
6144                                 if (array_data [i] == null)
6145                                         initializers [i] = SLE.Expression.Default (array_element_type.GetMetaInfo ());
6146                                 else
6147                                         initializers [i] = array_data [i].MakeExpression (ctx);
6148                         }
6149
6150                         return SLE.Expression.NewArrayInit (array_element_type.GetMetaInfo (), initializers);
6151                 }
6152 #endif
6153                 //
6154                 // Emits the initializers for the array
6155                 //
6156                 void EmitStaticInitializers (EmitContext ec)
6157                 {
6158                         // FIXME: This should go to Resolve !
6159                         if (TypeManager.void_initializearray_array_fieldhandle == null) {
6160                                 TypeManager.void_initializearray_array_fieldhandle = TypeManager.GetPredefinedMethod (
6161                                         TypeManager.runtime_helpers_type, "InitializeArray", loc,
6162                                         TypeManager.array_type, TypeManager.runtime_field_handle_type);
6163                                 if (TypeManager.void_initializearray_array_fieldhandle == null)
6164                                         return;
6165                         }
6166
6167                         //
6168                         // First, the static data
6169                         //
6170                         FieldBuilder fb;
6171
6172                         byte [] data = MakeByteBlob ();
6173
6174                         fb = RootContext.MakeStaticData (data);
6175
6176                         ec.Emit (OpCodes.Dup);
6177                         ec.Emit (OpCodes.Ldtoken, fb);
6178                         ec.Emit (OpCodes.Call, TypeManager.void_initializearray_array_fieldhandle);
6179                 }
6180
6181                 //
6182                 // Emits pieces of the array that can not be computed at compile
6183                 // time (variables and string locations).
6184                 //
6185                 // This always expect the top value on the stack to be the array
6186                 //
6187                 void EmitDynamicInitializers (EmitContext ec, bool emitConstants)
6188                 {
6189                         int dims = bounds.Count;
6190                         var current_pos = new int [dims];
6191
6192                         for (int i = 0; i < array_data.Count; i++){
6193
6194                                 Expression e = array_data [i];
6195                                 var c = e as Constant;
6196
6197                                 // Constant can be initialized via StaticInitializer
6198                                 if (c == null || (c != null && emitConstants && !c.IsDefaultInitializer (array_element_type))) {
6199                                         TypeSpec etype = e.Type;
6200
6201                                         ec.Emit (OpCodes.Dup);
6202
6203                                         for (int idx = 0; idx < dims; idx++)
6204                                                 ec.EmitInt (current_pos [idx]);
6205
6206                                         //
6207                                         // If we are dealing with a struct, get the
6208                                         // address of it, so we can store it.
6209                                         //
6210                                         if ((dims == 1) && TypeManager.IsStruct (etype) &&
6211                                             (!TypeManager.IsBuiltinOrEnum (etype) ||
6212                                              etype == TypeManager.decimal_type)) {
6213
6214                                                 ec.Emit (OpCodes.Ldelema, etype);
6215                                         }
6216
6217                                         e.Emit (ec);
6218
6219                                         ec.EmitArrayStore ((ArrayContainer) type);
6220                                 }
6221
6222                                 //
6223                                 // Advance counter
6224                                 //
6225                                 for (int j = dims - 1; j >= 0; j--){
6226                                         current_pos [j]++;
6227                                         if (current_pos [j] < bounds [j])
6228                                                 break;
6229                                         current_pos [j] = 0;
6230                                 }
6231                         }
6232                 }
6233
6234                 public override void Emit (EmitContext ec)
6235                 {
6236                         if (first_emit != null) {
6237                                 first_emit.Emit (ec);
6238                                 first_emit_temp.Store (ec);
6239                         }
6240
6241                         foreach (Expression e in arguments)
6242                                 e.Emit (ec);
6243
6244                         ec.EmitArrayNew ((ArrayContainer) type);
6245
6246                         if (initializers == null)
6247                                 return;
6248
6249                         // Emit static initializer for arrays which have contain more than 2 items and
6250                         // the static initializer will initialize at least 25% of array values.
6251                         // NOTE: const_initializers_count does not contain default constant values.
6252                         if (const_initializers_count > 2 && const_initializers_count * 4 > (array_data.Count) &&
6253                                 (TypeManager.IsPrimitiveType (array_element_type) || TypeManager.IsEnumType (array_element_type))) {
6254                                 EmitStaticInitializers (ec);
6255
6256                                 if (!only_constant_initializers)
6257                                         EmitDynamicInitializers (ec, false);
6258                         } else {
6259                                 EmitDynamicInitializers (ec, true);
6260                         }
6261
6262                         if (first_emit_temp != null)
6263                                 first_emit_temp.Release (ec);
6264                 }
6265
6266                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
6267                 {
6268                         // no multi dimensional or jagged arrays
6269                         if (arguments.Count != 1 || array_element_type.IsArray) {
6270                                 base.EncodeAttributeValue (rc, enc, targetType);
6271                                 return;
6272                         }
6273
6274                         // No array covariance, except for array -> object
6275                         if (type != targetType) {
6276                                 if (targetType != TypeManager.object_type) {
6277                                         base.EncodeAttributeValue (rc, enc, targetType);
6278                                         return;
6279                                 }
6280
6281                                 enc.Encode (type);
6282                         }
6283
6284                         // Single dimensional array of 0 size
6285                         if (array_data == null) {
6286                                 IntConstant ic = arguments[0] as IntConstant;
6287                                 if (ic == null || !ic.IsDefaultValue) {
6288                                         base.EncodeAttributeValue (rc, enc, targetType);
6289                                 } else {
6290                                         enc.Stream.Write (0);
6291                                 }
6292
6293                                 return;
6294                         }
6295
6296                         enc.Stream.Write ((int) array_data.Count);
6297                         foreach (var element in array_data) {
6298                                 element.EncodeAttributeValue (rc, enc, array_element_type);
6299                         }
6300                 }
6301
6302                 protected override void CloneTo (CloneContext clonectx, Expression t)
6303                 {
6304                         ArrayCreation target = (ArrayCreation) t;
6305
6306                         if (requested_base_type != null)
6307                                 target.requested_base_type = (FullNamedExpression)requested_base_type.Clone (clonectx);
6308
6309                         if (arguments != null){
6310                                 target.arguments = new List<Expression> (arguments.Count);
6311                                 foreach (Expression e in arguments)
6312                                         target.arguments.Add (e.Clone (clonectx));
6313                         }
6314
6315                         if (initializers != null)
6316                                 target.initializers = (ArrayInitializer) initializers.Clone (clonectx);
6317                 }
6318         }
6319
6320         //
6321         // Represents an implicitly typed array epxression
6322         //
6323         class ImplicitlyTypedArrayCreation : ArrayCreation
6324         {
6325                 public ImplicitlyTypedArrayCreation (ComposedTypeSpecifier rank, ArrayInitializer initializers, Location loc)
6326                         : base (null, rank, initializers, loc)
6327                 {
6328                 }
6329
6330                 public ImplicitlyTypedArrayCreation (ArrayInitializer initializers, Location loc)
6331                         : base (null, initializers, loc)
6332                 {
6333                 }
6334
6335                 protected override Expression DoResolve (ResolveContext ec)
6336                 {
6337                         if (type != null)
6338                                 return this;
6339
6340                         dimensions = rank.Dimension;
6341
6342                         if (!ResolveInitializers (ec))
6343                                 return null;
6344
6345                         if (array_element_type == null || array_element_type == TypeManager.null_type ||
6346                                 array_element_type == TypeManager.void_type || array_element_type == InternalType.AnonymousMethod ||
6347                                 array_element_type == InternalType.MethodGroup ||
6348                                 arguments.Count != rank.Dimension) {
6349                                 Error_NoBestType (ec);
6350                                 return null;
6351                         }
6352
6353                         //
6354                         // At this point we found common base type for all initializer elements
6355                         // but we have to be sure that all static initializer elements are of
6356                         // same type
6357                         //
6358                         UnifyInitializerElement (ec);
6359
6360                         type = ArrayContainer.MakeType (array_element_type, dimensions);
6361                         eclass = ExprClass.Value;
6362                         return this;
6363                 }
6364
6365                 void Error_NoBestType (ResolveContext ec)
6366                 {
6367                         ec.Report.Error (826, loc,
6368                                 "The type of an implicitly typed array cannot be inferred from the initializer. Try specifying array type explicitly");
6369                 }
6370
6371                 //
6372                 // Converts static initializer only
6373                 //
6374                 void UnifyInitializerElement (ResolveContext ec)
6375                 {
6376                         for (int i = 0; i < array_data.Count; ++i) {
6377                                 Expression e = (Expression)array_data[i];
6378                                 if (e != null)
6379                                         array_data [i] = Convert.ImplicitConversion (ec, e, array_element_type, Location.Null);
6380                         }
6381                 }
6382
6383                 protected override Expression ResolveArrayElement (ResolveContext ec, Expression element)
6384                 {
6385                         element = element.Resolve (ec);
6386                         if (element == null)
6387                                 return null;
6388
6389                         if (array_element_type == null) {
6390                                 if (element.Type != TypeManager.null_type)
6391                                         array_element_type = element.Type;
6392
6393                                 return element;
6394                         }
6395
6396                         if (Convert.ImplicitConversionExists (ec, element, array_element_type)) {
6397                                 return element;
6398                         }
6399
6400                         if (Convert.ImplicitConversionExists (ec, new TypeExpression (array_element_type, loc), element.Type)) {
6401                                 array_element_type = element.Type;
6402                                 return element;
6403                         }
6404
6405                         Error_NoBestType (ec);
6406                         return null;
6407                 }
6408         }
6409
6410         public sealed class CompilerGeneratedThis : This
6411         {
6412                 public static This Instance = new CompilerGeneratedThis ();
6413
6414                 private CompilerGeneratedThis ()
6415                         : base (Location.Null)
6416                 {
6417                 }
6418
6419                 public CompilerGeneratedThis (TypeSpec type, Location loc)
6420                         : base (loc)
6421                 {
6422                         this.type = type;
6423                 }
6424
6425                 protected override Expression DoResolve (ResolveContext ec)
6426                 {
6427                         eclass = ExprClass.Variable;
6428                         if (type == null)
6429                                 type = ec.CurrentType;
6430
6431                         return this;
6432                 }
6433
6434                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6435                 {
6436                         return null;
6437                 }
6438         }
6439
6440         /// <summary>
6441         ///   Represents the `this' construct
6442         /// </summary>
6443
6444         public class This : VariableReference
6445         {
6446                 sealed class ThisVariable : ILocalVariable
6447                 {
6448                         public static readonly ILocalVariable Instance = new ThisVariable ();
6449
6450                         public void Emit (EmitContext ec)
6451                         {
6452                                 ec.Emit (OpCodes.Ldarg_0);
6453                         }
6454
6455                         public void EmitAssign (EmitContext ec)
6456                         {
6457                                 throw new InvalidOperationException ();
6458                         }
6459
6460                         public void EmitAddressOf (EmitContext ec)
6461                         {
6462                                 ec.Emit (OpCodes.Ldarg_0);
6463                         }
6464                 }
6465
6466                 VariableInfo variable_info;
6467
6468                 public This (Location loc)
6469                 {
6470                         this.loc = loc;
6471                 }
6472
6473                 #region Properties
6474
6475                 public override string Name {
6476                         get { return "this"; }
6477                 }
6478
6479                 public override bool IsRef {
6480                         get { return type.IsStruct; }
6481                 }
6482
6483                 protected override ILocalVariable Variable {
6484                         get { return ThisVariable.Instance; }
6485                 }
6486
6487                 public override VariableInfo VariableInfo {
6488                         get { return variable_info; }
6489                 }
6490
6491                 public override bool IsFixed {
6492                         get { return false; }
6493                 }
6494
6495                 #endregion
6496
6497                 protected virtual void Error_ThisNotAvailable (ResolveContext ec)
6498                 {
6499                         if (ec.IsStatic && !ec.HasSet (ResolveContext.Options.ConstantScope)) {
6500                                 ec.Report.Error (26, loc, "Keyword `this' is not valid in a static property, static method, or static field initializer");
6501                         } else if (ec.CurrentAnonymousMethod != null) {
6502                                 ec.Report.Error (1673, loc,
6503                                         "Anonymous methods inside structs cannot access instance members of `this'. " +
6504                                         "Consider copying `this' to a local variable outside the anonymous method and using the local instead");
6505                         } else {
6506                                 ec.Report.Error (27, loc, "Keyword `this' is not available in the current context");
6507                         }
6508                 }
6509
6510                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6511                 {
6512                         if (ae == null)
6513                                 return null;
6514
6515                         AnonymousMethodStorey storey = ae.Storey;
6516                         while (storey != null) {
6517                                 AnonymousMethodStorey temp = storey.Parent as AnonymousMethodStorey;
6518                                 if (temp == null)
6519                                         return storey.HoistedThis;
6520
6521                                 storey = temp;
6522                         }
6523
6524                         return null;
6525                 }
6526
6527                 public static bool IsThisAvailable (ResolveContext ec, bool ignoreAnonymous)
6528                 {
6529                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope))
6530                                 return false;
6531
6532                         if (ignoreAnonymous || ec.CurrentAnonymousMethod == null)
6533                                 return true;
6534
6535                         if (TypeManager.IsStruct (ec.CurrentType) && ec.CurrentIterator == null)
6536                                 return false;
6537
6538                         return true;
6539                 }
6540
6541                 public virtual void ResolveBase (ResolveContext ec)
6542                 {
6543                         if (!IsThisAvailable (ec, false)) {
6544                                 Error_ThisNotAvailable (ec);
6545                         }
6546
6547                         var block = ec.CurrentBlock;
6548                         if (block != null) {
6549                                 if (block.Toplevel.ThisVariable != null)
6550                                         variable_info = block.Toplevel.ThisVariable.VariableInfo;
6551
6552                                 AnonymousExpression am = ec.CurrentAnonymousMethod;
6553                                 if (am != null && ec.IsVariableCapturingRequired) {
6554                                         am.SetHasThisAccess ();
6555                                 }
6556                         }
6557
6558                         eclass = ExprClass.Variable;
6559                         type = ec.CurrentType;
6560                 }
6561
6562                 //
6563                 // Called from Invocation to check if the invocation is correct
6564                 //
6565                 public override void CheckMarshalByRefAccess (ResolveContext ec)
6566                 {
6567                         if ((variable_info != null) && !(TypeManager.IsStruct (type) && ec.OmitStructFlowAnalysis) &&
6568                             !variable_info.IsAssigned (ec)) {
6569                                 ec.Report.Error (188, loc,
6570                                         "The `this' object cannot be used before all of its fields are assigned to");
6571                                 variable_info.SetAssigned (ec);
6572                         }
6573                 }
6574
6575                 public override Expression CreateExpressionTree (ResolveContext ec)
6576                 {
6577                         Arguments args = new Arguments (1);
6578                         args.Add (new Argument (this));
6579
6580                         // Use typeless constant for ldarg.0 to save some
6581                         // space and avoid problems with anonymous stories
6582                         return CreateExpressionFactoryCall (ec, "Constant", args);
6583                 }
6584
6585                 protected override Expression DoResolve (ResolveContext ec)
6586                 {
6587                         ResolveBase (ec);
6588                         return this;
6589                 }
6590
6591                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6592                 {
6593                         ResolveBase (ec);
6594
6595                         if (variable_info != null)
6596                                 variable_info.SetAssigned (ec);
6597
6598                         if (ec.CurrentType.IsClass){
6599                                 if (right_side == EmptyExpression.UnaryAddress)
6600                                         ec.Report.Error (459, loc, "Cannot take the address of `this' because it is read-only");
6601                                 else if (right_side == EmptyExpression.OutAccess.Instance)
6602                                         ec.Report.Error (1605, loc, "Cannot pass `this' as a ref or out argument because it is read-only");
6603                                 else
6604                                         ec.Report.Error (1604, loc, "Cannot assign to `this' because it is read-only");
6605                         }
6606
6607                         return this;
6608                 }
6609
6610                 public override int GetHashCode()
6611                 {
6612                         throw new NotImplementedException ();
6613                 }
6614
6615                 public override bool Equals (object obj)
6616                 {
6617                         This t = obj as This;
6618                         if (t == null)
6619                                 return false;
6620
6621                         return true;
6622                 }
6623
6624                 protected override void CloneTo (CloneContext clonectx, Expression t)
6625                 {
6626                         // Nothing
6627                 }
6628
6629                 public override void SetHasAddressTaken ()
6630                 {
6631                         // Nothing
6632                 }
6633         }
6634
6635         /// <summary>
6636         ///   Represents the `__arglist' construct
6637         /// </summary>
6638         public class ArglistAccess : Expression
6639         {
6640                 public ArglistAccess (Location loc)
6641                 {
6642                         this.loc = loc;
6643                 }
6644
6645                 public override Expression CreateExpressionTree (ResolveContext ec)
6646                 {
6647                         throw new NotSupportedException ("ET");
6648                 }
6649
6650                 protected override Expression DoResolve (ResolveContext ec)
6651                 {
6652                         eclass = ExprClass.Variable;
6653                         type = TypeManager.runtime_argument_handle_type;
6654
6655                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope) || !ec.CurrentBlock.Toplevel.Parameters.HasArglist) {
6656                                 ec.Report.Error (190, loc,
6657                                         "The __arglist construct is valid only within a variable argument method");
6658                         }
6659
6660                         return this;
6661                 }
6662
6663                 public override void Emit (EmitContext ec)
6664                 {
6665                         ec.Emit (OpCodes.Arglist);
6666                 }
6667
6668                 protected override void CloneTo (CloneContext clonectx, Expression target)
6669                 {
6670                         // nothing.
6671                 }
6672         }
6673
6674         /// <summary>
6675         ///   Represents the `__arglist (....)' construct
6676         /// </summary>
6677         public class Arglist : Expression
6678         {
6679                 Arguments Arguments;
6680
6681                 public Arglist (Location loc)
6682                         : this (null, loc)
6683                 {
6684                 }
6685
6686                 public Arglist (Arguments args, Location l)
6687                 {
6688                         Arguments = args;
6689                         loc = l;
6690                 }
6691
6692                 public Type[] ArgumentTypes {
6693                     get {
6694                                 if (Arguments == null)
6695                                         return System.Type.EmptyTypes;
6696
6697                         var retval = new Type [Arguments.Count];
6698                         for (int i = 0; i < retval.Length; i++)
6699                                         retval[i] = Arguments[i].Expr.Type.GetMetaInfo ();
6700
6701                         return retval;
6702                     }
6703                 }
6704
6705                 public override Expression CreateExpressionTree (ResolveContext ec)
6706                 {
6707                         ec.Report.Error (1952, loc, "An expression tree cannot contain a method with variable arguments");
6708                         return null;
6709                 }
6710
6711                 protected override Expression DoResolve (ResolveContext ec)
6712                 {
6713                         eclass = ExprClass.Variable;
6714                         type = InternalType.Arglist;
6715                         if (Arguments != null) {
6716                                 bool dynamic;   // Can be ignored as there is always only 1 overload
6717                                 Arguments.Resolve (ec, out dynamic);
6718                         }
6719
6720                         return this;
6721                 }
6722
6723                 public override void Emit (EmitContext ec)
6724                 {
6725                         if (Arguments != null)
6726                                 Arguments.Emit (ec);
6727                 }
6728
6729                 protected override void CloneTo (CloneContext clonectx, Expression t)
6730                 {
6731                         Arglist target = (Arglist) t;
6732
6733                         if (Arguments != null)
6734                                 target.Arguments = Arguments.Clone (clonectx);
6735                 }
6736         }
6737
6738         /// <summary>
6739         ///   Implements the typeof operator
6740         /// </summary>
6741         public class TypeOf : Expression {
6742                 FullNamedExpression QueriedType;
6743                 TypeSpec typearg;
6744
6745                 public TypeOf (FullNamedExpression queried_type, Location l)
6746                 {
6747                         QueriedType = queried_type;
6748                         loc = l;
6749                 }
6750
6751                 #region Properties
6752                 public TypeSpec TypeArgument {
6753                         get {
6754                                 return typearg;
6755                         }
6756                 }
6757
6758                 public FullNamedExpression TypeExpression {
6759                         get {
6760                                 return QueriedType;
6761                         }
6762                 }
6763
6764                 #endregion
6765
6766                 public override Expression CreateExpressionTree (ResolveContext ec)
6767                 {
6768                         Arguments args = new Arguments (2);
6769                         args.Add (new Argument (this));
6770                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
6771                         return CreateExpressionFactoryCall (ec, "Constant", args);
6772                 }
6773
6774                 protected override Expression DoResolve (ResolveContext ec)
6775                 {
6776                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
6777                         if (texpr == null)
6778                                 return null;
6779
6780                         typearg = texpr.Type;
6781
6782                         if (typearg == TypeManager.void_type && !(QueriedType is TypeExpression)) {
6783                                 ec.Report.Error (673, loc, "System.Void cannot be used from C#. Use typeof (void) to get the void type object");
6784                         } else if (typearg.IsPointer && !ec.IsUnsafe){
6785                                 UnsafeError (ec, loc);
6786                         } else if (texpr is DynamicTypeExpr) {
6787                                 ec.Report.Error (1962, QueriedType.Location,
6788                                         "The typeof operator cannot be used on the dynamic type");
6789                         }
6790
6791                         type = TypeManager.type_type;
6792
6793                         return DoResolveBase ();
6794                 }
6795
6796                 protected Expression DoResolveBase ()
6797                 {
6798                         if (TypeManager.system_type_get_type_from_handle == null) {
6799                                 TypeManager.system_type_get_type_from_handle = TypeManager.GetPredefinedMethod (
6800                                         TypeManager.type_type, "GetTypeFromHandle", loc, TypeManager.runtime_handle_type);
6801                         }
6802
6803                         // Even though what is returned is a type object, it's treated as a value by the compiler.
6804                         // In particular, 'typeof (Foo).X' is something totally different from 'Foo.X'.
6805                         eclass = ExprClass.Value;
6806                         return this;
6807                 }
6808
6809                 static bool ContainsTypeParameter (TypeSpec type)
6810                 {
6811                         if (type.Kind == MemberKind.TypeParameter)
6812                                 return true;
6813
6814                         var element_container = type as ElementTypeSpec;
6815                         if (element_container != null)
6816                                 return ContainsTypeParameter (element_container.Element);
6817
6818                         foreach (var t in type.TypeArguments) {
6819                                 if (ContainsTypeParameter (t)) {
6820                                         return true;
6821                                 }
6822                         }
6823
6824                         return false;
6825                 }
6826
6827                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, TypeSpec targetType)
6828                 {
6829                         // Target type is not System.Type therefore must be object
6830                         // and we need to use different encoding sequence
6831                         if (targetType != type)
6832                                 enc.Encode (type);
6833
6834                         if (ContainsTypeParameter (typearg)) {
6835                                 rc.Compiler.Report.Error (416, loc, "`{0}': an attribute argument cannot use type parameters",
6836                                         TypeManager.CSharpName (typearg));
6837                                 return;
6838                         }
6839
6840                         enc.EncodeTypeName (typearg);
6841                 }
6842
6843                 public override void Emit (EmitContext ec)
6844                 {
6845                         ec.Emit (OpCodes.Ldtoken, typearg);
6846                         ec.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
6847                 }
6848
6849                 protected override void CloneTo (CloneContext clonectx, Expression t)
6850                 {
6851                         TypeOf target = (TypeOf) t;
6852                         if (QueriedType != null)
6853                                 target.QueriedType = (FullNamedExpression) QueriedType.Clone (clonectx);
6854                 }
6855         }
6856
6857         class TypeOfMethod : TypeOfMember<MethodSpec>
6858         {
6859                 public TypeOfMethod (MethodSpec method, Location loc)
6860                         : base (method, loc)
6861                 {
6862                 }
6863
6864                 protected override Expression DoResolve (ResolveContext ec)
6865                 {
6866                         if (member.IsConstructor) {
6867                                 type = TypeManager.ctorinfo_type;
6868                                 if (type == null)
6869                                         type = TypeManager.ctorinfo_type = TypeManager.CoreLookupType (ec.Compiler, "System.Reflection", "ConstructorInfo", MemberKind.Class, true);
6870                         } else {
6871                                 type = TypeManager.methodinfo_type;
6872                                 if (type == null)
6873                                         type = TypeManager.methodinfo_type = TypeManager.CoreLookupType (ec.Compiler, "System.Reflection", "MethodInfo", MemberKind.Class, true);
6874                         }
6875
6876                         return base.DoResolve (ec);
6877                 }
6878
6879                 public override void Emit (EmitContext ec)
6880                 {
6881                         ec.Emit (OpCodes.Ldtoken, member);
6882
6883                         base.Emit (ec);
6884                         ec.Emit (OpCodes.Castclass, type);
6885                 }
6886
6887                 protected override string GetMethodName {
6888                         get { return "GetMethodFromHandle"; }
6889                 }
6890
6891                 protected override string RuntimeHandleName {
6892                         get { return "RuntimeMethodHandle"; }
6893                 }
6894
6895                 protected override MethodSpec TypeFromHandle {
6896                         get {
6897                                 return TypeManager.methodbase_get_type_from_handle;
6898                         }
6899                         set {
6900                                 TypeManager.methodbase_get_type_from_handle = value;
6901                         }
6902                 }
6903
6904                 protected override MethodSpec TypeFromHandleGeneric {
6905                         get {
6906                                 return TypeManager.methodbase_get_type_from_handle_generic;
6907                         }
6908                         set {
6909                                 TypeManager.methodbase_get_type_from_handle_generic = value;
6910                         }
6911                 }
6912
6913                 protected override string TypeName {
6914                         get { return "MethodBase"; }
6915                 }
6916         }
6917
6918         abstract class TypeOfMember<T> : Expression where T : MemberSpec
6919         {
6920                 protected readonly T member;
6921
6922                 protected TypeOfMember (T member, Location loc)
6923                 {
6924                         this.member = member;
6925                         this.loc = loc;
6926                 }
6927
6928                 public override Expression CreateExpressionTree (ResolveContext ec)
6929                 {
6930                         Arguments args = new Arguments (2);
6931                         args.Add (new Argument (this));
6932                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
6933                         return CreateExpressionFactoryCall (ec, "Constant", args);
6934                 }
6935
6936                 protected override Expression DoResolve (ResolveContext ec)
6937                 {
6938                         bool is_generic = member.DeclaringType.IsGenericOrParentIsGeneric;
6939                         var mi = is_generic ? TypeFromHandleGeneric : TypeFromHandle;
6940
6941                         if (mi == null) {
6942                                 TypeSpec t = TypeManager.CoreLookupType (ec.Compiler, "System.Reflection", TypeName, MemberKind.Class, true);
6943                                 TypeSpec handle_type = TypeManager.CoreLookupType (ec.Compiler, "System", RuntimeHandleName, MemberKind.Struct, true);
6944
6945                                 if (t == null || handle_type == null)
6946                                         return null;
6947
6948                                 mi = TypeManager.GetPredefinedMethod (t, GetMethodName, loc,
6949                                         is_generic ?
6950                                         new TypeSpec[] { handle_type, TypeManager.runtime_handle_type } :
6951                                         new TypeSpec[] { handle_type } );
6952
6953                                 if (is_generic)
6954                                         TypeFromHandleGeneric = mi;
6955                                 else
6956                                         TypeFromHandle = mi;
6957                         }
6958
6959                         eclass = ExprClass.Value;
6960                         return this;
6961                 }
6962
6963                 public override void Emit (EmitContext ec)
6964                 {
6965                         bool is_generic = member.DeclaringType.IsGenericOrParentIsGeneric;
6966                         MethodSpec mi;
6967                         if (is_generic) {
6968                                 mi = TypeFromHandleGeneric;
6969                                 ec.Emit (OpCodes.Ldtoken, member.DeclaringType);
6970                         } else {
6971                                 mi = TypeFromHandle;
6972                         }
6973
6974                         ec.Emit (OpCodes.Call, mi);
6975                 }
6976
6977                 protected abstract string GetMethodName { get; }
6978                 protected abstract string RuntimeHandleName { get; }
6979                 protected abstract MethodSpec TypeFromHandle { get; set; }
6980                 protected abstract MethodSpec TypeFromHandleGeneric { get; set; }
6981                 protected abstract string TypeName { get; }
6982         }
6983
6984         class TypeOfField : TypeOfMember<FieldSpec>
6985         {
6986                 public TypeOfField (FieldSpec field, Location loc)
6987                         : base (field, loc)
6988                 {
6989                 }
6990
6991                 protected override Expression DoResolve (ResolveContext ec)
6992                 {
6993                         if (TypeManager.fieldinfo_type == null)
6994                                 TypeManager.fieldinfo_type = TypeManager.CoreLookupType (ec.Compiler, "System.Reflection", TypeName, MemberKind.Class, true);
6995
6996                         type = TypeManager.fieldinfo_type;
6997                         return base.DoResolve (ec);
6998                 }
6999
7000                 public override void Emit (EmitContext ec)
7001                 {
7002                         ec.Emit (OpCodes.Ldtoken, member);
7003                         base.Emit (ec);
7004                 }
7005
7006                 protected override string GetMethodName {
7007                         get { return "GetFieldFromHandle"; }
7008                 }
7009
7010                 protected override string RuntimeHandleName {
7011                         get { return "RuntimeFieldHandle"; }
7012                 }
7013
7014                 protected override MethodSpec TypeFromHandle {
7015                         get {
7016                                 return TypeManager.fieldinfo_get_field_from_handle;
7017                         }
7018                         set {
7019                                 TypeManager.fieldinfo_get_field_from_handle = value;
7020                         }
7021                 }
7022
7023                 protected override MethodSpec TypeFromHandleGeneric {
7024                         get {
7025                                 return TypeManager.fieldinfo_get_field_from_handle_generic;
7026                         }
7027                         set {
7028                                 TypeManager.fieldinfo_get_field_from_handle_generic = value;
7029                         }
7030                 }
7031
7032                 protected override string TypeName {
7033                         get { return "FieldInfo"; }
7034                 }
7035         }
7036
7037         /// <summary>
7038         ///   Implements the sizeof expression
7039         /// </summary>
7040         public class SizeOf : Expression {
7041                 readonly Expression QueriedType;
7042                 TypeSpec type_queried;
7043
7044                 public SizeOf (Expression queried_type, Location l)
7045                 {
7046                         this.QueriedType = queried_type;
7047                         loc = l;
7048                 }
7049
7050                 public override Expression CreateExpressionTree (ResolveContext ec)
7051                 {
7052                         Error_PointerInsideExpressionTree (ec);
7053                         return null;
7054                 }
7055
7056                 protected override Expression DoResolve (ResolveContext ec)
7057                 {
7058                         TypeExpr texpr = QueriedType.ResolveAsTypeTerminal (ec, false);
7059                         if (texpr == null)
7060                                 return null;
7061
7062                         type_queried = texpr.Type;
7063                         if (TypeManager.IsEnumType (type_queried))
7064                                 type_queried = EnumSpec.GetUnderlyingType (type_queried);
7065
7066                         int size_of = GetTypeSize (type_queried);
7067                         if (size_of > 0) {
7068                                 return new IntConstant (size_of, loc).Resolve (ec);
7069                         }
7070
7071                         if (!TypeManager.VerifyUnmanaged (ec.Compiler, type_queried, loc)){
7072                                 return null;
7073                         }
7074
7075                         if (!ec.IsUnsafe) {
7076                                 ec.Report.Error (233, loc,
7077                                         "`{0}' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.Runtime.InteropServices.Marshal.SizeOf)",
7078                                         TypeManager.CSharpName (type_queried));
7079                         }
7080
7081                         type = TypeManager.int32_type;
7082                         eclass = ExprClass.Value;
7083                         return this;
7084                 }
7085
7086                 public override void Emit (EmitContext ec)
7087                 {
7088                         ec.Emit (OpCodes.Sizeof, type_queried);
7089                 }
7090
7091                 protected override void CloneTo (CloneContext clonectx, Expression t)
7092                 {
7093                 }
7094         }
7095
7096         /// <summary>
7097         ///   Implements the qualified-alias-member (::) expression.
7098         /// </summary>
7099         public class QualifiedAliasMember : MemberAccess
7100         {
7101                 readonly string alias;
7102                 public static readonly string GlobalAlias = "global";
7103
7104                 public QualifiedAliasMember (string alias, string identifier, Location l)
7105                         : base (null, identifier, l)
7106                 {
7107                         this.alias = alias;
7108                 }
7109
7110                 public QualifiedAliasMember (string alias, string identifier, TypeArguments targs, Location l)
7111                         : base (null, identifier, targs, l)
7112                 {
7113                         this.alias = alias;
7114                 }
7115
7116                 public QualifiedAliasMember (string alias, string identifier, int arity, Location l)
7117                         : base (null, identifier, arity, l)
7118                 {
7119                         this.alias = alias;
7120                 }
7121
7122                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
7123                 {
7124                         if (alias == GlobalAlias) {
7125                                 expr = GlobalRootNamespace.Instance;
7126                                 return base.ResolveAsTypeStep (ec, silent);
7127                         }
7128
7129                         int errors = ec.Compiler.Report.Errors;
7130                         expr = ec.LookupNamespaceAlias (alias);
7131                         if (expr == null) {
7132                                 if (errors == ec.Compiler.Report.Errors)
7133                                         ec.Compiler.Report.Error (432, loc, "Alias `{0}' not found", alias);
7134                                 return null;
7135                         }
7136
7137                         FullNamedExpression fne = base.ResolveAsTypeStep (ec, silent);
7138                         if (fne == null)
7139                                 return null;
7140
7141                         if (expr.eclass == ExprClass.Type) {
7142                                 if (!silent) {
7143                                         ec.Compiler.Report.Error (431, loc,
7144                                                 "Alias `{0}' cannot be used with '::' since it denotes a type. Consider replacing '::' with '.'", alias);
7145                                 }
7146                                 return null;
7147                         }
7148
7149                         return fne;
7150                 }
7151
7152                 protected override Expression DoResolve (ResolveContext ec)
7153                 {
7154                         return ResolveAsTypeStep (ec, false);
7155                 }
7156
7157                 protected override void Error_IdentifierNotFound (IMemberContext rc, TypeSpec expr_type, string identifier)
7158                 {
7159                         rc.Compiler.Report.Error (687, loc,
7160                                 "A namespace alias qualifier `{0}' did not resolve to a namespace or a type",
7161                                 GetSignatureForError ());
7162                 }
7163
7164                 public override string GetSignatureForError ()
7165                 {
7166                         string name = Name;
7167                         if (targs != null) {
7168                                 name = Name + "<" + targs.GetSignatureForError () + ">";
7169                         }
7170
7171                         return alias + "::" + name;
7172                 }
7173
7174                 public override Expression LookupNameExpression (ResolveContext rc, bool readMode, bool invocableOnly)
7175                 {
7176                         return DoResolve (rc);
7177                 }
7178
7179                 protected override void CloneTo (CloneContext clonectx, Expression t)
7180                 {
7181                         // Nothing
7182                 }
7183         }
7184
7185         /// <summary>
7186         ///   Implements the member access expression
7187         /// </summary>
7188         public class MemberAccess : ATypeNameExpression
7189         {
7190                 protected Expression expr;
7191
7192                 public MemberAccess (Expression expr, string id)
7193                         : base (id, expr.Location)
7194                 {
7195                         this.expr = expr;
7196                 }
7197
7198                 public MemberAccess (Expression expr, string identifier, Location loc)
7199                         : base (identifier, loc)
7200                 {
7201                         this.expr = expr;
7202                 }
7203
7204                 public MemberAccess (Expression expr, string identifier, TypeArguments args, Location loc)
7205                         : base (identifier, args, loc)
7206                 {
7207                         this.expr = expr;
7208                 }
7209
7210                 public MemberAccess (Expression expr, string identifier, int arity, Location loc)
7211                         : base (identifier, arity, loc)
7212                 {
7213                         this.expr = expr;
7214                 }
7215
7216                 public Expression LeftExpression {
7217                         get {
7218                                 return expr;
7219                         }
7220                 }
7221
7222                 protected override Expression DoResolve (ResolveContext ec)
7223                 {
7224                         return DoResolveName (ec, null);
7225                 }
7226
7227                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
7228                 {
7229                         return DoResolveName (ec, right_side);
7230                 }
7231
7232                 Expression DoResolveName (ResolveContext rc, Expression right_side)
7233                 {
7234                         Expression e = LookupNameExpression (rc, right_side == null, false);
7235                         if (e == null)
7236                                 return null;
7237
7238                         if (right_side != null)
7239                                 e = e.ResolveLValue (rc, right_side);
7240                         else
7241                                 e = e.Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.Type);
7242
7243                         return e;
7244                 }
7245
7246                 public override Expression LookupNameExpression (ResolveContext rc, bool readMode, bool invocableOnly)
7247                 {
7248                         var sn = expr as SimpleName;
7249                         const ResolveFlags flags = ResolveFlags.VariableOrValue | ResolveFlags.Type;
7250
7251                         //
7252                         // Resolve the expression with flow analysis turned off, we'll do the definite
7253                         // assignment checks later.  This is because we don't know yet what the expression
7254                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
7255                         // definite assignment check on the actual field and not on the whole struct.
7256                         //
7257                         using (rc.Set (ResolveContext.Options.OmitStructFlowAnalysis)) {
7258                                 if (sn != null) {
7259                                         expr = sn.LookupNameExpression (rc, true, false);
7260
7261                                         // Call resolve on expression which does have type set as we need expression type
7262                                         // TODO: I should probably ensure that the type is always set and leave resolve for the final
7263                                         if (expr is VariableReference || expr is ConstantExpr || expr is Linq.TransparentMemberAccess) {
7264                                                 using (rc.With (ResolveContext.Options.DoFlowAnalysis, false)) {
7265                                                         expr = expr.Resolve (rc);
7266                                                 }
7267                                         } else if (expr is TypeParameterExpr) {
7268                                                 expr.Error_UnexpectedKind (rc, flags, expr.Location);
7269                                                 expr = null;
7270                                         }
7271                                 } else {
7272                                         expr = expr.Resolve (rc, flags);
7273                                 }
7274                         }
7275
7276                         if (expr == null)
7277                                 return null;
7278
7279                         Namespace ns = expr as Namespace;
7280                         if (ns != null) {
7281                                 FullNamedExpression retval = ns.Lookup (rc.Compiler, Name, Arity, loc);
7282
7283                                 if (retval == null) {
7284                                         ns.Error_NamespaceDoesNotExist (loc, Name, Arity, rc);
7285                                         return null;
7286                                 }
7287
7288                                 if (HasTypeArguments)
7289                                         return new GenericTypeExpr (retval.Type, targs, loc);
7290
7291                                 return retval;
7292                         }
7293
7294                         TypeSpec expr_type = expr.Type;
7295                         if (expr_type == InternalType.Dynamic) {
7296                                 Arguments args = new Arguments (1);
7297                                 args.Add (new Argument (expr));
7298                                 return new DynamicMemberBinder (Name, args, loc);
7299                         }
7300
7301                         const MemberKind dot_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.Delegate | MemberKind.Enum |
7302                                 MemberKind.Interface | MemberKind.TypeParameter | MemberKind.ArrayType;
7303
7304                         if ((expr_type.Kind & dot_kinds) == 0 || expr_type == TypeManager.void_type) {
7305                                 Unary.Error_OperatorCannotBeApplied (rc, loc, ".", expr_type);
7306                                 return null;
7307                         }
7308
7309                         var current_type = rc.CurrentType;
7310                         var lookup_arity = Arity;
7311                         bool errorMode = false;
7312                         Expression member_lookup;
7313                         while (true) {
7314                                 member_lookup = MemberLookup (errorMode ? null : rc, current_type, expr_type, Name, lookup_arity, invocableOnly, loc);
7315                                 if (member_lookup == null) {
7316                                         //
7317                                         // Try to look for extension method when member lookup failed
7318                                         //
7319                                         if (MethodGroupExpr.IsExtensionMethodArgument (expr)) {
7320                                                 NamespaceEntry scope = null;
7321                                                 var methods = rc.LookupExtensionMethod (expr_type, Name, lookup_arity, ref scope);
7322                                                 if (methods != null) {
7323                                                         var emg = new ExtensionMethodGroupExpr (methods, scope, expr, loc);
7324                                                         if (HasTypeArguments) {
7325                                                                 if (!targs.Resolve (rc))
7326                                                                         return null;
7327
7328                                                                 emg.SetTypeArguments (rc, targs);
7329                                                         }
7330
7331                                                         // TODO: Should it really skip the checks bellow
7332                                                         return emg.Resolve (rc);
7333                                                 }
7334                                         }
7335                                 }
7336
7337                                 if (errorMode) {
7338                                         if (member_lookup == null) {
7339                                                 if (expr is TypeExpr)
7340                                                         base.Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
7341                                                 else
7342                                                         Error_TypeDoesNotContainDefinition (rc, expr_type, Name);
7343
7344                                                 return null;
7345                                         }
7346
7347                                         if (member_lookup is MethodGroupExpr) {
7348                                                 // Leave it to overload resolution to report correct error
7349                                         } else {
7350                                                 // TODO: rc.SymbolRelatedToPreviousError
7351                                                 ErrorIsInaccesible (rc, member_lookup.GetSignatureForError (), loc);
7352                                         }
7353                                         break;
7354                                 }
7355
7356                                 if (member_lookup != null)
7357                                         break;
7358
7359                                 current_type = null;
7360                                 lookup_arity = 0;
7361                                 invocableOnly = false;
7362                                 errorMode = true;
7363                         }
7364
7365                         MemberExpr me;
7366                         TypeExpr texpr = member_lookup as TypeExpr;
7367
7368                         if (texpr != null) {
7369                                 if (!(expr is TypeExpr)) {
7370                                         me = expr as MemberExpr;
7371                                         if (me == null || me.ProbeIdenticalTypeName (rc, expr, sn) == expr) {
7372                                                 rc.Report.Error (572, loc, "`{0}': cannot reference a type through an expression; try `{1}' instead",
7373                                                         Name, member_lookup.GetSignatureForError ());
7374                                                 return null;
7375                                         }
7376                                 }
7377
7378                                 if (!texpr.Type.IsAccessible (rc.CurrentType)) {
7379                                         rc.Report.SymbolRelatedToPreviousError (member_lookup.Type);
7380                                         ErrorIsInaccesible (rc, member_lookup.Type.GetSignatureForError (), loc);
7381                                         return null;
7382                                 }
7383
7384                                 if (HasTypeArguments) {
7385                                         return new GenericTypeExpr (member_lookup.Type, targs, loc);
7386                                 }
7387
7388                                 return member_lookup;
7389                         }
7390
7391                         me = member_lookup as MemberExpr;
7392
7393                         if (sn != null && me.IsStatic)
7394                                 expr = me.ProbeIdenticalTypeName (rc, expr, sn);
7395
7396                         me = me.ResolveMemberAccess (rc, expr, sn);
7397
7398                         if (Arity > 0) {
7399                                 if (!targs.Resolve (rc))
7400                                         return null;
7401
7402                                 me.SetTypeArguments (rc, targs);
7403                         }
7404
7405                         if (sn != null && (!TypeManager.IsValueType (expr_type) || me is PropertyExpr)) {
7406                                 if (me.IsInstance) {
7407                                         LocalVariableReference var = expr as LocalVariableReference;
7408                                         if (var != null && !var.VerifyAssigned (rc))
7409                                                 return null;
7410                                 }
7411                         }
7412
7413                         return me;
7414                 }
7415
7416                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
7417                 {
7418                         return ResolveNamespaceOrType (ec, silent);
7419                 }
7420
7421                 public FullNamedExpression ResolveNamespaceOrType (IMemberContext rc, bool silent)
7422                 {
7423                         FullNamedExpression expr_resolved = expr.ResolveAsTypeStep (rc, silent);
7424
7425                         if (expr_resolved == null)
7426                                 return null;
7427
7428                         Namespace ns = expr_resolved as Namespace;
7429                         if (ns != null) {
7430                                 FullNamedExpression retval = ns.Lookup (rc.Compiler, Name, Arity, loc);
7431
7432                                 if (retval == null) {
7433                                         if (!silent)
7434                                                 ns.Error_NamespaceDoesNotExist (loc, Name, Arity, rc);
7435                                 } else if (HasTypeArguments) {
7436                                         retval = new GenericTypeExpr (retval.Type, targs, loc).ResolveAsTypeStep (rc, silent);
7437                                 }
7438
7439                                 return retval;
7440                         }
7441
7442                         TypeExpr tnew_expr = expr_resolved.ResolveAsTypeTerminal (rc, false);
7443                         if (tnew_expr == null)
7444                                 return null;
7445
7446                         TypeSpec expr_type = tnew_expr.Type;
7447                         if (TypeManager.IsGenericParameter (expr_type)) {
7448                                 rc.Compiler.Report.Error (704, loc, "A nested type cannot be specified through a type parameter `{0}'",
7449                                         tnew_expr.GetSignatureForError ());
7450                                 return null;
7451                         }
7452
7453                         var nested = MemberCache.FindNestedType (expr_type, Name, Arity);
7454                         if (nested == null) {
7455                                 if (silent)
7456                                         return null;
7457
7458                                 Error_IdentifierNotFound (rc, expr_type, Name);
7459                                 return null;
7460                         }
7461
7462                         if (!nested.IsAccessible (rc.CurrentType ?? InternalType.FakeInternalType)) {
7463                                 ErrorIsInaccesible (rc, nested.GetSignatureForError (), loc);
7464                         }
7465
7466                         TypeExpr texpr;
7467                         if (HasTypeArguments) {
7468                                 texpr = new GenericTypeExpr (nested, targs, loc);
7469                         } else {
7470                                 texpr = new TypeExpression (nested, loc);
7471                         }
7472
7473                         return texpr.ResolveAsTypeStep (rc, false);
7474                 }
7475
7476                 protected virtual void Error_IdentifierNotFound (IMemberContext rc, TypeSpec expr_type, string identifier)
7477                 {
7478                         var nested = MemberCache.FindNestedType (expr_type, Name, -System.Math.Max (1, Arity));
7479
7480                         if (nested != null) {
7481                                 Error_TypeArgumentsCannotBeUsed (rc.Compiler.Report, expr.Location, nested, Arity);
7482                                 return;
7483                         }
7484
7485                         var any_other_member = MemberLookup (null, rc.CurrentType, expr_type, Name, 0, false, loc);
7486                         if (any_other_member != null) {
7487                                 any_other_member.Error_UnexpectedKind (rc.Compiler.Report, null, "type", loc);
7488                                 return;
7489                         }
7490
7491                         rc.Compiler.Report.Error (426, loc, "The nested type `{0}' does not exist in the type `{1}'",
7492                                 Name, expr_type.GetSignatureForError ());
7493                 }
7494
7495                 protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
7496                 {
7497                         if (RootContext.Version > LanguageVersion.ISO_2 && !ec.Compiler.IsRuntimeBinder && MethodGroupExpr.IsExtensionMethodArgument (expr)) {
7498                                 ec.Report.Error (1061, loc,
7499                                         "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?)",
7500                                         type.GetSignatureForError (), name);
7501                                 return;
7502                         }
7503
7504                         base.Error_TypeDoesNotContainDefinition (ec, type, name);
7505                 }
7506
7507                 public override string GetSignatureForError ()
7508                 {
7509                         return expr.GetSignatureForError () + "." + base.GetSignatureForError ();
7510                 }
7511
7512                 protected override void CloneTo (CloneContext clonectx, Expression t)
7513                 {
7514                         MemberAccess target = (MemberAccess) t;
7515
7516                         target.expr = expr.Clone (clonectx);
7517                 }
7518         }
7519
7520         /// <summary>
7521         ///   Implements checked expressions
7522         /// </summary>
7523         public class CheckedExpr : Expression {
7524
7525                 public Expression Expr;
7526
7527                 public CheckedExpr (Expression e, Location l)
7528                 {
7529                         Expr = e;
7530                         loc = l;
7531                 }
7532
7533                 public override Expression CreateExpressionTree (ResolveContext ec)
7534                 {
7535                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
7536                                 return Expr.CreateExpressionTree (ec);
7537                 }
7538
7539                 protected override Expression DoResolve (ResolveContext ec)
7540                 {
7541                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
7542                                 Expr = Expr.Resolve (ec);
7543
7544                         if (Expr == null)
7545                                 return null;
7546
7547                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
7548                                 return Expr;
7549
7550                         eclass = Expr.eclass;
7551                         type = Expr.Type;
7552                         return this;
7553                 }
7554
7555                 public override void Emit (EmitContext ec)
7556                 {
7557                         using (ec.With (EmitContext.Options.AllCheckStateFlags, true))
7558                                 Expr.Emit (ec);
7559                 }
7560
7561                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
7562                 {
7563                         using (ec.With (EmitContext.Options.AllCheckStateFlags, true))
7564                                 Expr.EmitBranchable (ec, target, on_true);
7565                 }
7566
7567                 public override SLE.Expression MakeExpression (BuilderContext ctx)
7568                 {
7569                         using (ctx.With (BuilderContext.Options.AllCheckStateFlags, true)) {
7570                                 return Expr.MakeExpression (ctx);
7571                         }
7572                 }
7573
7574                 protected override void CloneTo (CloneContext clonectx, Expression t)
7575                 {
7576                         CheckedExpr target = (CheckedExpr) t;
7577
7578                         target.Expr = Expr.Clone (clonectx);
7579                 }
7580         }
7581
7582         /// <summary>
7583         ///   Implements the unchecked expression
7584         /// </summary>
7585         public class UnCheckedExpr : Expression {
7586
7587                 public Expression Expr;
7588
7589                 public UnCheckedExpr (Expression e, Location l)
7590                 {
7591                         Expr = e;
7592                         loc = l;
7593                 }
7594
7595                 public override Expression CreateExpressionTree (ResolveContext ec)
7596                 {
7597                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
7598                                 return Expr.CreateExpressionTree (ec);
7599                 }
7600
7601                 protected override Expression DoResolve (ResolveContext ec)
7602                 {
7603                         using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
7604                                 Expr = Expr.Resolve (ec);
7605
7606                         if (Expr == null)
7607                                 return null;
7608
7609                         if (Expr is Constant || Expr is MethodGroupExpr || Expr is AnonymousMethodExpression || Expr is DefaultValueExpression)
7610                                 return Expr;
7611
7612                         eclass = Expr.eclass;
7613                         type = Expr.Type;
7614                         return this;
7615                 }
7616
7617                 public override void Emit (EmitContext ec)
7618                 {
7619                         using (ec.With (EmitContext.Options.AllCheckStateFlags, false))
7620                                 Expr.Emit (ec);
7621                 }
7622
7623                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
7624                 {
7625                         using (ec.With (EmitContext.Options.AllCheckStateFlags, false))
7626                                 Expr.EmitBranchable (ec, target, on_true);
7627                 }
7628
7629                 protected override void CloneTo (CloneContext clonectx, Expression t)
7630                 {
7631                         UnCheckedExpr target = (UnCheckedExpr) t;
7632
7633                         target.Expr = Expr.Clone (clonectx);
7634                 }
7635         }
7636
7637         /// <summary>
7638         ///   An Element Access expression.
7639         ///
7640         ///   During semantic analysis these are transformed into
7641         ///   IndexerAccess, ArrayAccess or a PointerArithmetic.
7642         /// </summary>
7643         public class ElementAccess : Expression {
7644                 public Arguments Arguments;
7645                 public Expression Expr;
7646
7647                 public ElementAccess (Expression e, Arguments args, Location loc)
7648                 {
7649                         Expr = e;
7650                         this.loc = loc;
7651                         this.Arguments = args;
7652                 }
7653
7654                 //
7655                 // We perform some simple tests, and then to "split" the emit and store
7656                 // code we create an instance of a different class, and return that.
7657                 //
7658                 Expression CreateAccessExpression (ResolveContext ec)
7659                 {
7660                         if (type.IsArray)
7661                                 return (new ArrayAccess (this, loc));
7662
7663                         if (type.IsPointer)
7664                                 return MakePointerAccess (ec, type);
7665
7666                         FieldExpr fe = Expr as FieldExpr;
7667                         if (fe != null) {
7668                                 var ff = fe.Spec as FixedFieldSpec;
7669                                 if (ff != null) {
7670                                         return MakePointerAccess (ec, ff.ElementType);
7671                                 }
7672                         }
7673
7674                         var indexers = MemberCache.FindMembers (type, MemberCache.IndexerNameAlias, false);
7675                         if (indexers != null || type == InternalType.Dynamic) {
7676                                 return new IndexerExpr (indexers, this);
7677                         }
7678
7679                         ec.Report.Error (21, loc, "Cannot apply indexing with [] to an expression of type `{0}'",
7680                                 type.GetSignatureForError ());
7681                         return null;
7682                 }
7683
7684                 public override Expression CreateExpressionTree (ResolveContext ec)
7685                 {
7686                         Arguments args = Arguments.CreateForExpressionTree (ec, Arguments,
7687                                 Expr.CreateExpressionTree (ec));
7688
7689                         return CreateExpressionFactoryCall (ec, "ArrayIndex", args);
7690                 }
7691
7692                 Expression MakePointerAccess (ResolveContext ec, TypeSpec type)
7693                 {
7694                         if (Arguments.Count != 1){
7695                                 ec.Report.Error (196, loc, "A pointer must be indexed by only one value");
7696                                 return null;
7697                         }
7698
7699                         if (Arguments [0] is NamedArgument)
7700                                 Error_NamedArgument ((NamedArgument) Arguments[0], ec.Report);
7701
7702                         Expression p = new PointerArithmetic (Binary.Operator.Addition, Expr, Arguments [0].Expr.Resolve (ec), type, loc);
7703                         return new Indirection (p, loc);
7704                 }
7705
7706                 protected override Expression DoResolve (ResolveContext ec)
7707                 {
7708                         Expr = Expr.Resolve (ec);
7709                         if (Expr == null)
7710                                 return null;
7711
7712                         type = Expr.Type;
7713
7714                         // TODO: Create 1 result for Resolve and ResolveLValue ?
7715                         var res = CreateAccessExpression (ec);
7716                         if (res == null)
7717                                 return null;
7718
7719                         return res.Resolve (ec);
7720                 }
7721
7722                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
7723                 {
7724                         Expr = Expr.Resolve (ec);
7725                         if (Expr == null)
7726                                 return null;
7727
7728                         type = Expr.Type;
7729
7730                         var res = CreateAccessExpression (ec);
7731                         if (res == null)
7732                                 return null;
7733
7734                         return res.ResolveLValue (ec, right_side);
7735                 }
7736
7737                 public override void Emit (EmitContext ec)
7738                 {
7739                         throw new Exception ("Should never be reached");
7740                 }
7741
7742                 public static void Error_NamedArgument (NamedArgument na, Report Report)
7743                 {
7744                         Report.Error (1742, na.Location, "An element access expression cannot use named argument");
7745                 }
7746
7747                 public override string GetSignatureForError ()
7748                 {
7749                         return Expr.GetSignatureForError ();
7750                 }
7751
7752                 protected override void CloneTo (CloneContext clonectx, Expression t)
7753                 {
7754                         ElementAccess target = (ElementAccess) t;
7755
7756                         target.Expr = Expr.Clone (clonectx);
7757                         if (Arguments != null)
7758                                 target.Arguments = Arguments.Clone (clonectx);
7759                 }
7760         }
7761
7762         /// <summary>
7763         ///   Implements array access
7764         /// </summary>
7765         public class ArrayAccess : Expression, IDynamicAssign, IMemoryLocation {
7766                 //
7767                 // Points to our "data" repository
7768                 //
7769                 ElementAccess ea;
7770
7771                 LocalTemporary temp;
7772
7773                 bool prepared;
7774
7775                 public ArrayAccess (ElementAccess ea_data, Location l)
7776                 {
7777                         ea = ea_data;
7778                         loc = l;
7779                 }
7780
7781                 public override Expression CreateExpressionTree (ResolveContext ec)
7782                 {
7783                         return ea.CreateExpressionTree (ec);
7784                 }
7785
7786                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
7787                 {
7788                         return DoResolve (ec);
7789                 }
7790
7791                 protected override Expression DoResolve (ResolveContext ec)
7792                 {
7793                         // dynamic is used per argument in ConvertExpressionToArrayIndex case
7794                         bool dynamic;
7795                         ea.Arguments.Resolve (ec, out dynamic);
7796
7797                         var ac = ea.Expr.Type as ArrayContainer;
7798                         int rank = ea.Arguments.Count;
7799                         if (ac.Rank != rank) {
7800                                 ec.Report.Error (22, ea.Location, "Wrong number of indexes `{0}' inside [], expected `{1}'",
7801                                           rank.ToString (), ac.Rank.ToString ());
7802                                 return null;
7803                         }
7804
7805                         type = ac.Element;
7806                         if (type.IsPointer && !ec.IsUnsafe) {
7807                                 UnsafeError (ec, ea.Location);
7808                         }
7809
7810                         foreach (Argument a in ea.Arguments) {
7811                                 if (a is NamedArgument)
7812                                         ElementAccess.Error_NamedArgument ((NamedArgument) a, ec.Report);
7813
7814                                 a.Expr = ConvertExpressionToArrayIndex (ec, a.Expr);
7815                         }
7816
7817                         eclass = ExprClass.Variable;
7818
7819                         return this;
7820                 }
7821
7822                 protected override void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
7823                 {
7824                         ec.Report.Warning (251, 2, loc, "Indexing an array with a negative index (array indices always start at zero)");
7825                 }
7826
7827                 //
7828                 // Load the array arguments into the stack.
7829                 //
7830                 void LoadArrayAndArguments (EmitContext ec)
7831                 {
7832                         ea.Expr.Emit (ec);
7833
7834                         for (int i = 0; i < ea.Arguments.Count; ++i) {
7835                                 ea.Arguments [i].Emit (ec);
7836                         }
7837                 }
7838
7839                 public void Emit (EmitContext ec, bool leave_copy)
7840                 {
7841                         var ac = ea.Expr.Type as ArrayContainer;
7842
7843                         if (prepared) {
7844                                 ec.EmitLoadFromPtr (type);
7845                         } else {
7846                                 LoadArrayAndArguments (ec);
7847                                 ec.EmitArrayLoad (ac);
7848                         }
7849
7850                         if (leave_copy) {
7851                                 ec.Emit (OpCodes.Dup);
7852                                 temp = new LocalTemporary (this.type);
7853                                 temp.Store (ec);
7854                         }
7855                 }
7856
7857                 public override void Emit (EmitContext ec)
7858                 {
7859                         Emit (ec, false);
7860                 }
7861
7862                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
7863                 {
7864                         var ac = (ArrayContainer) ea.Expr.Type;
7865                         TypeSpec t = source.Type;
7866                         prepared = prepare_for_load;
7867
7868                         if (prepared) {
7869                                 AddressOf (ec, AddressOp.LoadStore);
7870                                 ec.Emit (OpCodes.Dup);
7871                         } else {
7872                                 LoadArrayAndArguments (ec);
7873
7874                                 //
7875                                 // If we are dealing with a struct, get the
7876                                 // address of it, so we can store it.
7877                                 //
7878                                 // The stobj opcode used by value types will need
7879                                 // an address on the stack, not really an array/array
7880                                 // pair
7881                                 //
7882                                 if (ac.Rank == 1 && TypeManager.IsStruct (t) &&
7883                                         (!TypeManager.IsBuiltinOrEnum (t) ||
7884                                          t == TypeManager.decimal_type)) {
7885
7886                                         ec.Emit (OpCodes.Ldelema, t);
7887                                 }
7888                         }
7889
7890                         source.Emit (ec);
7891                         if (leave_copy) {
7892                                 ec.Emit (OpCodes.Dup);
7893                                 temp = new LocalTemporary (this.type);
7894                                 temp.Store (ec);
7895                         }
7896
7897                         if (prepared) {
7898                                 ec.EmitStoreFromPtr (t);
7899                         } else {
7900                                 ec.EmitArrayStore (ac);
7901                         }
7902
7903                         if (temp != null) {
7904                                 temp.Emit (ec);
7905                                 temp.Release (ec);
7906                         }
7907                 }
7908
7909                 public void EmitNew (EmitContext ec, New source, bool leave_copy)
7910                 {
7911                         if (!source.Emit (ec, this)) {
7912                                 if (leave_copy)
7913                                         throw new NotImplementedException ();
7914
7915                                 return;
7916                         }
7917
7918                         throw new NotImplementedException ();
7919                 }
7920
7921                 public void AddressOf (EmitContext ec, AddressOp mode)
7922                 {
7923                         var ac = (ArrayContainer) ea.Expr.Type;
7924
7925                         LoadArrayAndArguments (ec);
7926                         ec.EmitArrayAddress (ac);
7927                 }
7928
7929                 public SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
7930                 {
7931 #if NET_4_0
7932                         return SLE.Expression.ArrayAccess (
7933                                 ea.Expr.MakeExpression (ctx),
7934                                 Arguments.MakeExpression (ea.Arguments, ctx));
7935 #else
7936                         throw new NotImplementedException ();
7937 #endif
7938                 }
7939
7940                 public override SLE.Expression MakeExpression (BuilderContext ctx)
7941                 {
7942                         return SLE.Expression.ArrayIndex (
7943                                 ea.Expr.MakeExpression (ctx),
7944                                 Arguments.MakeExpression (ea.Arguments, ctx));
7945                 }
7946         }
7947
7948         //
7949         // Indexer access expression
7950         //
7951         class IndexerExpr : PropertyOrIndexerExpr<IndexerSpec>, OverloadResolver.IBaseMembersProvider
7952         {
7953                 LocalTemporary prepared_value;
7954                 IList<MemberSpec> indexers;
7955                 Arguments arguments;
7956
7957                 public IndexerExpr (IList<MemberSpec> indexers, ElementAccess ea)
7958                         : base (ea.Location)
7959                 {
7960                         this.indexers = indexers;
7961                         this.InstanceExpression = ea.Expr;
7962                         this.arguments = ea.Arguments;
7963                 }
7964
7965                 #region Properties
7966                 protected override TypeSpec DeclaringType {
7967                         get {
7968                                 return best_candidate.DeclaringType;
7969                         }
7970                 }
7971
7972                 public override bool IsInstance {
7973                         get {
7974                                 return true;
7975                         }
7976                 }
7977
7978                 public override bool IsStatic {
7979                         get {
7980                                 return false;
7981                         }
7982                 }
7983
7984                 public override string Name {
7985                         get {
7986                                 return "this";
7987                         }
7988                 }
7989
7990                 #endregion
7991
7992                 public override Expression CreateExpressionTree (ResolveContext ec)
7993                 {
7994                         Arguments args = Arguments.CreateForExpressionTree (ec, arguments,
7995                                 InstanceExpression.CreateExpressionTree (ec),
7996                                 new TypeOfMethod (Getter, loc));
7997
7998                         return CreateExpressionFactoryCall (ec, "Call", args);
7999                 }
8000
8001                 public override void Emit (EmitContext ec, bool leave_copy)
8002                 {
8003                         if (prepared) {
8004                                 prepared_value.Emit (ec);
8005                         } else {
8006                                 Invocation.EmitCall (ec, InstanceExpression, Getter, arguments, loc, false, false);
8007                         }
8008
8009                         if (leave_copy) {
8010                                 ec.Emit (OpCodes.Dup);
8011                                 temp = new LocalTemporary (Type);
8012                                 temp.Store (ec);
8013                         }
8014                 }
8015
8016                 public override void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
8017                 {
8018                         prepared = prepare_for_load;
8019                         Expression value = source;
8020
8021                         if (prepared) {
8022                                 Invocation.EmitCall (ec, InstanceExpression, Getter,
8023                                         arguments, loc, true, false);
8024
8025                                 prepared_value = new LocalTemporary (type);
8026                                 prepared_value.Store (ec);
8027                                 source.Emit (ec);
8028                                 prepared_value.Release (ec);
8029
8030                                 if (leave_copy) {
8031                                         ec.Emit (OpCodes.Dup);
8032                                         temp = new LocalTemporary (Type);
8033                                         temp.Store (ec);
8034                                 }
8035                         } else if (leave_copy) {
8036                                 temp = new LocalTemporary (Type);
8037                                 source.Emit (ec);
8038                                 temp.Store (ec);
8039                                 value = temp;
8040                         }
8041
8042                         if (!prepared)
8043                                 arguments.Add (new Argument (value));
8044
8045                         Invocation.EmitCall (ec, InstanceExpression, Setter, arguments, loc, false, prepared);
8046
8047                         if (temp != null) {
8048                                 temp.Emit (ec);
8049                                 temp.Release (ec);
8050                         }
8051                 }
8052
8053                 public override string GetSignatureForError ()
8054                 {
8055                         return best_candidate.GetSignatureForError ();
8056                 }
8057
8058                 public override SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
8059                 {
8060                         var value = new[] { source.MakeExpression (ctx) };
8061                         var args = Arguments.MakeExpression (arguments, ctx).Concat (value);
8062 #if NET_4_0
8063                         return SLE.Expression.Block (
8064                                         SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Setter.GetMetaInfo (), args),
8065                                         value [0]);
8066 #else
8067                         return args.First ();
8068 #endif
8069                 }
8070
8071                 public override SLE.Expression MakeExpression (BuilderContext ctx)
8072                 {
8073                         var args = Arguments.MakeExpression (arguments, ctx);
8074                         return SLE.Expression.Call (InstanceExpression.MakeExpression (ctx), (MethodInfo) Getter.GetMetaInfo (), args);
8075                 }
8076
8077                 protected override Expression OverloadResolve (ResolveContext rc, Expression right_side)
8078                 {
8079                         if (best_candidate != null)
8080                                 return this;
8081
8082                         eclass = ExprClass.IndexerAccess;
8083
8084                         bool dynamic;
8085                         arguments.Resolve (rc, out dynamic);
8086
8087                         if (indexers == null && InstanceExpression.Type == InternalType.Dynamic) {
8088                                 dynamic = true;
8089                         } else {
8090                                 var res = new OverloadResolver (indexers, OverloadResolver.Restrictions.None, loc);
8091                                 res.BaseMembersProvider = this;
8092
8093                                 // TODO: Do I need 2 argument sets?
8094                                 best_candidate = res.ResolveMember<IndexerSpec> (rc, ref arguments);
8095                                 if (best_candidate != null)
8096                                         type = best_candidate.MemberType;
8097                                 else if (!res.BestCandidateIsDynamic)
8098                                         return null;
8099                         }
8100
8101                         if (dynamic || type == InternalType.Dynamic) {
8102                                 Arguments args = new Arguments (arguments.Count + 1);
8103                                 if (IsBase) {
8104                                         rc.Report.Error (1972, loc,
8105                                                 "The indexer base access cannot be dynamically dispatched. Consider casting the dynamic arguments or eliminating the base access");
8106                                 } else {
8107                                         args.Add (new Argument (InstanceExpression));
8108                                 }
8109                                 args.AddRange (arguments);
8110
8111                                 best_candidate = null;
8112                                 return new DynamicIndexBinder (args, loc);
8113                         }
8114
8115                         ResolveInstanceExpression (rc);
8116                         CheckProtectedMemberAccess (rc, best_candidate);
8117                         return this;
8118                 }
8119
8120                 protected override void CloneTo (CloneContext clonectx, Expression t)
8121                 {
8122                         IndexerExpr target = (IndexerExpr) t;
8123
8124                         if (arguments != null)
8125                                 target.arguments = arguments.Clone (clonectx);
8126                 }
8127
8128                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
8129                 {
8130                         Error_TypeArgumentsCannotBeUsed (ec.Report, "indexer", GetSignatureForError (), loc);
8131                 }
8132
8133                 #region IBaseMembersProvider Members
8134
8135                 IList<MemberSpec> OverloadResolver.IBaseMembersProvider.GetBaseMembers (TypeSpec baseType)
8136                 {
8137                         return baseType == null ? null : MemberCache.FindMembers (baseType, MemberCache.IndexerNameAlias, false);
8138                 }
8139
8140                 MethodGroupExpr OverloadResolver.IBaseMembersProvider.LookupExtensionMethod (ResolveContext rc)
8141                 {
8142                         return null;
8143                 }
8144
8145                 #endregion
8146         }
8147
8148         //
8149         // A base access expression
8150         //
8151         public class BaseThis : This
8152         {
8153                 public BaseThis (Location loc)
8154                         : base (loc)
8155                 {
8156                 }
8157
8158                 public BaseThis (TypeSpec type, Location loc)
8159                         : base (loc)
8160                 {
8161                         this.type = type;
8162                         eclass = ExprClass.Variable;
8163                 }
8164
8165                 #region Properties
8166
8167                 public override string Name {
8168                         get {
8169                                 return "base";
8170                         }
8171                 }
8172
8173                 #endregion
8174
8175                 public override Expression CreateExpressionTree (ResolveContext ec)
8176                 {
8177                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
8178                         return base.CreateExpressionTree (ec);
8179                 }
8180
8181                 public override void Emit (EmitContext ec)
8182                 {
8183                         base.Emit (ec);
8184
8185                         if (ec.CurrentType.IsStruct) {
8186                                 ec.Emit (OpCodes.Ldobj, ec.CurrentType);
8187                                 ec.Emit (OpCodes.Box, ec.CurrentType);
8188                         }
8189                 }
8190
8191                 protected override void Error_ThisNotAvailable (ResolveContext ec)
8192                 {
8193                         if (ec.IsStatic) {
8194                                 ec.Report.Error (1511, loc, "Keyword `base' is not available in a static method");
8195                         } else {
8196                                 ec.Report.Error (1512, loc, "Keyword `base' is not available in the current context");
8197                         }
8198                 }
8199
8200                 public override void ResolveBase (ResolveContext ec)
8201                 {
8202                         base.ResolveBase (ec);
8203                         type = ec.CurrentType.BaseType;
8204                 }
8205         }
8206
8207         /// <summary>
8208         ///   This class exists solely to pass the Type around and to be a dummy
8209         ///   that can be passed to the conversion functions (this is used by
8210         ///   foreach implementation to typecast the object return value from
8211         ///   get_Current into the proper type.  All code has been generated and
8212         ///   we only care about the side effect conversions to be performed
8213         ///
8214         ///   This is also now used as a placeholder where a no-action expression
8215         ///   is needed (the `New' class).
8216         /// </summary>
8217         public class EmptyExpression : Expression {
8218                 public static readonly Expression Null = new EmptyExpression ();
8219
8220                 public class OutAccess : EmptyExpression
8221                 {
8222                         public static readonly OutAccess Instance = new OutAccess ();
8223
8224                         public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
8225                         {
8226                                 rc.Report.Error (206, right_side.Location,
8227                                         "A property, indexer or dynamic member access may not be passed as `ref' or `out' parameter");
8228
8229                                 return null;
8230                         }
8231                 }
8232
8233                 public static readonly EmptyExpression LValueMemberAccess = new EmptyExpression ();
8234                 public static readonly EmptyExpression LValueMemberOutAccess = new EmptyExpression ();
8235                 public static readonly EmptyExpression UnaryAddress = new EmptyExpression ();
8236                 public static readonly EmptyExpression EventAddition = new EmptyExpression ();
8237                 public static readonly EmptyExpression EventSubtraction = new EmptyExpression ();
8238
8239                 static EmptyExpression temp = new EmptyExpression ();
8240                 public static EmptyExpression Grab ()
8241                 {
8242                         EmptyExpression retval = temp == null ? new EmptyExpression () : temp;
8243                         temp = null;
8244                         return retval;
8245                 }
8246
8247                 public static void Release (EmptyExpression e)
8248                 {
8249                         temp = e;
8250                 }
8251
8252                 EmptyExpression ()
8253                 {
8254                         // FIXME: Don't set to object
8255                         type = TypeManager.object_type;
8256                         eclass = ExprClass.Value;
8257                         loc = Location.Null;
8258                 }
8259
8260                 public EmptyExpression (TypeSpec t)
8261                 {
8262                         type = t;
8263                         eclass = ExprClass.Value;
8264                         loc = Location.Null;
8265                 }
8266
8267                 public override Expression CreateExpressionTree (ResolveContext ec)
8268                 {
8269                         throw new NotSupportedException ("ET");
8270                 }
8271
8272                 protected override Expression DoResolve (ResolveContext ec)
8273                 {
8274                         return this;
8275                 }
8276
8277                 public override void Emit (EmitContext ec)
8278                 {
8279                         // nothing, as we only exist to not do anything.
8280                 }
8281
8282                 public override void EmitSideEffect (EmitContext ec)
8283                 {
8284                 }
8285
8286                 //
8287                 // This is just because we might want to reuse this bad boy
8288                 // instead of creating gazillions of EmptyExpressions.
8289                 // (CanImplicitConversion uses it)
8290                 //
8291                 public void SetType (TypeSpec t)
8292                 {
8293                         type = t;
8294                 }
8295         }
8296
8297         //
8298         // Empty statement expression
8299         //
8300         public sealed class EmptyExpressionStatement : ExpressionStatement
8301         {
8302                 public static readonly EmptyExpressionStatement Instance = new EmptyExpressionStatement ();
8303
8304                 private EmptyExpressionStatement ()
8305                 {
8306                         loc = Location.Null;
8307                 }
8308
8309                 public override Expression CreateExpressionTree (ResolveContext ec)
8310                 {
8311                         return null;
8312                 }
8313
8314                 public override void EmitStatement (EmitContext ec)
8315                 {
8316                         // Do nothing
8317                 }
8318
8319                 protected override Expression DoResolve (ResolveContext ec)
8320                 {
8321                         eclass = ExprClass.Value;
8322                         type = TypeManager.object_type;
8323                         return this;
8324                 }
8325
8326                 public override void Emit (EmitContext ec)
8327                 {
8328                         // Do nothing
8329                 }
8330         }
8331
8332         public class UserCast : Expression {
8333                 MethodSpec method;
8334                 Expression source;
8335
8336                 public UserCast (MethodSpec method, Expression source, Location l)
8337                 {
8338                         this.method = method;
8339                         this.source = source;
8340                         type = method.ReturnType;
8341                         loc = l;
8342                 }
8343
8344                 public Expression Source {
8345                         get {
8346                                 return source;
8347                         }
8348                 }
8349
8350                 public override Expression CreateExpressionTree (ResolveContext ec)
8351                 {
8352                         Arguments args = new Arguments (3);
8353                         args.Add (new Argument (source.CreateExpressionTree (ec)));
8354                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
8355                         args.Add (new Argument (new TypeOfMethod (method, loc)));
8356                         return CreateExpressionFactoryCall (ec, "Convert", args);
8357                 }
8358
8359                 protected override Expression DoResolve (ResolveContext ec)
8360                 {
8361                         ObsoleteAttribute oa = method.GetAttributeObsolete ();
8362                         if (oa != null)
8363                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
8364
8365                         eclass = ExprClass.Value;
8366                         return this;
8367                 }
8368
8369                 public override void Emit (EmitContext ec)
8370                 {
8371                         source.Emit (ec);
8372                         ec.Emit (OpCodes.Call, method);
8373                 }
8374
8375                 public override string GetSignatureForError ()
8376                 {
8377                         return TypeManager.CSharpSignature (method);
8378                 }
8379
8380                 public override SLE.Expression MakeExpression (BuilderContext ctx)
8381                 {
8382                         return SLE.Expression.Convert (source.MakeExpression (ctx), type.GetMetaInfo (), (MethodInfo) method.GetMetaInfo ());
8383                 }
8384         }
8385
8386         //
8387         // Holds additional type specifiers like ?, *, []
8388         //
8389         public class ComposedTypeSpecifier
8390         {
8391                 public static readonly ComposedTypeSpecifier SingleDimension = new ComposedTypeSpecifier (1, Location.Null);
8392
8393                 public readonly int Dimension;
8394                 public readonly Location Location;
8395
8396                 public ComposedTypeSpecifier (int specifier, Location loc)
8397                 {
8398                         this.Dimension = specifier;
8399                         this.Location = loc;
8400                 }
8401
8402                 #region Properties
8403                 public bool IsNullable {
8404                         get {
8405                                 return Dimension == -1;
8406                         }
8407                 }
8408
8409                 public bool IsPointer {
8410                         get {
8411                                 return Dimension == -2;
8412                         }
8413                 }
8414
8415                 public ComposedTypeSpecifier Next { get; set; }
8416
8417                 #endregion
8418
8419                 public static ComposedTypeSpecifier CreateArrayDimension (int dimension, Location loc)
8420                 {
8421                         return new ComposedTypeSpecifier (dimension, loc);
8422                 }
8423
8424                 public static ComposedTypeSpecifier CreateNullable (Location loc)
8425                 {
8426                         return new ComposedTypeSpecifier (-1, loc);
8427                 }
8428
8429                 public static ComposedTypeSpecifier CreatePointer (Location loc)
8430                 {
8431                         return new ComposedTypeSpecifier (-2, loc);
8432                 }
8433
8434                 public string GetSignatureForError ()
8435                 {
8436                         string s =
8437                                 IsPointer ? "*" :
8438                                 IsNullable ? "?" :
8439                                 ArrayContainer.GetPostfixSignature (Dimension);
8440
8441                         return Next != null ? s + Next.GetSignatureForError () : s;
8442                 }
8443         }
8444
8445         // <summary>
8446         //   This class is used to "construct" the type during a typecast
8447         //   operation.  Since the Type.GetType class in .NET can parse
8448         //   the type specification, we just use this to construct the type
8449         //   one bit at a time.
8450         // </summary>
8451         public class ComposedCast : TypeExpr {
8452                 FullNamedExpression left;
8453                 ComposedTypeSpecifier spec;
8454
8455                 public ComposedCast (FullNamedExpression left, ComposedTypeSpecifier spec)
8456                 {
8457                         if (spec == null)
8458                                 throw new ArgumentNullException ("spec");
8459
8460                         this.left = left;
8461                         this.spec = spec;
8462                         this.loc = spec.Location;
8463                 }
8464
8465                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
8466                 {
8467                         TypeExpr lexpr = left.ResolveAsTypeTerminal (ec, false);
8468                         if (lexpr == null)
8469                                 return null;
8470
8471                         type = lexpr.Type;
8472                         eclass = ExprClass.Type;
8473
8474                         var single_spec = spec;
8475
8476                         if (single_spec.IsNullable) {
8477                                 lexpr = new Nullable.NullableType (lexpr, loc);
8478                                 lexpr = lexpr.ResolveAsTypeTerminal (ec, false);
8479                                 if (lexpr != null)
8480                                         type = lexpr.Type;
8481
8482                                 single_spec = single_spec.Next;
8483                         } else if (single_spec.IsPointer) {
8484                                 if (!TypeManager.VerifyUnmanaged (ec.Compiler, type, loc))
8485                                         return null;
8486
8487                                 if (!ec.IsUnsafe) {
8488                                         UnsafeError (ec.Compiler.Report, loc);
8489                                 }
8490
8491                                 type = PointerContainer.MakeType (type);
8492                                 single_spec = single_spec.Next;
8493                         }
8494
8495                         if (single_spec != null && single_spec.Dimension > 0) {
8496                                 if (TypeManager.IsSpecialType (type)) {
8497                                         ec.Compiler.Report.Error (611, loc, "Array elements cannot be of type `{0}'", type.GetSignatureForError ());
8498                                 } else if (type.IsStatic) {
8499                                         ec.Compiler.Report.SymbolRelatedToPreviousError (type);
8500                                         ec.Compiler.Report.Error (719, loc, "Array elements cannot be of static type `{0}'",
8501                                                 type.GetSignatureForError ());
8502                                 } else {
8503                                         MakeArray (single_spec);
8504                                 }
8505                         }
8506
8507                         return this;
8508                 }
8509
8510                 void MakeArray (ComposedTypeSpecifier spec)
8511                 {
8512                         if (spec.Next != null)
8513                                 MakeArray (spec.Next);
8514
8515                         type = ArrayContainer.MakeType (type, spec.Dimension);
8516                 }
8517
8518                 public override string GetSignatureForError ()
8519                 {
8520                         return left.GetSignatureForError () + spec.GetSignatureForError ();
8521                 }
8522         }
8523
8524         public class FixedBufferPtr : Expression {
8525                 Expression array;
8526
8527                 public FixedBufferPtr (Expression array, TypeSpec array_type, Location l)
8528                 {
8529                         this.array = array;
8530                         this.loc = l;
8531
8532                         type = PointerContainer.MakeType (array_type);
8533                         eclass = ExprClass.Value;
8534                 }
8535
8536                 public override Expression CreateExpressionTree (ResolveContext ec)
8537                 {
8538                         Error_PointerInsideExpressionTree (ec);
8539                         return null;
8540                 }
8541
8542                 public override void Emit(EmitContext ec)
8543                 {
8544                         array.Emit (ec);
8545                 }
8546
8547                 protected override Expression DoResolve (ResolveContext ec)
8548                 {
8549                         //
8550                         // We are born fully resolved
8551                         //
8552                         return this;
8553                 }
8554         }
8555
8556
8557         //
8558         // This class is used to represent the address of an array, used
8559         // only by the Fixed statement, this generates "&a [0]" construct
8560         // for fixed (char *pa = a)
8561         //
8562         public class ArrayPtr : FixedBufferPtr {
8563                 TypeSpec array_type;
8564
8565                 public ArrayPtr (Expression array, TypeSpec array_type, Location l):
8566                         base (array, array_type, l)
8567                 {
8568                         this.array_type = array_type;
8569                 }
8570
8571                 public override void Emit (EmitContext ec)
8572                 {
8573                         base.Emit (ec);
8574
8575                         ec.EmitInt (0);
8576                         ec.Emit (OpCodes.Ldelema, array_type);
8577                 }
8578         }
8579
8580         //
8581         // Encapsulates a conversion rules required for array indexes
8582         //
8583         public class ArrayIndexCast : TypeCast
8584         {
8585                 public ArrayIndexCast (Expression expr)
8586                         : base (expr, TypeManager.int32_type)
8587                 {
8588                         if (expr.Type == TypeManager.int32_type)
8589                                 throw new ArgumentException ("unnecessary array index conversion");
8590                 }
8591
8592                 public override Expression CreateExpressionTree (ResolveContext ec)
8593                 {
8594                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
8595                                 return base.CreateExpressionTree (ec);
8596                         }
8597                 }
8598
8599                 public override void Emit (EmitContext ec)
8600                 {
8601                         child.Emit (ec);
8602
8603                         var expr_type = child.Type;
8604
8605                         if (expr_type == TypeManager.uint32_type)
8606                                 ec.Emit (OpCodes.Conv_U);
8607                         else if (expr_type == TypeManager.int64_type)
8608                                 ec.Emit (OpCodes.Conv_Ovf_I);
8609                         else if (expr_type == TypeManager.uint64_type)
8610                                 ec.Emit (OpCodes.Conv_Ovf_I_Un);
8611                         else
8612                                 throw new InternalErrorException ("Cannot emit cast to unknown array element type", type);
8613                 }
8614         }
8615
8616         //
8617         // Implements the `stackalloc' keyword
8618         //
8619         public class StackAlloc : Expression {
8620                 TypeSpec otype;
8621                 Expression t;
8622                 Expression count;
8623
8624                 public StackAlloc (Expression type, Expression count, Location l)
8625                 {
8626                         t = type;
8627                         this.count = count;
8628                         loc = l;
8629                 }
8630
8631                 public override Expression CreateExpressionTree (ResolveContext ec)
8632                 {
8633                         throw new NotSupportedException ("ET");
8634                 }
8635
8636                 protected override Expression DoResolve (ResolveContext ec)
8637                 {
8638                         count = count.Resolve (ec);
8639                         if (count == null)
8640                                 return null;
8641
8642                         if (count.Type != TypeManager.uint32_type){
8643                                 count = Convert.ImplicitConversionRequired (ec, count, TypeManager.int32_type, loc);
8644                                 if (count == null)
8645                                         return null;
8646                         }
8647
8648                         Constant c = count as Constant;
8649                         if (c != null && c.IsNegative) {
8650                                 ec.Report.Error (247, loc, "Cannot use a negative size with stackalloc");
8651                         }
8652
8653                         if (ec.HasAny (ResolveContext.Options.CatchScope | ResolveContext.Options.FinallyScope)) {
8654                                 ec.Report.Error (255, loc, "Cannot use stackalloc in finally or catch");
8655                         }
8656
8657                         TypeExpr texpr = t.ResolveAsTypeTerminal (ec, false);
8658                         if (texpr == null)
8659                                 return null;
8660
8661                         otype = texpr.Type;
8662
8663                         if (!TypeManager.VerifyUnmanaged (ec.Compiler, otype, loc))
8664                                 return null;
8665
8666                         type = PointerContainer.MakeType (otype);
8667                         eclass = ExprClass.Value;
8668
8669                         return this;
8670                 }
8671
8672                 public override void Emit (EmitContext ec)
8673                 {
8674                         int size = GetTypeSize (otype);
8675
8676                         count.Emit (ec);
8677
8678                         if (size == 0)
8679                                 ec.Emit (OpCodes.Sizeof, otype);
8680                         else
8681                                 ec.EmitInt (size);
8682
8683                         ec.Emit (OpCodes.Mul_Ovf_Un);
8684                         ec.Emit (OpCodes.Localloc);
8685                 }
8686
8687                 protected override void CloneTo (CloneContext clonectx, Expression t)
8688                 {
8689                         StackAlloc target = (StackAlloc) t;
8690                         target.count = count.Clone (clonectx);
8691                         target.t = t.Clone (clonectx);
8692                 }
8693         }
8694
8695         //
8696         // An object initializer expression
8697         //
8698         public class ElementInitializer : Assign
8699         {
8700                 public readonly string Name;
8701
8702                 public ElementInitializer (string name, Expression initializer, Location loc)
8703                         : base (null, initializer, loc)
8704                 {
8705                         this.Name = name;
8706                 }
8707
8708                 protected override void CloneTo (CloneContext clonectx, Expression t)
8709                 {
8710                         ElementInitializer target = (ElementInitializer) t;
8711                         target.source = source.Clone (clonectx);
8712                 }
8713
8714                 public override Expression CreateExpressionTree (ResolveContext ec)
8715                 {
8716                         Arguments args = new Arguments (2);
8717                         FieldExpr fe = target as FieldExpr;
8718                         if (fe != null)
8719                                 args.Add (new Argument (fe.CreateTypeOfExpression ()));
8720                         else
8721                                 args.Add (new Argument (((PropertyExpr)target).CreateSetterTypeOfExpression ()));
8722
8723                         args.Add (new Argument (source.CreateExpressionTree (ec)));
8724                         return CreateExpressionFactoryCall (ec,
8725                                 source is CollectionOrObjectInitializers ? "ListBind" : "Bind",
8726                                 args);
8727                 }
8728
8729                 protected override Expression DoResolve (ResolveContext ec)
8730                 {
8731                         if (source == null)
8732                                 return EmptyExpressionStatement.Instance;
8733
8734                         var t = ec.CurrentInitializerVariable.Type;
8735
8736                         var member = MemberLookup (ec, ec.CurrentType, t, Name, 0, false, loc);
8737                         if (member == null) {
8738                                 member = Expression.MemberLookup (null, ec.CurrentType, t, Name, 0, false, loc);
8739
8740                                 if (member != null) {
8741                                         // TODO: ec.Report.SymbolRelatedToPreviousError (member);
8742                                         ErrorIsInaccesible (ec, member.GetSignatureForError (), loc);
8743                                         return null;
8744                                 }
8745                         }
8746
8747                         if (member == null) {
8748                                 Error_TypeDoesNotContainDefinition (ec, loc, t, Name);
8749                                 return null;
8750                         }
8751
8752                         if (!(member is PropertyExpr || member is FieldExpr)) {
8753                                 ec.Report.Error (1913, loc,
8754                                         "Member `{0}' cannot be initialized. An object initializer may only be used for fields, or properties",
8755                                         member.GetSignatureForError ());
8756
8757                                 return null;
8758                         }
8759
8760                         var me = member as MemberExpr;
8761                         if (me.IsStatic) {
8762                                 ec.Report.Error (1914, loc,
8763                                         "Static field or property `{0}' cannot be assigned in an object initializer",
8764                                         me.GetSignatureForError ());
8765                         }
8766
8767                         target = me;
8768                         me.InstanceExpression = ec.CurrentInitializerVariable;
8769
8770                         if (source is CollectionOrObjectInitializers) {
8771                                 Expression previous = ec.CurrentInitializerVariable;
8772                                 ec.CurrentInitializerVariable = target;
8773                                 source = source.Resolve (ec);
8774                                 ec.CurrentInitializerVariable = previous;
8775                                 if (source == null)
8776                                         return null;
8777
8778                                 eclass = source.eclass;
8779                                 type = source.Type;
8780                                 return this;
8781                         }
8782
8783                         return base.DoResolve (ec);
8784                 }
8785
8786                 public override void EmitStatement (EmitContext ec)
8787                 {
8788                         if (source is CollectionOrObjectInitializers)
8789                                 source.Emit (ec);
8790                         else
8791                                 base.EmitStatement (ec);
8792                 }
8793         }
8794
8795         //
8796         // A collection initializer expression
8797         //
8798         class CollectionElementInitializer : Invocation
8799         {
8800                 public class ElementInitializerArgument : Argument
8801                 {
8802                         public ElementInitializerArgument (Expression e)
8803                                 : base (e)
8804                         {
8805                         }
8806                 }
8807
8808                 sealed class AddMemberAccess : MemberAccess
8809                 {
8810                         public AddMemberAccess (Expression expr, Location loc)
8811                                 : base (expr, "Add", loc)
8812                         {
8813                         }
8814
8815                         protected override void Error_TypeDoesNotContainDefinition (ResolveContext ec, TypeSpec type, string name)
8816                         {
8817                                 if (TypeManager.HasElementType (type))
8818                                         return;
8819
8820                                 base.Error_TypeDoesNotContainDefinition (ec, type, name);
8821                         }
8822                 }
8823
8824                 public CollectionElementInitializer (Expression argument)
8825                         : base (null, new Arguments (1))
8826                 {
8827                         base.arguments.Add (new ElementInitializerArgument (argument));
8828                         this.loc = argument.Location;
8829                 }
8830
8831                 public CollectionElementInitializer (List<Expression> arguments, Location loc)
8832                         : base (null, new Arguments (arguments.Count))
8833                 {
8834                         foreach (Expression e in arguments)
8835                                 base.arguments.Add (new ElementInitializerArgument (e));
8836
8837                         this.loc = loc;
8838                 }
8839
8840                 public override Expression CreateExpressionTree (ResolveContext ec)
8841                 {
8842                         Arguments args = new Arguments (2);
8843                         args.Add (new Argument (mg.CreateExpressionTree (ec)));
8844
8845                         var expr_initializers = new ArrayInitializer (arguments.Count, loc);
8846                         foreach (Argument a in arguments)
8847                                 expr_initializers.Add (a.CreateExpressionTree (ec));
8848
8849                         args.Add (new Argument (new ArrayCreation (
8850                                 CreateExpressionTypeExpression (ec, loc), expr_initializers, loc)));
8851                         return CreateExpressionFactoryCall (ec, "ElementInit", args);
8852                 }
8853
8854                 protected override void CloneTo (CloneContext clonectx, Expression t)
8855                 {
8856                         CollectionElementInitializer target = (CollectionElementInitializer) t;
8857                         if (arguments != null)
8858                                 target.arguments = arguments.Clone (clonectx);
8859                 }
8860
8861                 protected override Expression DoResolve (ResolveContext ec)
8862                 {
8863                         base.expr = new AddMemberAccess (ec.CurrentInitializerVariable, loc);
8864
8865                         return base.DoResolve (ec);
8866                 }
8867         }
8868
8869         //
8870         // A block of object or collection initializers
8871         //
8872         public class CollectionOrObjectInitializers : ExpressionStatement
8873         {
8874                 IList<Expression> initializers;
8875                 bool is_collection_initialization;
8876
8877                 public static readonly CollectionOrObjectInitializers Empty =
8878                         new CollectionOrObjectInitializers (Array.AsReadOnly (new Expression [0]), Location.Null);
8879
8880                 public CollectionOrObjectInitializers (IList<Expression> initializers, Location loc)
8881                 {
8882                         this.initializers = initializers;
8883                         this.loc = loc;
8884                 }
8885
8886                 public bool IsEmpty {
8887                         get {
8888                                 return initializers.Count == 0;
8889                         }
8890                 }
8891
8892                 public bool IsCollectionInitializer {
8893                         get {
8894                                 return is_collection_initialization;
8895                         }
8896                 }
8897
8898                 protected override void CloneTo (CloneContext clonectx, Expression target)
8899                 {
8900                         CollectionOrObjectInitializers t = (CollectionOrObjectInitializers) target;
8901
8902                         t.initializers = new List<Expression> (initializers.Count);
8903                         foreach (var e in initializers)
8904                                 t.initializers.Add (e.Clone (clonectx));
8905                 }
8906
8907                 public override Expression CreateExpressionTree (ResolveContext ec)
8908                 {
8909                         var expr_initializers = new ArrayInitializer (initializers.Count, loc);
8910                         foreach (Expression e in initializers) {
8911                                 Expression expr = e.CreateExpressionTree (ec);
8912                                 if (expr != null)
8913                                         expr_initializers.Add (expr);
8914                         }
8915
8916                         return new ImplicitlyTypedArrayCreation (expr_initializers, loc);
8917                 }
8918
8919                 protected override Expression DoResolve (ResolveContext ec)
8920                 {
8921                         List<string> element_names = null;
8922                         for (int i = 0; i < initializers.Count; ++i) {
8923                                 Expression initializer = initializers [i];
8924                                 ElementInitializer element_initializer = initializer as ElementInitializer;
8925
8926                                 if (i == 0) {
8927                                         if (element_initializer != null) {
8928                                                 element_names = new List<string> (initializers.Count);
8929                                                 element_names.Add (element_initializer.Name);
8930                                         } else if (initializer is CompletingExpression){
8931                                                 initializer.Resolve (ec);
8932                                                 throw new InternalErrorException ("This line should never be reached");
8933                                         } else {
8934                                                 if (!ec.CurrentInitializerVariable.Type.ImplementsInterface (TypeManager.ienumerable_type)) {
8935                                                         ec.Report.Error (1922, loc, "A field or property `{0}' cannot be initialized with a collection " +
8936                                                                 "object initializer because type `{1}' does not implement `{2}' interface",
8937                                                                 ec.CurrentInitializerVariable.GetSignatureForError (),
8938                                                                 TypeManager.CSharpName (ec.CurrentInitializerVariable.Type),
8939                                                                 TypeManager.CSharpName (TypeManager.ienumerable_type));
8940                                                         return null;
8941                                                 }
8942                                                 is_collection_initialization = true;
8943                                         }
8944                                 } else {
8945                                         if (is_collection_initialization != (element_initializer == null)) {
8946                                                 ec.Report.Error (747, initializer.Location, "Inconsistent `{0}' member declaration",
8947                                                         is_collection_initialization ? "collection initializer" : "object initializer");
8948                                                 continue;
8949                                         }
8950
8951                                         if (!is_collection_initialization) {
8952                                                 if (element_names.Contains (element_initializer.Name)) {
8953                                                         ec.Report.Error (1912, element_initializer.Location,
8954                                                                 "An object initializer includes more than one member `{0}' initialization",
8955                                                                 element_initializer.Name);
8956                                                 } else {
8957                                                         element_names.Add (element_initializer.Name);
8958                                                 }
8959                                         }
8960                                 }
8961
8962                                 Expression e = initializer.Resolve (ec);
8963                                 if (e == EmptyExpressionStatement.Instance)
8964                                         initializers.RemoveAt (i--);
8965                                 else
8966                                         initializers [i] = e;
8967                         }
8968
8969                         type = ec.CurrentInitializerVariable.Type;
8970                         if (is_collection_initialization) {
8971                                 if (TypeManager.HasElementType (type)) {
8972                                         ec.Report.Error (1925, loc, "Cannot initialize object of type `{0}' with a collection initializer",
8973                                                 TypeManager.CSharpName (type));
8974                                 }
8975                         }
8976
8977                         eclass = ExprClass.Variable;
8978                         return this;
8979                 }
8980
8981                 public override void Emit (EmitContext ec)
8982                 {
8983                         EmitStatement (ec);
8984                 }
8985
8986                 public override void EmitStatement (EmitContext ec)
8987                 {
8988                         foreach (ExpressionStatement e in initializers)
8989                                 e.EmitStatement (ec);
8990                 }
8991         }
8992
8993         //
8994         // New expression with element/object initializers
8995         //
8996         public class NewInitialize : New
8997         {
8998                 //
8999                 // This class serves as a proxy for variable initializer target instances.
9000                 // A real variable is assigned later when we resolve left side of an
9001                 // assignment
9002                 //
9003                 sealed class InitializerTargetExpression : Expression, IMemoryLocation
9004                 {
9005                         NewInitialize new_instance;
9006
9007                         public InitializerTargetExpression (NewInitialize newInstance)
9008                         {
9009                                 this.type = newInstance.type;
9010                                 this.loc = newInstance.loc;
9011                                 this.eclass = newInstance.eclass;
9012                                 this.new_instance = newInstance;
9013                         }
9014
9015                         public override Expression CreateExpressionTree (ResolveContext ec)
9016                         {
9017                                 // Should not be reached
9018                                 throw new NotSupportedException ("ET");
9019                         }
9020
9021                         protected override Expression DoResolve (ResolveContext ec)
9022                         {
9023                                 return this;
9024                         }
9025
9026                         public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
9027                         {
9028                                 return this;
9029                         }
9030
9031                         public override void Emit (EmitContext ec)
9032                         {
9033                                 Expression e = (Expression) new_instance.instance;
9034                                 e.Emit (ec);
9035                         }
9036
9037                         #region IMemoryLocation Members
9038
9039                         public void AddressOf (EmitContext ec, AddressOp mode)
9040                         {
9041                                 new_instance.instance.AddressOf (ec, mode);
9042                         }
9043
9044                         #endregion
9045                 }
9046
9047                 CollectionOrObjectInitializers initializers;
9048                 IMemoryLocation instance;
9049
9050                 public NewInitialize (FullNamedExpression requested_type, Arguments arguments, CollectionOrObjectInitializers initializers, Location l)
9051                         : base (requested_type, arguments, l)
9052                 {
9053                         this.initializers = initializers;
9054                 }
9055
9056                 protected override IMemoryLocation EmitAddressOf (EmitContext ec, AddressOp Mode)
9057                 {
9058                         instance = base.EmitAddressOf (ec, Mode);
9059
9060                         if (!initializers.IsEmpty)
9061                                 initializers.Emit (ec);
9062
9063                         return instance;
9064                 }
9065
9066                 protected override void CloneTo (CloneContext clonectx, Expression t)
9067                 {
9068                         base.CloneTo (clonectx, t);
9069
9070                         NewInitialize target = (NewInitialize) t;
9071                         target.initializers = (CollectionOrObjectInitializers) initializers.Clone (clonectx);
9072                 }
9073
9074                 public override Expression CreateExpressionTree (ResolveContext ec)
9075                 {
9076                         Arguments args = new Arguments (2);
9077                         args.Add (new Argument (base.CreateExpressionTree (ec)));
9078                         if (!initializers.IsEmpty)
9079                                 args.Add (new Argument (initializers.CreateExpressionTree (ec)));
9080
9081                         return CreateExpressionFactoryCall (ec,
9082                                 initializers.IsCollectionInitializer ? "ListInit" : "MemberInit",
9083                                 args);
9084                 }
9085
9086                 protected override Expression DoResolve (ResolveContext ec)
9087                 {
9088                         Expression e = base.DoResolve (ec);
9089                         if (type == null)
9090                                 return null;
9091
9092                         Expression previous = ec.CurrentInitializerVariable;
9093                         ec.CurrentInitializerVariable = new InitializerTargetExpression (this);
9094                         initializers.Resolve (ec);
9095                         ec.CurrentInitializerVariable = previous;
9096                         return e;
9097                 }
9098
9099                 public override bool Emit (EmitContext ec, IMemoryLocation target)
9100                 {
9101                         bool left_on_stack = base.Emit (ec, target);
9102
9103                         if (initializers.IsEmpty)
9104                                 return left_on_stack;
9105
9106                         LocalTemporary temp = target as LocalTemporary;
9107                         if (temp == null) {
9108                                 if (!left_on_stack) {
9109                                         VariableReference vr = target as VariableReference;
9110
9111                                         // FIXME: This still does not work correctly for pre-set variables
9112                                         if (vr != null && vr.IsRef)
9113                                                 target.AddressOf (ec, AddressOp.Load);
9114
9115                                         ((Expression) target).Emit (ec);
9116                                         left_on_stack = true;
9117                                 }
9118
9119                                 temp = new LocalTemporary (type);
9120                         }
9121
9122                         instance = temp;
9123                         if (left_on_stack)
9124                                 temp.Store (ec);
9125
9126                         initializers.Emit (ec);
9127
9128                         if (left_on_stack) {
9129                                 temp.Emit (ec);
9130                                 temp.Release (ec);
9131                         }
9132
9133                         return left_on_stack;
9134                 }
9135
9136                 public override bool HasInitializer {
9137                         get {
9138                                 return !initializers.IsEmpty;
9139                         }
9140                 }
9141         }
9142
9143         public class NewAnonymousType : New
9144         {
9145                 static readonly AnonymousTypeParameter[] EmptyParameters = new AnonymousTypeParameter[0];
9146
9147                 List<AnonymousTypeParameter> parameters;
9148                 readonly TypeContainer parent;
9149                 AnonymousTypeClass anonymous_type;
9150
9151                 public NewAnonymousType (List<AnonymousTypeParameter> parameters, TypeContainer parent, Location loc)
9152                          : base (null, null, loc)
9153                 {
9154                         this.parameters = parameters;
9155                         this.parent = parent;
9156                 }
9157
9158                 protected override void CloneTo (CloneContext clonectx, Expression target)
9159                 {
9160                         if (parameters == null)
9161                                 return;
9162
9163                         NewAnonymousType t = (NewAnonymousType) target;
9164                         t.parameters = new List<AnonymousTypeParameter> (parameters.Count);
9165                         foreach (AnonymousTypeParameter atp in parameters)
9166                                 t.parameters.Add ((AnonymousTypeParameter) atp.Clone (clonectx));
9167                 }
9168
9169                 AnonymousTypeClass CreateAnonymousType (ResolveContext ec, IList<AnonymousTypeParameter> parameters)
9170                 {
9171                         AnonymousTypeClass type = parent.Module.Compiled.GetAnonymousType (parameters);
9172                         if (type != null)
9173                                 return type;
9174
9175                         type = AnonymousTypeClass.Create (ec.Compiler, parent, parameters, loc);
9176                         if (type == null)
9177                                 return null;
9178
9179                         type.CreateType ();
9180                         type.DefineType ();
9181                         type.ResolveTypeParameters ();
9182                         type.Define ();
9183                         type.EmitType ();
9184                         if (ec.Report.Errors == 0)
9185                                 type.CloseType ();
9186
9187                         parent.Module.Compiled.AddAnonymousType (type);
9188                         return type;
9189                 }
9190
9191                 public override Expression CreateExpressionTree (ResolveContext ec)
9192                 {
9193                         if (parameters == null)
9194                                 return base.CreateExpressionTree (ec);
9195
9196                         var init = new ArrayInitializer (parameters.Count, loc);
9197                         foreach (Property p in anonymous_type.Properties)
9198                                 init.Add (new TypeOfMethod (MemberCache.GetMember (type, p.Get.Spec), loc));
9199
9200                         var ctor_args = new ArrayInitializer (Arguments.Count, loc);
9201                         foreach (Argument a in Arguments)
9202                                 ctor_args.Add (a.CreateExpressionTree (ec));
9203
9204                         Arguments args = new Arguments (3);
9205                         args.Add (new Argument (new TypeOfMethod (method, loc)));
9206                         args.Add (new Argument (new ArrayCreation (TypeManager.expression_type_expr, ctor_args, loc)));
9207                         args.Add (new Argument (new ImplicitlyTypedArrayCreation (init, loc)));
9208
9209                         return CreateExpressionFactoryCall (ec, "New", args);
9210                 }
9211
9212                 protected override Expression DoResolve (ResolveContext ec)
9213                 {
9214                         if (ec.HasSet (ResolveContext.Options.ConstantScope)) {
9215                                 ec.Report.Error (836, loc, "Anonymous types cannot be used in this expression");
9216                                 return null;
9217                         }
9218
9219                         if (parameters == null) {
9220                                 anonymous_type = CreateAnonymousType (ec, EmptyParameters);
9221                                 RequestedType = new TypeExpression (anonymous_type.Definition, loc);
9222                                 return base.DoResolve (ec);
9223                         }
9224
9225                         bool error = false;
9226                         Arguments = new Arguments (parameters.Count);
9227                         TypeExpression [] t_args = new TypeExpression [parameters.Count];
9228                         for (int i = 0; i < parameters.Count; ++i) {
9229                                 Expression e = ((AnonymousTypeParameter) parameters [i]).Resolve (ec);
9230                                 if (e == null) {
9231                                         error = true;
9232                                         continue;
9233                                 }
9234
9235                                 Arguments.Add (new Argument (e));
9236                                 t_args [i] = new TypeExpression (e.Type, e.Location);
9237                         }
9238
9239                         if (error)
9240                                 return null;
9241
9242                         anonymous_type = CreateAnonymousType (ec, parameters);
9243                         if (anonymous_type == null)
9244                                 return null;
9245
9246                         RequestedType = new GenericTypeExpr (anonymous_type.Definition, new TypeArguments (t_args), loc);
9247                         return base.DoResolve (ec);
9248                 }
9249         }
9250
9251         public class AnonymousTypeParameter : ShimExpression
9252         {
9253                 public readonly string Name;
9254
9255                 public AnonymousTypeParameter (Expression initializer, string name, Location loc)
9256                         : base (initializer)
9257                 {
9258                         this.Name = name;
9259                         this.loc = loc;
9260                 }
9261
9262                 public AnonymousTypeParameter (Parameter parameter)
9263                         : base (new SimpleName (parameter.Name, parameter.Location))
9264                 {
9265                         this.Name = parameter.Name;
9266                         this.loc = parameter.Location;
9267                 }
9268
9269                 public override bool Equals (object o)
9270                 {
9271                         AnonymousTypeParameter other = o as AnonymousTypeParameter;
9272                         return other != null && Name == other.Name;
9273                 }
9274
9275                 public override int GetHashCode ()
9276                 {
9277                         return Name.GetHashCode ();
9278                 }
9279
9280                 protected override Expression DoResolve (ResolveContext ec)
9281                 {
9282                         Expression e = expr.Resolve (ec);
9283                         if (e == null)
9284                                 return null;
9285
9286                         if (e.eclass == ExprClass.MethodGroup) {
9287                                 Error_InvalidInitializer (ec, e.ExprClassName);
9288                                 return null;
9289                         }
9290
9291                         type = e.Type;
9292                         if (type == TypeManager.void_type || type == TypeManager.null_type ||
9293                                 type == InternalType.AnonymousMethod || type.IsPointer) {
9294                                 Error_InvalidInitializer (ec, e.GetSignatureForError ());
9295                                 return null;
9296                         }
9297
9298                         return e;
9299                 }
9300
9301                 protected virtual void Error_InvalidInitializer (ResolveContext ec, string initializer)
9302                 {
9303                         ec.Report.Error (828, loc, "An anonymous type property `{0}' cannot be initialized with `{1}'",
9304                                 Name, initializer);
9305                 }
9306         }
9307 }