2010-06-18 Marek Safar <marek.safar@gmail.com>
[mono.git] / mcs / mcs / dynamic.cs
1 //
2 // dynamic.cs: support for dynamic expressions
3 //
4 // Authors: Marek Safar (marek.safar@gmail.com)
5 //
6 // Dual licensed under the terms of the MIT X11 or GNU GPL
7 //
8 // Copyright 2009 Novell, Inc
9 //
10
11 using System;
12 using System.Reflection.Emit;
13 using SLE = System.Linq.Expressions;
14
15 #if NET_4_0
16 using System.Dynamic;
17 #endif
18
19 namespace Mono.CSharp
20 {
21         //
22         // A copy of Microsoft.CSharp/Microsoft.CSharp.RuntimeBinder/CSharpBinderFlags.cs
23         // has to be kept in sync
24         //
25         [Flags]
26         public enum CSharpBinderFlags
27         {
28                 None = 0,
29                 CheckedContext = 1,
30                 InvokeSimpleName = 1 << 1,
31                 InvokeSpecialName = 1 << 2,
32                 BinaryOperationLogical = 1 << 3,
33                 ConvertExplicit = 1 << 4,
34                 ConvertArrayIndex = 1 << 5,
35                 ResultIndexed = 1 << 6,
36                 ValueFromCompoundAssignment = 1 << 7,
37                 ResultDiscarded = 1 << 8
38         }
39
40         //
41         // Type expression with internal dynamic type symbol
42         //
43         class DynamicTypeExpr : TypeExpr
44         {
45                 public DynamicTypeExpr (Location loc)
46                 {
47                         this.loc = loc;
48
49                         type = InternalType.Dynamic;
50                         eclass = ExprClass.Type;
51                 }
52
53                 public override bool CheckAccessLevel (IMemberContext ds)
54                 {
55                         return true;
56                 }
57
58                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
59                 {
60                         return this;
61                 }
62         }
63
64         #region Dynamic runtime binder expressions
65
66         //
67         // Expression created from runtime dynamic object value by dynamic binder
68         //
69         public class RuntimeValueExpression : Expression, IDynamicAssign, IMemoryLocation
70         {
71 #if !NET_4_0
72                 public class DynamicMetaObject
73                 {
74                         public TypeSpec RuntimeType;
75                         public TypeSpec LimitType;
76                         public SLE.Expression Expression;
77                 }
78 #endif
79
80                 readonly DynamicMetaObject obj;
81
82                 public RuntimeValueExpression (DynamicMetaObject obj, TypeSpec type)
83                 {
84                         this.obj = obj;
85                         this.type = type;
86                         this.eclass = ExprClass.Variable;
87                 }
88
89                 #region Properties
90
91                 public bool IsSuggestionOnly { get; set; }
92
93                 public DynamicMetaObject MetaObject {
94                         get { return obj; }
95                 }
96
97                 #endregion
98
99                 public void AddressOf (EmitContext ec, AddressOp mode)
100                 {
101                         throw new NotImplementedException ();
102                 }
103
104                 public override Expression CreateExpressionTree (ResolveContext ec)
105                 {
106                         throw new NotImplementedException ();
107                 }
108
109                 protected override Expression DoResolve (ResolveContext ec)
110                 {
111                         return this;
112                 }
113
114                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
115                 {
116                         return this;
117                 }
118
119                 public override void Emit (EmitContext ec)
120                 {
121                         throw new NotImplementedException ();
122                 }
123
124                 #region IAssignMethod Members
125
126                 public void Emit (EmitContext ec, bool leave_copy)
127                 {
128                         throw new NotImplementedException ();
129                 }
130
131                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
132                 {
133                         throw new NotImplementedException ();
134                 }
135
136                 #endregion
137
138                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
139                 {
140                         return obj.Expression;
141                 }
142
143                 public override SLE.Expression MakeExpression (BuilderContext ctx)
144                 {
145                         return SLE.Expression.Convert (obj.Expression, type.GetMetaInfo ());
146                 }
147         }
148
149         //
150         // Wraps runtime dynamic expression into expected type. Needed
151         // to satify expected type check by dynamic binder and no conversion
152         // is required (ResultDiscarded).
153         //
154         public class DynamicResultCast : ShimExpression
155         {
156                 public DynamicResultCast (TypeSpec type, Expression expr)
157                         : base (expr)
158                 {
159                         this.type = type;
160                 }
161
162                 protected override Expression DoResolve (ResolveContext ec)
163                 {
164                         expr = expr.Resolve (ec);
165                         eclass = ExprClass.Value;
166                         return this;
167                 }
168
169 #if NET_4_0
170                 public override SLE.Expression MakeExpression (BuilderContext ctx)
171                 {
172                         return SLE.Expression.Block (expr.MakeExpression (ctx), SLE.Expression.Default (type.GetMetaInfo ()));
173                 }
174 #endif
175         }
176
177         #endregion
178
179         //
180         // Creates dynamic binder expression
181         //
182         interface IDynamicBinder
183         {
184                 Expression CreateCallSiteBinder (ResolveContext ec, Arguments args);
185         }
186
187         //
188         // Extends standard assignment interface for expressions
189         // supported by dynamic resolver
190         //
191         interface IDynamicAssign : IAssignMethod
192         {
193 #if NET_4_0
194                 SLE.Expression MakeAssignExpression (BuilderContext ctx);
195 #endif
196         }
197
198         //
199         // Base dynamic expression statement creator
200         //
201         class DynamicExpressionStatement : ExpressionStatement
202         {
203                 class StaticDataClass : CompilerGeneratedClass
204                 {
205                         public StaticDataClass ()
206                                 : base (new RootDeclSpace (new NamespaceEntry (null, null, null)),
207                                         new MemberName (CompilerGeneratedClass.MakeName (null, "c", "DynamicSites", 0)),
208                                         Modifiers.INTERNAL | Modifiers.STATIC)
209                         {
210                         }
211                 }
212
213                 //
214                 // Binder flag dynamic constant, the value is combination of
215                 // flags known at resolve stage and flags known only at emit
216                 // stage
217                 //
218                 protected class BinderFlags : EnumConstant
219                 {
220                         DynamicExpressionStatement statement;
221                         CSharpBinderFlags flags;
222
223                         public BinderFlags (CSharpBinderFlags flags, DynamicExpressionStatement statement)
224                                 : base (statement.loc)
225                         {
226                                 this.flags = flags;
227                                 this.statement = statement;
228                         }
229
230                         protected override Expression DoResolve (ResolveContext ec)
231                         {
232                                 Child = new IntConstant ((int) (flags | statement.flags), statement.loc).Resolve (ec);
233
234                                 type = TypeManager.binder_flags;
235                                 eclass = Child.eclass;
236                                 return this;
237                         }
238                 }
239
240                 static StaticDataClass global_site_container;
241                 static int field_counter;
242                 static int container_counter;
243
244                 readonly Arguments arguments;
245                 protected IDynamicBinder binder;
246                 protected Expression binder_expr;
247
248                 // Used by BinderFlags
249                 protected CSharpBinderFlags flags;
250
251                 public DynamicExpressionStatement (IDynamicBinder binder, Arguments args, Location loc)
252                 {
253                         this.binder = binder;
254                         this.arguments = args;
255                         this.loc = loc;
256                 }
257
258                 public Arguments Arguments {
259                         get {
260                                 return arguments;
261                         }
262                 }
263
264                 static TypeContainer CreateSiteContainer ()
265                 {
266                         if (global_site_container == null) {
267                                 global_site_container = new StaticDataClass ();
268                                 RootContext.ToplevelTypes.AddCompilerGeneratedClass (global_site_container);
269                                 global_site_container.CreateType ();
270                                 global_site_container.DefineType ();
271                                 global_site_container.Define ();
272                         }
273
274                         return global_site_container;
275                 }
276
277                 static Field CreateSiteField (FullNamedExpression type)
278                 {
279                         TypeContainer site_container = CreateSiteContainer ();
280                         Field f = new Field (site_container, type, Modifiers.PUBLIC | Modifiers.STATIC,
281                                 new MemberName ("Site" +  field_counter++), null);
282                         f.Define ();
283
284                         site_container.AddField (f);
285                         return f;
286                 }
287
288                 public override Expression CreateExpressionTree (ResolveContext ec)
289                 {
290                         ec.Report.Error (1963, loc, "An expression tree cannot contain a dynamic operation");
291                         return null;
292                 }
293
294                 protected override Expression DoResolve (ResolveContext ec)
295                 {
296                         if (DoResolveCore (ec))
297                                 binder_expr = binder.CreateCallSiteBinder (ec, arguments);
298
299                         return this;
300                 }
301
302                 protected bool DoResolveCore (ResolveContext rc)
303                 {
304                         int errors = rc.Report.Errors;
305
306                         if (TypeManager.binder_type == null) {
307                                 var t = TypeManager.CoreLookupType (rc.Compiler,
308                                         "Microsoft.CSharp.RuntimeBinder", "Binder", MemberKind.Class, true);
309                                 if (t != null)
310                                         TypeManager.binder_type = new TypeExpression (t, Location.Null);
311                         }
312
313                         if (TypeManager.call_site_type == null)
314                                 TypeManager.call_site_type = TypeManager.CoreLookupType (rc.Compiler,
315                                         "System.Runtime.CompilerServices", "CallSite", MemberKind.Class, true);
316
317                         if (TypeManager.generic_call_site_type == null)
318                                 TypeManager.generic_call_site_type = TypeManager.CoreLookupType (rc.Compiler,
319                                         "System.Runtime.CompilerServices", "CallSite", 1, MemberKind.Class, true);
320
321                         if (TypeManager.binder_flags == null) {
322                                 TypeManager.binder_flags = TypeManager.CoreLookupType (rc.Compiler,
323                                         "Microsoft.CSharp.RuntimeBinder", "CSharpBinderFlags", MemberKind.Enum, true);
324                         }
325
326                         eclass = ExprClass.Value;
327
328                         if (type == null)
329                                 type = InternalType.Dynamic;
330
331                         if (rc.Report.Errors == errors)
332                                 return true;
333
334                         rc.Report.Error (1969, loc,
335                                 "Dynamic operation cannot be compiled without `Microsoft.CSharp.dll' assembly reference");
336                         return false;
337                 }
338
339                 public override void Emit (EmitContext ec)
340                 {
341                         EmitCall (ec, binder_expr, arguments,  false);
342                 }
343
344                 public override void EmitStatement (EmitContext ec)
345                 {
346                         EmitCall (ec, binder_expr, arguments, true);
347                 }
348
349                 protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
350                 {
351                         int dyn_args_count = arguments == null ? 0 : arguments.Count;
352                         TypeExpr site_type = CreateSiteType (RootContext.ToplevelTypes.Compiler, arguments, dyn_args_count, isStatement);
353                         FieldExpr site_field_expr = new FieldExpr (CreateSiteField (site_type), loc);
354
355                         SymbolWriter.OpenCompilerGeneratedBlock (ec);
356
357                         Arguments args = new Arguments (1);
358                         args.Add (new Argument (binder));
359                         StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));
360                         
361                         BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);             
362                         if (s.Resolve (bc)) {
363                                 Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc), loc), s, loc);
364                                 init.Emit (ec);
365                         }
366
367                         args = new Arguments (1 + dyn_args_count);
368                         args.Add (new Argument (site_field_expr));
369                         if (arguments != null) {
370                                 foreach (Argument a in arguments) {
371                                         if (a is NamedArgument) {
372                                                 // Name is not valid in this context
373                                                 args.Add (new Argument (a.Expr, a.ArgType));
374                                                 continue;
375                                         }
376
377                                         args.Add (a);
378                                 }
379                         }
380
381                         Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
382                         if (target != null)
383                                 target.Emit (ec);
384
385                         SymbolWriter.CloseCompilerGeneratedBlock (ec);
386                 }
387
388                 public static MemberAccess GetBinderNamespace (Location loc)
389                 {
390                         return new MemberAccess (new MemberAccess (
391                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
392                 }
393
394                 public static MemberAccess GetBinder (string name, Location loc)
395                 {
396                         return new MemberAccess (TypeManager.binder_type, name, loc);
397                 }
398
399                 TypeExpr CreateSiteType (CompilerContext ctx, Arguments arguments, int dyn_args_count, bool is_statement)
400                 {
401                         int default_args = is_statement ? 1 : 2;
402
403                         bool has_ref_out_argument = false;
404                         FullNamedExpression[] targs = new FullNamedExpression[dyn_args_count + default_args];
405                         targs [0] = new TypeExpression (TypeManager.call_site_type, loc);
406                         for (int i = 0; i < dyn_args_count; ++i) {
407                                 TypeSpec arg_type;
408                                 Argument a = arguments [i];
409                                 if (a.Type == TypeManager.null_type)
410                                         arg_type = TypeManager.object_type;
411                                 else
412                                         arg_type = a.Type;
413
414                                 if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
415                                         has_ref_out_argument = true;
416
417                                 targs [i + 1] = new TypeExpression (arg_type, loc);
418                         }
419
420                         TypeExpr del_type = null;
421                         if (!has_ref_out_argument) {
422                                 string d_name = is_statement ? "Action" : "Func";
423
424                                 TypeSpec t = TypeManager.CoreLookupType (ctx, "System", d_name, dyn_args_count + default_args, MemberKind.Delegate, false);
425                                 if (t != null) {
426                                         if (!is_statement)
427                                                 targs [targs.Length - 1] = new TypeExpression (type, loc);
428
429                                         del_type = new GenericTypeExpr (t, new TypeArguments (targs), loc);
430                                 }
431                         }
432
433                         //
434                         // Create custom delegate when no appropriate predefined one is found
435                         //
436                         if (del_type == null) {
437                                 TypeSpec rt = is_statement ? TypeManager.void_type : type;
438                                 Parameter[] p = new Parameter [dyn_args_count + 1];
439                                 p[0] = new Parameter (targs [0], "p0", Parameter.Modifier.NONE, null, loc);
440
441                                 for (int i = 1; i < dyn_args_count + 1; ++i)
442                                         p[i] = new Parameter (targs[i], "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
443
444                                 TypeContainer parent = CreateSiteContainer ();
445                                 Delegate d = new Delegate (parent.NamespaceEntry, parent, new TypeExpression (rt, loc),
446                                         Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
447                                         new MemberName ("Container" + container_counter++.ToString ("X")),
448                                         new ParametersCompiled (ctx, p), null);
449
450                                 d.CreateType ();
451                                 d.DefineType ();
452                                 d.Define ();
453                                 d.Emit ();
454
455                                 parent.AddDelegate (d);
456                                 del_type = new TypeExpression (d.Definition, loc);
457                         }
458
459                         TypeExpr site_type = new GenericTypeExpr (TypeManager.generic_call_site_type, new TypeArguments (del_type), loc);
460                         return site_type;
461                 }
462
463                 public static void Reset ()
464                 {
465                         global_site_container = null;
466                         field_counter = container_counter = 0;
467                 }
468         }
469
470         //
471         // Dynamic member access compound assignment for events
472         //
473         class DynamicEventCompoundAssign : DynamicExpressionStatement, IDynamicBinder
474         {
475                 string name;
476                 Statement condition;
477
478                 public DynamicEventCompoundAssign (string name, Arguments args, ExpressionStatement assignment, ExpressionStatement invoke, Location loc)
479                         : base (null, args, loc)
480                 {
481                         this.name = name;
482                         base.binder = this;
483
484                         // Used by += or -= only
485                         type = TypeManager.bool_type;
486
487                         condition = new If (
488                                 new Binary (Binary.Operator.Equality, this, new BoolLiteral (true, loc), loc),
489                                 new StatementExpression (invoke), new StatementExpression (assignment),
490                                 loc);
491                 }
492
493                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
494                 {
495                         Arguments binder_args = new Arguments (3);
496
497                         binder_args.Add (new Argument (new BinderFlags (0, this)));
498                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
499                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
500
501                         return new Invocation (GetBinder ("IsEvent", loc), binder_args);
502                 }
503
504                 public override void EmitStatement (EmitContext ec)
505                 {
506                         condition.Emit (ec);
507                 }
508         }
509
510         class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
511         {
512                 public DynamicConversion (TypeSpec targetType, CSharpBinderFlags flags, Arguments args, Location loc)
513                         : base (null, args, loc)
514                 {
515                         type = targetType;
516                         base.flags = flags;
517                         base.binder = this;
518                 }
519
520                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
521                 {
522                         Arguments binder_args = new Arguments (3);
523
524                         flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
525
526                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
527                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));                                            
528                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
529                         return new Invocation (GetBinder ("Convert", loc), binder_args);
530                 }
531         }
532
533         class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
534         {
535                 public DynamicConstructorBinder (TypeSpec type, Arguments args, Location loc)
536                         : base (null, args, loc)
537                 {
538                         this.type = type;
539                         base.binder = this;
540                 }
541
542                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
543                 {
544                         Arguments binder_args = new Arguments (3);
545
546                         binder_args.Add (new Argument (new BinderFlags (0, this)));
547                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
548                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
549
550                         return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
551                 }
552         }
553
554         class DynamicIndexBinder : DynamicMemberAssignable
555         {
556                 public DynamicIndexBinder (Arguments args, Location loc)
557                         : base (args, loc)
558                 {
559                 }
560
561                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
562                 {
563                         Arguments binder_args = new Arguments (3);
564
565                         binder_args.Add (new Argument (new BinderFlags (0, this)));
566                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
567                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
568
569                         return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
570                 }
571         }
572
573         class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
574         {
575                 ATypeNameExpression member;
576
577                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
578                         : base (null, args, loc)
579                 {
580                         base.binder = this;
581                         this.member = member;
582                 }
583
584                 //
585                 // When a return type is known not to be dynamic
586                 //
587                 public DynamicInvocation (ATypeNameExpression member, Arguments args, TypeSpec type, Location loc)
588                         : this (member, args, loc)
589                 {
590                         this.type = type;
591                 }
592
593                 public static DynamicInvocation CreateSpecialNameInvoke (ATypeNameExpression member, Arguments args, Location loc)
594                 {
595                         return new DynamicInvocation (member, args, loc) {
596                                 flags = CSharpBinderFlags.InvokeSpecialName
597                         };
598                 }
599
600                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
601                 {
602                         Arguments binder_args = new Arguments (member != null ? 5 : 3);
603                         bool is_member_access = member is MemberAccess;
604
605                         CSharpBinderFlags call_flags;
606                         if (!is_member_access && member is SimpleName) {
607                                 call_flags = CSharpBinderFlags.InvokeSimpleName;
608                                 is_member_access = true;
609                         } else {
610                                 call_flags = 0;
611                         }
612
613                         binder_args.Add (new Argument (new BinderFlags (call_flags, this)));
614
615                         if (is_member_access)
616                                 binder_args.Add (new Argument (new StringLiteral (member.Name, member.Location)));
617
618                         if (member != null && member.HasTypeArguments) {
619                                 TypeArguments ta = member.TypeArguments;
620                                 if (ta.Resolve (ec)) {
621                                         var targs = new ArrayInitializer (ta.Count, loc);
622                                         foreach (TypeSpec t in ta.Arguments)
623                                                 targs.Add (new TypeOf (new TypeExpression (t, loc), loc));
624
625                                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (targs, loc)));
626                                 }
627                         } else if (is_member_access) {
628                                 binder_args.Add (new Argument (new NullLiteral (loc)));
629                         }
630
631                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
632
633                         Expression real_args;
634                         if (args == null) {
635                                 // Cannot be null because .NET trips over
636                                 real_args = new ArrayCreation (
637                                         new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc),
638                                         new ArrayInitializer (0, loc), loc);
639                         } else {
640                                 real_args = new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc);
641                         }
642
643                         binder_args.Add (new Argument (real_args));
644
645                         return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
646                 }
647
648                 public override void EmitStatement (EmitContext ec)
649                 {
650                         flags |= CSharpBinderFlags.ResultDiscarded;
651                         base.EmitStatement (ec);
652                 }
653         }
654
655         class DynamicMemberBinder : DynamicMemberAssignable
656         {
657                 readonly string name;
658
659                 public DynamicMemberBinder (string name, Arguments args, Location loc)
660                         : base (args, loc)
661                 {
662                         this.name = name;
663                 }
664
665                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
666                 {
667                         Arguments binder_args = new Arguments (4);
668
669                         binder_args.Add (new Argument (new BinderFlags (0, this)));
670                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
671                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
672                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
673
674                         return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
675                 }
676         }
677
678         //
679         // Any member binder which can be source and target of assignment
680         //
681         abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
682         {
683                 Expression setter;
684                 Arguments setter_args;
685
686                 protected DynamicMemberAssignable (Arguments args, Location loc)
687                         : base (null, args, loc)
688                 {
689                         base.binder = this;
690                 }
691
692                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
693                 {
694                         //
695                         // DoResolve always uses getter
696                         //
697                         return CreateCallSiteBinder (ec, args, false);
698                 }
699
700                 protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);
701
702                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
703                 {
704                         if (right_side == EmptyExpression.OutAccess.Instance) {
705                                 right_side.DoResolveLValue (rc, this);
706                                 return null;
707                         }
708
709                         if (DoResolveCore (rc)) {
710                                 setter_args = new Arguments (Arguments.Count + 1);
711                                 setter_args.AddRange (Arguments);
712                                 setter_args.Add (new Argument (right_side));
713                                 setter = CreateCallSiteBinder (rc, setter_args, true);
714                         }
715
716                         eclass = ExprClass.Variable;
717                         return this;
718                 }
719
720                 public override void Emit (EmitContext ec)
721                 {
722                         // It's null for ResolveLValue used without assignment
723                         if (binder_expr == null)
724                                 EmitCall (ec, setter, Arguments, false);
725                         else
726                                 base.Emit (ec);
727                 }
728
729                 public override void EmitStatement (EmitContext ec)
730                 {
731                         // It's null for ResolveLValue used without assignment
732                         if (binder_expr == null)
733                                 EmitCall (ec, setter, Arguments, true);
734                         else
735                                 base.EmitStatement (ec);
736                 }
737
738                 #region IAssignMethod Members
739
740                 public void Emit (EmitContext ec, bool leave_copy)
741                 {
742                         throw new NotImplementedException ();
743                 }
744
745                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
746                 {
747                         EmitCall (ec, setter, setter_args, !leave_copy);
748                 }
749
750                 #endregion
751         }
752
753         class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
754         {
755                 string name;
756
757                 public DynamicUnaryConversion (string name, Arguments args, Location loc)
758                         : base (null, args, loc)
759                 {
760                         this.name = name;
761                         base.binder = this;
762                         if (name == "IsTrue" || name == "IsFalse")
763                                 type = TypeManager.bool_type;
764                 }
765
766                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
767                 {
768                         Arguments binder_args = new Arguments (4);
769
770                         MemberAccess sle = new MemberAccess (new MemberAccess (
771                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
772
773                         var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
774
775                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
776                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
777                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
778                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));
779
780                         return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
781                 }
782         }
783 }