mcs/mcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //     Marek Safar (marek.safar@gmail.com)
   8 //
   9 // Dual licensed under the terms of the MIT X11 or GNU GPL
  10 //
  11 // Copyright 2001 Ximian, Inc (http://www.ximian.com)
  12 // Copyright 2003-2009 Novell, Inc (http://www.novell.com)
  13 //
  14
  15 using System;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Collections.Generic;
  19
  20 namespace Mono.CSharp {
  21
  22         //
  23         // Delegate container implementation
  24         //
  25         public class Delegate : TypeContainer, IParametersMember
  26         {
  27                 FullNamedExpression ReturnType;
  28                 readonly ParametersCompiled parameters;
  29
  30                 Constructor Constructor;
  31                 Method InvokeBuilder;
  32                 Method BeginInvokeBuilder;
  33                 Method EndInvokeBuilder;
  34
  35                 static readonly string[] attribute_targets = new string [] { "type", "return" };
  36
  37                 public static readonly string InvokeMethodName = "Invoke";
  38
  39                 Expression instance_expr;
  40                 ReturnParameter return_attributes;
  41
  42                 const Modifiers MethodModifiers = Modifiers.PUBLIC | Modifiers.VIRTUAL;
  43
  44                 const Modifiers AllowedModifiers =
  45                         Modifiers.NEW |
  46                         Modifiers.PUBLIC |
  47                         Modifiers.PROTECTED |
  48                         Modifiers.INTERNAL |
  49                         Modifiers.UNSAFE |
  50                         Modifiers.PRIVATE;
  51
  52                 public Delegate (NamespaceEntry ns, DeclSpace parent, FullNamedExpression type,
  53                                  Modifiers mod_flags, MemberName name, ParametersCompiled param_list,
  54                                  Attributes attrs)
  55                         : base (ns, parent, name, attrs, MemberKind.Delegate)
  56
  57                 {
  58                         this.ReturnType = type;
  59                         ModFlags        = ModifiersExtensions.Check (AllowedModifiers, mod_flags,
  60                                                            IsTopLevel ? Modifiers.INTERNAL :
  61                                                            Modifiers.PRIVATE, name.Location, Report);
  62                         parameters      = param_list;
  63                         spec = new TypeSpec (Kind, null, this, null, ModFlags | Modifiers.SEALED);
  64                 }
  65
  66                 #region Properties
  67                 public TypeSpec MemberType {
  68                         get {
  69                                 return ReturnType.Type;
  70                         }
  71                 }
  72
  73                 public AParametersCollection Parameters {
  74                         get {
  75                                 return parameters;
  76                         }
  77                 }
  78                 #endregion
  79
  80                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  81                 {
  82                         if (a.Target == AttributeTargets.ReturnValue) {
  83                                 if (return_attributes == null)
  84                                         return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
  85
  86                                 return_attributes.ApplyAttributeBuilder (a, ctor, cdata, pa);
  87                                 return;
  88                         }
  89
  90                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
  91                 }
  92
  93                 public override AttributeTargets AttributeTargets {
  94                         get {
  95                                 return AttributeTargets.Delegate;
  96                         }
  97                 }
  98
  99                 protected override bool DoDefineMembers ()
 100                 {
 101                         var ctor_parameters = ParametersCompiled.CreateFullyResolved (
 102                                 new [] {
 103                                         new Parameter (new TypeExpression (TypeManager.object_type, Location), "object", Parameter.Modifier.NONE, null, Location),
 104                                         new Parameter (new TypeExpression (TypeManager.intptr_type, Location), "method", Parameter.Modifier.NONE, null, Location)
 105                                 },
 106                                 new [] {
 107                                         TypeManager.object_type,
 108                                         TypeManager.intptr_type
 109                                 }
 110                         );
 111
 112                         Constructor = new Constructor (this, System.Reflection.ConstructorInfo.ConstructorName,
 113                                 Modifiers.PUBLIC, null, ctor_parameters, null, Location);
 114                         Constructor.Define ();
 115
 116                         //
 117                         // Here the various methods like Invoke, BeginInvoke etc are defined
 118                         //
 119                         // First, call the `out of band' special method for
 120                         // defining recursively any types we need:
 121                         //
 122                         var p = parameters;
 123
 124                         if (!p.Resolve (this))
 125                                 return false;
 126
 127                         //
 128                         // Invoke method
 129                         //
 130
 131                         // Check accessibility
 132                         foreach (var partype in p.Types) {
 133                                 if (!IsAccessibleAs (partype)) {
 134                                         Report.SymbolRelatedToPreviousError (partype);
 135                                         Report.Error (59, Location,
 136                                                 "Inconsistent accessibility: parameter type `{0}' is less accessible than delegate `{1}'",
 137                                                 TypeManager.CSharpName (partype), GetSignatureForError ());
 138                                 }
 139                         }
 140
 141                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 142                         if (ReturnType == null)
 143                                 return false;
 144
 145                         var ret_type = ReturnType.Type;
 146
 147                         //
 148                         // We don't have to check any others because they are all
 149                         // guaranteed to be accessible - they are standard types.
 150                         //
 151                         if (!IsAccessibleAs (ret_type)) {
 152                                 Report.SymbolRelatedToPreviousError (ret_type);
 153                                 Report.Error (58, Location,
 154                                                   "Inconsistent accessibility: return type `" +
 155                                                   TypeManager.CSharpName (ret_type) + "' is less " +
 156                                                   "accessible than delegate `" + GetSignatureForError () + "'");
 157                                 return false;
 158                         }
 159
 160                         CheckProtectedModifier ();
 161
 162                         if (RootContext.StdLib && TypeManager.IsSpecialType (ret_type)) {
 163                                 Method.Error1599 (Location, ret_type, Report);
 164                                 return false;
 165                         }
 166
 167                         TypeManager.CheckTypeVariance (ret_type, Variance.Covariant, this);
 168
 169                         InvokeBuilder = new Method (this, null, ReturnType, MethodModifiers, new MemberName (InvokeMethodName), p, null);
 170                         InvokeBuilder.Define ();
 171
 172                         //
 173                         // Don't emit async method for compiler generated delegates (e.g. dynamic site containers)
 174                         //
 175                         if (TypeManager.iasyncresult_type != null && TypeManager.asynccallback_type != null && !IsCompilerGenerated) {
 176                                 DefineAsyncMethods (Parameters.CallingConvention);
 177                         }
 178
 179                         return true;
 180                 }
 181
 182                 void DefineAsyncMethods (CallingConventions cc)
 183                 {
 184                         //
 185                         // BeginInvoke
 186                         //
 187                         ParametersCompiled async_parameters;
 188                         if (Parameters.Count == 0) {
 189                                 async_parameters = ParametersCompiled.EmptyReadOnlyParameters;
 190                         } else {
 191                                 var compiled = new Parameter[Parameters.Count];
 192                                 for (int i = 0; i < compiled.Length; ++i)
 193                                         compiled[i] = new Parameter (new TypeExpression (Parameters.Types[i], Location),
 194                                                 Parameters.FixedParameters[i].Name,
 195                                                 Parameters.FixedParameters[i].ModFlags & (Parameter.Modifier.REF | Parameter.Modifier.OUT),
 196                                                 null, Location);
 197
 198                                 async_parameters = new ParametersCompiled (compiled);
 199                         }
 200
 201                         async_parameters = ParametersCompiled.MergeGenerated (Compiler, async_parameters, false,
 202                                 new Parameter[] {
 203                                         new Parameter (new TypeExpression (TypeManager.asynccallback_type, Location), "callback", Parameter.Modifier.NONE, null, Location),
 204                                         new Parameter (new TypeExpression (TypeManager.object_type, Location), "object", Parameter.Modifier.NONE, null, Location)
 205                                 },
 206                                 new [] {
 207                                         TypeManager.asynccallback_type,
 208                                         TypeManager.object_type
 209                                 }
 210                         );
 211
 212                         BeginInvokeBuilder = new Method (this, null,
 213                                 new TypeExpression (TypeManager.iasyncresult_type, Location), MethodModifiers,
 214                                 new MemberName ("BeginInvoke"), async_parameters, null);
 215                         BeginInvokeBuilder.Define ();
 216
 217                         //
 218                         // EndInvoke is a bit more interesting, all the parameters labeled as
 219                         // out or ref have to be duplicated here.
 220                         //
 221
 222                         //
 223                         // Define parameters, and count out/ref parameters
 224                         //
 225                         ParametersCompiled end_parameters;
 226                         int out_params = 0;
 227
 228                         foreach (Parameter p in Parameters.FixedParameters) {
 229                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 230                                         ++out_params;
 231                         }
 232
 233                         if (out_params > 0) {
 234                                 var end_param_types = new TypeSpec [out_params];
 235                                 Parameter[] end_params = new Parameter[out_params];
 236
 237                                 int param = 0;
 238                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 239                                         Parameter p = parameters [i];
 240                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 241                                                 continue;
 242
 243                                         end_param_types[param] = Parameters.Types[i];
 244                                         end_params[param] = p;
 245                                         ++param;
 246                                 }
 247                                 end_parameters = ParametersCompiled.CreateFullyResolved (end_params, end_param_types);
 248                         } else {
 249                                 end_parameters = ParametersCompiled.EmptyReadOnlyParameters;
 250                         }
 251
 252                         end_parameters = ParametersCompiled.MergeGenerated (Compiler, end_parameters, false,
 253                                 new Parameter (
 254                                         new TypeExpression (TypeManager.iasyncresult_type, Location),
 255                                         "result", Parameter.Modifier.NONE, null, Location),
 256                                 TypeManager.iasyncresult_type);
 257
 258                         //
 259                         // Create method, define parameters, register parameters with type system
 260                         //
 261                         EndInvokeBuilder = new Method (this, null, ReturnType, MethodModifiers, new MemberName ("EndInvoke"), end_parameters, null);
 262                         EndInvokeBuilder.Define ();
 263                 }
 264
 265                 public override void DefineConstants ()
 266                 {
 267                         if (!Parameters.IsEmpty) {
 268                                 parameters.ResolveDefaultValues (this);
 269                         }
 270                 }
 271
 272                 public override void EmitType ()
 273                 {
 274                         if (ReturnType.Type == InternalType.Dynamic) {
 275                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 276                                 Compiler.PredefinedAttributes.Dynamic.EmitAttribute (return_attributes.Builder);
 277                         } else {
 278                                 var trans_flags = TypeManager.HasDynamicTypeUsed (ReturnType.Type);
 279                                 if (trans_flags != null) {
 280                                         var pa = Compiler.PredefinedAttributes.DynamicTransform;
 281                                         if (pa.Constructor != null || pa.ResolveConstructor (Location, ArrayContainer.MakeType (TypeManager.bool_type))) {
 282                                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 283                                                 return_attributes.Builder.SetCustomAttribute (
 284                                                         new CustomAttributeBuilder (pa.Constructor, new object [] { trans_flags }));
 285                                         }
 286                                 }
 287                         }
 288
 289                         parameters.ApplyAttributes (this, InvokeBuilder.MethodBuilder);
 290
 291                         Constructor.ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 292                         InvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 293
 294                         if (BeginInvokeBuilder != null) {
 295                                 BeginInvokeBuilder.ParameterInfo.ApplyAttributes (this, BeginInvokeBuilder.MethodBuilder);
 296
 297                                 BeginInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 298                                 EndInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 299                         }
 300
 301                         if (OptAttributes != null) {
 302                                 OptAttributes.Emit ();
 303                         }
 304
 305                         base.Emit ();
 306                 }
 307
 308                 protected override TypeExpr[] ResolveBaseTypes (out TypeExpr base_class)
 309                 {
 310                         base_type = TypeManager.multicast_delegate_type;
 311                         base_class = null;
 312                         return null;
 313                 }
 314
 315                 protected override TypeAttributes TypeAttr {
 316                         get {
 317                                 return ModifiersExtensions.TypeAttr (ModFlags, IsTopLevel) |
 318                                         TypeAttributes.Class | TypeAttributes.Sealed |
 319                                         base.TypeAttr;
 320                         }
 321                 }
 322
 323                 public override string[] ValidAttributeTargets {
 324                         get {
 325                                 return attribute_targets;
 326                         }
 327                 }
 328
 329                 //TODO: duplicate
 330                 protected override bool VerifyClsCompliance ()
 331                 {
 332                         if (!base.VerifyClsCompliance ()) {
 333                                 return false;
 334                         }
 335
 336                         parameters.VerifyClsCompliance (this);
 337
 338                         if (!ReturnType.Type.IsCLSCompliant ()) {
 339                                 Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
 340                                         GetSignatureForError ());
 341                         }
 342                         return true;
 343                 }
 344
 345
 346                 public static MethodSpec GetConstructor (CompilerContext ctx, TypeSpec container_type, TypeSpec delType)
 347                 {
 348                         var ctor = MemberCache.FindMember (delType, MemberFilter.Constructor (null), BindingRestriction.DeclaredOnly);
 349                         return (MethodSpec) ctor;
 350                 }
 351
 352                 //
 353                 // Returns the "Invoke" from a delegate type
 354                 //
 355                 public static MethodSpec GetInvokeMethod (CompilerContext ctx, TypeSpec delType)
 356                 {
 357                         var invoke = MemberCache.FindMember (delType,
 358                                 MemberFilter.Method (InvokeMethodName, 0, null, null),
 359                                 BindingRestriction.DeclaredOnly);
 360
 361                         return (MethodSpec) invoke;
 362                 }
 363
 364                 public static AParametersCollection GetParameters (CompilerContext ctx, TypeSpec delType)
 365                 {
 366                         var invoke_mb = GetInvokeMethod (ctx, delType);
 367                         return invoke_mb.Parameters;
 368                 }
 369
 370                 //
 371                 // 15.2 Delegate compatibility
 372                 //
 373                 public static bool IsTypeCovariant (Expression a, TypeSpec b)
 374                 {
 375                         //
 376                         // For each value parameter (a parameter with no ref or out modifier), an
 377                         // identity conversion or implicit reference conversion exists from the
 378                         // parameter type in D to the corresponding parameter type in M
 379                         //
 380                         if (a.Type == b)
 381                                 return true;
 382
 383                         if (RootContext.Version == LanguageVersion.ISO_1)
 384                                 return false;
 385
 386                         return Convert.ImplicitReferenceConversionExists (a, b);
 387                 }
 388
 389                 public static string FullDelegateDesc (MethodSpec invoke_method)
 390                 {
 391                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 392                 }
 393
 394                 public Expression InstanceExpression {
 395                         get {
 396                                 return instance_expr;
 397                         }
 398                         set {
 399                                 instance_expr = value;
 400                         }
 401                 }
 402         }
 403
 404         //
 405         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 406         //
 407         public abstract class DelegateCreation : Expression, OverloadResolver.IErrorHandler
 408         {
 409                 protected MethodSpec constructor_method;
 410                 protected MethodGroupExpr method_group;
 411
 412                 public static Arguments CreateDelegateMethodArguments (AParametersCollection pd, TypeSpec[] types, Location loc)
 413                 {
 414                         Arguments delegate_arguments = new Arguments (pd.Count);
 415                         for (int i = 0; i < pd.Count; ++i) {
 416                                 Argument.AType atype_modifier;
 417                                 switch (pd.FixedParameters [i].ModFlags) {
 418                                 case Parameter.Modifier.REF:
 419                                         atype_modifier = Argument.AType.Ref;
 420                                         break;
 421                                 case Parameter.Modifier.OUT:
 422                                         atype_modifier = Argument.AType.Out;
 423                                         break;
 424                                 default:
 425                                         atype_modifier = 0;
 426                                         break;
 427                                 }
 428
 429                                 delegate_arguments.Add (new Argument (new TypeExpression (types [i], loc), atype_modifier));
 430                         }
 431
 432                         return delegate_arguments;
 433                 }
 434
 435                 public override Expression CreateExpressionTree (ResolveContext ec)
 436                 {
 437                         MemberAccess ma = new MemberAccess (new MemberAccess (new QualifiedAliasMember ("global", "System", loc), "Delegate", loc), "CreateDelegate", loc);
 438
 439                         Arguments args = new Arguments (3);
 440                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 441                         args.Add (new Argument (new NullLiteral (loc)));
 442                         args.Add (new Argument (method_group.CreateExpressionTree (ec)));
 443                         Expression e = new Invocation (ma, args).Resolve (ec);
 444                         if (e == null)
 445                                 return null;
 446
 447                         e = Convert.ExplicitConversion (ec, e, type, loc);
 448                         if (e == null)
 449                                 return null;
 450
 451                         return e.CreateExpressionTree (ec);
 452                 }
 453
 454                 protected override Expression DoResolve (ResolveContext ec)
 455                 {
 456                         constructor_method = Delegate.GetConstructor (ec.Compiler, ec.CurrentType, type);
 457
 458                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, type);
 459
 460                         Arguments arguments = CreateDelegateMethodArguments (invoke_method.Parameters, invoke_method.Parameters.Types, loc);
 461                         method_group = method_group.OverloadResolve (ec, ref arguments, this, OverloadResolver.Restrictions.CovariantDelegate);
 462                         if (method_group == null)
 463                                 return null;
 464
 465                         var delegate_method = method_group.BestCandidate;
 466
 467                         if (TypeManager.IsNullableType (delegate_method.DeclaringType)) {
 468                                 ec.Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
 469                                         delegate_method.GetSignatureForError ());
 470                                 return null;
 471                         }
 472
 473                         Invocation.IsSpecialMethodInvocation (ec, delegate_method, loc);
 474
 475                         ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
 476                         if (emg != null) {
 477                                 method_group.InstanceExpression = emg.ExtensionExpression;
 478                                 TypeSpec e_type = emg.ExtensionExpression.Type;
 479                                 if (TypeManager.IsValueType (e_type)) {
 480                                         ec.Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 481                                                 delegate_method.GetSignatureForError (), TypeManager.CSharpName (e_type));
 482                                 }
 483                         }
 484
 485                         TypeSpec rt = delegate_method.ReturnType;
 486                         Expression ret_expr = new TypeExpression (rt, loc);
 487                         if (!Delegate.IsTypeCovariant (ret_expr, invoke_method.ReturnType)) {
 488                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 489                         }
 490
 491                         if (delegate_method.IsConditionallyExcluded (loc)) {
 492                                 ec.Report.SymbolRelatedToPreviousError (delegate_method);
 493                                 MethodOrOperator m = delegate_method.MemberDefinition as MethodOrOperator;
 494                                 if (m != null && m.IsPartialDefinition) {
 495                                         ec.Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
 496                                                 delegate_method.GetSignatureForError ());
 497                                 } else {
 498                                         ec.Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 499                                                 TypeManager.CSharpSignature (delegate_method));
 500                                 }
 501                         }
 502
 503                         var expr = method_group.InstanceExpression;
 504                         if (expr != null && (expr.Type.IsGenericParameter || !TypeManager.IsReferenceType (expr.Type)))
 505                                 method_group.InstanceExpression = new BoxedCast (expr, TypeManager.object_type);
 506
 507                         eclass = ExprClass.Value;
 508                         return this;
 509                 }
 510
 511                 public override void Emit (EmitContext ec)
 512                 {
 513                         if (method_group.InstanceExpression == null)
 514                                 ec.Emit (OpCodes.Ldnull);
 515                         else
 516                                 method_group.InstanceExpression.Emit (ec);
 517
 518                         var delegate_method = method_group.BestCandidate;
 519
 520                         // Any delegate must be sealed
 521                         if (!delegate_method.DeclaringType.IsDelegate && delegate_method.IsVirtual && !method_group.IsBase) {
 522                                 ec.Emit (OpCodes.Dup);
 523                                 ec.Emit (OpCodes.Ldvirtftn, delegate_method);
 524                         } else {
 525                                 ec.Emit (OpCodes.Ldftn, delegate_method);
 526                         }
 527
 528                         ec.Emit (OpCodes.Newobj, constructor_method);
 529                 }
 530
 531                 void Error_ConversionFailed (ResolveContext ec, MethodSpec method, Expression return_type)
 532                 {
 533                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, type);
 534                         string member_name = method_group.InstanceExpression != null ?
 535                                 Delegate.FullDelegateDesc (method) :
 536                                 TypeManager.GetFullNameSignature (method);
 537
 538                         ec.Report.SymbolRelatedToPreviousError (type);
 539                         ec.Report.SymbolRelatedToPreviousError (method);
 540                         if (RootContext.Version == LanguageVersion.ISO_1) {
 541                                 ec.Report.Error (410, loc, "A method or delegate `{0} {1}' parameters and return type must be same as delegate `{2} {3}' parameters and return type",
 542                                         TypeManager.CSharpName (method.ReturnType), member_name,
 543                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 544                                 return;
 545                         }
 546
 547                         if (return_type == null) {
 548                                 ec.Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 549                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 550                                 return;
 551                         }
 552
 553                         ec.Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 554                                 return_type.GetSignatureForError (), member_name,
 555                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 556                 }
 557
 558                 public static bool ImplicitStandardConversionExists (ResolveContext ec, MethodGroupExpr mg, TypeSpec target_type)
 559                 {
 560                         if (target_type == TypeManager.delegate_type || target_type == TypeManager.multicast_delegate_type)
 561                                 return false;
 562
 563                         var invoke = Delegate.GetInvokeMethod (ec.Compiler, target_type);
 564
 565                         Arguments arguments = CreateDelegateMethodArguments (invoke.Parameters, invoke.Parameters.Types, mg.Location);
 566                         return mg.OverloadResolve (ec, ref arguments, null, OverloadResolver.Restrictions.CovariantDelegate | OverloadResolver.Restrictions.ProbingOnly) != null;
 567                 }
 568
 569                 #region IErrorHandler Members
 570
 571                 bool OverloadResolver.IErrorHandler.AmbiguousCandidates (ResolveContext ec, MemberSpec best, MemberSpec ambiguous)
 572                 {
 573                         return false;
 574                 }
 575
 576                 bool OverloadResolver.IErrorHandler.ArgumentMismatch (ResolveContext rc, MemberSpec best, Argument arg, int index)
 577                 {
 578                         Error_ConversionFailed (rc, best as MethodSpec, null);
 579                         return true;
 580                 }
 581
 582                 bool OverloadResolver.IErrorHandler.NoArgumentMatch (ResolveContext rc, MemberSpec best)
 583                 {
 584                         Error_ConversionFailed (rc, best as MethodSpec, null);
 585                         return true;
 586                 }
 587
 588                 bool OverloadResolver.IErrorHandler.TypeInferenceFailed (ResolveContext rc, MemberSpec best)
 589                 {
 590                         return false;
 591                 }
 592
 593                 #endregion
 594         }
 595
 596         //
 597         // Created from the conversion code
 598         //
 599         public class ImplicitDelegateCreation : DelegateCreation
 600         {
 601                 ImplicitDelegateCreation (TypeSpec t, MethodGroupExpr mg, Location l)
 602                 {
 603                         type = t;
 604                         this.method_group = mg;
 605                         loc = l;
 606                 }
 607
 608                 static public Expression Create (ResolveContext ec, MethodGroupExpr mge,
 609                                                  TypeSpec target_type, Location loc)
 610                 {
 611                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 612                         return d.DoResolve (ec);
 613                 }
 614         }
 615
 616         //
 617         // A delegate-creation-expression, invoked from the `New' class
 618         //
 619         public class NewDelegate : DelegateCreation
 620         {
 621                 public Arguments Arguments;
 622
 623                 //
 624                 // This constructor is invoked from the `New' expression
 625                 //
 626                 public NewDelegate (TypeSpec type, Arguments Arguments, Location loc)
 627                 {
 628                         this.type = type;
 629                         this.Arguments = Arguments;
 630                         this.loc  = loc;
 631                 }
 632
 633                 protected override Expression DoResolve (ResolveContext ec)
 634                 {
 635                         if (Arguments == null || Arguments.Count != 1) {
 636                                 ec.Report.Error (149, loc, "Method name expected");
 637                                 return null;
 638                         }
 639
 640                         Argument a = Arguments [0];
 641                         if (!a.ResolveMethodGroup (ec))
 642                                 return null;
 643
 644                         Expression e = a.Expr;
 645
 646                         AnonymousMethodExpression ame = e as AnonymousMethodExpression;
 647                         if (ame != null && RootContext.Version != LanguageVersion.ISO_1) {
 648                                 e = ame.Compatible (ec, type);
 649                                 if (e == null)
 650                                         return null;
 651
 652                                 return e.Resolve (ec);
 653                         }
 654
 655                         method_group = e as MethodGroupExpr;
 656                         if (method_group == null) {
 657                                 if (e.Type == InternalType.Dynamic) {
 658                                         e = Convert.ImplicitConversionRequired (ec, e, type, loc);
 659                                 } else if (!e.Type.IsDelegate) {
 660                                         e.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup | ResolveFlags.Type, loc);
 661                                         return null;
 662                                 }
 663
 664                                 //
 665                                 // An argument is not a method but another delegate
 666                                 //
 667                                 method_group = new MethodGroupExpr (Delegate.GetInvokeMethod (ec.Compiler, e.Type), e.Type, loc);
 668                                 method_group.InstanceExpression = e;
 669                         }
 670
 671                         return base.DoResolve (ec);
 672                 }
 673         }
 674
 675         //
 676         // Invocation converted to delegate Invoke call
 677         //
 678         class DelegateInvocation : ExpressionStatement
 679         {
 680                 readonly Expression InstanceExpr;
 681                 Arguments arguments;
 682                 MethodSpec method;
 683
 684                 public DelegateInvocation (Expression instance_expr, Arguments args, Location loc)
 685                 {
 686                         this.InstanceExpr = instance_expr;
 687                         this.arguments = args;
 688                         this.loc = loc;
 689                 }
 690
 691                 public override Expression CreateExpressionTree (ResolveContext ec)
 692                 {
 693                         Arguments args = Arguments.CreateForExpressionTree (ec, this.arguments,
 694                                 InstanceExpr.CreateExpressionTree (ec));
 695
 696                         return CreateExpressionFactoryCall (ec, "Invoke", args);
 697                 }
 698
 699                 protected override Expression DoResolve (ResolveContext ec)
 700                 {
 701                         if (InstanceExpr is EventExpr) {
 702                                 ((EventExpr) InstanceExpr).Error_CannotAssign (ec);
 703                                 return null;
 704                         }
 705
 706                         TypeSpec del_type = InstanceExpr.Type;
 707                         if (del_type == null)
 708                                 return null;
 709
 710                         //
 711                         // Do only core overload resolution the rest of the checks has been
 712                         // done on primary expression
 713                         //
 714                         method = Delegate.GetInvokeMethod (ec.Compiler, del_type);
 715                         var res = new OverloadResolver (new MemberSpec[] { method }, OverloadResolver.Restrictions.DelegateInvoke, loc);
 716                         var valid = res.ResolveMember<MethodSpec> (ec, ref arguments);
 717                         if (valid == null && !res.BestCandidateIsDynamic)
 718                                 return null;
 719
 720                         type = method.ReturnType;
 721                         eclass = ExprClass.Value;
 722                         return this;
 723                 }
 724
 725                 public override void Emit (EmitContext ec)
 726                 {
 727                         //
 728                         // Invocation on delegates call the virtual Invoke member
 729                         // so we are always `instance' calls
 730                         //
 731                         Invocation.EmitCall (ec, InstanceExpr, method, arguments, loc);
 732                 }
 733
 734                 public override void EmitStatement (EmitContext ec)
 735                 {
 736                         Emit (ec);
 737                         //
 738                         // Pop the return value if there is one
 739                         //
 740                         if (type != TypeManager.void_type)
 741                                 ec.Emit (OpCodes.Pop);
 742                 }
 743
 744                 public override System.Linq.Expressions.Expression MakeExpression (BuilderContext ctx)
 745                 {
 746                         return Invocation.MakeExpression (ctx, InstanceExpr, method, arguments);
 747                 }
 748         }
 749 }