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
  26         {
  27                 FullNamedExpression ReturnType;
  28                 public 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                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
  67                 {
  68                         if (a.Target == AttributeTargets.ReturnValue) {
  69                                 if (return_attributes == null)
  70                                         return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
  71
  72                                 return_attributes.ApplyAttributeBuilder (a, ctor, cdata, pa);
  73                                 return;
  74                         }
  75
  76                         base.ApplyAttributeBuilder (a, ctor, cdata, pa);
  77                 }
  78
  79                 public override AttributeTargets AttributeTargets {
  80                         get {
  81                                 return AttributeTargets.Delegate;
  82                         }
  83                 }
  84
  85                 public override TypeSpec BaseType {
  86                         get {
  87                                 return TypeManager.multicast_delegate_type;
  88                         }
  89                 }
  90
  91                 protected override bool DoDefineMembers ()
  92                 {
  93                         var ctor_parameters = ParametersCompiled.CreateFullyResolved (
  94                                 new [] {
  95                                         new Parameter (new TypeExpression (TypeManager.object_type, Location), "object", Parameter.Modifier.NONE, null, Location),
  96                                         new Parameter (new TypeExpression (TypeManager.intptr_type, Location), "method", Parameter.Modifier.NONE, null, Location)
  97                                 },
  98                                 new [] {
  99                                         TypeManager.object_type,
 100                                         TypeManager.intptr_type
 101                                 }
 102                         );
 103
 104                         Constructor = new Constructor (this, System.Reflection.ConstructorInfo.ConstructorName,
 105                                 Modifiers.PUBLIC, null, ctor_parameters, null, Location);
 106                         Constructor.Define ();
 107
 108                         //
 109                         // Here the various methods like Invoke, BeginInvoke etc are defined
 110                         //
 111                         // First, call the `out of band' special method for
 112                         // defining recursively any types we need:
 113                         //
 114                         var p = Parameters;
 115
 116                         if (!p.Resolve (this))
 117                                 return false;
 118
 119                         //
 120                         // Invoke method
 121                         //
 122
 123                         // Check accessibility
 124                         foreach (var partype in p.Types) {
 125                                 if (!IsAccessibleAs (partype)) {
 126                                         Report.SymbolRelatedToPreviousError (partype);
 127                                         Report.Error (59, Location,
 128                                                 "Inconsistent accessibility: parameter type `{0}' is less accessible than delegate `{1}'",
 129                                                 TypeManager.CSharpName (partype), GetSignatureForError ());
 130                                 }
 131                         }
 132
 133                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 134                         if (ReturnType == null)
 135                                 return false;
 136
 137                         var ret_type = ReturnType.Type;
 138
 139                         //
 140                         // We don't have to check any others because they are all
 141                         // guaranteed to be accessible - they are standard types.
 142                         //
 143                         if (!IsAccessibleAs (ret_type)) {
 144                                 Report.SymbolRelatedToPreviousError (ret_type);
 145                                 Report.Error (58, Location,
 146                                                   "Inconsistent accessibility: return type `" +
 147                                                   TypeManager.CSharpName (ret_type) + "' is less " +
 148                                                   "accessible than delegate `" + GetSignatureForError () + "'");
 149                                 return false;
 150                         }
 151
 152                         CheckProtectedModifier ();
 153
 154                         if (RootContext.StdLib && TypeManager.IsSpecialType (ret_type)) {
 155                                 Method.Error1599 (Location, ret_type, Report);
 156                                 return false;
 157                         }
 158
 159                         TypeManager.CheckTypeVariance (ret_type, Variance.Covariant, this);
 160
 161                         InvokeBuilder = new Method (this, null, ReturnType, MethodModifiers, new MemberName (InvokeMethodName), p, null);
 162                         InvokeBuilder.Define ();
 163
 164                         //
 165                         // Don't emit async method for compiler generated delegates (e.g. dynamic site containers)
 166                         //
 167                         if (TypeManager.iasyncresult_type != null && TypeManager.asynccallback_type != null && !IsCompilerGenerated) {
 168                                 DefineAsyncMethods (Parameters.CallingConvention);
 169                         }
 170
 171                         return true;
 172                 }
 173
 174                 void DefineAsyncMethods (CallingConventions cc)
 175                 {
 176                         //
 177                         // BeginInvoke
 178                         //
 179                         Parameter[] compiled = new Parameter[Parameters.Count];
 180                         for (int i = 0; i < compiled.Length; ++i)
 181                                 compiled[i] = new Parameter (new TypeExpression (Parameters.Types[i], Location),
 182                                         Parameters.FixedParameters[i].Name,
 183                                         Parameters.FixedParameters[i].ModFlags & (Parameter.Modifier.REF | Parameter.Modifier.OUT),
 184                                         null, Location);
 185
 186                         ParametersCompiled async_parameters = new ParametersCompiled (Compiler, compiled);
 187
 188                         async_parameters = ParametersCompiled.MergeGenerated (Compiler, async_parameters, false,
 189                                 new Parameter[] {
 190                                         new Parameter (new TypeExpression (TypeManager.asynccallback_type, Location), "callback", Parameter.Modifier.NONE, null, Location),
 191                                         new Parameter (new TypeExpression (TypeManager.object_type, Location), "object", Parameter.Modifier.NONE, null, Location)
 192                                 },
 193                                 new [] {
 194                                         TypeManager.asynccallback_type,
 195                                         TypeManager.object_type
 196                                 }
 197                         );
 198
 199                         BeginInvokeBuilder = new Method (this, null,
 200                                 new TypeExpression (TypeManager.iasyncresult_type, Location), MethodModifiers,
 201                                 new MemberName ("BeginInvoke"), async_parameters, null);
 202                         BeginInvokeBuilder.Define ();
 203
 204                         //
 205                         // EndInvoke is a bit more interesting, all the parameters labeled as
 206                         // out or ref have to be duplicated here.
 207                         //
 208
 209                         //
 210                         // Define parameters, and count out/ref parameters
 211                         //
 212                         ParametersCompiled end_parameters;
 213                         int out_params = 0;
 214
 215                         foreach (Parameter p in Parameters.FixedParameters) {
 216                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 217                                         ++out_params;
 218                         }
 219
 220                         if (out_params > 0) {
 221                                 var end_param_types = new TypeSpec [out_params];
 222                                 Parameter[] end_params = new Parameter[out_params];
 223
 224                                 int param = 0;
 225                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 226                                         Parameter p = Parameters [i];
 227                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 228                                                 continue;
 229
 230                                         end_param_types[param] = Parameters.Types[i];
 231                                         end_params[param] = p;
 232                                         ++param;
 233                                 }
 234                                 end_parameters = ParametersCompiled.CreateFullyResolved (end_params, end_param_types);
 235                         } else {
 236                                 end_parameters = ParametersCompiled.EmptyReadOnlyParameters;
 237                         }
 238
 239                         end_parameters = ParametersCompiled.MergeGenerated (Compiler, end_parameters, false,
 240                                 new Parameter (
 241                                         new TypeExpression (TypeManager.iasyncresult_type, Location),
 242                                         "result", Parameter.Modifier.NONE, null, Location),
 243                                 TypeManager.iasyncresult_type);
 244
 245                         //
 246                         // Create method, define parameters, register parameters with type system
 247                         //
 248                         EndInvokeBuilder = new Method (this, null, ReturnType, MethodModifiers, new MemberName ("EndInvoke"), end_parameters, null);
 249                         EndInvokeBuilder.Define ();
 250                 }
 251
 252                 public override void DefineConstants ()
 253                 {
 254                         if (!Parameters.IsEmpty && Parameters[Parameters.Count - 1].HasDefaultValue) {
 255                                 var rc = new ResolveContext (this);
 256                                 Parameters.ResolveDefaultValues (rc);
 257                         }
 258                 }
 259
 260                 public override void EmitType ()
 261                 {
 262                         if (ReturnType.Type == InternalType.Dynamic) {
 263                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 264                                 PredefinedAttributes.Get.Dynamic.EmitAttribute (return_attributes.Builder);
 265                         } else {
 266                                 var trans_flags = TypeManager.HasDynamicTypeUsed (ReturnType.Type);
 267                                 if (trans_flags != null) {
 268                                         var pa = PredefinedAttributes.Get.DynamicTransform;
 269                                         if (pa.Constructor != null || pa.ResolveConstructor (Location, ArrayContainer.MakeType (TypeManager.bool_type))) {
 270                                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 271                                                 return_attributes.Builder.SetCustomAttribute (
 272                                                         new CustomAttributeBuilder (pa.Constructor, new object [] { trans_flags }));
 273                                         }
 274                                 }
 275                         }
 276
 277                         Parameters.ApplyAttributes (InvokeBuilder.MethodBuilder);
 278
 279                         Constructor.ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 280                         InvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 281
 282                         if (BeginInvokeBuilder != null) {
 283                                 BeginInvokeBuilder.ParameterInfo.ApplyAttributes (BeginInvokeBuilder.MethodBuilder);
 284
 285                                 BeginInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 286                                 EndInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 287                         }
 288
 289                         if (OptAttributes != null) {
 290                                 OptAttributes.Emit ();
 291                         }
 292
 293                         base.Emit ();
 294                 }
 295
 296                 protected override TypeAttributes TypeAttr {
 297                         get {
 298                                 return ModifiersExtensions.TypeAttr (ModFlags, IsTopLevel) |
 299                                         TypeAttributes.Class | TypeAttributes.Sealed |
 300                                         base.TypeAttr;
 301                         }
 302                 }
 303
 304                 public override string[] ValidAttributeTargets {
 305                         get {
 306                                 return attribute_targets;
 307                         }
 308                 }
 309
 310                 //TODO: duplicate
 311                 protected override bool VerifyClsCompliance ()
 312                 {
 313                         if (!base.VerifyClsCompliance ()) {
 314                                 return false;
 315                         }
 316
 317                         Parameters.VerifyClsCompliance (this);
 318
 319                         if (!ReturnType.Type.IsCLSCompliant ()) {
 320                                 Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
 321                                         GetSignatureForError ());
 322                         }
 323                         return true;
 324                 }
 325
 326
 327                 public static MethodSpec GetConstructor (CompilerContext ctx, TypeSpec container_type, TypeSpec delType)
 328                 {
 329                         var ctor = MemberCache.FindMember (delType, MemberFilter.Constructor (null), BindingRestriction.DeclaredOnly);
 330                         return (MethodSpec) ctor;
 331                 }
 332
 333                 //
 334                 // Returns the "Invoke" from a delegate type
 335                 //
 336                 public static MethodSpec GetInvokeMethod (CompilerContext ctx, TypeSpec delType)
 337                 {
 338                         var invoke = MemberCache.FindMember (delType,
 339                                 MemberFilter.Method (InvokeMethodName, 0, null, null),
 340                                 BindingRestriction.DeclaredOnly);
 341
 342                         return (MethodSpec) invoke;
 343                 }
 344
 345                 public static AParametersCollection GetParameters (CompilerContext ctx, TypeSpec delType)
 346                 {
 347                         var invoke_mb = GetInvokeMethod (ctx, delType);
 348                         return invoke_mb.Parameters;
 349                 }
 350
 351                 //
 352                 // 15.2 Delegate compatibility
 353                 //
 354                 public static bool IsTypeCovariant (Expression a, TypeSpec b)
 355                 {
 356                         //
 357                         // For each value parameter (a parameter with no ref or out modifier), an
 358                         // identity conversion or implicit reference conversion exists from the
 359                         // parameter type in D to the corresponding parameter type in M
 360                         //
 361                         if (a.Type == b)
 362                                 return true;
 363
 364                         if (RootContext.Version == LanguageVersion.ISO_1)
 365                                 return false;
 366
 367                         return Convert.ImplicitReferenceConversionExists (a, b);
 368                 }
 369
 370                 public static string FullDelegateDesc (MethodSpec invoke_method)
 371                 {
 372                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 373                 }
 374
 375                 public Expression InstanceExpression {
 376                         get {
 377                                 return instance_expr;
 378                         }
 379                         set {
 380                                 instance_expr = value;
 381                         }
 382                 }
 383         }
 384
 385         //
 386         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 387         //
 388         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 389         {
 390                 protected MethodSpec constructor_method;
 391                 protected MethodSpec delegate_method;
 392                 // We keep this to handle IsBase only
 393                 protected MethodGroupExpr method_group;
 394                 protected Expression delegate_instance_expression;
 395
 396                 // TODO: Should either cache it or use interface to abstract it
 397                 public static Arguments CreateDelegateMethodArguments (AParametersCollection pd, Location loc)
 398                 {
 399                         Arguments delegate_arguments = new Arguments (pd.Count);
 400                         for (int i = 0; i < pd.Count; ++i) {
 401                                 Argument.AType atype_modifier;
 402                                 TypeSpec atype = pd.Types [i];
 403                                 switch (pd.FixedParameters [i].ModFlags) {
 404                                 case Parameter.Modifier.REF:
 405                                         atype_modifier = Argument.AType.Ref;
 406                                         //atype = atype.GetElementType ();
 407                                         break;
 408                                 case Parameter.Modifier.OUT:
 409                                         atype_modifier = Argument.AType.Out;
 410                                         //atype = atype.GetElementType ();
 411                                         break;
 412                                 default:
 413                                         atype_modifier = 0;
 414                                         break;
 415                                 }
 416                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 417                         }
 418                         return delegate_arguments;
 419                 }
 420
 421                 public override Expression CreateExpressionTree (ResolveContext ec)
 422                 {
 423                         MemberAccess ma = new MemberAccess (new MemberAccess (new QualifiedAliasMember ("global", "System", loc), "Delegate", loc), "CreateDelegate", loc);
 424
 425                         Arguments args = new Arguments (3);
 426                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 427                         args.Add (new Argument (new NullLiteral (loc)));
 428                         args.Add (new Argument (new TypeOfMethod (delegate_method, loc)));
 429                         Expression e = new Invocation (ma, args).Resolve (ec);
 430                         if (e == null)
 431                                 return null;
 432
 433                         e = Convert.ExplicitConversion (ec, e, type, loc);
 434                         if (e == null)
 435                                 return null;
 436
 437                         return e.CreateExpressionTree (ec);
 438                 }
 439
 440                 protected override Expression DoResolve (ResolveContext ec)
 441                 {
 442                         constructor_method = Delegate.GetConstructor (ec.Compiler, ec.CurrentType, type);
 443
 444                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, type);
 445                         method_group.DelegateType = type;
 446                         method_group.CustomErrorHandler = this;
 447
 448                         Arguments arguments = CreateDelegateMethodArguments (invoke_method.Parameters, loc);
 449                         method_group = method_group.OverloadResolve (ec, ref arguments, false, loc);
 450                         if (method_group == null)
 451                                 return null;
 452
 453                         delegate_method = (MethodSpec) method_group;
 454
 455                         if (TypeManager.IsNullableType (delegate_method.DeclaringType)) {
 456                                 ec.Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
 457                                         TypeManager.GetFullNameSignature (delegate_method));
 458                                 return null;
 459                         }
 460
 461                         Invocation.IsSpecialMethodInvocation (ec, delegate_method, loc);
 462
 463                         ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
 464                         if (emg != null) {
 465                                 delegate_instance_expression = emg.ExtensionExpression;
 466                                 TypeSpec e_type = delegate_instance_expression.Type;
 467                                 if (TypeManager.IsValueType (e_type)) {
 468                                         ec.Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 469                                                 delegate_method.GetSignatureForError (), TypeManager.CSharpName (e_type));
 470                                 }
 471                         }
 472
 473                         TypeSpec rt = delegate_method.ReturnType;
 474                         Expression ret_expr = new TypeExpression (rt, loc);
 475                         if (!Delegate.IsTypeCovariant (ret_expr, invoke_method.ReturnType)) {
 476                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 477                         }
 478
 479                         if (delegate_method.IsConditionallyExcluded (loc)) {
 480                                 ec.Report.SymbolRelatedToPreviousError (delegate_method);
 481                                 MethodOrOperator m = delegate_method.MemberDefinition as MethodOrOperator;
 482                                 if (m != null && m.IsPartialDefinition) {
 483                                         ec.Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
 484                                                 delegate_method.GetSignatureForError ());
 485                                 } else {
 486                                         ec.Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 487                                                 TypeManager.CSharpSignature (delegate_method));
 488                                 }
 489                         }
 490
 491                         DoResolveInstanceExpression (ec);
 492                         eclass = ExprClass.Value;
 493                         return this;
 494                 }
 495
 496                 void DoResolveInstanceExpression (ResolveContext ec)
 497                 {
 498                         //
 499                         // Argument is another delegate
 500                         //
 501                         if (delegate_instance_expression != null)
 502                                 return;
 503
 504                         if (method_group.IsStatic) {
 505                                 delegate_instance_expression = null;
 506                                 return;
 507                         }
 508
 509                         Expression instance = method_group.InstanceExpression;
 510                         if (instance != null && instance != EmptyExpression.Null) {
 511                                 delegate_instance_expression = instance;
 512                                 TypeSpec instance_type = delegate_instance_expression.Type;
 513                                 if (TypeManager.IsValueType (instance_type) || TypeManager.IsGenericParameter (instance_type)) {
 514                                         delegate_instance_expression = new BoxedCast (
 515                                                 delegate_instance_expression, TypeManager.object_type);
 516                                 }
 517                         } else {
 518                                 delegate_instance_expression = ec.GetThis (loc);
 519                         }
 520                 }
 521
 522                 public override void Emit (EmitContext ec)
 523                 {
 524                         if (delegate_instance_expression == null)
 525                                 ec.Emit (OpCodes.Ldnull);
 526                         else
 527                                 delegate_instance_expression.Emit (ec);
 528
 529                         // Any delegate must be sealed
 530                         if (!delegate_method.DeclaringType.IsDelegate && delegate_method.IsVirtual && !method_group.IsBase) {
 531                                 ec.Emit (OpCodes.Dup);
 532                                 ec.Emit (OpCodes.Ldvirtftn, delegate_method);
 533                         } else {
 534                                 ec.Emit (OpCodes.Ldftn, delegate_method);
 535                         }
 536
 537                         ec.Emit (OpCodes.Newobj, constructor_method);
 538                 }
 539
 540                 void Error_ConversionFailed (ResolveContext ec, MethodSpec method, Expression return_type)
 541                 {
 542                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, type);
 543                         string member_name = delegate_instance_expression != null ?
 544                                 Delegate.FullDelegateDesc (method) :
 545                                 TypeManager.GetFullNameSignature (method);
 546
 547                         ec.Report.SymbolRelatedToPreviousError (type);
 548                         ec.Report.SymbolRelatedToPreviousError (method);
 549                         if (RootContext.Version == LanguageVersion.ISO_1) {
 550                                 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",
 551                                         TypeManager.CSharpName (method.ReturnType), member_name,
 552                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 553                                 return;
 554                         }
 555                         if (return_type == null) {
 556                                 ec.Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 557                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 558                                 return;
 559                         }
 560
 561                         ec.Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 562                                 return_type.GetSignatureForError (), member_name,
 563                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 564                 }
 565
 566                 public static bool ImplicitStandardConversionExists (ResolveContext ec, MethodGroupExpr mg, TypeSpec target_type)
 567                 {
 568                         if (target_type == TypeManager.delegate_type || target_type == TypeManager.multicast_delegate_type)
 569                                 return false;
 570
 571                         mg.DelegateType = target_type;
 572                         var invoke = Delegate.GetInvokeMethod (ec.Compiler, target_type);
 573
 574                         Arguments arguments = CreateDelegateMethodArguments (invoke.Parameters, mg.Location);
 575                         return mg.OverloadResolve (ec, ref arguments, true, mg.Location) != null;
 576                 }
 577
 578                 #region IErrorHandler Members
 579
 580                 public bool NoExactMatch (ResolveContext ec, MethodSpec method)
 581                 {
 582                         if (method.IsGeneric)
 583                                 return false;
 584
 585                         Error_ConversionFailed (ec, method, null);
 586                         return true;
 587                 }
 588
 589                 public bool AmbiguousCall (ResolveContext ec, MethodSpec ambiguous)
 590                 {
 591                         return false;
 592                 }
 593
 594                 #endregion
 595         }
 596
 597         //
 598         // Created from the conversion code
 599         //
 600         public class ImplicitDelegateCreation : DelegateCreation
 601         {
 602                 ImplicitDelegateCreation (TypeSpec t, MethodGroupExpr mg, Location l)
 603                 {
 604                         type = t;
 605                         this.method_group = mg;
 606                         loc = l;
 607                 }
 608
 609                 static public Expression Create (ResolveContext ec, MethodGroupExpr mge,
 610                                                  TypeSpec target_type, Location loc)
 611                 {
 612                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 613                         return d.DoResolve (ec);
 614                 }
 615         }
 616
 617         //
 618         // A delegate-creation-expression, invoked from the `New' class
 619         //
 620         public class NewDelegate : DelegateCreation
 621         {
 622                 public Arguments Arguments;
 623
 624                 //
 625                 // This constructor is invoked from the `New' expression
 626                 //
 627                 public NewDelegate (TypeSpec type, Arguments Arguments, Location loc)
 628                 {
 629                         this.type = type;
 630                         this.Arguments = Arguments;
 631                         this.loc  = loc;
 632                 }
 633
 634                 protected override Expression DoResolve (ResolveContext ec)
 635                 {
 636                         if (Arguments == null || Arguments.Count != 1) {
 637                                 ec.Report.Error (149, loc, "Method name expected");
 638                                 return null;
 639                         }
 640
 641                         Argument a = Arguments [0];
 642                         if (!a.ResolveMethodGroup (ec))
 643                                 return null;
 644
 645                         Expression e = a.Expr;
 646
 647                         AnonymousMethodExpression ame = e as AnonymousMethodExpression;
 648                         if (ame != null && RootContext.Version != LanguageVersion.ISO_1) {
 649                                 e = ame.Compatible (ec, type);
 650                                 if (e == null)
 651                                         return null;
 652
 653                                 return e.Resolve (ec);
 654                         }
 655
 656                         method_group = e as MethodGroupExpr;
 657                         if (method_group == null) {
 658                                 if (e.Type == InternalType.Dynamic) {
 659                                         e = Convert.ImplicitConversionRequired (ec, e, type, loc);
 660                                 } else if (!e.Type.IsDelegate) {
 661                                         e.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup | ResolveFlags.Type, loc);
 662                                         return null;
 663                                 }
 664
 665                                 //
 666                                 // An argument is not a method but another delegate
 667                                 //
 668                                 delegate_instance_expression = e;
 669                                 method_group = new MethodGroupExpr (Delegate.GetInvokeMethod (ec.Compiler, e.Type), e.Type, loc);
 670                         }
 671
 672                         return base.DoResolve (ec);
 673                 }
 674         }
 675
 676         //
 677         // Invocation converted to delegate Invoke call
 678         //
 679         class DelegateInvocation : ExpressionStatement
 680         {
 681                 readonly Expression InstanceExpr;
 682                 Arguments arguments;
 683                 MethodSpec method;
 684
 685                 public DelegateInvocation (Expression instance_expr, Arguments args, Location loc)
 686                 {
 687                         this.InstanceExpr = instance_expr;
 688                         this.arguments = args;
 689                         this.loc = loc;
 690                 }
 691
 692                 public override Expression CreateExpressionTree (ResolveContext ec)
 693                 {
 694                         Arguments args = Arguments.CreateForExpressionTree (ec, this.arguments,
 695                                 InstanceExpr.CreateExpressionTree (ec));
 696
 697                         return CreateExpressionFactoryCall (ec, "Invoke", args);
 698                 }
 699
 700                 protected override Expression DoResolve (ResolveContext ec)
 701                 {
 702                         if (InstanceExpr is EventExpr) {
 703                                 ((EventExpr) InstanceExpr).Error_CannotAssign (ec);
 704                                 return null;
 705                         }
 706
 707                         TypeSpec del_type = InstanceExpr.Type;
 708                         if (del_type == null)
 709                                 return null;
 710
 711                         method = Delegate.GetInvokeMethod (ec.Compiler, del_type);
 712                         var mb = method;
 713                         var me = new MethodGroupExpr (mb, del_type, loc);
 714                         me.InstanceExpression = InstanceExpr;
 715
 716                         AParametersCollection pd = mb.Parameters;
 717                         int pd_count = pd.Count;
 718
 719                         int arg_count = arguments == null ? 0 : arguments.Count;
 720
 721                         bool params_method = pd.HasParams;
 722                         bool is_params_applicable = false;
 723                         bool is_applicable = me.IsApplicable (ec, ref arguments, arg_count, ref mb, ref is_params_applicable) == 0;
 724                         if (arguments != null)
 725                                 arg_count = arguments.Count;
 726
 727                         if (!is_applicable && !params_method && arg_count != pd_count) {
 728                                 ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 729                                         TypeManager.CSharpName (del_type), arg_count.ToString ());
 730                         } else if (arguments == null || !arguments.HasDynamic) {
 731                                 me.VerifyArgumentsCompat (ec, ref arguments, arg_count, mb,
 732                                         is_params_applicable || (!is_applicable && params_method), false, loc);
 733                         }
 734
 735                         type = method.ReturnType;
 736                         eclass = ExprClass.Value;
 737                         return this;
 738                 }
 739
 740                 public override void Emit (EmitContext ec)
 741                 {
 742                         //
 743                         // Invocation on delegates call the virtual Invoke member
 744                         // so we are always `instance' calls
 745                         //
 746                         Invocation.EmitCall (ec, false, InstanceExpr, method, arguments, loc);
 747                 }
 748
 749                 public override void EmitStatement (EmitContext ec)
 750                 {
 751                         Emit (ec);
 752                         //
 753                         // Pop the return value if there is one
 754                         //
 755                         if (type != TypeManager.void_type)
 756                                 ec.Emit (OpCodes.Pop);
 757                 }
 758
 759                 public override System.Linq.Expressions.Expression MakeExpression (BuilderContext ctx)
 760                 {
 761                         return Invocation.MakeExpression (ctx, InstanceExpr, method, arguments);
 762                 }
 763         }
 764 }