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
  19 namespace Mono.CSharp {
  20
  21         //
  22         // Delegate container implementation
  23         //
  24         public class Delegate : TypeContainer
  25         {
  26                 FullNamedExpression ReturnType;
  27                 public readonly AParametersCollection Parameters;
  28
  29                 // TODO: Maybe I can keep member cache only and not the builders
  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                 }
  64
  65                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
  66                 {
  67                         if (a.Target == AttributeTargets.ReturnValue) {
  68                                 if (return_attributes == null)
  69                                         return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
  70
  71                                 return_attributes.ApplyAttributeBuilder (a, cb, pa);
  72                                 return;
  73                         }
  74
  75                         base.ApplyAttributeBuilder (a, cb, pa);
  76                 }
  77
  78                 public override AttributeTargets AttributeTargets {
  79                         get {
  80                                 return AttributeTargets.Delegate;
  81                         }
  82                 }
  83
  84                 protected override Type BaseType {
  85                         get {
  86                                 return TypeManager.multicast_delegate_type;
  87                         }
  88                 }
  89
  90                 protected override bool DoDefineMembers ()
  91                 {
  92                         if (IsGeneric) {
  93                                 foreach (TypeParameter type_param in TypeParameters) {
  94                                         if (!type_param.Resolve (this))
  95                                                 return false;
  96                                 }
  97
  98                                 foreach (TypeParameter type_param in TypeParameters) {
  99                                         if (!type_param.DefineType (this))
 100                                                 return false;
 101                                 }
 102                         }
 103
 104                         member_cache = new MemberCache (BaseType, this);
 105
 106                         var ctor_parameters = ParametersCompiled.CreateFullyResolved (
 107                                 new [] {
 108                                         new Parameter (new TypeExpression (TypeManager.object_type, Location), "object", Parameter.Modifier.NONE, null, Location),
 109                                         new Parameter (new TypeExpression (TypeManager.intptr_type, Location), "method", Parameter.Modifier.NONE, null, Location)
 110                                 },
 111                                 new [] {
 112                                         TypeManager.object_type,
 113                                         TypeManager.intptr_type
 114                                 }
 115                         );
 116
 117                         Constructor = new Constructor (this, System.Reflection.ConstructorInfo.ConstructorName,
 118                                 Modifiers.PUBLIC, null, ctor_parameters, null, Location);
 119                         Constructor.Define ();
 120
 121                         //
 122                         // Here the various methods like Invoke, BeginInvoke etc are defined
 123                         //
 124                         // First, call the `out of band' special method for
 125                         // defining recursively any types we need:
 126                         //
 127                         var p = Parameters.AsCompiled;
 128
 129                         if (!p.Resolve (this))
 130                                 return false;
 131
 132                         //
 133                         // Invoke method
 134                         //
 135
 136                         // Check accessibility
 137                         foreach (var partype in p.Types) {
 138                                 if (!IsAccessibleAs (partype)) {
 139                                         Report.SymbolRelatedToPreviousError (partype);
 140                                         Report.Error (59, Location,
 141                                                 "Inconsistent accessibility: parameter type `{0}' is less accessible than delegate `{1}'",
 142                                                 TypeManager.CSharpName (partype), GetSignatureForError ());
 143                                 }
 144                         }
 145
 146                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 147                         if (ReturnType == null)
 148                                 return false;
 149
 150                         var ret_type = ReturnType.Type;
 151
 152                         //
 153                         // We don't have to check any others because they are all
 154                         // guaranteed to be accessible - they are standard types.
 155                         //
 156                         if (!IsAccessibleAs (ret_type)) {
 157                                 Report.SymbolRelatedToPreviousError (ret_type);
 158                                 Report.Error (58, Location,
 159                                                   "Inconsistent accessibility: return type `" +
 160                                                   TypeManager.CSharpName (ret_type) + "' is less " +
 161                                                   "accessible than delegate `" + GetSignatureForError () + "'");
 162                                 return false;
 163                         }
 164
 165                         CheckProtectedModifier ();
 166
 167                         if (RootContext.StdLib && TypeManager.IsSpecialType (ret_type)) {
 168                                 Method.Error1599 (Location, ret_type, Report);
 169                                 return false;
 170                         }
 171
 172                         TypeManager.CheckTypeVariance (ret_type, Variance.Covariant, this);
 173
 174                         InvokeBuilder = new Method (this, null, ReturnType, MethodModifiers, new MemberName (InvokeMethodName), p, null);
 175                         InvokeBuilder.Define ();
 176
 177                         //
 178                         // Don't emit async method for compiler generated delegates (e.g. dynamic site containers)
 179                         //
 180                         if (TypeManager.iasyncresult_type != null && TypeManager.asynccallback_type != null && !IsCompilerGenerated) {
 181                                 DefineAsyncMethods (Parameters.CallingConvention);
 182                         }
 183
 184                         return true;
 185                 }
 186
 187                 void DefineAsyncMethods (CallingConventions cc)
 188                 {
 189                         //
 190                         // BeginInvoke
 191                         //
 192                         Parameter[] compiled = new Parameter[Parameters.Count];
 193                         for (int i = 0; i < compiled.Length; ++i)
 194                                 compiled[i] = new Parameter (new TypeExpression (Parameters.Types[i], Location),
 195                                         Parameters.FixedParameters[i].Name,
 196                                         Parameters.FixedParameters[i].ModFlags & (Parameter.Modifier.REF | Parameter.Modifier.OUT),
 197                                         null, Location);
 198
 199                         ParametersCompiled async_parameters = new ParametersCompiled (Compiler, compiled);
 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 Type [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.AsCompiled [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 Emit ()
 266                 {
 267                         if (TypeManager.IsDynamicType (ReturnType.Type)) {
 268                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 269                                 PredefinedAttributes.Get.Dynamic.EmitAttribute (return_attributes.Builder);
 270                         } else {
 271                                 var trans_flags = TypeManager.HasDynamicTypeUsed (ReturnType.Type);
 272                                 if (trans_flags != null) {
 273                                         var pa = PredefinedAttributes.Get.DynamicTransform;
 274                                         if (pa.Constructor != null || pa.ResolveConstructor (Location, TypeManager.bool_type.MakeArrayType ())) {
 275                                                 return_attributes = new ReturnParameter (this, InvokeBuilder.MethodBuilder, Location);
 276                                                 return_attributes.Builder.SetCustomAttribute (
 277                                                         new CustomAttributeBuilder (pa.Constructor, new object [] { trans_flags }));
 278                                         }
 279                                 }
 280                         }
 281
 282                         Parameters.AsCompiled.ApplyAttributes (InvokeBuilder.MethodBuilder);
 283
 284                         Constructor.ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 285                         InvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 286
 287                         if (BeginInvokeBuilder != null) {
 288                                 BeginInvokeBuilder.Parameters.ApplyAttributes (BeginInvokeBuilder.MethodBuilder);
 289
 290                                 BeginInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 291                                 EndInvokeBuilder.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 292                         }
 293
 294                         if (OptAttributes != null) {
 295                                 OptAttributes.Emit ();
 296                         }
 297
 298                         base.Emit ();
 299                 }
 300
 301                 protected override TypeAttributes TypeAttr {
 302                         get {
 303                                 return ModifiersExtensions.TypeAttr (ModFlags, IsTopLevel) |
 304                                         TypeAttributes.Class | TypeAttributes.Sealed |
 305                                         base.TypeAttr;
 306                         }
 307                 }
 308
 309                 public override string[] ValidAttributeTargets {
 310                         get {
 311                                 return attribute_targets;
 312                         }
 313                 }
 314
 315                 //TODO: duplicate
 316                 protected override bool VerifyClsCompliance ()
 317                 {
 318                         if (!base.VerifyClsCompliance ()) {
 319                                 return false;
 320                         }
 321
 322                         Parameters.AsCompiled.VerifyClsCompliance (this);
 323
 324                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 325                                 Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
 326                                         GetSignatureForError ());
 327                         }
 328                         return true;
 329                 }
 330
 331
 332                 public static MethodSpec GetConstructor (CompilerContext ctx, Type container_type, Type delegate_type)
 333                 {
 334                         Type dt = delegate_type;
 335                         Type[] g_args = null;
 336                         if (TypeManager.IsGenericType (delegate_type)) {
 337                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 338                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 339                         }
 340
 341                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 342                         if (d != null) {
 343                                 if (g_args != null)
 344                                         return Import.CreateMethod (TypeBuilder.GetConstructor (dt, d.Constructor.ConstructorBuilder));
 345
 346                                 return d.Constructor.Spec;
 347                         }
 348
 349                         Expression ml = Expression.MemberLookup (ctx, container_type,
 350                                 null, dt, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 351                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly, Location.Null);
 352
 353                         MethodGroupExpr mg = ml as MethodGroupExpr;
 354                         if (mg == null) {
 355                                 ctx.Report.Error (-100, Location.Null, "Internal error: could not find delegate constructor!");
 356                                 // FIXME: null will cause a crash later
 357                                 return null;
 358                         }
 359
 360                         return mg.Methods[0];
 361                 }
 362
 363                 //
 364                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 365                 // to extract the signature of a delegate.
 366                 //
 367                 public static MethodSpec GetInvokeMethod (CompilerContext ctx, Type container_type, Type delegate_type)
 368                 {
 369                         Type dt = delegate_type;
 370
 371                         Type[] g_args = null;
 372                         if (TypeManager.IsGenericType (delegate_type)) {
 373                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 374                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 375                         }
 376
 377                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 378                         MethodSpec invoke;
 379                         if (d != null) {
 380                                 if (g_args != null) {
 381                                         invoke = Import.CreateMethod (TypeBuilder.GetMethod (dt, d.InvokeBuilder.MethodBuilder));
 382 #if MS_COMPATIBLE
 383 //                                      ParametersCompiled p = (ParametersCompiled) d.Parameters.InflateTypes (g_args, g_args);
 384 //                                      TypeManager.RegisterMethod (invoke, p);
 385 #endif
 386                                         return invoke;
 387                                 }
 388                                 return d.InvokeBuilder.Spec;
 389                         }
 390
 391                         Expression ml = Expression.MemberLookup (ctx, container_type, null, dt,
 392                                 "Invoke", Location.Null);
 393
 394                         MethodGroupExpr mg = ml as MethodGroupExpr;
 395                         if (mg == null) {
 396                                 ctx.Report.Error (-100, Location.Null, "Internal error: could not find Invoke method!");
 397                                 // FIXME: null will cause a crash later
 398                                 return null;
 399                         }
 400
 401                         invoke = mg.Methods[0];
 402 #if MS_COMPATIBLE
 403 //                      if (g_args != null) {
 404 //                              AParametersCollection p = TypeManager.GetParameterData (invoke);
 405 //                              p = p.InflateTypes (g_args, g_args);
 406 //                              TypeManager.RegisterMethod (invoke, p);
 407 //                              return invoke;
 408 //                      }
 409 #endif
 410
 411                         return invoke;
 412                 }
 413
 414                 //
 415                 // 15.2 Delegate compatibility
 416                 //
 417                 public static bool IsTypeCovariant (Expression a, Type b)
 418                 {
 419                         //
 420                         // For each value parameter (a parameter with no ref or out modifier), an
 421                         // identity conversion or implicit reference conversion exists from the
 422                         // parameter type in D to the corresponding parameter type in M
 423                         //
 424                         if (a.Type == b)
 425                                 return true;
 426
 427                         if (RootContext.Version == LanguageVersion.ISO_1)
 428                                 return false;
 429
 430                         return Convert.ImplicitReferenceConversionExists (a, b);
 431                 }
 432
 433                 public static string FullDelegateDesc (MethodSpec invoke_method)
 434                 {
 435                         return TypeManager.GetFullNameSignature (invoke_method.MetaInfo).Replace (".Invoke", "");
 436                 }
 437
 438                 public Expression InstanceExpression {
 439                         get {
 440                                 return instance_expr;
 441                         }
 442                         set {
 443                                 instance_expr = value;
 444                         }
 445                 }
 446         }
 447
 448         //
 449         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 450         //
 451         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 452         {
 453                 protected MethodSpec constructor_method;
 454                 protected MethodSpec delegate_method;
 455                 // We keep this to handle IsBase only
 456                 protected MethodGroupExpr method_group;
 457                 protected Expression delegate_instance_expression;
 458
 459                 // TODO: Should either cache it or use interface to abstract it
 460                 public static Arguments CreateDelegateMethodArguments (AParametersCollection pd, Location loc)
 461                 {
 462                         Arguments delegate_arguments = new Arguments (pd.Count);
 463                         for (int i = 0; i < pd.Count; ++i) {
 464                                 Argument.AType atype_modifier;
 465                                 Type atype = pd.Types [i];
 466                                 switch (pd.FixedParameters [i].ModFlags) {
 467                                 case Parameter.Modifier.REF:
 468                                         atype_modifier = Argument.AType.Ref;
 469                                         //atype = atype.GetElementType ();
 470                                         break;
 471                                 case Parameter.Modifier.OUT:
 472                                         atype_modifier = Argument.AType.Out;
 473                                         //atype = atype.GetElementType ();
 474                                         break;
 475                                 default:
 476                                         atype_modifier = 0;
 477                                         break;
 478                                 }
 479                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 480                         }
 481                         return delegate_arguments;
 482                 }
 483
 484                 public override Expression CreateExpressionTree (ResolveContext ec)
 485                 {
 486                         MemberAccess ma = new MemberAccess (new MemberAccess (new QualifiedAliasMember ("global", "System", loc), "Delegate", loc), "CreateDelegate", loc);
 487
 488                         Arguments args = new Arguments (3);
 489                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 490                         args.Add (new Argument (new NullLiteral (loc)));
 491                         args.Add (new Argument (new TypeOfMethod (delegate_method, loc)));
 492                         Expression e = new Invocation (ma, args).Resolve (ec);
 493                         if (e == null)
 494                                 return null;
 495
 496                         e = Convert.ExplicitConversion (ec, e, type, loc);
 497                         if (e == null)
 498                                 return null;
 499
 500                         return e.CreateExpressionTree (ec);
 501                 }
 502
 503                 protected override Expression DoResolve (ResolveContext ec)
 504                 {
 505                         constructor_method = Delegate.GetConstructor (ec.Compiler, ec.CurrentType, type);
 506
 507                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, type);
 508                         method_group.DelegateType = type;
 509                         method_group.CustomErrorHandler = this;
 510
 511                         Arguments arguments = CreateDelegateMethodArguments (invoke_method.Parameters, loc);
 512                         method_group = method_group.OverloadResolve (ec, ref arguments, false, loc);
 513                         if (method_group == null)
 514                                 return null;
 515
 516                         delegate_method = (MethodSpec) method_group;
 517
 518                         if (TypeManager.IsNullableType (delegate_method.DeclaringType)) {
 519                                 ec.Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
 520                                         TypeManager.GetFullNameSignature (delegate_method.MetaInfo));
 521                                 return null;
 522                         }
 523
 524                         Invocation.IsSpecialMethodInvocation (ec, delegate_method, loc);
 525
 526                         ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
 527                         if (emg != null) {
 528                                 delegate_instance_expression = emg.ExtensionExpression;
 529                                 Type e_type = delegate_instance_expression.Type;
 530                                 if (TypeManager.IsValueType (e_type)) {
 531                                         ec.Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 532                                                 TypeManager.CSharpSignature (delegate_method.MetaInfo), TypeManager.CSharpName (e_type));
 533                                 }
 534                         }
 535
 536                         Type rt = TypeManager.TypeToCoreType (delegate_method.ReturnType);
 537                         Expression ret_expr = new TypeExpression (rt, loc);
 538                         if (!Delegate.IsTypeCovariant (ret_expr, (TypeManager.TypeToCoreType (invoke_method.ReturnType)))) {
 539                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 540                         }
 541
 542                         if (Invocation.IsMethodExcluded (delegate_method, loc)) {
 543                                 ec.Report.SymbolRelatedToPreviousError (delegate_method.MetaInfo);
 544                                 MethodOrOperator m = TypeManager.GetMethod (delegate_method.MetaInfo) as MethodOrOperator;
 545                                 if (m != null && m.IsPartialDefinition) {
 546                                         ec.Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
 547                                                 TypeManager.CSharpSignature (delegate_method.MetaInfo));
 548                                 } else {
 549                                         ec.Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 550                                                 TypeManager.CSharpSignature (delegate_method.MetaInfo));
 551                                 }
 552                         }
 553
 554                         DoResolveInstanceExpression (ec);
 555                         eclass = ExprClass.Value;
 556                         return this;
 557                 }
 558
 559                 void DoResolveInstanceExpression (ResolveContext ec)
 560                 {
 561                         //
 562                         // Argument is another delegate
 563                         //
 564                         if (delegate_instance_expression != null)
 565                                 return;
 566
 567                         if (method_group.IsStatic) {
 568                                 delegate_instance_expression = null;
 569                                 return;
 570                         }
 571
 572                         Expression instance = method_group.InstanceExpression;
 573                         if (instance != null && instance != EmptyExpression.Null) {
 574                                 delegate_instance_expression = instance;
 575                                 Type instance_type = delegate_instance_expression.Type;
 576                                 if (TypeManager.IsValueType (instance_type) || TypeManager.IsGenericParameter (instance_type)) {
 577                                         delegate_instance_expression = new BoxedCast (
 578                                                 delegate_instance_expression, TypeManager.object_type);
 579                                 }
 580                         } else {
 581                                 delegate_instance_expression = ec.GetThis (loc);
 582                         }
 583                 }
 584
 585                 public override void Emit (EmitContext ec)
 586                 {
 587                         if (delegate_instance_expression == null)
 588                                 ec.ig.Emit (OpCodes.Ldnull);
 589                         else
 590                                 delegate_instance_expression.Emit (ec);
 591
 592                         if (!delegate_method.DeclaringType.IsSealed && delegate_method.IsVirtual && !method_group.IsBase) {
 593                                 ec.ig.Emit (OpCodes.Dup);
 594                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method.MetaInfo);
 595                         } else {
 596                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method.MetaInfo);
 597                         }
 598
 599                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method.MetaInfo);
 600                 }
 601
 602                 void Error_ConversionFailed (ResolveContext ec, MethodSpec method, Expression return_type)
 603                 {
 604                         var invoke_method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, type);
 605                         string member_name = delegate_instance_expression != null ?
 606                                 Delegate.FullDelegateDesc (method) :
 607                                 TypeManager.GetFullNameSignature (method.MetaInfo);
 608
 609                         ec.Report.SymbolRelatedToPreviousError (type);
 610                         ec.Report.SymbolRelatedToPreviousError (method.MetaInfo);
 611                         if (RootContext.Version == LanguageVersion.ISO_1) {
 612                                 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",
 613                                         TypeManager.CSharpName (method.ReturnType), member_name,
 614                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 615                                 return;
 616                         }
 617                         if (return_type == null) {
 618                                 ec.Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 619                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 620                                 return;
 621                         }
 622
 623                         ec.Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 624                                 return_type.GetSignatureForError (), member_name,
 625                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 626                 }
 627
 628                 public static bool ImplicitStandardConversionExists (ResolveContext ec, MethodGroupExpr mg, Type target_type)
 629                 {
 630                         if (target_type == TypeManager.delegate_type || target_type == TypeManager.multicast_delegate_type)
 631                                 return false;
 632
 633                         mg.DelegateType = target_type;
 634                         var invoke = Delegate.GetInvokeMethod (ec.Compiler, null, target_type);
 635
 636                         Arguments arguments = CreateDelegateMethodArguments (invoke.Parameters, mg.Location);
 637                         return mg.OverloadResolve (ec, ref arguments, true, mg.Location) != null;
 638                 }
 639
 640                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 641                 {
 642                         if (delegate_instance_expression != null)
 643                                 delegate_instance_expression.MutateHoistedGenericType (storey);
 644
 645                         storey.MutateGenericMethod (delegate_method);
 646                         storey.MutateConstructor (constructor_method);
 647                 }
 648
 649                 #region IErrorHandler Members
 650
 651                 public bool NoExactMatch (ResolveContext ec, MethodSpec method)
 652                 {
 653                         if (method.IsGenericMethod)
 654                                 return false;
 655
 656                         Error_ConversionFailed (ec, method, null);
 657                         return true;
 658                 }
 659
 660                 public bool AmbiguousCall (ResolveContext ec, MethodSpec ambiguous)
 661                 {
 662                         return false;
 663                 }
 664
 665                 #endregion
 666         }
 667
 668         //
 669         // Created from the conversion code
 670         //
 671         public class ImplicitDelegateCreation : DelegateCreation
 672         {
 673                 ImplicitDelegateCreation (Type t, MethodGroupExpr mg, Location l)
 674                 {
 675                         type = t;
 676                         this.method_group = mg;
 677                         loc = l;
 678                 }
 679
 680                 static public Expression Create (ResolveContext ec, MethodGroupExpr mge,
 681                                                  Type target_type, Location loc)
 682                 {
 683                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 684                         return d.DoResolve (ec);
 685                 }
 686         }
 687
 688         //
 689         // A delegate-creation-expression, invoked from the `New' class
 690         //
 691         public class NewDelegate : DelegateCreation
 692         {
 693                 public Arguments Arguments;
 694
 695                 //
 696                 // This constructor is invoked from the `New' expression
 697                 //
 698                 public NewDelegate (Type type, Arguments Arguments, Location loc)
 699                 {
 700                         this.type = type;
 701                         this.Arguments = Arguments;
 702                         this.loc  = loc;
 703                 }
 704
 705                 protected override Expression DoResolve (ResolveContext ec)
 706                 {
 707                         if (Arguments == null || Arguments.Count != 1) {
 708                                 ec.Report.Error (149, loc, "Method name expected");
 709                                 return null;
 710                         }
 711
 712                         Argument a = Arguments [0];
 713                         if (!a.ResolveMethodGroup (ec))
 714                                 return null;
 715
 716                         Expression e = a.Expr;
 717
 718                         AnonymousMethodExpression ame = e as AnonymousMethodExpression;
 719                         if (ame != null && RootContext.Version != LanguageVersion.ISO_1) {
 720                                 e = ame.Compatible (ec, type);
 721                                 if (e == null)
 722                                         return null;
 723
 724                                 return e.Resolve (ec);
 725                         }
 726
 727                         method_group = e as MethodGroupExpr;
 728                         if (method_group == null) {
 729                                 if (TypeManager.IsDynamicType (e.Type)) {
 730                                         e = Convert.ImplicitConversionRequired (ec, e, type, loc);
 731                                 } else if (!TypeManager.IsDelegateType (e.Type)) {
 732                                         e.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup | ResolveFlags.Type, loc);
 733                                         return null;
 734                                 }
 735
 736                                 //
 737                                 // An argument is not a method but another delegate
 738                                 //
 739                                 delegate_instance_expression = e;
 740                                 method_group = new MethodGroupExpr (new [] {
 741                                         Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, e.Type) }, e.Type, loc);
 742                         }
 743
 744                         return base.DoResolve (ec);
 745                 }
 746         }
 747
 748         //
 749         // Invocation converted to delegate Invoke call
 750         //
 751         class DelegateInvocation : ExpressionStatement
 752         {
 753                 readonly Expression InstanceExpr;
 754                 Arguments arguments;
 755                 MethodSpec method;
 756
 757                 public DelegateInvocation (Expression instance_expr, Arguments args, Location loc)
 758                 {
 759                         this.InstanceExpr = instance_expr;
 760                         this.arguments = args;
 761                         this.loc = loc;
 762                 }
 763
 764                 public override Expression CreateExpressionTree (ResolveContext ec)
 765                 {
 766                         Arguments args = Arguments.CreateForExpressionTree (ec, this.arguments,
 767                                 InstanceExpr.CreateExpressionTree (ec));
 768
 769                         return CreateExpressionFactoryCall (ec, "Invoke", args);
 770                 }
 771
 772                 protected override Expression DoResolve (ResolveContext ec)
 773                 {
 774                         if (InstanceExpr is EventExpr) {
 775                                 ((EventExpr) InstanceExpr).Error_CannotAssign (ec);
 776                                 return null;
 777                         }
 778
 779                         Type del_type = InstanceExpr.Type;
 780                         if (del_type == null)
 781                                 return null;
 782
 783                         method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, del_type);
 784                         var mb = method;
 785                         var me = new MethodGroupExpr (new [] { mb }, del_type, loc);
 786                         me.InstanceExpression = InstanceExpr;
 787
 788                         AParametersCollection pd = mb.Parameters;
 789                         int pd_count = pd.Count;
 790
 791                         int arg_count = arguments == null ? 0 : arguments.Count;
 792
 793                         bool params_method = pd.HasParams;
 794                         bool is_params_applicable = false;
 795                         bool is_applicable = me.IsApplicable (ec, ref arguments, arg_count, ref mb, ref is_params_applicable) == 0;
 796                         if (arguments != null)
 797                                 arg_count = arguments.Count;
 798
 799                         if (!is_applicable && !params_method && arg_count != pd_count) {
 800                                 ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 801                                         TypeManager.CSharpName (del_type), arg_count.ToString ());
 802                         } else if (arguments == null || !arguments.HasDynamic) {
 803                                 me.VerifyArgumentsCompat (ec, ref arguments, arg_count, mb,
 804                                         is_params_applicable || (!is_applicable && params_method), false, loc);
 805                         }
 806
 807                         type = TypeManager.TypeToCoreType (method.ReturnType);
 808                         eclass = ExprClass.Value;
 809                         return this;
 810                 }
 811
 812                 public override void Emit (EmitContext ec)
 813                 {
 814                         //
 815                         // Invocation on delegates call the virtual Invoke member
 816                         // so we are always `instance' calls
 817                         //
 818                         Invocation.EmitCall (ec, false, InstanceExpr, method, arguments, loc);
 819                 }
 820
 821                 public override void EmitStatement (EmitContext ec)
 822                 {
 823                         Emit (ec);
 824                         //
 825                         // Pop the return value if there is one
 826                         //
 827                         if (type != TypeManager.void_type)
 828                                 ec.ig.Emit (OpCodes.Pop);
 829                 }
 830
 831                 public override System.Linq.Expressions.Expression MakeExpression (BuilderContext ctx)
 832                 {
 833                         return Invocation.MakeExpression (ctx, InstanceExpr, method, arguments);
 834                 }
 835
 836                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 837                 {
 838                         storey.MutateGenericMethod (method);
 839                         type = storey.MutateType (type);
 840
 841                         if (arguments != null)
 842                                 arguments.MutateHoistedGenericType (storey);
 843
 844                         InstanceExpr.MutateHoistedGenericType (storey);
 845                 }
 846         }
 847 }