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.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         //
  23         // Delegate container implementation
  24         //
  25         public class Delegate : TypeContainer
  26         {
  27                 FullNamedExpression ReturnType;
  28                 public ParametersCompiled      Parameters;
  29
  30                 public ConstructorBuilder ConstructorBuilder;
  31                 public MethodBuilder      InvokeBuilder;
  32                 public MethodBuilder      BeginInvokeBuilder;
  33                 public MethodBuilder      EndInvokeBuilder;
  34
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
  44                         MethodAttributes.Virtual | MethodAttributes.NewSlot;
  45
  46                 const int AllowedModifiers =
  47                         Modifiers.NEW |
  48                         Modifiers.PUBLIC |
  49                         Modifiers.PROTECTED |
  50                         Modifiers.INTERNAL |
  51                         Modifiers.UNSAFE |
  52                         Modifiers.PRIVATE;
  53
  54                 public Delegate (NamespaceEntry ns, DeclSpace parent, FullNamedExpression type,
  55                                  int mod_flags, MemberName name, ParametersCompiled param_list,
  56                                  Attributes attrs)
  57                         : base (ns, parent, name, attrs, Kind.Delegate)
  58
  59                 {
  60                         this.ReturnType = type;
  61                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  62                                                            IsTopLevel ? Modifiers.INTERNAL :
  63                                                            Modifiers.PRIVATE, name.Location, Report);
  64                         Parameters      = param_list;
  65                 }
  66
  67                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
  68                 {
  69                         if (a.Target == AttributeTargets.ReturnValue) {
  70                                 if (return_attributes == null)
  71                                         return_attributes = new ReturnParameter (this, InvokeBuilder, Location);
  72
  73                                 return_attributes.ApplyAttributeBuilder (a, cb, pa);
  74                                 return;
  75                         }
  76
  77                         base.ApplyAttributeBuilder (a, cb, pa);
  78                 }
  79
  80                 public override AttributeTargets AttributeTargets {
  81                         get {
  82                                 return AttributeTargets.Delegate;
  83                         }
  84                 }
  85
  86                 protected override bool DoDefineMembers ()
  87                 {
  88                         if (IsGeneric) {
  89                                 foreach (TypeParameter type_param in TypeParameters) {
  90                                         if (!type_param.Resolve (this))
  91                                                 return false;
  92                                 }
  93
  94                                 foreach (TypeParameter type_param in TypeParameters) {
  95                                         if (!type_param.DefineType (this))
  96                                                 return false;
  97                                 }
  98                         }
  99
 100                         member_cache = new MemberCache (TypeManager.multicast_delegate_type, this);
 101
 102                         // FIXME: POSSIBLY make this static, as it is always constant
 103                         //
 104                         Type [] const_arg_types = new Type [2];
 105                         const_arg_types [0] = TypeManager.object_type;
 106                         const_arg_types [1] = TypeManager.intptr_type;
 107
 108                         const MethodAttributes ctor_mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 109                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 110
 111                         ConstructorBuilder = TypeBuilder.DefineConstructor (ctor_mattr,
 112                                                                             CallingConventions.Standard,
 113                                                                             const_arg_types);
 114
 115                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 116                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 117                         //
 118                         // HACK because System.Reflection.Emit is lame
 119                         //
 120                         IParameterData [] fixed_pars = new IParameterData [] {
 121                                 new ParameterData ("object", Parameter.Modifier.NONE),
 122                                 new ParameterData ("method", Parameter.Modifier.NONE)
 123                         };
 124
 125                         AParametersCollection const_parameters = new ParametersImported (
 126                                 fixed_pars,
 127                                 new Type[] { TypeManager.object_type, TypeManager.intptr_type });
 128
 129                         TypeManager.RegisterMethod (ConstructorBuilder, const_parameters);
 130                         member_cache.AddMember (ConstructorBuilder, this);
 131
 132                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 133
 134                         //
 135                         // Here the various methods like Invoke, BeginInvoke etc are defined
 136                         //
 137                         // First, call the `out of band' special method for
 138                         // defining recursively any types we need:
 139
 140                         if (!Parameters.Resolve (this))
 141                                 return false;
 142
 143                         //
 144                         // Invoke method
 145                         //
 146
 147                         // Check accessibility
 148                         foreach (Type partype in Parameters.Types){
 149                                 if (!IsAccessibleAs (partype)) {
 150                                         Report.SymbolRelatedToPreviousError (partype);
 151                                         Report.Error (59, Location,
 152                                                       "Inconsistent accessibility: parameter type `{0}' is less accessible than delegate `{1}'",
 153                                                       TypeManager.CSharpName (partype),
 154                                                       GetSignatureForError ());
 155                                         return false;
 156                                 }
 157                         }
 158
 159                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 160                         if (ReturnType == null)
 161                                 return false;
 162
 163                         ret_type = ReturnType.Type;
 164
 165                         if (!IsAccessibleAs (ret_type)) {
 166                                 Report.SymbolRelatedToPreviousError (ret_type);
 167                                 Report.Error (58, Location,
 168                                               "Inconsistent accessibility: return type `" +
 169                                               TypeManager.CSharpName (ret_type) + "' is less " +
 170                                               "accessible than delegate `" + GetSignatureForError () + "'");
 171                                 return false;
 172                         }
 173
 174                         CheckProtectedModifier ();
 175
 176                         if (RootContext.StdLib && TypeManager.IsSpecialType (ret_type)) {
 177                                 Method.Error1599 (Location, ret_type, Report);
 178                                 return false;
 179                         }
 180
 181                         TypeManager.CheckTypeVariance (ret_type, Variance.Covariant, this);
 182
 183                         //
 184                         // We don't have to check any others because they are all
 185                         // guaranteed to be accessible - they are standard types.
 186                         //
 187
 188                         CallingConventions cc = Parameters.CallingConvention;
 189
 190                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 191                                                                   mattr,
 192                                                                   cc,
 193                                                                   ret_type,
 194                                                                   Parameters.GetEmitTypes ());
 195
 196                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 197
 198                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 199                         member_cache.AddMember (InvokeBuilder, this);
 200
 201                         //
 202                         // Don't emit async method for compiler generated delegates (e.g. dynamic site containers)
 203                         //
 204                         if (TypeManager.iasyncresult_type != null && TypeManager.asynccallback_type != null && !IsCompilerGenerated) {
 205                                 DefineAsyncMethods (cc);
 206                         }
 207
 208                         return true;
 209                 }
 210
 211                 void DefineAsyncMethods (CallingConventions cc)
 212                 {
 213                         //
 214                         // BeginInvoke
 215                         //
 216                         ParametersCompiled async_parameters = ParametersCompiled.MergeGenerated (Compiler, Parameters, false,
 217                                 new Parameter [] {
 218                                         new Parameter (null, "callback", Parameter.Modifier.NONE, null, Location),
 219                                         new Parameter (null, "object", Parameter.Modifier.NONE, null, Location)
 220                                 },
 221                                 new Type [] {
 222                                         TypeManager.asynccallback_type,
 223                                         TypeManager.object_type
 224                                 }
 225                         );
 226
 227                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 228                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.GetEmitTypes ());
 229
 230                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 231                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 232                         member_cache.AddMember (BeginInvokeBuilder, this);
 233
 234                         //
 235                         // EndInvoke is a bit more interesting, all the parameters labeled as
 236                         // out or ref have to be duplicated here.
 237                         //
 238
 239                         //
 240                         // Define parameters, and count out/ref parameters
 241                         //
 242                         ParametersCompiled end_parameters;
 243                         int out_params = 0;
 244
 245                         foreach (Parameter p in Parameters.FixedParameters) {
 246                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 247                                         ++out_params;
 248                         }
 249
 250                         if (out_params > 0) {
 251                                 Type [] end_param_types = new Type [out_params];
 252                                 Parameter[] end_params = new Parameter [out_params];
 253
 254                                 int param = 0;
 255                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 256                                         Parameter p = Parameters [i];
 257                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 258                                                 continue;
 259
 260                                         end_param_types [param] = Parameters.Types [i];
 261                                         end_params [param] = p;
 262                                         ++param;
 263                                 }
 264                                 end_parameters = ParametersCompiled.CreateFullyResolved (end_params, end_param_types);
 265                         } else {
 266                                 end_parameters = ParametersCompiled.EmptyReadOnlyParameters;
 267                         }
 268
 269                         end_parameters = ParametersCompiled.MergeGenerated (Compiler, end_parameters, false,
 270                                 new Parameter (null, "result", Parameter.Modifier.NONE, null, Location), TypeManager.iasyncresult_type);
 271
 272                         //
 273                         // Create method, define parameters, register parameters with type system
 274                         //
 275                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.GetEmitTypes ());
 276                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 277
 278                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 279                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 280                         member_cache.AddMember (EndInvokeBuilder, this);
 281                 }
 282
 283                 public override void Emit ()
 284                 {
 285                         if (TypeManager.IsDynamicType (ret_type)) {
 286                                 return_attributes = new ReturnParameter (this, InvokeBuilder, Location);
 287                                 PredefinedAttributes.Get.Dynamic.EmitAttribute (return_attributes.Builder);
 288                         } else {
 289                                 var trans_flags = TypeManager.HasDynamicTypeUsed (ret_type);
 290                                 if (trans_flags != null) {
 291                                         var pa = PredefinedAttributes.Get.DynamicTransform;
 292                                         if (pa.Constructor != null || pa.ResolveConstructor (Location, TypeManager.bool_type.MakeArrayType ())) {
 293                                                 return_attributes = new ReturnParameter (this, InvokeBuilder, Location);
 294                                                 return_attributes.Builder.SetCustomAttribute (
 295                                                         new CustomAttributeBuilder (pa.Constructor, new object [] { trans_flags }));
 296                                         }
 297                                 }
 298                         }
 299
 300                         Parameters.ApplyAttributes (InvokeBuilder);
 301
 302                         if (BeginInvokeBuilder != null) {
 303                                 ParametersCompiled p = (ParametersCompiled) TypeManager.GetParameterData (BeginInvokeBuilder);
 304                                 p.ApplyAttributes (BeginInvokeBuilder);
 305                         }
 306
 307                         if (OptAttributes != null) {
 308                                 OptAttributes.Emit ();
 309                         }
 310
 311                         base.Emit ();
 312                 }
 313
 314                 protected override TypeAttributes TypeAttr {
 315                         get {
 316                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 317                                         TypeAttributes.Class | TypeAttributes.Sealed |
 318                                         base.TypeAttr;
 319                         }
 320                 }
 321
 322                 public override string[] ValidAttributeTargets {
 323                         get {
 324                                 return attribute_targets;
 325                         }
 326                 }
 327
 328                 //TODO: duplicate
 329                 protected override bool VerifyClsCompliance ()
 330                 {
 331                         if (!base.VerifyClsCompliance ()) {
 332                                 return false;
 333                         }
 334
 335                         Parameters.VerifyClsCompliance (this);
 336
 337                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 338                                 Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
 339                                         GetSignatureForError ());
 340                         }
 341                         return true;
 342                 }
 343
 344
 345                 public static ConstructorInfo GetConstructor (CompilerContext ctx, Type container_type, Type delegate_type)
 346                 {
 347                         Type dt = delegate_type;
 348                         Type[] g_args = null;
 349                         if (TypeManager.IsGenericType (delegate_type)) {
 350                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 351                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 352                         }
 353
 354                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 355                         if (d != null) {
 356                                 if (g_args != null)
 357                                         return TypeBuilder.GetConstructor (dt, d.ConstructorBuilder);
 358
 359                                 return d.ConstructorBuilder;
 360                         }
 361
 362                         Expression ml = Expression.MemberLookup (ctx, container_type,
 363                                 null, dt, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 364                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly, Location.Null);
 365
 366                         MethodGroupExpr mg = ml as MethodGroupExpr;
 367                         if (mg == null) {
 368                                 ctx.Report.Error (-100, Location.Null, "Internal error: could not find delegate constructor!");
 369                                 // FIXME: null will cause a crash later
 370                                 return null;
 371                         }
 372
 373                         return (ConstructorInfo) mg.Methods[0];
 374                 }
 375
 376                 //
 377                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 378                 // to extract the signature of a delegate.
 379                 //
 380                 public static MethodInfo GetInvokeMethod (CompilerContext ctx, Type container_type, Type delegate_type)
 381                 {
 382                         Type dt = delegate_type;
 383
 384                         Type[] g_args = null;
 385                         if (TypeManager.IsGenericType (delegate_type)) {
 386                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 387                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 388                         }
 389
 390                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 391                         MethodInfo invoke;
 392                         if (d != null) {
 393                                 if (g_args != null) {
 394                                         invoke = TypeBuilder.GetMethod (dt, d.InvokeBuilder);
 395 #if MS_COMPATIBLE
 396                                         ParametersCompiled p = (ParametersCompiled) d.Parameters.InflateTypes (g_args, g_args);
 397                                         TypeManager.RegisterMethod (invoke, p);
 398 #endif
 399                                         return invoke;
 400                                 }
 401                                 return d.InvokeBuilder;
 402                         }
 403
 404                         Expression ml = Expression.MemberLookup (ctx, container_type, null, dt,
 405                                 "Invoke", Location.Null);
 406
 407                         MethodGroupExpr mg = ml as MethodGroupExpr;
 408                         if (mg == null) {
 409                                 ctx.Report.Error (-100, Location.Null, "Internal error: could not find Invoke method!");
 410                                 // FIXME: null will cause a crash later
 411                                 return null;
 412                         }
 413
 414                         invoke = (MethodInfo) mg.Methods[0];
 415 #if MS_COMPATIBLE
 416                         if (g_args != null) {
 417                                 AParametersCollection p = TypeManager.GetParameterData (invoke);
 418                                 p = p.InflateTypes (g_args, g_args);
 419                                 TypeManager.RegisterMethod (invoke, p);
 420                                 return invoke;
 421                         }
 422 #endif
 423
 424                         return invoke;
 425                 }
 426
 427                 //
 428                 // 15.2 Delegate compatibility
 429                 //
 430                 public static bool IsTypeCovariant (Expression a, Type b)
 431                 {
 432                         //
 433                         // For each value parameter (a parameter with no ref or out modifier), an
 434                         // identity conversion or implicit reference conversion exists from the
 435                         // parameter type in D to the corresponding parameter type in M
 436                         //
 437                         if (a.Type == b)
 438                                 return true;
 439
 440                         if (RootContext.Version == LanguageVersion.ISO_1)
 441                                 return false;
 442
 443                         return Convert.ImplicitReferenceConversionExists (a, b);
 444                 }
 445
 446                 public static string FullDelegateDesc (MethodBase invoke_method)
 447                 {
 448                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 449                 }
 450
 451                 public Expression InstanceExpression {
 452                         get {
 453                                 return instance_expr;
 454                         }
 455                         set {
 456                                 instance_expr = value;
 457                         }
 458                 }
 459
 460                 public MethodBase TargetMethod {
 461                         get {
 462                                 return delegate_method;
 463                         }
 464                         set {
 465                                 delegate_method = value;
 466                         }
 467                 }
 468
 469                 public Type TargetReturnType {
 470                         get {
 471                                 return ret_type;
 472                         }
 473                 }
 474         }
 475
 476         //
 477         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 478         //
 479         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 480         {
 481                 protected ConstructorInfo constructor_method;
 482                 protected MethodInfo delegate_method;
 483                 // We keep this to handle IsBase only
 484                 protected MethodGroupExpr method_group;
 485                 protected Expression delegate_instance_expression;
 486
 487                 // TODO: Should either cache it or use interface to abstract it
 488                 public static Arguments CreateDelegateMethodArguments (AParametersCollection pd, Location loc)
 489                 {
 490                         Arguments delegate_arguments = new Arguments (pd.Count);
 491                         for (int i = 0; i < pd.Count; ++i) {
 492                                 Argument.AType atype_modifier;
 493                                 Type atype = pd.Types [i];
 494                                 switch (pd.FixedParameters [i].ModFlags) {
 495                                 case Parameter.Modifier.REF:
 496                                         atype_modifier = Argument.AType.Ref;
 497                                         //atype = atype.GetElementType ();
 498                                         break;
 499                                 case Parameter.Modifier.OUT:
 500                                         atype_modifier = Argument.AType.Out;
 501                                         //atype = atype.GetElementType ();
 502                                         break;
 503                                 default:
 504                                         atype_modifier = 0;
 505                                         break;
 506                                 }
 507                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 508                         }
 509                         return delegate_arguments;
 510                 }
 511
 512                 public override Expression CreateExpressionTree (ResolveContext ec)
 513                 {
 514                         MemberAccess ma = new MemberAccess (new MemberAccess (new QualifiedAliasMember ("global", "System", loc), "Delegate", loc), "CreateDelegate", loc);
 515
 516                         Arguments args = new Arguments (3);
 517                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 518                         args.Add (new Argument (new NullLiteral (loc)));
 519                         args.Add (new Argument (new TypeOfMethod (delegate_method, loc)));
 520                         Expression e = new Invocation (ma, args).Resolve (ec);
 521                         if (e == null)
 522                                 return null;
 523
 524                         e = Convert.ExplicitConversion (ec, e, type, loc);
 525                         if (e == null)
 526                                 return null;
 527
 528                         return e.CreateExpressionTree (ec);
 529                 }
 530
 531                 protected override Expression DoResolve (ResolveContext ec)
 532                 {
 533                         constructor_method = Delegate.GetConstructor (ec.Compiler, ec.CurrentType, type);
 534
 535                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, type);
 536                         method_group.DelegateType = type;
 537                         method_group.CustomErrorHandler = this;
 538
 539                         Arguments arguments = CreateDelegateMethodArguments (TypeManager.GetParameterData (invoke_method), loc);
 540                         method_group = method_group.OverloadResolve (ec, ref arguments, false, loc);
 541                         if (method_group == null)
 542                                 return null;
 543
 544                         delegate_method = (MethodInfo) method_group;
 545
 546                         if (TypeManager.IsNullableType (delegate_method.DeclaringType)) {
 547                                 ec.Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
 548                                         TypeManager.GetFullNameSignature (delegate_method));
 549                                 return null;
 550                         }
 551
 552                         Invocation.IsSpecialMethodInvocation (ec, delegate_method, loc);
 553
 554                         ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
 555                         if (emg != null) {
 556                                 delegate_instance_expression = emg.ExtensionExpression;
 557                                 Type e_type = delegate_instance_expression.Type;
 558                                 if (TypeManager.IsValueType (e_type)) {
 559                                         ec.Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 560                                                 TypeManager.CSharpSignature (delegate_method), TypeManager.CSharpName (e_type));
 561                                 }
 562                         }
 563
 564                         Type rt = TypeManager.TypeToCoreType (delegate_method.ReturnType);
 565                         Expression ret_expr = new TypeExpression (rt, loc);
 566                         if (!Delegate.IsTypeCovariant (ret_expr, (TypeManager.TypeToCoreType (invoke_method.ReturnType)))) {
 567                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 568                         }
 569
 570                         if (Invocation.IsMethodExcluded (delegate_method, loc)) {
 571                                 ec.Report.SymbolRelatedToPreviousError (delegate_method);
 572                                 MethodOrOperator m = TypeManager.GetMethod (delegate_method) as MethodOrOperator;
 573                                 if (m != null && m.IsPartialDefinition) {
 574                                         ec.Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
 575                                                 TypeManager.CSharpSignature (delegate_method));
 576                                 } else {
 577                                         ec.Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 578                                                 TypeManager.CSharpSignature (delegate_method));
 579                                 }
 580                         }
 581
 582                         DoResolveInstanceExpression (ec);
 583                         eclass = ExprClass.Value;
 584                         return this;
 585                 }
 586
 587                 void DoResolveInstanceExpression (ResolveContext ec)
 588                 {
 589                         //
 590                         // Argument is another delegate
 591                         //
 592                         if (delegate_instance_expression != null)
 593                                 return;
 594
 595                         if (method_group.IsStatic) {
 596                                 delegate_instance_expression = null;
 597                                 return;
 598                         }
 599
 600                         Expression instance = method_group.InstanceExpression;
 601                         if (instance != null && instance != EmptyExpression.Null) {
 602                                 delegate_instance_expression = instance;
 603                                 Type instance_type = delegate_instance_expression.Type;
 604                                 if (TypeManager.IsValueType (instance_type) || TypeManager.IsGenericParameter (instance_type)) {
 605                                         delegate_instance_expression = new BoxedCast (
 606                                                 delegate_instance_expression, TypeManager.object_type);
 607                                 }
 608                         } else {
 609                                 delegate_instance_expression = ec.GetThis (loc);
 610                         }
 611                 }
 612
 613                 public override void Emit (EmitContext ec)
 614                 {
 615                         if (delegate_instance_expression == null)
 616                                 ec.ig.Emit (OpCodes.Ldnull);
 617                         else
 618                                 delegate_instance_expression.Emit (ec);
 619
 620                         if (!delegate_method.DeclaringType.IsSealed && delegate_method.IsVirtual && !method_group.IsBase) {
 621                                 ec.ig.Emit (OpCodes.Dup);
 622                                 ec.ig.Emit (OpCodes.Ldvirtftn, delegate_method);
 623                         } else {
 624                                 ec.ig.Emit (OpCodes.Ldftn, delegate_method);
 625                         }
 626
 627                         ec.ig.Emit (OpCodes.Newobj, constructor_method);
 628                 }
 629
 630                 void Error_ConversionFailed (ResolveContext ec, MethodBase method, Expression return_type)
 631                 {
 632                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, type);
 633                         string member_name = delegate_instance_expression != null ?
 634                                 Delegate.FullDelegateDesc (method) :
 635                                 TypeManager.GetFullNameSignature (method);
 636
 637                         ec.Report.SymbolRelatedToPreviousError (type);
 638                         ec.Report.SymbolRelatedToPreviousError (method);
 639                         if (RootContext.Version == LanguageVersion.ISO_1) {
 640                                 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",
 641                                         TypeManager.CSharpName (((MethodInfo) method).ReturnType), member_name,
 642                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 643                                 return;
 644                         }
 645                         if (return_type == null) {
 646                                 ec.Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 647                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 648                                 return;
 649                         }
 650
 651                         ec.Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 652                                 return_type.GetSignatureForError (), member_name,
 653                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 654                 }
 655
 656                 public static bool ImplicitStandardConversionExists (ResolveContext ec, MethodGroupExpr mg, Type target_type)
 657                 {
 658                         if (target_type == TypeManager.delegate_type || target_type == TypeManager.multicast_delegate_type)
 659                                 return false;
 660
 661                         mg.DelegateType = target_type;
 662                         MethodInfo invoke = Delegate.GetInvokeMethod (ec.Compiler, null, target_type);
 663
 664                         Arguments arguments = CreateDelegateMethodArguments (TypeManager.GetParameterData (invoke), mg.Location);
 665                         return mg.OverloadResolve (ec, ref arguments, true, mg.Location) != null;
 666                 }
 667
 668                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 669                 {
 670                         if (delegate_instance_expression != null)
 671                                 delegate_instance_expression.MutateHoistedGenericType (storey);
 672
 673                         delegate_method = storey.MutateGenericMethod (delegate_method);
 674                         constructor_method = storey.MutateConstructor (constructor_method);
 675                 }
 676
 677                 #region IErrorHandler Members
 678
 679                 public bool NoExactMatch (ResolveContext ec, MethodBase method)
 680                 {
 681                         if (TypeManager.IsGenericMethod (method))
 682                                 return false;
 683
 684                         Error_ConversionFailed (ec, method, null);
 685                         return true;
 686                 }
 687
 688                 public bool AmbiguousCall (ResolveContext ec, MethodBase ambiguous)
 689                 {
 690                         return false;
 691                 }
 692
 693                 #endregion
 694         }
 695
 696         //
 697         // Created from the conversion code
 698         //
 699         public class ImplicitDelegateCreation : DelegateCreation
 700         {
 701                 ImplicitDelegateCreation (Type t, MethodGroupExpr mg, Location l)
 702                 {
 703                         type = t;
 704                         this.method_group = mg;
 705                         loc = l;
 706                 }
 707
 708                 static public Expression Create (ResolveContext ec, MethodGroupExpr mge,
 709                                                  Type target_type, Location loc)
 710                 {
 711                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 712                         return d.DoResolve (ec);
 713                 }
 714         }
 715
 716         //
 717         // A delegate-creation-expression, invoked from the `New' class
 718         //
 719         public class NewDelegate : DelegateCreation
 720         {
 721                 public Arguments Arguments;
 722
 723                 //
 724                 // This constructor is invoked from the `New' expression
 725                 //
 726                 public NewDelegate (Type type, Arguments Arguments, Location loc)
 727                 {
 728                         this.type = type;
 729                         this.Arguments = Arguments;
 730                         this.loc  = loc;
 731                 }
 732
 733                 protected override Expression DoResolve (ResolveContext ec)
 734                 {
 735                         if (Arguments == null || Arguments.Count != 1) {
 736                                 ec.Report.Error (149, loc, "Method name expected");
 737                                 return null;
 738                         }
 739
 740                         Argument a = Arguments [0];
 741                         if (!a.ResolveMethodGroup (ec))
 742                                 return null;
 743
 744                         Expression e = a.Expr;
 745
 746                         AnonymousMethodExpression ame = e as AnonymousMethodExpression;
 747                         if (ame != null && RootContext.Version != LanguageVersion.ISO_1) {
 748                                 e = ame.Compatible (ec, type);
 749                                 if (e == null)
 750                                         return null;
 751
 752                                 return e.Resolve (ec);
 753                         }
 754
 755                         method_group = e as MethodGroupExpr;
 756                         if (method_group == null) {
 757                                 if (TypeManager.IsDynamicType (e.Type)) {
 758                                         e = Convert.ImplicitConversionRequired (ec, e, type, loc);
 759                                 } else if (!TypeManager.IsDelegateType (e.Type)) {
 760                                         e.Error_UnexpectedKind (ec, ResolveFlags.MethodGroup | ResolveFlags.Type, loc);
 761                                         return null;
 762                                 }
 763
 764                                 //
 765                                 // An argument is not a method but another delegate
 766                                 //
 767                                 delegate_instance_expression = e;
 768                                 method_group = new MethodGroupExpr (new MemberInfo [] {
 769                                         Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, e.Type) }, e.Type, loc);
 770                         }
 771
 772                         return base.DoResolve (ec);
 773                 }
 774         }
 775
 776         //
 777         // Invocation converted to delegate Invoke call
 778         //
 779         class DelegateInvocation : ExpressionStatement
 780         {
 781                 readonly Expression InstanceExpr;
 782                 Arguments arguments;
 783                 MethodInfo method;
 784
 785                 public DelegateInvocation (Expression instance_expr, Arguments args, Location loc)
 786                 {
 787                         this.InstanceExpr = instance_expr;
 788                         this.arguments = args;
 789                         this.loc = loc;
 790                 }
 791
 792                 public override Expression CreateExpressionTree (ResolveContext ec)
 793                 {
 794                         Arguments args = Arguments.CreateForExpressionTree (ec, this.arguments,
 795                                 InstanceExpr.CreateExpressionTree (ec));
 796
 797                         return CreateExpressionFactoryCall (ec, "Invoke", args);
 798                 }
 799
 800                 protected override Expression DoResolve (ResolveContext ec)
 801                 {
 802                         if (InstanceExpr is EventExpr) {
 803                                 ((EventExpr) InstanceExpr).Error_CannotAssign (ec);
 804                                 return null;
 805                         }
 806
 807                         Type del_type = InstanceExpr.Type;
 808                         if (del_type == null)
 809                                 return null;
 810
 811                         method = Delegate.GetInvokeMethod (ec.Compiler, ec.CurrentType, del_type);
 812                         MethodBase mb = method;
 813                         var me = new MethodGroupExpr (new [] { mb }, del_type, loc);
 814                         me.InstanceExpression = InstanceExpr;
 815
 816                         AParametersCollection pd = TypeManager.GetParameterData (mb);
 817                         int pd_count = pd.Count;
 818
 819                         int arg_count = arguments == null ? 0 : arguments.Count;
 820
 821                         bool params_method = pd.HasParams;
 822                         bool is_params_applicable = false;
 823                         bool is_applicable = me.IsApplicable (ec, ref arguments, arg_count, ref mb, ref is_params_applicable) == 0;
 824                         if (arguments != null)
 825                                 arg_count = arguments.Count;
 826
 827                         if (!is_applicable && !params_method && arg_count != pd_count) {
 828                                 ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 829                                         TypeManager.CSharpName (del_type), arg_count.ToString ());
 830                         } else if (arguments == null || !arguments.HasDynamic) {
 831                                 me.VerifyArgumentsCompat (ec, ref arguments, arg_count, mb,
 832                                         is_params_applicable || (!is_applicable && params_method), false, loc);
 833                         }
 834
 835                         type = TypeManager.TypeToCoreType (method.ReturnType);
 836                         eclass = ExprClass.Value;
 837                         return this;
 838                 }
 839
 840                 public override void Emit (EmitContext ec)
 841                 {
 842                         //
 843                         // Invocation on delegates call the virtual Invoke member
 844                         // so we are always `instance' calls
 845                         //
 846                         Invocation.EmitCall (ec, false, InstanceExpr, method, arguments, loc);
 847                 }
 848
 849                 public override void EmitStatement (EmitContext ec)
 850                 {
 851                         Emit (ec);
 852                         //
 853                         // Pop the return value if there is one
 854                         //
 855                         if (type != TypeManager.void_type)
 856                                 ec.ig.Emit (OpCodes.Pop);
 857                 }
 858
 859 #if NET_4_0
 860                 public override System.Linq.Expressions.Expression MakeExpression (BuilderContext ctx)
 861                 {
 862                         return Invocation.MakeExpression (ctx, InstanceExpr, method, arguments);
 863                 }
 864 #endif
 865
 866                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 867                 {
 868                         method = storey.MutateGenericMethod (method);
 869                         type = storey.MutateType (type);
 870
 871                         if (arguments != null)
 872                                 arguments.MutateHoistedGenericType (storey);
 873
 874                         InstanceExpr.MutateHoistedGenericType (storey);
 875                 }
 876         }
 877 }