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