mcs/mcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //     Marek Safar (marek.safar@gmail.com)
   8 //
   9 // Dual licensed under the terms of the MIT X11 or GNU GPL
  10 //
  11 // Copyright 2001 Ximian, Inc (http://www.ximian.com)
  12 // Copyright 2003-2008 Novell, Inc (http://www.ximian.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         /// <summary>
  24         ///   Holds Delegates
  25         /// </summary>
  26         public class Delegate : DeclSpace, IMemberContainer
  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                 MemberCache member_cache;
  45
  46                 const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
  47                         MethodAttributes.Virtual | MethodAttributes.NewSlot;
  48
  49                 const int AllowedModifiers =
  50                         Modifiers.NEW |
  51                         Modifiers.PUBLIC |
  52                         Modifiers.PROTECTED |
  53                         Modifiers.INTERNAL |
  54                         Modifiers.UNSAFE |
  55                         Modifiers.PRIVATE;
  56
  57                 public Delegate (NamespaceEntry ns, DeclSpace parent, FullNamedExpression type,
  58                                  int mod_flags, MemberName name, ParametersCompiled param_list,
  59                                  Attributes attrs)
  60                         : base (ns, parent, name, attrs)
  61
  62                 {
  63                         this.ReturnType = type;
  64                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  65                                                            IsTopLevel ? Modifiers.INTERNAL :
  66                                                            Modifiers.PRIVATE, name.Location);
  67                         Parameters      = param_list;
  68                 }
  69
  70                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
  71                 {
  72                         if (a.Target == AttributeTargets.ReturnValue) {
  73                                 if (return_attributes == null)
  74                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  75
  76                                 return_attributes.ApplyAttributeBuilder (a, cb, pa);
  77                                 return;
  78                         }
  79
  80                         base.ApplyAttributeBuilder (a, cb, pa);
  81                 }
  82
  83                 public override TypeBuilder DefineType ()
  84                 {
  85                         if (TypeBuilder != null)
  86                                 return TypeBuilder;
  87
  88                         if (IsTopLevel) {
  89                                 if (TypeManager.NamespaceClash (Name, Location))
  90                                         return null;
  91
  92                                 ModuleBuilder builder = Module.Builder;
  93
  94                                 TypeBuilder = builder.DefineType (
  95                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
  96                         } else {
  97                                 TypeBuilder builder = Parent.TypeBuilder;
  98
  99                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 100                                 TypeBuilder = builder.DefineNestedType (
 101                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 102                         }
 103
 104                         TypeManager.AddUserType (this);
 105
 106 #if GMCS_SOURCE
 107                         if (IsGeneric) {
 108                                 string[] param_names = new string [TypeParameters.Length];
 109                                 for (int i = 0; i < TypeParameters.Length; i++)
 110                                         param_names [i] = TypeParameters [i].Name;
 111
 112                                 GenericTypeParameterBuilder[] gen_params;
 113                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 114
 115                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 116                                 for (int i = offset; i < gen_params.Length; i++)
 117                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 118
 119                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 120                                         if (!type_param.Resolve (this))
 121                                                 return null;
 122                                 }
 123
 124                                 Expression current = new SimpleName (
 125                                         MemberName.Basename, TypeParameters, Location);
 126                                 current = current.ResolveAsTypeTerminal (this, false);
 127                                 if (current == null)
 128                                         return null;
 129
 130                                 CurrentType = current.Type;
 131                         }
 132 #endif
 133
 134                         return TypeBuilder;
 135                 }
 136
 137                 public override bool Define ()
 138                 {
 139                         if (IsGeneric) {
 140                                 foreach (TypeParameter type_param in TypeParameters) {
 141                                         if (!type_param.Resolve (this))
 142                                                 return false;
 143                                 }
 144
 145                                 foreach (TypeParameter type_param in TypeParameters) {
 146                                         if (!type_param.DefineType (this))
 147                                                 return false;
 148                                 }
 149                         }
 150
 151                         member_cache = new MemberCache (TypeManager.multicast_delegate_type, this);
 152
 153                         // FIXME: POSSIBLY make this static, as it is always constant
 154                         //
 155                         Type [] const_arg_types = new Type [2];
 156                         const_arg_types [0] = TypeManager.object_type;
 157                         const_arg_types [1] = TypeManager.intptr_type;
 158
 159                         const MethodAttributes ctor_mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 160                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 161
 162                         ConstructorBuilder = TypeBuilder.DefineConstructor (ctor_mattr,
 163                                                                             CallingConventions.Standard,
 164                                                                             const_arg_types);
 165
 166                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 167                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 168                         //
 169                         // HACK because System.Reflection.Emit is lame
 170                         //
 171                         IParameterData [] fixed_pars = new IParameterData [] {
 172                                 new ParameterData ("object", Parameter.Modifier.NONE),
 173                                 new ParameterData ("method", Parameter.Modifier.NONE)
 174                         };
 175
 176                         AParametersCollection const_parameters = new ParametersImported (
 177                                 fixed_pars,
 178                                 new Type[] { TypeManager.object_type, TypeManager.intptr_type });
 179
 180                         TypeManager.RegisterMethod (ConstructorBuilder, const_parameters);
 181                         member_cache.AddMember (ConstructorBuilder, this);
 182
 183                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 184
 185                         //
 186                         // Here the various methods like Invoke, BeginInvoke etc are defined
 187                         //
 188                         // First, call the `out of band' special method for
 189                         // defining recursively any types we need:
 190
 191                         if (!Parameters.Resolve (this))
 192                                 return false;
 193
 194                         //
 195                         // Invoke method
 196                         //
 197
 198                         // Check accessibility
 199                         foreach (Type partype in Parameters.Types){
 200                                 if (!IsAccessibleAs (partype)) {
 201                                         Report.SymbolRelatedToPreviousError (partype);
 202                                         Report.Error (59, Location,
 203                                                       "Inconsistent accessibility: parameter type `{0}' is less accessible than delegate `{1}'",
 204                                                       TypeManager.CSharpName (partype),
 205                                                       GetSignatureForError ());
 206                                         return false;
 207                                 }
 208                         }
 209
 210                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 211                         if (ReturnType == null)
 212                                 return false;
 213
 214                         ret_type = ReturnType.Type;
 215
 216                         if (!IsAccessibleAs (ret_type)) {
 217                                 Report.SymbolRelatedToPreviousError (ret_type);
 218                                 Report.Error (58, Location,
 219                                               "Inconsistent accessibility: return type `" +
 220                                               TypeManager.CSharpName (ret_type) + "' is less " +
 221                                               "accessible than delegate `" + GetSignatureForError () + "'");
 222                                 return false;
 223                         }
 224
 225                         CheckProtectedModifier ();
 226
 227                         if (RootContext.StdLib && TypeManager.IsSpecialType (ret_type)) {
 228                                 Method.Error1599 (Location, ret_type);
 229                                 return false;
 230                         }
 231
 232                         TypeManager.CheckTypeVariance (ret_type, Variance.Covariant, this);
 233
 234                         //
 235                         // We don't have to check any others because they are all
 236                         // guaranteed to be accessible - they are standard types.
 237                         //
 238
 239                         CallingConventions cc = Parameters.CallingConvention;
 240
 241                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 242                                                                   mattr,
 243                                                                   cc,
 244                                                                   ret_type,
 245                                                                   Parameters.GetEmitTypes ());
 246
 247                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 248
 249                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 250                         member_cache.AddMember (InvokeBuilder, this);
 251
 252                         if (TypeManager.iasyncresult_type != null && TypeManager.asynccallback_type != null) {
 253                                 DefineAsyncMethods (cc);
 254                         }
 255
 256                         return true;
 257                 }
 258
 259                 void DefineAsyncMethods (CallingConventions cc)
 260                 {
 261                         //
 262                         // BeginInvoke
 263                         //
 264                         ParametersCompiled async_parameters = ParametersCompiled.MergeGenerated (Parameters, false,
 265                                 new Parameter [] {
 266                                         new Parameter (null, "callback", Parameter.Modifier.NONE, null, Location),
 267                                         new Parameter (null, "object", Parameter.Modifier.NONE, null, Location)
 268                                 },
 269                                 new Type [] {
 270                                         TypeManager.asynccallback_type,
 271                                         TypeManager.object_type
 272                                 }
 273                         );
 274
 275                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 276                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.GetEmitTypes ());
 277
 278                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 279                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 280                         member_cache.AddMember (BeginInvokeBuilder, this);
 281
 282                         //
 283                         // EndInvoke is a bit more interesting, all the parameters labeled as
 284                         // out or ref have to be duplicated here.
 285                         //
 286
 287                         //
 288                         // Define parameters, and count out/ref parameters
 289                         //
 290                         ParametersCompiled end_parameters;
 291                         int out_params = 0;
 292
 293                         foreach (Parameter p in Parameters.FixedParameters) {
 294                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 295                                         ++out_params;
 296                         }
 297
 298                         if (out_params > 0) {
 299                                 Type [] end_param_types = new Type [out_params];
 300                                 Parameter[] end_params = new Parameter [out_params];
 301
 302                                 int param = 0;
 303                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 304                                         Parameter p = Parameters [i];
 305                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 306                                                 continue;
 307
 308                                         end_param_types [param] = Parameters.Types [i];
 309                                         end_params [param] = p;
 310                                         ++param;
 311                                 }
 312                                 end_parameters = ParametersCompiled.CreateFullyResolved (end_params, end_param_types);
 313                         } else {
 314                                 end_parameters = ParametersCompiled.EmptyReadOnlyParameters;
 315                         }
 316
 317                         end_parameters = ParametersCompiled.MergeGenerated (end_parameters, false,
 318                                 new Parameter (null, "result", Parameter.Modifier.NONE, null, Location), TypeManager.iasyncresult_type);
 319
 320                         //
 321                         // Create method, define parameters, register parameters with type system
 322                         //
 323                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.GetEmitTypes ());
 324                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 325
 326                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 327                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 328                         member_cache.AddMember (EndInvokeBuilder, this);
 329                 }
 330
 331                 public override void Emit ()
 332                 {
 333                         if (TypeManager.IsDynamicType (ret_type)) {
 334                                 return_attributes = new ReturnParameter (InvokeBuilder, Location);
 335                                 return_attributes.EmitPredefined (PredefinedAttributes.Get.Dynamic, Location);
 336                         }
 337
 338                         Parameters.ApplyAttributes (InvokeBuilder);
 339
 340                         if (BeginInvokeBuilder != null) {
 341                                 ParametersCompiled p = (ParametersCompiled) TypeManager.GetParameterData (BeginInvokeBuilder);
 342                                 p.ApplyAttributes (BeginInvokeBuilder);
 343                         }
 344
 345                         if (OptAttributes != null) {
 346                                 OptAttributes.Emit ();
 347                         }
 348
 349                         base.Emit ();
 350                 }
 351
 352                 protected override TypeAttributes TypeAttr {
 353                         get {
 354                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 355                                         TypeAttributes.Class | TypeAttributes.Sealed |
 356                                         base.TypeAttr;
 357                         }
 358                 }
 359
 360                 public override string[] ValidAttributeTargets {
 361                         get {
 362                                 return attribute_targets;
 363                         }
 364                 }
 365
 366                 //TODO: duplicate
 367                 protected override bool VerifyClsCompliance ()
 368                 {
 369                         if (!base.VerifyClsCompliance ()) {
 370                                 return false;
 371                         }
 372
 373                         Parameters.VerifyClsCompliance ();
 374
 375                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 376                                 Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
 377                                         GetSignatureForError ());
 378                         }
 379                         return true;
 380                 }
 381
 382
 383                 public static ConstructorInfo GetConstructor (Type container_type, Type delegate_type)
 384                 {
 385                         Type dt = delegate_type;
 386                         Type[] g_args = null;
 387                         if (TypeManager.IsGenericType (delegate_type)) {
 388                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 389                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 390                         }
 391
 392                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 393                         if (d != null) {
 394 #if GMCS_SOURCE
 395                                 if (g_args != null)
 396                                         return TypeBuilder.GetConstructor (dt, d.ConstructorBuilder);
 397 #endif
 398                                 return d.ConstructorBuilder;
 399                         }
 400
 401                         Expression ml = Expression.MemberLookup (container_type,
 402                                 null, dt, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 403                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly, Location.Null);
 404
 405                         MethodGroupExpr mg = ml as MethodGroupExpr;
 406                         if (mg == null) {
 407                                 Report.Error (-100, Location.Null, "Internal error: could not find delegate constructor!");
 408                                 // FIXME: null will cause a crash later
 409                                 return null;
 410                         }
 411
 412                         return (ConstructorInfo) mg.Methods[0];
 413                 }
 414
 415                 //
 416                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 417                 // to extract the signature of a delegate.
 418                 //
 419                 public static MethodInfo GetInvokeMethod (Type container_type, Type delegate_type)
 420                 {
 421                         Type dt = delegate_type;
 422
 423                         Type[] g_args = null;
 424                         if (TypeManager.IsGenericType (delegate_type)) {
 425                                 g_args = TypeManager.GetTypeArguments (delegate_type);
 426                                 delegate_type = TypeManager.DropGenericTypeArguments (delegate_type);
 427                         }
 428
 429                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 430                         MethodInfo invoke;
 431                         if (d != null) {
 432 #if GMCS_SOURCE
 433                                 if (g_args != null) {
 434                                         invoke = TypeBuilder.GetMethod (dt, d.InvokeBuilder);
 435 #if MS_COMPATIBLE
 436                                         ParametersCompiled p = (ParametersCompiled) d.Parameters.InflateTypes (g_args, g_args);
 437                                         TypeManager.RegisterMethod (invoke, p);
 438 #endif
 439                                         return invoke;
 440                                 }
 441 #endif
 442                                 return d.InvokeBuilder;
 443                         }
 444
 445                         Expression ml = Expression.MemberLookup (container_type, null, dt,
 446                                 "Invoke", Location.Null);
 447
 448                         MethodGroupExpr mg = ml as MethodGroupExpr;
 449                         if (mg == null) {
 450                                 Report.Error (-100, Location.Null, "Internal error: could not find Invoke method!");
 451                                 // FIXME: null will cause a crash later
 452                                 return null;
 453                         }
 454
 455                         invoke = (MethodInfo) mg.Methods[0];
 456 #if MS_COMPATIBLE
 457                         if (g_args != null) {
 458                                 AParametersCollection p = TypeManager.GetParameterData (invoke);
 459                                 p = p.InflateTypes (g_args, g_args);
 460                                 TypeManager.RegisterMethod (invoke, p);
 461                                 return invoke;
 462                         }
 463 #endif
 464
 465                         return invoke;
 466                 }
 467
 468                 //
 469                 // 15.2 Delegate compatibility
 470                 //
 471                 public static bool IsTypeCovariant (Expression a, Type b)
 472                 {
 473                         //
 474                         // For each value parameter (a parameter with no ref or out modifier), an
 475                         // identity conversion or implicit reference conversion exists from the
 476                         // parameter type in D to the corresponding parameter type in M
 477                         //
 478                         if (a.Type == b)
 479                                 return true;
 480
 481                         if (RootContext.Version == LanguageVersion.ISO_1)
 482                                 return false;
 483
 484                         return Convert.ImplicitReferenceConversionExists (a, b);
 485                 }
 486
 487                 // <summary>
 488                 //  Verifies whether the invocation arguments are compatible with the
 489                 //  delegate's target method
 490                 // </summary>
 491                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type, ref Arguments args, Location loc)
 492                 {
 493                         int arg_count;
 494
 495                         if (args == null)
 496                                 arg_count = 0;
 497                         else
 498                                 arg_count = args.Count;
 499
 500                         MethodBase mb = GetInvokeMethod (ec.ContainerType, delegate_type);
 501                         MethodGroupExpr me = new MethodGroupExpr (new MemberInfo [] { mb }, delegate_type, loc);
 502
 503                         AParametersCollection pd = TypeManager.GetParameterData (mb);
 504
 505                         int pd_count = pd.Count;
 506
 507                         bool params_method = pd.HasParams;
 508                         bool is_params_applicable = false;
 509                         bool is_applicable = me.IsApplicable (ec, ref args, arg_count, ref mb, ref is_params_applicable) == 0;
 510                         if (args != null)
 511                                 arg_count = args.Count;
 512
 513                         if (!is_applicable && !params_method && arg_count != pd_count) {
 514                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 515                                         TypeManager.CSharpName (delegate_type), arg_count.ToString ());
 516                                 return false;
 517                         }
 518
 519                         return me.VerifyArgumentsCompat (
 520                                         ec, ref args, arg_count, mb,
 521                                         is_params_applicable || (!is_applicable && params_method),
 522                                         false, loc);
 523                 }
 524
 525                 public static string FullDelegateDesc (MethodBase invoke_method)
 526                 {
 527                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 528                 }
 529
 530                 public override MemberCache MemberCache {
 531                         get {
 532                                 return member_cache;
 533                         }
 534                 }
 535
 536                 public Expression InstanceExpression {
 537                         get {
 538                                 return instance_expr;
 539                         }
 540                         set {
 541                                 instance_expr = value;
 542                         }
 543                 }
 544
 545                 public MethodBase TargetMethod {
 546                         get {
 547                                 return delegate_method;
 548                         }
 549                         set {
 550                                 delegate_method = value;
 551                         }
 552                 }
 553
 554                 public Type TargetReturnType {
 555                         get {
 556                                 return ret_type;
 557                         }
 558                 }
 559
 560                 public override AttributeTargets AttributeTargets {
 561                         get {
 562                                 return AttributeTargets.Delegate;
 563                         }
 564                 }
 565
 566                 //
 567                 //   Represents header string for documentation comment.
 568                 //
 569                 public override string DocCommentHeader {
 570                         get { return "T:"; }
 571                 }
 572
 573                 #region IMemberContainer Members
 574
 575                 string IMemberContainer.Name
 576                 {
 577                         get { throw new NotImplementedException (); }
 578                 }
 579
 580                 Type IMemberContainer.Type
 581                 {
 582                         get { throw new NotImplementedException (); }
 583                 }
 584
 585                 MemberCache IMemberContainer.BaseCache
 586                 {
 587                         get { throw new NotImplementedException (); }
 588                 }
 589
 590                 bool IMemberContainer.IsInterface {
 591                         get {
 592                                 return false;
 593                         }
 594                 }
 595
 596                 MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
 597                 {
 598                         throw new NotImplementedException ();
 599                 }
 600
 601                 #endregion
 602         }
 603
 604         //
 605         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 606         //
 607         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 608         {
 609                 protected ConstructorInfo constructor_method;
 610                 protected MethodInfo delegate_method;
 611                 // We keep this to handle IsBase only
 612                 protected MethodGroupExpr method_group;
 613                 protected Expression delegate_instance_expression;
 614
 615                 // TODO: Should either cache it or use interface to abstract it
 616                 public static Arguments CreateDelegateMethodArguments (AParametersCollection pd, Location loc)
 617                 {
 618                         Arguments delegate_arguments = new Arguments (pd.Count);
 619                         for (int i = 0; i < pd.Count; ++i) {
 620                                 Argument.AType atype_modifier;
 621                                 Type atype = pd.Types [i];
 622                                 switch (pd.FixedParameters [i].ModFlags) {
 623                                 case Parameter.Modifier.REF:
 624                                         atype_modifier = Argument.AType.Ref;
 625                                         //atype = atype.GetElementType ();
 626                                         break;
 627                                 case Parameter.Modifier.OUT:
 628                                         atype_modifier = Argument.AType.Out;
 629                                         //atype = atype.GetElementType ();
 630                                         break;
 631                                 default:
 632                                         atype_modifier = 0;
 633                                         break;
 634                                 }
 635                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 636                         }
 637                         return delegate_arguments;
 638                 }
 639
 640                 public override Expression CreateExpressionTree (EmitContext ec)
 641                 {
 642                         MemberAccess ma = new MemberAccess (new MemberAccess (new QualifiedAliasMember ("global", "System", loc), "Delegate", loc), "CreateDelegate", loc);
 643
 644                         Arguments args = new Arguments (3);
 645                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 646                         args.Add (new Argument (new NullLiteral (loc)));
 647                         args.Add (new Argument (new TypeOfMethod (delegate_method, loc)));
 648                         Expression e = new Invocation (ma, args).Resolve (ec);
 649                         if (e == null)
 650                                 return null;
 651
 652                         e = Convert.ExplicitConversion (ec, e, type, loc);
 653                         if (e == null)
 654                                 return null;
 655
 656                         return e.CreateExpressionTree (ec);
 657                 }
 658
 659                 public override Expression DoResolve (EmitContext ec)
 660                 {
 661                         constructor_method = Delegate.GetConstructor (ec.ContainerType, type);
 662
 663                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 664                         method_group.DelegateType = type;
 665                         method_group.CustomErrorHandler = this;
 666
 667                         Arguments arguments = CreateDelegateMethodArguments (TypeManager.GetParameterData (invoke_method), loc);
 668                         method_group = method_group.OverloadResolve (ec, ref arguments, false, loc);
 669                         if (method_group == null)
 670                                 return null;
 671
 672                         delegate_method = (MethodInfo) method_group;
 673
 674                         if (TypeManager.IsNullableType (delegate_method.DeclaringType)) {
 675                                 Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
 676                                         TypeManager.GetFullNameSignature (delegate_method));
 677                                 return null;
 678                         }
 679
 680                         Invocation.IsSpecialMethodInvocation (delegate_method, loc);
 681
 682                         ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
 683                         if (emg != null) {
 684                                 delegate_instance_expression = emg.ExtensionExpression;
 685                                 Type e_type = delegate_instance_expression.Type;
 686                                 if (TypeManager.IsValueType (e_type)) {
 687                                         Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 688                                                 TypeManager.CSharpSignature (delegate_method), TypeManager.CSharpName (e_type));
 689                                 }
 690                         }
 691
 692                         Type rt = TypeManager.TypeToCoreType (delegate_method.ReturnType);
 693                         Expression ret_expr = new TypeExpression (rt, loc);
 694                         if (!Delegate.IsTypeCovariant (ret_expr, (TypeManager.TypeToCoreType (invoke_method.ReturnType)))) {
 695                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 696                         }
 697
 698                         if (Invocation.IsMethodExcluded (delegate_method, loc)) {
 699                                 Report.SymbolRelatedToPreviousError (delegate_method);
 700                                 MethodOrOperator m = TypeManager.GetMethod (delegate_method) as MethodOrOperator;
 701                                 if (m != null && m.IsPartialDefinition) {
 702                                         Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
 703                                                 TypeManager.CSharpSignature (delegate_method));
 704                                 } else {
 705                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 706                                                 TypeManager.CSharpSignature (delegate_method));
 707                                 }
 708                         }
 709
 710                         DoResolveInstanceExpression (ec);
 711                         eclass = ExprClass.Value;
 712                         return this;
 713                 }
 714
 715                 void DoResolveInstanceExpression (EmitContext ec)
 716                 {
 717                         //
 718                         // Argument is another delegate
 719                         //
 720                         if (delegate_instance_expression != null)
 721                                 return;
 722
 723                         Expression instance = method_group.InstanceExpression;
 724                         if (instance != null && instance != EmptyExpression.Null) {
 725                                 delegate_instance_expression = instance;
 726                                 Type instance_type = delegate_instance_expression.Type;
 727                                 if (TypeManager.IsValueType (instance_type) || TypeManager.IsGenericParameter (instance_type)) {
 728                                         delegate_instance_expression = new BoxedCast (
 729                                                 delegate_instance_expression, TypeManager.object_type);
 730                                 }
 731                         } else if (!delegate_method.IsStatic && !ec.IsStatic) {
 732                                 delegate_instance_expression = ec.GetThis (loc);
 733                         }
 734                 }
 735
 736                 public override void Emit (EmitContext ec)
 737                 {
 738                         if (delegate_instance_expression == null)
 739                                 ec.ig.Emit (OpCodes.Ldnull);
 740                         else
 741                                 delegate_instance_expression.Emit (ec);
 742
 743                         if (!delegate_method.DeclaringType.IsSealed && delegate_method.IsVirtual && !method_group.IsBase) {
 744                                 ec.ig.Emit (OpCodes.Dup);
 745                                 ec.ig.Emit (OpCodes.Ldvirtftn, delegate_method);
 746                         } else {
 747                                 ec.ig.Emit (OpCodes.Ldftn, delegate_method);
 748                         }
 749
 750                         ec.ig.Emit (OpCodes.Newobj, constructor_method);
 751                 }
 752
 753                 void Error_ConversionFailed (EmitContext ec, MethodBase method, Expression return_type)
 754                 {
 755                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 756                         string member_name = delegate_instance_expression != null ?
 757                                 Delegate.FullDelegateDesc (method) :
 758                                 TypeManager.GetFullNameSignature (method);
 759
 760                         Report.SymbolRelatedToPreviousError (type);
 761                         Report.SymbolRelatedToPreviousError (method);
 762                         if (RootContext.Version == LanguageVersion.ISO_1) {
 763                                 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",
 764                                         TypeManager.CSharpName (((MethodInfo) method).ReturnType), member_name,
 765                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 766                                 return;
 767                         }
 768                         if (return_type == null) {
 769                                 Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 770                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 771                                 return;
 772                         }
 773
 774                         Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 775                                 return_type.GetSignatureForError (), member_name,
 776                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 777                 }
 778
 779                 public static bool ImplicitStandardConversionExists (EmitContext ec, MethodGroupExpr mg, Type target_type)
 780                 {
 781                         if (target_type == TypeManager.delegate_type || target_type == TypeManager.multicast_delegate_type)
 782                                 return false;
 783
 784                         mg.DelegateType = target_type;
 785                         MethodInfo invoke = Delegate.GetInvokeMethod (null, target_type);
 786
 787                         Arguments arguments = CreateDelegateMethodArguments (TypeManager.GetParameterData (invoke), mg.Location);
 788                         return mg.OverloadResolve (ec, ref arguments, true, mg.Location) != null;
 789                 }
 790
 791                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 792                 {
 793                         if (delegate_instance_expression != null)
 794                                 delegate_instance_expression.MutateHoistedGenericType (storey);
 795
 796                         delegate_method = storey.MutateGenericMethod (delegate_method);
 797                         constructor_method = storey.MutateConstructor (constructor_method);
 798                 }
 799
 800                 #region IErrorHandler Members
 801
 802                 public bool NoExactMatch (EmitContext ec, MethodBase method)
 803                 {
 804                         if (TypeManager.IsGenericMethod (method))
 805                                 return false;
 806
 807                         Error_ConversionFailed (ec, method, null);
 808                         return true;
 809                 }
 810
 811                 public bool AmbiguousCall (MethodBase ambiguous)
 812                 {
 813                         return false;
 814                 }
 815
 816                 #endregion
 817         }
 818
 819         //
 820         // Created from the conversion code
 821         //
 822         public class ImplicitDelegateCreation : DelegateCreation
 823         {
 824                 ImplicitDelegateCreation (Type t, MethodGroupExpr mg, Location l)
 825                 {
 826                         type = t;
 827                         this.method_group = mg;
 828                         loc = l;
 829                 }
 830
 831                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 832                                                  Type target_type, Location loc)
 833                 {
 834                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 835                         return d.DoResolve (ec);
 836                 }
 837         }
 838
 839         //
 840         // A delegate-creation-expression, invoked from the `New' class
 841         //
 842         public class NewDelegate : DelegateCreation
 843         {
 844                 public Arguments Arguments;
 845
 846                 //
 847                 // This constructor is invoked from the `New' expression
 848                 //
 849                 public NewDelegate (Type type, Arguments Arguments, Location loc)
 850                 {
 851                         this.type = type;
 852                         this.Arguments = Arguments;
 853                         this.loc  = loc;
 854                 }
 855
 856                 public override Expression DoResolve (EmitContext ec)
 857                 {
 858                         if (Arguments == null || Arguments.Count != 1) {
 859                                 Error_InvalidDelegateArgument ();
 860                                 return null;
 861                         }
 862
 863                         Argument a = Arguments [0];
 864                         if (!a.ResolveMethodGroup (ec))
 865                                 return null;
 866
 867                         Expression e = a.Expr;
 868
 869                         AnonymousMethodExpression ame = e as AnonymousMethodExpression;
 870                         if (ame != null && RootContext.Version != LanguageVersion.ISO_1) {
 871                                 e = ame.Compatible (ec, type);
 872                                 if (e == null)
 873                                         return null;
 874
 875                                 return e.Resolve (ec);
 876                         }
 877
 878                         method_group = e as MethodGroupExpr;
 879                         if (method_group == null) {
 880                                 if (!TypeManager.IsDelegateType (e.Type)) {
 881                                         e.Error_UnexpectedKind (ResolveFlags.MethodGroup | ResolveFlags.Type, loc);
 882                                         return null;
 883                                 }
 884
 885                                 //
 886                                 // An argument is not a method but another delegate
 887                                 //
 888                                 delegate_instance_expression = e;
 889                                 method_group = new MethodGroupExpr (new MemberInfo [] {
 890                                         Delegate.GetInvokeMethod (ec.ContainerType, e.Type) }, e.Type, loc);
 891                         }
 892
 893                         return base.DoResolve (ec);
 894                 }
 895
 896                 void Error_InvalidDelegateArgument ()
 897                 {
 898                         Report.Error (149, loc, "Method name expected");
 899                 }
 900         }
 901
 902         public class DelegateInvocation : ExpressionStatement {
 903
 904                 readonly Expression InstanceExpr;
 905                 Arguments  Arguments;
 906                 MethodInfo method;
 907
 908                 public DelegateInvocation (Expression instance_expr, Arguments args, Location loc)
 909                 {
 910                         this.InstanceExpr = instance_expr;
 911                         this.Arguments = args;
 912                         this.loc = loc;
 913                 }
 914
 915                 public override Expression CreateExpressionTree (EmitContext ec)
 916                 {
 917                         Arguments args = Arguments.CreateForExpressionTree (ec, Arguments,
 918                                 InstanceExpr.CreateExpressionTree (ec));
 919
 920                         return CreateExpressionFactoryCall ("Invoke", args);
 921                 }
 922
 923                 public override Expression DoResolve (EmitContext ec)
 924                 {
 925                         if (InstanceExpr is EventExpr) {
 926                                 ((EventExpr) InstanceExpr).Error_CannotAssign ();
 927                                 return null;
 928                         }
 929
 930                         Type del_type = InstanceExpr.Type;
 931                         if (del_type == null)
 932                                 return null;
 933
 934                         if (!Delegate.VerifyApplicability (ec, del_type, ref Arguments, loc))
 935                                 return null;
 936
 937                         method = Delegate.GetInvokeMethod (ec.ContainerType, del_type);
 938                         type = TypeManager.TypeToCoreType (method.ReturnType);
 939                         eclass = ExprClass.Value;
 940
 941                         return this;
 942                 }
 943
 944                 public override void Emit (EmitContext ec)
 945                 {
 946                         //
 947                         // Invocation on delegates call the virtual Invoke member
 948                         // so we are always `instance' calls
 949                         //
 950                         Invocation.EmitCall (ec, false, InstanceExpr, method, Arguments, loc);
 951                 }
 952
 953                 public override void EmitStatement (EmitContext ec)
 954                 {
 955                         Emit (ec);
 956                         //
 957                         // Pop the return value if there is one
 958                         //
 959                         if (type != TypeManager.void_type)
 960                                 ec.ig.Emit (OpCodes.Pop);
 961                 }
 962
 963                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 964                 {
 965                         method = storey.MutateGenericMethod (method);
 966                         type = storey.MutateType (type);
 967
 968                         if (Arguments != null)
 969                                 Arguments.MutateHoistedGenericType (storey);
 970
 971                         InstanceExpr.MutateHoistedGenericType (storey);
 972                 }
 973         }
 974 }