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 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type ret_type;
  35
  36                 static string[] attribute_targets = new string [] { "type", "return" };
  37
  38                 Expression instance_expr;
  39                 MethodBase delegate_method;
  40                 ReturnParameter return_attributes;
  41
  42                 const int AllowedModifiers =
  43                         Modifiers.NEW |
  44                         Modifiers.PUBLIC |
  45                         Modifiers.PROTECTED |
  46                         Modifiers.INTERNAL |
  47                         Modifiers.UNSAFE |
  48                         Modifiers.PRIVATE;
  49
  50                 public Delegate (NamespaceEntry ns, DeclSpace parent, Expression type,
  51                                  int mod_flags, MemberName name, Parameters param_list,
  52                                  Attributes attrs)
  53                         : base (ns, parent, name, attrs)
  54
  55                 {
  56                         this.ReturnType = type;
  57                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  58                                                            IsTopLevel ? Modifiers.INTERNAL :
  59                                                            Modifiers.PRIVATE, name.Location);
  60                         Parameters      = param_list;
  61                 }
  62
  63                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  64                 {
  65                         if (a.Target == AttributeTargets.ReturnValue) {
  66                                 if (return_attributes == null)
  67                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  68
  69                                 return_attributes.ApplyAttributeBuilder (a, cb);
  70                                 return;
  71                         }
  72
  73                         base.ApplyAttributeBuilder (a, cb);
  74                 }
  75
  76                 public override TypeBuilder DefineType ()
  77                 {
  78                         if (TypeBuilder != null)
  79                                 return TypeBuilder;
  80
  81                         if (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  82                                 Namespace system = RootNamespace.Global.GetNamespace ("System", true);
  83                                 TypeExpr expr = system.Lookup (this, "MulticastDelegate", Location) as TypeExpr;
  84                                 TypeManager.multicast_delegate_type = expr.Type;
  85                         }
  86
  87                         if (TypeManager.multicast_delegate_type == null)
  88                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  89                                               "System.MulticastDelegate is resolved.  This can only " +
  90                                               "happen during corlib compilation, when using a delegate " +
  91                                               "in any of the `core' classes.  See bug #72015 for details.");
  92
  93                         if (IsTopLevel) {
  94                                 if (TypeManager.NamespaceClash (Name, Location))
  95                                         return null;
  96
  97                                 ModuleBuilder builder = CodeGen.Module.Builder;
  98
  99                                 TypeBuilder = builder.DefineType (
 100                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
 101                         } else {
 102                                 TypeBuilder builder = Parent.TypeBuilder;
 103
 104                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 105                                 TypeBuilder = builder.DefineNestedType (
 106                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 107                         }
 108
 109                         TypeManager.AddUserType (this);
 110
 111 #if GMCS_SOURCE
 112                         if (IsGeneric) {
 113                                 string[] param_names = new string [TypeParameters.Length];
 114                                 for (int i = 0; i < TypeParameters.Length; i++)
 115                                         param_names [i] = TypeParameters [i].Name;
 116
 117                                 GenericTypeParameterBuilder[] gen_params;
 118                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 119
 120                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 121                                 for (int i = offset; i < gen_params.Length; i++)
 122                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 123
 124                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 125                                         if (!type_param.Resolve (this))
 126                                                 return null;
 127                                 }
 128
 129                                 Expression current = new SimpleName (
 130                                         MemberName.Basename, TypeParameters, Location);
 131                                 current = current.ResolveAsTypeTerminal (this, false);
 132                                 if (current == null)
 133                                         return null;
 134
 135                                 CurrentType = current.Type;
 136                         }
 137 #endif
 138
 139                         return TypeBuilder;
 140                 }
 141
 142                 public override bool Define ()
 143                 {
 144 #if GMCS_SOURCE
 145                         if (IsGeneric) {
 146                                 foreach (TypeParameter type_param in TypeParameters) {
 147                                         if (!type_param.Resolve (this))
 148                                                 return false;
 149                                 }
 150
 151                                 foreach (TypeParameter type_param in TypeParameters) {
 152                                         if (!type_param.DefineType (this))
 153                                                 return false;
 154                                 }
 155
 156                                 foreach (TypeParameter type_param in TypeParameters) {
 157                                         if (!type_param.CheckDependencies ())
 158                                                 return false;
 159                                 }
 160                         }
 161 #endif
 162
 163                         // FIXME: POSSIBLY make this static, as it is always constant
 164                         //
 165                         Type [] const_arg_types = new Type [2];
 166                         const_arg_types [0] = TypeManager.object_type;
 167                         const_arg_types [1] = TypeManager.intptr_type;
 168
 169                         const MethodAttributes ctor_mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 170                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 171
 172                         ConstructorBuilder = TypeBuilder.DefineConstructor (ctor_mattr,
 173                                                                             CallingConventions.Standard,
 174                                                                             const_arg_types);
 175
 176                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 177                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 178                         //
 179                         // HACK because System.Reflection.Emit is lame
 180                         //
 181                         Parameter [] fixed_pars = new Parameter [2];
 182                         fixed_pars [0] = new Parameter (TypeManager.object_type, "object",
 183                                                         Parameter.Modifier.NONE, null, Location);
 184                         fixed_pars [1] = new Parameter (TypeManager.intptr_type, "method",
 185                                                         Parameter.Modifier.NONE, null, Location);
 186                         Parameters const_parameters = new Parameters (fixed_pars);
 187                         const_parameters.Resolve (null);
 188
 189                         TypeManager.RegisterMethod (ConstructorBuilder, const_parameters);
 190
 191
 192                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 193
 194                         //
 195                         // Here the various methods like Invoke, BeginInvoke etc are defined
 196                         //
 197                         // First, call the `out of band' special method for
 198                         // defining recursively any types we need:
 199
 200                         if (!Parameters.Resolve (this))
 201                                 return false;
 202
 203                         //
 204                         // Invoke method
 205                         //
 206
 207                         // Check accessibility
 208                         foreach (Type partype in Parameters.Types){
 209                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 210                                         Report.Error (59, Location,
 211                                                       "Inconsistent accessibility: parameter type `" +
 212                                                       TypeManager.CSharpName (partype) + "' is less " +
 213                                                       "accessible than delegate `" + Name + "'");
 214                                         return false;
 215                                 }
 216                         }
 217
 218                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 219                         if (ReturnType == null)
 220                                 return false;
 221
 222                         ret_type = ReturnType.Type;
 223
 224                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 225                                 Report.Error (58, Location,
 226                                               "Inconsistent accessibility: return type `" +
 227                                               TypeManager.CSharpName (ret_type) + "' is less " +
 228                                               "accessible than delegate `" + Name + "'");
 229                                 return false;
 230                         }
 231
 232                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 233                                 Method.Error1599 (Location, ret_type);
 234                                 return false;
 235                         }
 236
 237                         //
 238                         // We don't have to check any others because they are all
 239                         // guaranteed to be accessible - they are standard types.
 240                         //
 241
 242                         CallingConventions cc = Parameters.CallingConvention;
 243
 244                         const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual | MethodAttributes.NewSlot;
 245
 246                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 247                                                                   mattr,
 248                                                                   cc,
 249                                                                   ret_type,
 250                                                                   Parameters.Types);
 251
 252                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 253
 254                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 255
 256                         //
 257                         // BeginInvoke
 258                         //
 259
 260                         Parameters async_parameters = Parameters.MergeGenerated (Parameters,
 261                                 new Parameter (TypeManager.asynccallback_type, "callback", Parameter.Modifier.NONE, null, Location),
 262                                 new Parameter (TypeManager.object_type, "object", Parameter.Modifier.NONE, null, Location));
 263
 264                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 265                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.Types);
 266
 267                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 268                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 269
 270                         //
 271                         // EndInvoke is a bit more interesting, all the parameters labeled as
 272                         // out or ref have to be duplicated here.
 273                         //
 274
 275                         //
 276                         // Define parameters, and count out/ref parameters
 277                         //
 278                         Parameters end_parameters;
 279                         int out_params = 0;
 280
 281                         foreach (Parameter p in Parameters.FixedParameters) {
 282                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 283                                         ++out_params;
 284                         }
 285
 286                         if (out_params > 0) {
 287                                 Type [] end_param_types = new Type [out_params];
 288                                 Parameter [] end_params = new Parameter [out_params ];
 289
 290                                 int param = 0;
 291                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 292                                         Parameter p = Parameters.FixedParameters [i];
 293                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 294                                                 continue;
 295
 296                                         end_param_types [param] = p.ExternalType();
 297                                         end_params [param] = p;
 298                                         ++param;
 299                                 }
 300                                 end_parameters = new Parameters (end_params, end_param_types);
 301                         }
 302                         else {
 303                                 end_parameters = Parameters.EmptyReadOnlyParameters;
 304                         }
 305
 306                         end_parameters = Parameters.MergeGenerated (end_parameters,
 307                                 new Parameter (TypeManager.iasyncresult_type, "result", Parameter.Modifier.NONE, null, Location));
 308
 309                         //
 310                         // Create method, define parameters, register parameters with type system
 311                         //
 312                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.Types);
 313                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 314
 315                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 316                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 317
 318                         return true;
 319                 }
 320
 321                 public override void Emit ()
 322                 {
 323                         Parameters.ApplyAttributes (InvokeBuilder);
 324
 325                         Parameters p = (Parameters)TypeManager.GetParameterData (BeginInvokeBuilder);
 326                         p.ApplyAttributes (BeginInvokeBuilder);
 327
 328                         if (OptAttributes != null) {
 329                                 OptAttributes.Emit ();
 330                         }
 331
 332                         base.Emit ();
 333                 }
 334
 335                 protected override TypeAttributes TypeAttr {
 336                         get {
 337                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 338                                         TypeAttributes.Class | TypeAttributes.Sealed |
 339                                         base.TypeAttr;
 340                         }
 341                 }
 342
 343                 public override string[] ValidAttributeTargets {
 344                         get {
 345                                 return attribute_targets;
 346                         }
 347                 }
 348
 349                 //TODO: duplicate
 350                 protected override bool VerifyClsCompliance ()
 351                 {
 352                         if (!base.VerifyClsCompliance ()) {
 353                                 return false;
 354                         }
 355
 356                         Parameters.VerifyClsCompliance ();
 357
 358                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 359                                 Report.Error (3002, Location, "Return type of `{0}' is not CLS-compliant", GetSignatureForError ());
 360                         }
 361                         return true;
 362                 }
 363
 364                 //
 365                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 366                 // to extract the signature of a delegate.
 367                 //
 368                 public static MethodGroupExpr GetInvokeMethod (Type container_type, Type delegate_type, Location loc)
 369                 {
 370                         Expression ml = Expression.MemberLookup (container_type, null, delegate_type,
 371                                 "Invoke", loc);
 372
 373                         MethodGroupExpr mg = ml as MethodGroupExpr;
 374                         if (mg == null) {
 375                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 376                                 return null;
 377                         }
 378
 379                         return mg;
 380                 }
 381
 382                 /// <summary>
 383                 ///  Verifies whether the method in question is compatible with the delegate
 384                 ///  Returns the method itself if okay and null if not.
 385                 /// </summary>
 386                 public static MethodBase VerifyMethod (Type container_type, Type delegate_type,
 387                                                        MethodGroupExpr old_mg, MethodBase mb,
 388                                                        Location loc)
 389                 {
 390                         MethodGroupExpr mg = GetInvokeMethod (container_type, delegate_type, loc);
 391                         if (mg == null)
 392                                 return null;
 393
 394                         if (old_mg.HasTypeArguments)
 395                                 mg.HasTypeArguments = true;
 396
 397                         MethodBase invoke_mb = mg.Methods [0];
 398                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 399
 400 #if GMCS_SOURCE
 401                         if (!mg.HasTypeArguments &&
 402                             !TypeManager.InferTypeArguments (invoke_pd, ref mb))
 403                                 return null;
 404 #endif
 405
 406                         ParameterData pd = TypeManager.GetParameterData (mb);
 407
 408                         if (invoke_pd.Count != pd.Count)
 409                                 return null;
 410
 411                         for (int i = pd.Count; i > 0; ) {
 412                                 i--;
 413
 414                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 415                                 Type pd_type = pd.ParameterType (i);
 416                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 417                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 418
 419                                 invoke_pd_type_mod &= ~Parameter.Modifier.PARAMS;
 420                                 pd_type_mod &= ~Parameter.Modifier.PARAMS;
 421
 422                                 if (invoke_pd_type_mod != pd_type_mod)
 423                                         return null;
 424
 425                                 if (invoke_pd_type == pd_type)
 426                                         continue;
 427
 428                                 if (!Convert.ImplicitReferenceConversionExists (new EmptyExpression (invoke_pd_type), pd_type))
 429                                         return null;
 430
 431                                 if (RootContext.Version == LanguageVersion.ISO_1)
 432                                         return null;
 433                         }
 434
 435                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 436                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 437                         if (invoke_mb_retval == mb_retval)
 438                                 return mb;
 439
 440                         if (!Convert.ImplicitReferenceConversionExists (new EmptyExpression (mb_retval), invoke_mb_retval))
 441                                 return null;
 442
 443                         if (RootContext.Version == LanguageVersion.ISO_1)
 444                                 return null;
 445
 446                         return mb;
 447                 }
 448
 449                 // <summary>
 450                 //  Verifies whether the invocation arguments are compatible with the
 451                 //  delegate's target method
 452                 // </summary>
 453                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 454                                                         ArrayList args, Location loc)
 455                 {
 456                         int arg_count;
 457
 458                         if (args == null)
 459                                 arg_count = 0;
 460                         else
 461                                 arg_count = args.Count;
 462
 463                         Expression ml = Expression.MemberLookup (
 464                                 ec.ContainerType, delegate_type, "Invoke", loc);
 465
 466                         MethodGroupExpr me = ml as MethodGroupExpr;
 467                         if (me == null) {
 468                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 469                                 return false;
 470                         }
 471
 472                         MethodBase mb = me.Methods [0];
 473                         ParameterData pd = TypeManager.GetParameterData (mb);
 474
 475                         int pd_count = pd.Count;
 476
 477                         bool params_method = pd.HasParams;
 478                         bool is_params_applicable = false;
 479                         bool is_applicable = Invocation.IsApplicable (ec, me, args, arg_count, ref mb);
 480
 481                         if (!is_applicable && params_method &&
 482                             Invocation.IsParamsMethodApplicable (ec, me, args, arg_count, ref mb))
 483                                 is_applicable = is_params_applicable = true;
 484
 485                         if (!is_applicable && !params_method && arg_count != pd_count) {
 486                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 487                                         TypeManager.CSharpName (delegate_type), arg_count.ToString ());
 488                                 return false;
 489                         }
 490
 491                         return Invocation.VerifyArgumentsCompat (
 492                                         ec, args, arg_count, mb,
 493                                         is_params_applicable || (!is_applicable && params_method),
 494                                         delegate_type, false, loc);
 495                 }
 496
 497                 /// <summary>
 498                 ///  Verifies whether the delegate in question is compatible with this one in
 499                 ///  order to determine if instantiation from the same is possible.
 500                 /// </summary>
 501                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Location loc)
 502                 {
 503                         Expression ml = Expression.MemberLookup (
 504                                 ec.ContainerType, delegate_type, "Invoke", loc);
 505
 506                         if (!(ml is MethodGroupExpr)) {
 507                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 508                                 return false;
 509                         }
 510
 511                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 512                         ParameterData pd = TypeManager.GetParameterData (mb);
 513
 514                         Expression probe_ml = Expression.MemberLookup (
 515                                 ec.ContainerType, delegate_type, "Invoke", loc);
 516
 517                         if (!(probe_ml is MethodGroupExpr)) {
 518                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 519                                 return false;
 520                         }
 521
 522                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 523                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 524
 525                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 526                                 return false;
 527
 528                         if (pd.Count != probe_pd.Count)
 529                                 return false;
 530
 531                         for (int i = pd.Count; i > 0; ) {
 532                                 i--;
 533
 534                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 535                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 536                                         return false;
 537                         }
 538
 539                         return true;
 540                 }
 541
 542                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 543                 {
 544                         StringBuilder sb = new StringBuilder ();
 545                         sb.Append (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 546                         sb.Append (" ");
 547                         sb.Append (TypeManager.CSharpName (del_type));
 548                         sb.Append (pd.GetSignatureForError ());
 549                         return sb.ToString ();
 550                 }
 551
 552                 // Hack around System.Reflection as found everywhere else
 553                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 554                                                         MemberFilter filter, object criteria)
 555                 {
 556                         ArrayList members = new ArrayList (2);
 557
 558                         if ((mt & MemberTypes.Constructor) != 0) {
 559                                 if (ConstructorBuilder != null && filter (ConstructorBuilder, criteria))
 560                                         members.Add (ConstructorBuilder);
 561                         }
 562
 563                         if ((mt & MemberTypes.Method) != 0) {
 564                                 if (InvokeBuilder != null)
 565                                 if (filter (InvokeBuilder, criteria))
 566                                         members.Add (InvokeBuilder);
 567
 568                                 if (BeginInvokeBuilder != null)
 569                                 if (filter (BeginInvokeBuilder, criteria))
 570                                         members.Add (BeginInvokeBuilder);
 571
 572                                 if (EndInvokeBuilder != null)
 573                                 if (filter (EndInvokeBuilder, criteria))
 574                                         members.Add (EndInvokeBuilder);
 575                         }
 576
 577                         return new MemberList (members);
 578                 }
 579
 580                 public override MemberCache MemberCache {
 581                         get {
 582                                 return null;
 583                         }
 584                 }
 585
 586                 public Expression InstanceExpression {
 587                         get {
 588                                 return instance_expr;
 589                         }
 590                         set {
 591                                 instance_expr = value;
 592                         }
 593                 }
 594
 595                 public MethodBase TargetMethod {
 596                         get {
 597                                 return delegate_method;
 598                         }
 599                         set {
 600                                 delegate_method = value;
 601                         }
 602                 }
 603
 604                 public Type TargetReturnType {
 605                         get {
 606                                 return ret_type;
 607                         }
 608                 }
 609
 610                 public override AttributeTargets AttributeTargets {
 611                         get {
 612                                 return AttributeTargets.Delegate;
 613                         }
 614                 }
 615
 616                 //
 617                 //   Represents header string for documentation comment.
 618                 //
 619                 public override string DocCommentHeader {
 620                         get { return "T:"; }
 621                 }
 622         }
 623
 624         //
 625         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 626         //
 627         public abstract class DelegateCreation : Expression {
 628                 protected MethodBase constructor_method;
 629                 protected MethodBase delegate_method;
 630                 protected MethodGroupExpr method_group;
 631                 protected Expression delegate_instance_expression;
 632
 633                 protected DelegateCreation () {}
 634
 635                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 636                 {
 637                         string method_desc;
 638                         MethodBase found_method = mg.Methods [0];
 639
 640                         if (mg.Methods.Length > 1)
 641                                 method_desc = found_method.Name;
 642                         else
 643                                 method_desc = Invocation.FullMethodDesc (found_method);
 644
 645                         Expression invoke_method = Expression.MemberLookup (
 646                                 ec.ContainerType, type, "Invoke", MemberTypes.Method,
 647                                 Expression.AllBindingFlags, loc);
 648                         MethodInfo method = ((MethodGroupExpr) invoke_method).Methods [0] as MethodInfo;
 649
 650                         ParameterData param = TypeManager.GetParameterData (method);
 651                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 652
 653 #if GMCS_SOURCE
 654                         if (!mg.HasTypeArguments &&
 655                             !TypeManager.InferTypeArguments (param, ref found_method)) {
 656                                 Report.Error (411, loc, "The type arguments for " +
 657                                               "method `{0}' cannot be inferred from " +
 658                                               "the usage. Try specifying the type " +
 659                                               "arguments explicitly.", method_desc);
 660                                 return;
 661                         }
 662 #endif
 663                         Report.SymbolRelatedToPreviousError (found_method);
 664
 665                         if (RootContext.Version == LanguageVersion.ISO_1) {
 666                                 Report.Error (410, loc, "The method `{0}' parameters and return type must be same as delegate `{1}' parameters and return type",
 667                                         method_desc, delegate_desc);
 668                                 return;
 669                         }
 670
 671                         Type delegateType = method.ReturnType;
 672                         Type methodType = ((MethodInfo) found_method).ReturnType;
 673                         if (delegateType != methodType &&
 674                                 !Convert.ImplicitReferenceConversionExists (new EmptyExpression (methodType), delegateType)) {
 675                                 Report.Error (407, loc, "`{0}' has the wrong return type to match the delegate `{1}'", method_desc, delegate_desc);
 676                         } else {
 677                                 Report.Error (123, loc, "The method `{0}' parameters do not match delegate `{1}' parameters",
 678                                         TypeManager.CSharpSignature (found_method), delegate_desc);
 679                         }
 680                 }
 681
 682                 public override void Emit (EmitContext ec)
 683                 {
 684                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 685                                 ec.ig.Emit (OpCodes.Ldnull);
 686                         else
 687                                 delegate_instance_expression.Emit (ec);
 688
 689                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 690                                 ec.ig.Emit (OpCodes.Dup);
 691                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 692                         } else
 693                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 694                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 695                 }
 696
 697                 protected bool ResolveConstructorMethod (EmitContext ec)
 698                 {
 699                         Expression ml = Expression.MemberLookupFinal(ec,
 700                                 null, type, ".ctor", MemberTypes.Constructor, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 701
 702                         if (!(ml is MethodGroupExpr)) {
 703                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 704                                 return false;
 705                         }
 706
 707                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 708                         return true;
 709                 }
 710
 711                 public static MethodBase ImplicitStandardConversionExists (MethodGroupExpr mg, Type targetType)
 712                 {
 713                         foreach (MethodInfo mi in mg.Methods){
 714                                 MethodBase mb = Delegate.VerifyMethod (mg.DeclaringType, targetType, mg, mi, Location.Null);
 715                                 if (mb != null)
 716                                         return mb;
 717                         }
 718                         return null;
 719                 }
 720
 721                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 722                 {
 723                         delegate_method = ImplicitStandardConversionExists (mg, type);
 724
 725                         if (delegate_method == null) {
 726                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 727                                 return null;
 728                         }
 729
 730                         //
 731                         // Check safe/unsafe of the delegate
 732                         //
 733                         if (!ec.InUnsafe){
 734                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 735                                 int count = param.Count;
 736
 737                                 for (int i = 0; i < count; i++){
 738                                         if (param.ParameterType (i).IsPointer){
 739                                                 Expression.UnsafeError (loc);
 740                                                 return null;
 741                                         }
 742                                 }
 743                         }
 744
 745                         //TODO: implement caching when performance will be low
 746                         IMethodData md = TypeManager.GetMethod (
 747                                 TypeManager.DropGenericMethodArguments (delegate_method));
 748                         if (md == null) {
 749                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 750                                         Report.SymbolRelatedToPreviousError (delegate_method);
 751                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 752                                         return null;
 753                                 }
 754                         } else {
 755                                 md.SetMemberIsUsed ();
 756                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type) != null) {
 757                                         Report.SymbolRelatedToPreviousError (delegate_method);
 758                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 759                                         return null;
 760                                 }
 761                         }
 762
 763                         if (mg.InstanceExpression != null)
 764                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 765                         else if (ec.IsStatic) {
 766                                 if (!delegate_method.IsStatic) {
 767                                         Report.Error (120, loc, "`{0}': An object reference is required for the nonstatic field, method or property",
 768                                                       TypeManager.CSharpSignature (delegate_method));
 769                                         return null;
 770                                 }
 771                                 delegate_instance_expression = null;
 772                         } else
 773                                 delegate_instance_expression = ec.GetThis (loc);
 774
 775                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 776                                 delegate_instance_expression = new BoxedCast (
 777                                         delegate_instance_expression, TypeManager.object_type);
 778
 779                         method_group = mg;
 780                         eclass = ExprClass.Value;
 781                         return this;
 782                 }
 783         }
 784
 785         //
 786         // Created from the conversion code
 787         //
 788         public class ImplicitDelegateCreation : DelegateCreation {
 789
 790                 ImplicitDelegateCreation (Type t, Location l)
 791                 {
 792                         type = t;
 793                         loc = l;
 794                 }
 795
 796                 public override Expression DoResolve (EmitContext ec)
 797                 {
 798                         return this;
 799                 }
 800
 801                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 802                                                  Type target_type, Location loc)
 803                 {
 804                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 805                         if (!d.ResolveConstructorMethod (ec))
 806                                 return null;
 807
 808                         return d.ResolveMethodGroupExpr (ec, mge);
 809                 }
 810         }
 811
 812         //
 813         // A delegate-creation-expression, invoked from the `New' class
 814         //
 815         public class NewDelegate : DelegateCreation {
 816                 public ArrayList Arguments;
 817
 818                 //
 819                 // This constructor is invoked from the `New' expression
 820                 //
 821                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 822                 {
 823                         this.type = type;
 824                         this.Arguments = Arguments;
 825                         this.loc  = loc;
 826                 }
 827
 828                 public override Expression DoResolve (EmitContext ec)
 829                 {
 830                         if (Arguments == null) {
 831                                 Invocation.Error_WrongNumArguments (loc, GetSignatureForError (), 0);
 832                                 return null;
 833                         }
 834
 835                         if (!ResolveConstructorMethod (ec))
 836                                 return null;
 837
 838                         Argument a = (Argument) Arguments [0];
 839
 840                         if (!a.ResolveMethodGroup (ec))
 841                                 return null;
 842
 843                         Expression e = a.Expr;
 844
 845                         if (e is AnonymousMethodExpression && RootContext.Version != LanguageVersion.ISO_1)
 846                                 return ((AnonymousMethodExpression) e).Compatible (ec, type);
 847
 848                         MethodGroupExpr mg = e as MethodGroupExpr;
 849                         if (mg != null) {
 850                                 if (TypeManager.IsNullableType (mg.DeclaringType)) {
 851                                         Report.Error (1728, loc, "Cannot use method `{0}' as delegate creation expression because it is member of Nullable type",
 852                                                 mg.GetSignatureForError ());
 853                                         return null;
 854                                 }
 855
 856                                 return ResolveMethodGroupExpr (ec, mg);
 857                         }
 858
 859                         if (!TypeManager.IsDelegateType (e.Type)) {
 860                                 Report.Error (149, loc, "Method name expected");
 861                                 return null;
 862                         }
 863
 864                         method_group = Expression.MemberLookup (
 865                                 ec.ContainerType, type, "Invoke", MemberTypes.Method,
 866                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 867
 868                         if (method_group == null) {
 869                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 870                                 return null;
 871                         }
 872
 873                         // This is what MS' compiler reports. We could always choose
 874                         // to be more verbose and actually give delegate-level specifics
 875                         if (!Delegate.VerifyDelegate (ec, type, loc)) {
 876                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e.Type + "' " +
 877                                               "to type '" + type + "'");
 878                                 return null;
 879                         }
 880
 881                         delegate_instance_expression = e;
 882                         delegate_method = method_group.Methods [0];
 883
 884                         eclass = ExprClass.Value;
 885                         return this;
 886                 }
 887         }
 888
 889         public class DelegateInvocation : ExpressionStatement {
 890
 891                 public Expression InstanceExpr;
 892                 public ArrayList  Arguments;
 893
 894                 MethodBase method;
 895
 896                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 897                 {
 898                         this.InstanceExpr = instance_expr;
 899                         this.Arguments = args;
 900                         this.loc = loc;
 901                 }
 902
 903                 public override Expression DoResolve (EmitContext ec)
 904                 {
 905                         if (InstanceExpr is EventExpr) {
 906
 907                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 908
 909                                 Expression ml = MemberLookup (
 910                                         ec.ContainerType, ec.ContainerType, ei.Name,
 911                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 912
 913                                 if (ml == null) {
 914                                         //
 915                                         // If this is the case, then the Event does not belong
 916                                         // to this Type and so, according to the spec
 917                                         // cannot be accessed directly
 918                                         //
 919                                         // Note that target will not appear as an EventExpr
 920                                         // in the case it is being referenced within the same type container;
 921                                         // it will appear as a FieldExpr in that case.
 922                                         //
 923
 924                                         Assign.error70 (ei, loc);
 925                                         return null;
 926                                 }
 927                         }
 928
 929
 930                         Type del_type = InstanceExpr.Type;
 931                         if (del_type == null)
 932                                 return null;
 933
 934                         if (Arguments != null){
 935                                 foreach (Argument a in Arguments){
 936                                         if (!a.Resolve (ec, loc))
 937                                                 return null;
 938                                 }
 939                         }
 940
 941                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 942                                 return null;
 943
 944                         Expression lookup = Expression.MemberLookup (ec.ContainerType, del_type, "Invoke", loc);
 945                         if (!(lookup is MethodGroupExpr)) {
 946                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 947                                 return null;
 948                         }
 949
 950                         method = ((MethodGroupExpr) lookup).Methods [0];
 951                         type = ((MethodInfo) method).ReturnType;
 952                         eclass = ExprClass.Value;
 953
 954                         return this;
 955                 }
 956
 957                 public override void Emit (EmitContext ec)
 958                 {
 959                         //
 960                         // Invocation on delegates call the virtual Invoke member
 961                         // so we are always `instance' calls
 962                         //
 963                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 964                 }
 965
 966                 public override void EmitStatement (EmitContext ec)
 967                 {
 968                         Emit (ec);
 969                         //
 970                         // Pop the return value if there is one
 971                         //
 972                         if (method is MethodInfo){
 973                                 Type ret = ((MethodInfo)method).ReturnType;
 974                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
 975                                         ec.ig.Emit (OpCodes.Pop);
 976                         }
 977                 }
 978
 979         }
 980 }