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