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