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 (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  82                                 Namespace system = RootNamespace.Global.GetNamespace ("System", true);
  83                                 TypeExpr expr = system.Lookup (this, "MulticastDelegate", Location) as TypeExpr;
  84                                 TypeManager.multicast_delegate_type = expr.Type;
  85                         }
  86
  87                         if (TypeManager.multicast_delegate_type == null)
  88                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  89                                               "System.MulticastDelegate is resolved.  This can only " +
  90                                               "happen during corlib compilation, when using a delegate " +
  91                                               "in any of the `core' classes.  See bug #72015 for details.");
  92
  93                         if (IsTopLevel) {
  94                                 if (TypeManager.NamespaceClash (Name, Location))
  95                                         return null;
  96
  97                                 ModuleBuilder builder = CodeGen.Module.Builder;
  98
  99                                 TypeBuilder = builder.DefineType (
 100                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
 101                         } else {
 102                                 TypeBuilder builder = Parent.TypeBuilder;
 103
 104                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 105                                 TypeBuilder = builder.DefineNestedType (
 106                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 107                         }
 108
 109                         TypeManager.AddUserType (this);
 110
 111 #if GMCS_SOURCE
 112                         if (IsGeneric) {
 113                                 string[] param_names = new string [TypeParameters.Length];
 114                                 for (int i = 0; i < TypeParameters.Length; i++)
 115                                         param_names [i] = TypeParameters [i].Name;
 116
 117                                 GenericTypeParameterBuilder[] gen_params;
 118                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 119
 120                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 121                                 for (int i = offset; i < gen_params.Length; i++)
 122                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 123
 124                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 125                                         if (!type_param.Resolve (this))
 126                                                 return null;
 127                                 }
 128
 129                                 Expression current = new SimpleName (
 130                                         MemberName.Basename, TypeParameters, Location);
 131                                 current = current.ResolveAsTypeTerminal (this, false);
 132                                 if (current == null)
 133                                         return null;
 134
 135                                 CurrentType = current.Type;
 136                         }
 137 #endif
 138
 139                         return TypeBuilder;
 140                 }
 141
 142                 public override bool Define ()
 143                 {
 144 #if GMCS_SOURCE
 145                         if (IsGeneric) {
 146                                 foreach (TypeParameter type_param in TypeParameters) {
 147                                         if (!type_param.Resolve (this))
 148                                                 return false;
 149                                 }
 150
 151                                 foreach (TypeParameter type_param in TypeParameters) {
 152                                         if (!type_param.DefineType (this))
 153                                                 return false;
 154                                 }
 155
 156                                 foreach (TypeParameter type_param in TypeParameters) {
 157                                         if (!type_param.CheckDependencies ())
 158                                                 return false;
 159                                 }
 160                         }
 161 #endif
 162
 163                         // FIXME: POSSIBLY make this static, as it is always constant
 164                         //
 165                         Type [] const_arg_types = new Type [2];
 166                         const_arg_types [0] = TypeManager.object_type;
 167                         const_arg_types [1] = TypeManager.intptr_type;
 168
 169                         const MethodAttributes ctor_mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 170                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 171
 172                         ConstructorBuilder = TypeBuilder.DefineConstructor (ctor_mattr,
 173                                                                             CallingConventions.Standard,
 174                                                                             const_arg_types);
 175
 176                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 177                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 178                         //
 179                         // HACK because System.Reflection.Emit is lame
 180                         //
 181                         Parameter [] fixed_pars = new Parameter [2];
 182                         fixed_pars [0] = new Parameter (TypeManager.object_type, "object",
 183                                                         Parameter.Modifier.NONE, null, Location);
 184                         fixed_pars [1] = new Parameter (TypeManager.intptr_type, "method",
 185                                                         Parameter.Modifier.NONE, null, Location);
 186                         Parameters const_parameters = new Parameters (fixed_pars);
 187                         const_parameters.Resolve (null);
 188
 189                         TypeManager.RegisterMethod (ConstructorBuilder, const_parameters);
 190
 191
 192                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 193
 194                         //
 195                         // Here the various methods like Invoke, BeginInvoke etc are defined
 196                         //
 197                         // First, call the `out of band' special method for
 198                         // defining recursively any types we need:
 199
 200                         if (!Parameters.Resolve (this))
 201                                 return false;
 202
 203                         //
 204                         // Invoke method
 205                         //
 206
 207                         // Check accessibility
 208                         foreach (Type partype in Parameters.Types){
 209                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 210                                         Report.Error (59, Location,
 211                                                       "Inconsistent accessibility: parameter type `" +
 212                                                       TypeManager.CSharpName (partype) + "' is less " +
 213                                                       "accessible than delegate `" + Name + "'");
 214                                         return false;
 215                                 }
 216                         }
 217
 218                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 219                         if (ReturnType == null)
 220                                 return false;
 221
 222                         ret_type = ReturnType.Type;
 223
 224                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 225                                 Report.Error (58, Location,
 226                                               "Inconsistent accessibility: return type `" +
 227                                               TypeManager.CSharpName (ret_type) + "' is less " +
 228                                               "accessible than delegate `" + Name + "'");
 229                                 return false;
 230                         }
 231
 232                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 233                                 Method.Error1599 (Location, ret_type);
 234                                 return false;
 235                         }
 236
 237                         //
 238                         // We don't have to check any others because they are all
 239                         // guaranteed to be accessible - they are standard types.
 240                         //
 241
 242                         CallingConventions cc = Parameters.CallingConvention;
 243
 244                         const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual | MethodAttributes.NewSlot;
 245
 246                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 247                                                                   mattr,
 248                                                                   cc,
 249                                                                   ret_type,
 250                                                                   Parameters.Types);
 251
 252                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 253
 254                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 255
 256                         //
 257                         // BeginInvoke
 258                         //
 259
 260                         Parameters async_parameters = Parameters.MergeGenerated (Parameters,
 261                                 new Parameter (TypeManager.asynccallback_type, "callback", Parameter.Modifier.NONE, null, Location),
 262                                 new Parameter (TypeManager.object_type, "object", Parameter.Modifier.NONE, null, Location));
 263
 264                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 265                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.Types);
 266
 267                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 268                         async_parameters.ApplyAttributes (BeginInvokeBuilder);
 269                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 270
 271                         //
 272                         // EndInvoke is a bit more interesting, all the parameters labeled as
 273                         // out or ref have to be duplicated here.
 274                         //
 275
 276                         //
 277                         // Define parameters, and count out/ref parameters
 278                         //
 279                         Parameters end_parameters;
 280                         int out_params = 0;
 281
 282                         foreach (Parameter p in Parameters.FixedParameters) {
 283                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 284                                         ++out_params;
 285                         }
 286
 287                         if (out_params > 0) {
 288                                 Type [] end_param_types = new Type [out_params];
 289                                 Parameter [] end_params = new Parameter [out_params ];
 290
 291                                 int param = 0;
 292                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 293                                         Parameter p = Parameters.FixedParameters [i];
 294                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 295                                                 continue;
 296
 297                                         end_param_types [param] = p.ExternalType();
 298                                         end_params [param] = p;
 299                                         ++param;
 300                                 }
 301                                 end_parameters = new Parameters (end_params, end_param_types);
 302                         }
 303                         else {
 304                                 end_parameters = Parameters.EmptyReadOnlyParameters;
 305                         }
 306
 307                         end_parameters = Parameters.MergeGenerated (end_parameters,
 308                                 new Parameter (TypeManager.iasyncresult_type, "result", Parameter.Modifier.NONE, null, Location));
 309
 310                         //
 311                         // Create method, define parameters, register parameters with type system
 312                         //
 313                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.Types);
 314                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 315
 316                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 317                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 318
 319                         return true;
 320                 }
 321
 322                 public override void Emit ()
 323                 {
 324                         Parameters.ApplyAttributes (InvokeBuilder);
 325
 326                         if (OptAttributes != null) {
 327                                 OptAttributes.Emit ();
 328                         }
 329
 330                         base.Emit ();
 331                 }
 332
 333                 protected override TypeAttributes TypeAttr {
 334                         get {
 335                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 336                                         TypeAttributes.Class | TypeAttributes.Sealed |
 337                                         base.TypeAttr;
 338                         }
 339                 }
 340
 341                 public override string[] ValidAttributeTargets {
 342                         get {
 343                                 return attribute_targets;
 344                         }
 345                 }
 346
 347                 //TODO: duplicate
 348                 protected override bool VerifyClsCompliance ()
 349                 {
 350                         if (!base.VerifyClsCompliance ()) {
 351                                 return false;
 352                         }
 353
 354                         Parameters.VerifyClsCompliance ();
 355
 356                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 357                                 Report.Error (3002, Location, "Return type of `{0}' is not CLS-compliant", GetSignatureForError ());
 358                         }
 359                         return true;
 360                 }
 361
 362                 //
 363                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 364                 // to extract the signature of a delegate.
 365                 //
 366                 public static MethodGroupExpr GetInvokeMethod (Type container_type, Type delegate_type, Location loc)
 367                 {
 368                         Expression ml = Expression.MemberLookup (container_type, null, delegate_type,
 369                                 "Invoke", loc);
 370
 371                         MethodGroupExpr mg = ml as MethodGroupExpr;
 372                         if (mg == null) {
 373                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 374                                 return null;
 375                         }
 376
 377                         return mg;
 378                 }
 379
 380                 /// <summary>
 381                 ///  Verifies whether the method in question is compatible with the delegate
 382                 ///  Returns the method itself if okay and null if not.
 383                 /// </summary>
 384                 public static MethodBase VerifyMethod (Type container_type, Type delegate_type,
 385                                                        MethodGroupExpr old_mg, MethodBase mb,
 386                                                        Location loc)
 387                 {
 388                         MethodGroupExpr mg = GetInvokeMethod (container_type, delegate_type, loc);
 389                         if (mg == null)
 390                                 return null;
 391
 392                         if (old_mg.HasTypeArguments)
 393                                 mg.HasTypeArguments = true;
 394
 395                         MethodBase invoke_mb = mg.Methods [0];
 396                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 397
 398 #if GMCS_SOURCE
 399                         if (!mg.HasTypeArguments &&
 400                             !TypeManager.InferTypeArguments (invoke_pd, ref mb))
 401                                 return null;
 402 #endif
 403
 404                         ParameterData pd = TypeManager.GetParameterData (mb);
 405
 406                         if (invoke_pd.Count != pd.Count)
 407                                 return null;
 408
 409                         for (int i = pd.Count; i > 0; ) {
 410                                 i--;
 411
 412                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 413                                 Type pd_type = pd.ParameterType (i);
 414                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 415                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 416
 417                                 invoke_pd_type_mod &= ~Parameter.Modifier.PARAMS;
 418                                 pd_type_mod &= ~Parameter.Modifier.PARAMS;
 419
 420                                 if (invoke_pd_type_mod != pd_type_mod)
 421                                         return null;
 422
 423                                 if (invoke_pd_type == pd_type)
 424                                         continue;
 425
 426                                 if (!Convert.ImplicitReferenceConversionExists (new EmptyExpression (invoke_pd_type), pd_type))
 427                                         return null;
 428
 429                                 if (RootContext.Version == LanguageVersion.ISO_1)
 430                                         return null;
 431                         }
 432
 433                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 434                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 435                         if (invoke_mb_retval == mb_retval)
 436                                 return mb;
 437
 438                         if (!Convert.ImplicitReferenceConversionExists (new EmptyExpression (mb_retval), invoke_mb_retval))
 439                                 return null;
 440
 441                         if (RootContext.Version == LanguageVersion.ISO_1)
 442                                 return null;
 443
 444                         return mb;
 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 inferred from " +
 657                                               "the usage. Try specifying the type " +
 658                                               "arguments explicitly.", method_desc);
 659                                 return;
 660                         }
 661 #endif
 662                         Report.SymbolRelatedToPreviousError (found_method);
 663
 664                         if (RootContext.Version == LanguageVersion.ISO_1) {
 665                                 Report.Error (410, loc, "The method `{0}' parameters and return type must be same as delegate `{1}' parameters and return type",
 666                                         method_desc, delegate_desc);
 667                                 return;
 668                         }
 669
 670                         Type delegateType = method.ReturnType;
 671                         Type methodType = ((MethodInfo) found_method).ReturnType;
 672                         if (delegateType != methodType &&
 673                                 !Convert.ImplicitReferenceConversionExists (new EmptyExpression (methodType), delegateType)) {
 674                                 Report.Error (407, loc, "`{0}' has the wrong return type to match the delegate `{1}'", method_desc, delegate_desc);
 675                         } else {
 676                                 Report.Error (123, loc, "The method `{0}' parameters do not match delegate `{1}' parameters",
 677                                         TypeManager.CSharpSignature (found_method), delegate_desc);
 678                         }
 679                 }
 680
 681                 public override void Emit (EmitContext ec)
 682                 {
 683                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 684                                 ec.ig.Emit (OpCodes.Ldnull);
 685                         else
 686                                 delegate_instance_expression.Emit (ec);
 687
 688                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 689                                 ec.ig.Emit (OpCodes.Dup);
 690                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 691                         } else
 692                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 693                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 694                 }
 695
 696                 protected bool ResolveConstructorMethod (EmitContext ec)
 697                 {
 698                         Expression ml = Expression.MemberLookupFinal(ec,
 699                                 null, type, ".ctor", MemberTypes.Constructor, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 700
 701                         if (!(ml is MethodGroupExpr)) {
 702                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 703                                 return false;
 704                         }
 705
 706                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 707                         return true;
 708                 }
 709
 710                 public static MethodBase ImplicitStandardConversionExists (MethodGroupExpr mg, Type targetType)
 711                 {
 712                         foreach (MethodInfo mi in mg.Methods){
 713                                 MethodBase mb = Delegate.VerifyMethod (mg.DeclaringType, targetType, mg, mi, Location.Null);
 714                                 if (mb != null)
 715                                         return mb;
 716                         }
 717                         return null;
 718                 }
 719
 720                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 721                 {
 722                         delegate_method = ImplicitStandardConversionExists (mg, type);
 723
 724                         if (delegate_method == null) {
 725                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 726                                 return null;
 727                         }
 728
 729                         //
 730                         // Check safe/unsafe of the delegate
 731                         //
 732                         if (!ec.InUnsafe){
 733                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 734                                 int count = param.Count;
 735
 736                                 for (int i = 0; i < count; i++){
 737                                         if (param.ParameterType (i).IsPointer){
 738                                                 Expression.UnsafeError (loc);
 739                                                 return null;
 740                                         }
 741                                 }
 742                         }
 743
 744                         //TODO: implement caching when performance will be low
 745                         IMethodData md = TypeManager.GetMethod (delegate_method);
 746                         if (md == null) {
 747                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 748                                         Report.SymbolRelatedToPreviousError (delegate_method);
 749                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 750                                         return null;
 751                                 }
 752                         } else {
 753                                 md.SetMemberIsUsed ();
 754                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type) != null) {
 755                                         Report.SymbolRelatedToPreviousError (delegate_method);
 756                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 757                                         return null;
 758                                 }
 759                         }
 760
 761                         if (mg.InstanceExpression != null)
 762                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 763                         else if (ec.IsStatic) {
 764                                 if (!delegate_method.IsStatic) {
 765                                         Report.Error (120, loc, "`{0}': An object reference is required for the nonstatic field, method or property",
 766                                                       TypeManager.CSharpSignature (delegate_method));
 767                                         return null;
 768                                 }
 769                                 delegate_instance_expression = null;
 770                         } else
 771                                 delegate_instance_expression = ec.GetThis (loc);
 772
 773                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 774                                 delegate_instance_expression = new BoxedCast (
 775                                         delegate_instance_expression, TypeManager.object_type);
 776
 777                         method_group = mg;
 778                         eclass = ExprClass.Value;
 779                         return this;
 780                 }
 781         }
 782
 783         //
 784         // Created from the conversion code
 785         //
 786         public class ImplicitDelegateCreation : DelegateCreation {
 787
 788                 ImplicitDelegateCreation (Type t, Location l)
 789                 {
 790                         type = t;
 791                         loc = l;
 792                 }
 793
 794                 public override Expression DoResolve (EmitContext ec)
 795                 {
 796                         return this;
 797                 }
 798
 799                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 800                                                  Type target_type, Location loc)
 801                 {
 802                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 803                         if (!d.ResolveConstructorMethod (ec))
 804                                 return null;
 805
 806                         return d.ResolveMethodGroupExpr (ec, mge);
 807                 }
 808         }
 809
 810         //
 811         // A delegate-creation-expression, invoked from the `New' class
 812         //
 813         public class NewDelegate : DelegateCreation {
 814                 public ArrayList Arguments;
 815
 816                 //
 817                 // This constructor is invoked from the `New' expression
 818                 //
 819                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 820                 {
 821                         this.type = type;
 822                         this.Arguments = Arguments;
 823                         this.loc  = loc;
 824                 }
 825
 826                 public override Expression DoResolve (EmitContext ec)
 827                 {
 828                         if (Arguments == null) {
 829                                 Invocation.Error_WrongNumArguments (loc, GetSignatureForError (), 0);
 830                                 return null;
 831                         }
 832
 833                         if (!ResolveConstructorMethod (ec))
 834                                 return null;
 835
 836                         Argument a = (Argument) Arguments [0];
 837
 838                         if (!a.ResolveMethodGroup (ec))
 839                                 return null;
 840
 841                         Expression e = a.Expr;
 842
 843                         if (e is AnonymousMethodExpression && RootContext.Version != LanguageVersion.ISO_1)
 844                                 return ((AnonymousMethodExpression) e).Compatible (ec, type);
 845
 846                         MethodGroupExpr mg = e as MethodGroupExpr;
 847                         if (mg != null) {
 848                                 if (TypeManager.IsNullableType (mg.DeclaringType)) {
 849                                         Report.Error (1728, loc, "Cannot use method `{0}' as delegate creation expression because it is member of Nullable type",
 850                                                 mg.GetSignatureForError ());
 851                                         return null;
 852                                 }
 853
 854                                 return ResolveMethodGroupExpr (ec, mg);
 855                         }
 856
 857                         if (!TypeManager.IsDelegateType (e.Type)) {
 858                                 Report.Error (149, loc, "Method name expected");
 859                                 return null;
 860                         }
 861
 862                         method_group = Expression.MemberLookup (
 863                                 ec.ContainerType, type, "Invoke", MemberTypes.Method,
 864                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 865
 866                         if (method_group == null) {
 867                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 868                                 return null;
 869                         }
 870
 871                         // This is what MS' compiler reports. We could always choose
 872                         // to be more verbose and actually give delegate-level specifics
 873                         if (!Delegate.VerifyDelegate (ec, type, loc)) {
 874                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e.Type + "' " +
 875                                               "to type '" + type + "'");
 876                                 return null;
 877                         }
 878
 879                         delegate_instance_expression = e;
 880                         delegate_method = method_group.Methods [0];
 881
 882                         eclass = ExprClass.Value;
 883                         return this;
 884                 }
 885         }
 886
 887         public class DelegateInvocation : ExpressionStatement {
 888
 889                 public Expression InstanceExpr;
 890                 public ArrayList  Arguments;
 891
 892                 MethodBase method;
 893
 894                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 895                 {
 896                         this.InstanceExpr = instance_expr;
 897                         this.Arguments = args;
 898                         this.loc = loc;
 899                 }
 900
 901                 public override Expression DoResolve (EmitContext ec)
 902                 {
 903                         if (InstanceExpr is EventExpr) {
 904
 905                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 906
 907                                 Expression ml = MemberLookup (
 908                                         ec.ContainerType, ec.ContainerType, ei.Name,
 909                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 910
 911                                 if (ml == null) {
 912                                         //
 913                                         // If this is the case, then the Event does not belong
 914                                         // to this Type and so, according to the spec
 915                                         // cannot be accessed directly
 916                                         //
 917                                         // Note that target will not appear as an EventExpr
 918                                         // in the case it is being referenced within the same type container;
 919                                         // it will appear as a FieldExpr in that case.
 920                                         //
 921
 922                                         Assign.error70 (ei, loc);
 923                                         return null;
 924                                 }
 925                         }
 926
 927
 928                         Type del_type = InstanceExpr.Type;
 929                         if (del_type == null)
 930                                 return null;
 931
 932                         if (Arguments != null){
 933                                 foreach (Argument a in Arguments){
 934                                         if (!a.Resolve (ec, loc))
 935                                                 return null;
 936                                 }
 937                         }
 938
 939                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 940                                 return null;
 941
 942                         Expression lookup = Expression.MemberLookup (ec.ContainerType, del_type, "Invoke", loc);
 943                         if (!(lookup is MethodGroupExpr)) {
 944                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 945                                 return null;
 946                         }
 947
 948                         method = ((MethodGroupExpr) lookup).Methods [0];
 949                         type = ((MethodInfo) method).ReturnType;
 950                         eclass = ExprClass.Value;
 951
 952                         return this;
 953                 }
 954
 955                 public override void Emit (EmitContext ec)
 956                 {
 957                         //
 958                         // Invocation on delegates call the virtual Invoke member
 959                         // so we are always `instance' calls
 960                         //
 961                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 962                 }
 963
 964                 public override void EmitStatement (EmitContext ec)
 965                 {
 966                         Emit (ec);
 967                         //
 968                         // Pop the return value if there is one
 969                         //
 970                         if (method is MethodInfo){
 971                                 Type ret = ((MethodInfo)method).ReturnType;
 972                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
 973                                         ec.ig.Emit (OpCodes.Pop);
 974                         }
 975                 }
 976
 977         }
 978 }