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 [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, string name, Parameters param_list,
  53                                  Attributes attrs, Location l)
  54                         : base (ns, parent, name, attrs, l)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, l);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == "return") {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  83                                 TypeAttributes.Class | TypeAttributes.Sealed;
  84
  85                         if (IsTopLevel) {
  86                                 if (TypeManager.NamespaceClash (Name, Location))
  87                                         return null;
  88
  89                                 ModuleBuilder builder = CodeGen.Module.Builder;
  90
  91                                 TypeBuilder = builder.DefineType (
  92                                         Name, attr, TypeManager.multicast_delegate_type);
  93                         } else {
  94                                 TypeBuilder builder = Parent.TypeBuilder;
  95
  96                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
  97                                 TypeBuilder = builder.DefineNestedType (
  98                                         name, attr, TypeManager.multicast_delegate_type);
  99                         }
 100
 101                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 102
 103                         return TypeBuilder;
 104                 }
 105
 106                 public override bool DefineMembers (TypeContainer container)
 107                 {
 108                         return true;
 109                 }
 110
 111                 public override bool Define (TypeContainer container)
 112                 {
 113                         MethodAttributes mattr;
 114                         int i;
 115                         EmitContext ec = new EmitContext (this, this, Location, null,
 116                                                           null, ModFlags, false);
 117
 118                         // FIXME: POSSIBLY make this static, as it is always constant
 119                         //
 120                         Type [] const_arg_types = new Type [2];
 121                         const_arg_types [0] = TypeManager.object_type;
 122                         const_arg_types [1] = TypeManager.intptr_type;
 123
 124                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 125                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 126
 127                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 128                                                                             CallingConventions.Standard,
 129                                                                             const_arg_types);
 130
 131                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 132                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 133                         //
 134                         // HACK because System.Reflection.Emit is lame
 135                         //
 136                         //
 137                         // FIXME: POSSIBLY make these static, as they are always the same
 138                         Parameter [] fixed_pars = new Parameter [2];
 139                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 140                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 141                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 142
 143                         TypeManager.RegisterMethod (
 144                                 ConstructorBuilder,
 145                                 new InternalParameters (const_arg_types, const_parameters),
 146                                 const_arg_types);
 147
 148
 149                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 150
 151                         //
 152                         // Here the various methods like Invoke, BeginInvoke etc are defined
 153                         //
 154                         // First, call the `out of band' special method for
 155                         // defining recursively any types we need:
 156
 157                         if (!Parameters.ComputeAndDefineParameterTypes (this))
 158                                 return false;
 159
 160                         param_types = Parameters.GetParameterInfo (this);
 161                         if (param_types == null)
 162                                 return false;
 163
 164                         //
 165                         // Invoke method
 166                         //
 167
 168                         // Check accessibility
 169                         foreach (Type partype in param_types){
 170                                 if (!container.AsAccessible (partype, ModFlags)) {
 171                                         Report.Error (59, Location,
 172                                                       "Inconsistent accessibility: parameter type `" +
 173                                                       TypeManager.CSharpName (partype) + "` is less " +
 174                                                       "accessible than delegate `" + Name + "'");
 175                                         return false;
 176                                 }
 177                                 if (partype.IsPointer && !UnsafeOK (container))
 178                                         return false;
 179                         }
 180
 181                         ReturnType = ResolveTypeExpr (ReturnType, false, Location);
 182                         if (ReturnType == null)
 183                             return false;
 184
 185                         ret_type = ReturnType.Type;
 186                         if (ret_type == null)
 187                                 return false;
 188
 189                         if (!container.AsAccessible (ret_type, ModFlags)) {
 190                                 Report.Error (58, Location,
 191                                               "Inconsistent accessibility: return type `" +
 192                                               TypeManager.CSharpName (ret_type) + "` is less " +
 193                                               "accessible than delegate `" + Name + "'");
 194                                 return false;
 195                         }
 196
 197                         if (ret_type.IsPointer && !UnsafeOK (container))
 198                                 return false;
 199
 200                         //
 201                         // We don't have to check any others because they are all
 202                         // guaranteed to be accessible - they are standard types.
 203                         //
 204
 205                         CallingConventions cc = Parameters.GetCallingConvention ();
 206
 207                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 208
 209                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 210                                                                   mattr,
 211                                                                   cc,
 212                                                                   ret_type,
 213                                                                   param_types);
 214
 215                         //
 216                         // Define parameters, and count out/ref parameters
 217                         //
 218                         int out_params = 0;
 219                         i = 0;
 220                         if (Parameters.FixedParameters != null){
 221                                 int top = Parameters.FixedParameters.Length;
 222                                 Parameter p;
 223
 224                                 for (; i < top; i++) {
 225                                         p = Parameters.FixedParameters [i];
 226                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 227
 228                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 229                                                 out_params++;
 230                                 }
 231                         }
 232                         if (Parameters.ArrayParameter != null){
 233                                 Parameter p = Parameters.ArrayParameter;
 234                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 235                         }
 236
 237                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 238
 239                         TypeManager.RegisterMethod (InvokeBuilder,
 240                                                     new InternalParameters (container, Parameters),
 241                                                     param_types);
 242
 243                         //
 244                         // BeginInvoke
 245                         //
 246                         int params_num = param_types.Length;
 247                         Type [] async_param_types = new Type [params_num + 2];
 248
 249                         param_types.CopyTo (async_param_types, 0);
 250
 251                         async_param_types [params_num] = TypeManager.asynccallback_type;
 252                         async_param_types [params_num + 1] = TypeManager.object_type;
 253
 254                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 255                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 256
 257                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 258                                                                        mattr,
 259                                                                        cc,
 260                                                                        TypeManager.iasyncresult_type,
 261                                                                        async_param_types);
 262
 263                         i = 0;
 264                         if (Parameters.FixedParameters != null){
 265                                 int top = Parameters.FixedParameters.Length;
 266                                 Parameter p;
 267
 268                                 for (i = 0 ; i < top; i++) {
 269                                         p = Parameters.FixedParameters [i];
 270
 271                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 272                                 }
 273                         }
 274                         if (Parameters.ArrayParameter != null){
 275                                 Parameter p = Parameters.ArrayParameter;
 276                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 277
 278                                 i++;
 279                         }
 280
 281                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 282                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 283
 284                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 285
 286                         Parameter [] async_params = new Parameter [params_num + 2];
 287                         int n = 0;
 288                         if (Parameters.FixedParameters != null){
 289                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 290                                 n = Parameters.FixedParameters.Length;
 291                         }
 292                         if (Parameters.ArrayParameter != null)
 293                                 async_params [n] = Parameters.ArrayParameter;
 294
 295                         async_params [params_num] = new Parameter (
 296                                 TypeManager.system_asynccallback_expr, "callback",
 297                                                                    Parameter.Modifier.NONE, null);
 298                         async_params [params_num + 1] = new Parameter (
 299                                 TypeManager.system_object_expr, "object",
 300                                                                    Parameter.Modifier.NONE, null);
 301
 302                         Parameters async_parameters = new Parameters (async_params, null, Location);
 303                         async_parameters.ComputeAndDefineParameterTypes (this);
 304
 305                         async_parameters.ComputeAndDefineParameterTypes (this);
 306                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 307                                                     new InternalParameters (container, async_parameters),
 308                                                     async_param_types);
 309
 310                         //
 311                         // EndInvoke is a bit more interesting, all the parameters labeled as
 312                         // out or ref have to be duplicated here.
 313                         //
 314
 315                         Type [] end_param_types = new Type [out_params + 1];
 316                         Parameter [] end_params = new Parameter [out_params + 1];
 317                         int param = 0;
 318                         if (out_params > 0){
 319                                 int top = Parameters.FixedParameters.Length;
 320                                 for (i = 0; i < top; i++){
 321                                         Parameter p = Parameters.FixedParameters [i];
 322                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 323                                                 continue;
 324
 325                                         end_param_types [param] = param_types [i];
 326                                         end_params [param] = p;
 327                                         param++;
 328                                 }
 329                         }
 330                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 331                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 332
 333                         //
 334                         // Create method, define parameters, register parameters with type system
 335                         //
 336                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 337                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 338
 339                         //
 340                         // EndInvoke: Label the parameters
 341                         //
 342                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 343                         for (i = 0; i < end_params.Length-1; i++){
 344                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 345                         }
 346
 347                         Parameters end_parameters = new Parameters (end_params, null, Location);
 348                         end_parameters.ComputeAndDefineParameterTypes (this);
 349
 350                         TypeManager.RegisterMethod (
 351                                 EndInvokeBuilder,
 352                                 new InternalParameters (container, end_parameters),
 353                                 end_param_types);
 354
 355                         return true;
 356                 }
 357
 358                 public override void Emit (TypeContainer tc)
 359                 {
 360                         if (OptAttributes != null) {
 361                                 EmitContext ec = new EmitContext (tc, this, Location, null, null, ModFlags, false);
 362                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 363                                 OptAttributes.Emit (ec, this);
 364                         }
 365
 366                         base.Emit (tc);
 367                 }
 368
 369                 protected override string[] ValidAttributeTargets {
 370                         get {
 371                                 return attribute_targets;
 372                         }
 373                 }
 374
 375                 //TODO: duplicate
 376                 protected override bool VerifyClsCompliance (DeclSpace ds)
 377                 {
 378                         if (!base.VerifyClsCompliance (ds)) {
 379                                 return false;
 380                         }
 381
 382                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 383
 384                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 385                                 Report.Error_T (3002, Location, GetSignatureForError ());
 386                         }
 387                         return true;
 388                 }
 389
 390                 /// <summary>
 391                 ///  Verifies whether the method in question is compatible with the delegate
 392                 ///  Returns the method itself if okay and null if not.
 393                 /// </summary>
 394                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 395                                                        Location loc)
 396                 {
 397                         ParameterData pd = Invocation.GetParameterData (mb);
 398
 399                         int pd_count = pd.Count;
 400
 401                         Expression ml = Expression.MemberLookup (
 402                                 ec, delegate_type, "Invoke", loc);
 403
 404                         if (!(ml is MethodGroupExpr)) {
 405                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 406                                 return null;
 407                         }
 408
 409                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];
 410
 411                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 412
 413                         if (invoke_pd.Count != pd_count)
 414                                 return null;
 415
 416                         for (int i = pd_count; i > 0; ) {
 417                                 i--;
 418
 419                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i) &&
 420                                     invoke_pd.ParameterModifier (i) == pd.ParameterModifier (i))
 421                                         continue;
 422                                 else {
 423                                         return null;
 424                                 }
 425                         }
 426
 427                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)
 428                                 return mb;
 429                         else
 430                                 return null;
 431                 }
 432
 433                 // <summary>
 434                 //  Verifies whether the invocation arguments are compatible with the
 435                 //  delegate's target method
 436                 // </summary>
 437                 public static bool VerifyApplicability (EmitContext ec,
 438                                                         Type delegate_type,
 439                                                         ArrayList args,
 440                                                         Location loc)
 441                 {
 442                         int arg_count;
 443
 444                         if (args == null)
 445                                 arg_count = 0;
 446                         else
 447                                 arg_count = args.Count;
 448
 449                         Expression ml = Expression.MemberLookup (
 450                                 ec, delegate_type, "Invoke", loc);
 451
 452                         if (!(ml is MethodGroupExpr)) {
 453                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 454                                 return false;
 455                         }
 456
 457                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 458                         ParameterData pd = Invocation.GetParameterData (mb);
 459
 460                         int pd_count = pd.Count;
 461
 462                         bool params_method = (pd_count != 0) &&
 463                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 464
 465                         if (!params_method && pd_count != arg_count) {
 466                                 Report.Error (1593, loc,
 467                                               "Delegate '" + delegate_type.ToString ()
 468                                               + "' does not take '" + arg_count + "' arguments");
 469                                 return false;
 470                         }
 471
 472                         //
 473                         // Consider the case:
 474                         //   delegate void FOO(param object[] args);
 475                         //   FOO f = new FOO(...);
 476                         //   f(new object[] {1, 2, 3});
 477                         //
 478                         // This should be treated like f(1,2,3).  This is done by ignoring the
 479                         // 'param' modifier for that invocation.  If that fails, then the
 480                         // 'param' modifier is considered.
 481                         //
 482                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 483                         // the 'args' array.  However, the modifications appear idempotent.
 484                         // Normal 'Invocation's also have the same behaviour, implicitly.
 485                         //
 486
 487                         bool ans = false;
 488                         if (arg_count == pd_count)
 489                                 ans = Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, false, delegate_type, loc);
 490                         if (!ans && params_method)
 491                                 ans = Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, true,  delegate_type, loc);
 492                         return ans;
 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, Type probe_type, Location loc)
 500                 {
 501                         Expression ml = Expression.MemberLookup (
 502                                 ec, 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 = Invocation.GetParameterData (mb);
 511
 512                         Expression probe_ml = Expression.MemberLookup (
 513                                 ec, 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 = Invocation.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 (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 543
 544                         sb.Append (" " + del_type.ToString ());
 545                         sb.Append (" (");
 546
 547                         int length = pd.Count;
 548
 549                         for (int i = length; i > 0; ) {
 550                                 i--;
 551
 552                                 sb.Append (pd.ParameterDesc (length - i - 1));
 553                                 if (i != 0)
 554                                         sb.Append (", ");
 555                         }
 556
 557                         sb.Append (")");
 558                         return sb.ToString ();
 559
 560                 }
 561
 562                 // Hack around System.Reflection as found everywhere else
 563                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 564                                                         MemberFilter filter, object criteria)
 565                 {
 566                         ArrayList members = new ArrayList ();
 567
 568                         if ((mt & MemberTypes.Method) != 0) {
 569                                 if (ConstructorBuilder != null)
 570                                 if (filter (ConstructorBuilder, criteria))
 571                                         members.Add (ConstructorBuilder);
 572
 573                                 if (InvokeBuilder != null)
 574                                 if (filter (InvokeBuilder, criteria))
 575                                         members.Add (InvokeBuilder);
 576
 577                                 if (BeginInvokeBuilder != null)
 578                                 if (filter (BeginInvokeBuilder, criteria))
 579                                         members.Add (BeginInvokeBuilder);
 580
 581                                 if (EndInvokeBuilder != null)
 582                                 if (filter (EndInvokeBuilder, criteria))
 583                                         members.Add (EndInvokeBuilder);
 584                         }
 585
 586                         return new MemberList (members);
 587                 }
 588
 589                 public override MemberCache MemberCache {
 590                         get {
 591                                 return null;
 592                         }
 593                 }
 594
 595                 public Expression InstanceExpression {
 596                         get {
 597                                 return instance_expr;
 598                         }
 599                         set {
 600                                 instance_expr = value;
 601                         }
 602                 }
 603
 604                 public MethodBase TargetMethod {
 605                         get {
 606                                 return delegate_method;
 607                         }
 608                         set {
 609                                 delegate_method = value;
 610                         }
 611                 }
 612
 613                 public Type TargetReturnType {
 614                         get {
 615                                 return ret_type;
 616                         }
 617                 }
 618
 619                 public Type [] ParameterTypes {
 620                         get {
 621                                 return param_types;
 622                         }
 623                 }
 624
 625                 public override AttributeTargets AttributeTargets {
 626                         get {
 627                                 return AttributeTargets.Delegate | AttributeTargets.ReturnValue;
 628                         }
 629                 }
 630
 631                 protected override void VerifyObsoleteAttribute()
 632                 {
 633                         CheckUsageOfObsoleteAttribute (ret_type);
 634
 635                         foreach (Type type in param_types) {
 636                                 CheckUsageOfObsoleteAttribute (type);
 637                         }
 638                 }
 639         }
 640
 641         //
 642         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 643         //
 644         public abstract class DelegateCreation : Expression {
 645                 protected MethodBase constructor_method;
 646                 protected MethodBase delegate_method;
 647                 protected MethodGroupExpr method_group;
 648
 649                 public DelegateCreation () {}
 650
 651                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 652                 {
 653                         string method_desc;
 654
 655                         if (mg.Methods.Length > 1)
 656                                 method_desc = mg.Methods [0].Name;
 657                         else
 658                                 method_desc = Invocation.FullMethodDesc (mg.Methods [0]);
 659
 660                         Expression invoke_method = Expression.MemberLookup (
 661                                 ec, type, "Invoke", MemberTypes.Method,
 662                                 Expression.AllBindingFlags, loc);
 663                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 664                         ParameterData param = Invocation.GetParameterData (method);
 665                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 666
 667                         Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 668                                       "match delegate '" + delegate_desc + "'");
 669                 }
 670
 671                 public override void Emit (EmitContext ec)
 672                 {
 673                         if (method_group.InstanceExpression == null ||
 674                             delegate_method.IsStatic)
 675                                 ec.ig.Emit (OpCodes.Ldnull);
 676                         else
 677                                 method_group.InstanceExpression.Emit (ec);
 678
 679                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 680                                 ec.ig.Emit (OpCodes.Dup);
 681                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 682                         } else
 683                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 684                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 685                 }
 686
 687                 protected bool ResolveConstructorMethod (EmitContext ec)
 688                 {
 689                         Expression ml = Expression.MemberLookup (
 690                                 ec, type, ".ctor", loc);
 691
 692                         if (!(ml is MethodGroupExpr)) {
 693                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 694                                 return false;
 695                         }
 696
 697                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 698                         return true;
 699                 }
 700
 701                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 702                 {
 703                         foreach (MethodInfo mi in mg.Methods){
 704                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 705
 706                                 if (delegate_method != null)
 707                                         break;
 708                         }
 709
 710                         if (delegate_method == null) {
 711                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 712                                 return null;
 713                         }
 714
 715                         //
 716                         // Check safe/unsafe of the delegate
 717                         //
 718                         if (!ec.InUnsafe){
 719                                 ParameterData param = Invocation.GetParameterData (delegate_method);
 720                                 int count = param.Count;
 721
 722                                 for (int i = 0; i < count; i++){
 723                                         if (param.ParameterType (i).IsPointer){
 724                                                 Expression.UnsafeError (loc);
 725                                                 return null;
 726                                         }
 727                                 }
 728                         }
 729
 730                         //TODO: implement caching when performance will be low
 731                         IMethodData md = TypeManager.GetMethod (delegate_method);
 732                         if (md == null) {
 733                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 734                                         // Cannot create delegate with '{0}' because it has a Conditional attribute
 735                                         Report.Error_T (1618, loc, TypeManager.CSharpSignature (delegate_method));
 736                                 }
 737                         } else {
 738                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 739                                         // Cannot create delegate with '{0}' because it has a Conditional attribute
 740                                         Report.Error_T (1618, loc, TypeManager.CSharpSignature (delegate_method));
 741                                 }
 742                         }
 743
 744                         if (mg.InstanceExpression != null)
 745                                 mg.InstanceExpression = mg.InstanceExpression.Resolve (ec);
 746                         else if (ec.IsStatic) {
 747                                 if (!delegate_method.IsStatic) {
 748                                         Report.Error (120, loc,
 749                                                       "An object reference is required for the non-static method " +
 750                                                       delegate_method.Name);
 751                                         return null;
 752                                 }
 753                                 mg.InstanceExpression = null;
 754                         } else
 755                                 mg.InstanceExpression = ec.GetThis (loc);
 756
 757                         if (mg.InstanceExpression != null && mg.InstanceExpression.Type.IsValueType)
 758                                 mg.InstanceExpression = new BoxedCast (mg.InstanceExpression);
 759
 760                         method_group = mg;
 761                         eclass = ExprClass.Value;
 762                         return this;
 763                 }
 764         }
 765
 766         //
 767         // Created from the conversion code
 768         //
 769         public class ImplicitDelegateCreation : DelegateCreation {
 770
 771                 ImplicitDelegateCreation (Type t, Location l)
 772                 {
 773                         type = t;
 774                         loc = l;
 775                 }
 776
 777                 public override Expression DoResolve (EmitContext ec)
 778                 {
 779                         return this;
 780                 }
 781
 782                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 783                 {
 784                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 785                         if (d.ResolveConstructorMethod (ec))
 786                                 return d.ResolveMethodGroupExpr (ec, mge);
 787                         else
 788                                 return null;
 789                 }
 790         }
 791
 792         //
 793         // A delegate-creation-expression, invoked from the `New' class
 794         //
 795         public class NewDelegate : DelegateCreation {
 796                 public ArrayList Arguments;
 797
 798                 //
 799                 // This constructor is invoked from the `New' expression
 800                 //
 801                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 802                 {
 803                         this.type = type;
 804                         this.Arguments = Arguments;
 805                         this.loc  = loc;
 806                 }
 807
 808                 public override Expression DoResolve (EmitContext ec)
 809                 {
 810                         if (Arguments == null || Arguments.Count != 1) {
 811                                 Report.Error (149, loc,
 812                                               "Method name expected");
 813                                 return null;
 814                         }
 815
 816                         if (!ResolveConstructorMethod (ec))
 817                                 return null;
 818
 819                         Argument a = (Argument) Arguments [0];
 820
 821                         if (!a.ResolveMethodGroup (ec, loc))
 822                                 return null;
 823
 824                         Expression e = a.Expr;
 825
 826                         MethodGroupExpr mg = e as MethodGroupExpr;
 827                         if (mg != null)
 828                                 return ResolveMethodGroupExpr (ec, mg);
 829
 830                         Type e_type = e.Type;
 831
 832                         if (!TypeManager.IsDelegateType (e_type)) {
 833                                 e.Error_UnexpectedKind ("method");
 834                                 return null;
 835                         }
 836
 837                         method_group = Expression.MemberLookup (
 838                                 ec, type, "Invoke", MemberTypes.Method,
 839                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 840
 841                         if (method_group == null) {
 842                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 843                                 return null;
 844                         }
 845
 846                         // This is what MS' compiler reports. We could always choose
 847                         // to be more verbose and actually give delegate-level specifics
 848                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 849                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 850                                               "to type '" + type + "'");
 851                                 return null;
 852                         }
 853
 854                         method_group.InstanceExpression = e;
 855                         delegate_method = method_group.Methods [0];
 856
 857                         eclass = ExprClass.Value;
 858                         return this;
 859                 }
 860         }
 861
 862         public class DelegateInvocation : ExpressionStatement {
 863
 864                 public Expression InstanceExpr;
 865                 public ArrayList  Arguments;
 866
 867                 MethodBase method;
 868
 869                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 870                 {
 871                         this.InstanceExpr = instance_expr;
 872                         this.Arguments = args;
 873                         this.loc = loc;
 874                 }
 875
 876                 public override Expression DoResolve (EmitContext ec)
 877                 {
 878                         if (InstanceExpr is EventExpr) {
 879
 880                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 881
 882                                 Expression ml = MemberLookup (
 883                                         ec, ec.ContainerType, ei.Name,
 884                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 885
 886                                 if (ml == null) {
 887                                         //
 888                                         // If this is the case, then the Event does not belong
 889                                         // to this Type and so, according to the spec
 890                                         // cannot be accessed directly
 891                                         //
 892                                         // Note that target will not appear as an EventExpr
 893                                         // in the case it is being referenced within the same type container;
 894                                         // it will appear as a FieldExpr in that case.
 895                                         //
 896
 897                                         Assign.error70 (ei, loc);
 898                                         return null;
 899                                 }
 900                         }
 901
 902
 903                         Type del_type = InstanceExpr.Type;
 904                         if (del_type == null)
 905                                 return null;
 906
 907                         if (Arguments != null){
 908                                 foreach (Argument a in Arguments){
 909                                         if (!a.Resolve (ec, loc))
 910                                                 return null;
 911                                 }
 912                         }
 913
 914                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 915                                 return null;
 916
 917                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 918                         if (!(lookup is MethodGroupExpr)) {
 919                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 920                                 return null;
 921                         }
 922
 923                         method = ((MethodGroupExpr) lookup).Methods [0];
 924                         type = ((MethodInfo) method).ReturnType;
 925                         eclass = ExprClass.Value;
 926
 927                         return this;
 928                 }
 929
 930                 public override void Emit (EmitContext ec)
 931                 {
 932                         //
 933                         // Invocation on delegates call the virtual Invoke member
 934                         // so we are always `instance' calls
 935                         //
 936                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 937                 }
 938
 939                 public override void EmitStatement (EmitContext ec)
 940                 {
 941                         Emit (ec);
 942                         //
 943                         // Pop the return value if there is one
 944                         //
 945                         if (method is MethodInfo){
 946                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 947                                         ec.ig.Emit (OpCodes.Pop);
 948                         }
 949                 }
 950
 951         }
 952 }