mcs/anonymous.cs

   1 //
   2 // anonymous.cs: Support for anonymous methods and types
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximain.com)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11
  12 using System;
  13 using System.Text;
  14 using System.Collections;
  15 using System.Collections.Specialized;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18
  19 namespace Mono.CSharp {
  20
  21         public abstract class CompilerGeneratedClass : Class
  22         {
  23                 public static string MakeName (string host, string typePrefix, string name, int id)
  24                 {
  25                         return "<" + host + ">" + typePrefix + "__" + name + id.ToString ("X");
  26                 }
  27
  28                 protected CompilerGeneratedClass (DeclSpace parent, MemberName name, int mod)
  29                         : base (parent.NamespaceEntry, parent, name, mod | Modifiers.COMPILER_GENERATED | Modifiers.SEALED, null)
  30                 {
  31                 }
  32
  33                 protected CompilerGeneratedClass (DeclSpace parent, GenericMethod generic, MemberName name, int mod)
  34                         : this (parent, name, mod)
  35                 {
  36                         if (generic != null) {
  37                                 ArrayList list = new ArrayList ();
  38                                 foreach (TypeParameter tparam in generic.TypeParameters) {
  39                                         if (tparam.Constraints != null)
  40                                                 list.Add (tparam.Constraints.Clone ());
  41                                 }
  42                                 SetParameterInfo (list);
  43                         }
  44                 }
  45
  46                 protected void CheckMembersDefined ()
  47                 {
  48                         if (members_defined)
  49                                 throw new InternalErrorException ("Helper class already defined!");
  50                 }
  51         }
  52
  53         //
  54         // Anonymous method storey is created when an anonymous method uses
  55         // variable or parameter from outer scope. They are then hoisted to
  56         // anonymous method storey (captured)
  57         //
  58         public class AnonymousMethodStorey : CompilerGeneratedClass
  59         {
  60                 class StoreyFieldPair {
  61                         public readonly AnonymousMethodStorey Storey;
  62                         public readonly Field Field;
  63
  64                         public StoreyFieldPair (AnonymousMethodStorey storey, Field field)
  65                         {
  66                                 this.Storey = storey;
  67                                 this.Field = field;
  68                         }
  69
  70                         public override int GetHashCode ()
  71                         {
  72                                 return Storey.ID.GetHashCode ();
  73                         }
  74
  75                         public override bool Equals (object obj)
  76                         {
  77                                 return (AnonymousMethodStorey)obj == Storey;
  78                         }
  79                 }
  80
  81                 sealed class HoistedGenericField : Field
  82                 {
  83                         public HoistedGenericField (DeclSpace parent, FullNamedExpression type, int mod, string name,
  84                                   Attributes attrs, Location loc)
  85                                 : base (parent, type, mod, new MemberName (name, loc), attrs)
  86                         {
  87                         }
  88
  89                         protected override bool ResolveMemberType ()
  90                         {
  91                                 if (!base.ResolveMemberType ())
  92                                         return false;
  93
  94                                 AnonymousMethodStorey parent = ((AnonymousMethodStorey) Parent).GetGenericStorey ();
  95                                 if (parent != null)
  96                                         member_type = parent.MutateType (member_type);
  97
  98                                 return true;
  99                         }
 100                 }
 101
 102                 //
 103                 // Needed to delay hoisted _this_ initialization. When an anonymous
 104                 // method is used inside ctor and _this_ is hoisted, base ctor has to
 105                 // be called first, otherwise _this_ will be initialized with
 106                 // uninitialized value.
 107                 //
 108                 sealed class ThisInitializer : Statement
 109                 {
 110                         readonly HoistedThis hoisted_this;
 111
 112                         public ThisInitializer (HoistedThis hoisted_this)
 113                         {
 114                                 this.hoisted_this = hoisted_this;
 115                         }
 116
 117                         protected override void DoEmit (EmitContext ec)
 118                         {
 119                                 hoisted_this.EmitHoistingAssignment (ec);
 120                         }
 121
 122                         protected override void CloneTo (CloneContext clonectx, Statement target)
 123                         {
 124                                 // Nothing to clone
 125                         }
 126
 127                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 128                         {
 129                                 // Nothing to mutate
 130                         }
 131                 }
 132
 133                 // Unique storey ID
 134                 public readonly int ID;
 135                 static int unique_id;
 136
 137                 public readonly Block OriginalSourceBlock;
 138
 139                 // A list of StoreyFieldPair with local field keeping parent storey instance
 140                 ArrayList used_parent_storeys;
 141                 ArrayList children_references;
 142
 143                 // A list of hoisted parameters
 144                 protected ArrayList hoisted_params;
 145                 protected ArrayList hoisted_locals;
 146
 147                 // Hoisted this
 148                 protected HoistedThis hoisted_this;
 149
 150                 // Local variable which holds this storey instance
 151                 public LocalTemporary Instance;
 152
 153                 public AnonymousMethodStorey (Block block, TypeContainer parent, MemberBase host, GenericMethod generic, string name)
 154                         : base (parent, generic, MakeMemberName (host, name, generic, block.StartLocation), Modifiers.PRIVATE)
 155                 {
 156                         Parent = parent;
 157                         OriginalSourceBlock = block;
 158                         ID = unique_id++;
 159                 }
 160
 161                 static MemberName MakeMemberName (MemberBase host, string name, GenericMethod generic, Location loc)
 162                 {
 163                         string host_name = host == null ? null : host.Name;
 164                         string tname = MakeName (host_name, "c", name, unique_id);
 165                         TypeArguments args = null;
 166                         if (generic != null) {
 167                                 args = new TypeArguments ();
 168                                 foreach (TypeParameter tparam in generic.CurrentTypeParameters)
 169                                         args.Add (new TypeParameterName (tparam.Name, null, loc));
 170                         }
 171
 172                         return new MemberName (tname, args, loc);
 173                 }
 174
 175                 public void AddCapturedThisField (EmitContext ec)
 176                 {
 177                         TypeExpr type_expr = new TypeExpression (ec.CurrentType, Location);
 178                         Field f = AddCompilerGeneratedField ("<>f__this", type_expr);
 179                         f.Define ();
 180                         hoisted_this = new HoistedThis (this, f);
 181                 }
 182
 183                 public Field AddCapturedVariable (string name, Type type)
 184                 {
 185                         CheckMembersDefined ();
 186
 187                         FullNamedExpression field_type = new TypeExpression (type, Location);
 188                         if (!IsGeneric)
 189                                 return AddCompilerGeneratedField (name, field_type);
 190
 191                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 192                         Field f = new HoistedGenericField (this, field_type, mod, name, null, Location);
 193                         AddField (f);
 194                         return f;
 195                 }
 196
 197                 protected Field AddCompilerGeneratedField (string name, FullNamedExpression type)
 198                 {
 199                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 200                         Field f = new Field (this, type, mod, new MemberName (name, Location), null);
 201                         AddField (f);
 202                         return f;
 203                 }
 204
 205                 //
 206                 // Creates a link between block and the anonymous method storey
 207                 //
 208                 // An anonymous method can reference variables from any outer block, but they are
 209                 // hoisted in their own ExplicitBlock. When more than one block is referenced we
 210                 // need to create another link between those variable storeys
 211                 //
 212                 public void AddReferenceFromChildrenBlock (ExplicitBlock block)
 213                 {
 214                         if (children_references == null)
 215                                 children_references = new ArrayList ();
 216
 217                         if (!children_references.Contains (block))
 218                                 children_references.Add (block);
 219                 }
 220
 221                 public void AddParentStoreyReference (AnonymousMethodStorey storey)
 222                 {
 223                         CheckMembersDefined ();
 224
 225                         if (used_parent_storeys == null)
 226                                 used_parent_storeys = new ArrayList ();
 227                         else if (used_parent_storeys.IndexOf (storey) != -1)
 228                                 return;
 229
 230                         TypeExpr type_expr = new TypeExpression (storey.TypeBuilder, Location);
 231                         Field f = AddCompilerGeneratedField ("<>f__ref$" + storey.ID, type_expr);
 232                         used_parent_storeys.Add (new StoreyFieldPair (storey, f));
 233                 }
 234
 235                 public void CaptureLocalVariable (ResolveContext ec, LocalInfo local_info)
 236                 {
 237                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 238                         if (ec.CurrentBlock.Explicit != local_info.Block.Explicit)
 239                                 AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 240
 241                         if (local_info.HoistedVariableReference != null)
 242                                 return;
 243
 244                         HoistedVariable var = new HoistedLocalVariable (this, local_info, GetVariableMangledName (local_info));
 245                         local_info.HoistedVariableReference = var;
 246
 247                         if (hoisted_locals == null)
 248                                 hoisted_locals = new ArrayList ();
 249
 250                         hoisted_locals.Add (var);
 251                 }
 252
 253                 public void CaptureParameter (ResolveContext ec, ParameterReference param_ref)
 254                 {
 255                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 256                         AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 257
 258                         if (param_ref.GetHoistedVariable (ec) != null)
 259                                 return;
 260
 261                         if (hoisted_params == null)
 262                                 hoisted_params = new ArrayList (2);
 263
 264                         HoistedVariable expr = new HoistedParameter (this, param_ref);
 265                         param_ref.Parameter.HoistedVariableReference = expr;
 266                         hoisted_params.Add (expr);
 267                 }
 268
 269                 public void ChangeParentStorey (AnonymousMethodStorey parentStorey)
 270                 {
 271                         Parent = parentStorey;
 272                         type_params = null;
 273                 }
 274
 275                 //
 276                 // Initializes all hoisted variables
 277                 //
 278                 public void EmitStoreyInstantiation (EmitContext ec)
 279                 {
 280                         // There can be only one instance variable for each storey type
 281                         if (Instance != null)
 282                                 throw new InternalErrorException ();
 283
 284                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 285
 286                         //
 287                         // Create an instance of storey type
 288                         //
 289                         Expression storey_type_expr;
 290                         if (is_generic) {
 291                                 //
 292                                 // Use current method type parameter (MVAR) for top level storey only. All
 293                                 // nested storeys use class type parameter (VAR)
 294                                 //
 295                                 TypeParameter[] tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
 296                                         ec.CurrentAnonymousMethod.Storey.TypeParameters :
 297                                         ec.CurrentTypeParameters;
 298
 299                                 TypeArguments targs = new TypeArguments ();
 300
 301                                 if (tparams.Length < CountTypeParameters) {
 302                                         TypeParameter[] parent_tparams = ec.MemberContext.CurrentTypeDefinition.TypeParameters;
 303                                         for (int i = 0; i < parent_tparams.Length; ++i)
 304                                                 targs.Add (new TypeParameterExpr (parent_tparams[i], Location));
 305                                 }
 306
 307                                 for (int i = 0; i < tparams.Length; ++i)
 308                                         targs.Add (new TypeParameterExpr (tparams[i], Location));
 309
 310                                 storey_type_expr = new GenericTypeExpr (TypeBuilder, targs, Location);
 311                         } else {
 312                                 storey_type_expr = new TypeExpression (TypeBuilder, Location);
 313                         }
 314
 315                         ResolveContext rc = new ResolveContext (this);
 316                         Expression e = new New (storey_type_expr, null, Location).Resolve (rc);
 317                         e.Emit (ec);
 318
 319                         Instance = new LocalTemporary (storey_type_expr.Type);
 320                         Instance.Store (ec);
 321
 322                         EmitHoistedFieldsInitialization (ec);
 323
 324                         SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
 325                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 326                 }
 327
 328                 void EmitHoistedFieldsInitialization (EmitContext ec)
 329                 {
 330                         //
 331                         // Initialize all storey reference fields by using local or hoisted variables
 332                         //
 333                         if (used_parent_storeys != null) {
 334                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 335                                         //
 336                                         // Setting local field
 337                                         //
 338                                         Expression instace_expr = GetStoreyInstanceExpression (ec);
 339                                         FieldExpr f_set_expr = TypeManager.IsGenericType (instace_expr.Type) ?
 340                                                 new FieldExpr (sf.Field.FieldBuilder, instace_expr.Type, Location) :
 341                                                 new FieldExpr (sf.Field.FieldBuilder, Location);
 342                                         f_set_expr.InstanceExpression = instace_expr;
 343
 344                                         SimpleAssign a = new SimpleAssign (f_set_expr, sf.Storey.GetStoreyInstanceExpression (ec));
 345                                         if (a.Resolve (new ResolveContext (ec.MemberContext)) != null)
 346                                                 a.EmitStatement (ec);
 347                                 }
 348                         }
 349
 350                         //
 351                         // Define hoisted `this' in top-level storey only
 352                         //
 353                         if (OriginalSourceBlock.Explicit.HasCapturedThis && !(Parent is AnonymousMethodStorey)) {
 354                                 AddCapturedThisField (ec);
 355                                 OriginalSourceBlock.AddScopeStatement (new ThisInitializer (hoisted_this));
 356                         }
 357
 358                         //
 359                         // Setting currect anonymous method to null blocks any further variable hoisting
 360                         //
 361                         AnonymousExpression ae = ec.CurrentAnonymousMethod;
 362                         ec.CurrentAnonymousMethod = null;
 363
 364                         if (hoisted_params != null) {
 365                                 EmitHoistedParameters (ec, hoisted_params);
 366                         }
 367
 368                         ec.CurrentAnonymousMethod = ae;
 369                 }
 370
 371                 protected virtual void EmitHoistedParameters (EmitContext ec, ArrayList hoisted)
 372                 {
 373                         foreach (HoistedParameter hp in hoisted) {
 374                                 hp.EmitHoistingAssignment (ec);
 375                         }
 376                 }
 377
 378                 public override void EmitType ()
 379                 {
 380                         SymbolWriter.DefineAnonymousScope (ID);
 381
 382                         if (hoisted_this != null)
 383                                 hoisted_this.EmitSymbolInfo ();
 384
 385                         if (hoisted_locals != null) {
 386                                 foreach (HoistedVariable local in hoisted_locals)
 387                                         local.EmitSymbolInfo ();
 388                         }
 389
 390                         if (hoisted_params != null) {
 391                                 foreach (HoistedParameter param in hoisted_params)
 392                                         param.EmitSymbolInfo ();
 393                         }
 394
 395                         if (used_parent_storeys != null) {
 396                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 397                                         SymbolWriter.DefineCapturedScope (ID, sf.Storey.ID, sf.Field.Name);
 398                                 }
 399                         }
 400
 401                         base.EmitType ();
 402                 }
 403
 404                 public AnonymousMethodStorey GetGenericStorey ()
 405                 {
 406                         DeclSpace storey = this;
 407                         while (storey != null && storey.CurrentTypeParameters == null)
 408                                 storey = storey.Parent;
 409
 410                         return storey as AnonymousMethodStorey;
 411                 }
 412
 413                 //
 414                 // Returns a field which holds referenced storey instance
 415                 //
 416                 Field GetReferencedStoreyField (AnonymousMethodStorey storey)
 417                 {
 418                         if (used_parent_storeys == null)
 419                                 return null;
 420
 421                         foreach (StoreyFieldPair sf in used_parent_storeys) {
 422                                 if (sf.Storey == storey)
 423                                         return sf.Field;
 424                         }
 425
 426                         return null;
 427                 }
 428
 429                 //
 430                 // Creates storey instance expression regardless of currect IP
 431                 //
 432                 public Expression GetStoreyInstanceExpression (EmitContext ec)
 433                 {
 434                         AnonymousExpression am = ec.CurrentAnonymousMethod;
 435
 436                         //
 437                         // Access from original block -> storey
 438                         //
 439                         if (am == null)
 440                                 return Instance;
 441
 442                         //
 443                         // Access from anonymous method implemented as a static -> storey
 444                         //
 445                         if (am.Storey == null)
 446                                 return Instance;
 447
 448                         Field f = am.Storey.GetReferencedStoreyField (this);
 449                         if (f == null) {
 450                                 if (am.Storey == this) {
 451                                         //
 452                                         // Access inside of same storey (S -> S)
 453                                         //
 454                                         return new CompilerGeneratedThis (TypeBuilder, Location);
 455                                 }
 456                                 //
 457                                 // External field access
 458                                 //
 459                                 return Instance;
 460                         }
 461
 462                         //
 463                         // Storey was cached to local field
 464                         //
 465                         FieldExpr f_ind = new FieldExpr (f.FieldBuilder, Location);
 466                         f_ind.InstanceExpression = new CompilerGeneratedThis (TypeBuilder, Location);
 467                         return f_ind;
 468                 }
 469
 470                 protected virtual string GetVariableMangledName (LocalInfo local_info)
 471                 {
 472                         //
 473                         // No need to mangle anonymous method hoisted variables cause they
 474                         // are hoisted in their own scopes
 475                         //
 476                         return local_info.Name;
 477                 }
 478
 479                 public HoistedThis HoistedThis {
 480                         get { return hoisted_this; }
 481                 }
 482
 483                 //
 484                 // Mutate type dispatcher
 485                 //
 486                 public Type MutateType (Type type)
 487                 {
 488 #if GMCS_SOURCE
 489                         if (TypeManager.IsGenericType (type))
 490                                 return MutateGenericType (type);
 491
 492                         if (TypeManager.IsGenericParameter (type))
 493                                 return MutateGenericArgument (type);
 494
 495                         if (type.IsArray)
 496                                 return MutateArrayType (type);
 497 #endif
 498                         return type;
 499                 }
 500
 501                 //
 502                 // Changes method type arguments (MVAR) to storey (VAR) type arguments
 503                 //
 504                 public MethodInfo MutateGenericMethod (MethodInfo method)
 505                 {
 506 #if GMCS_SOURCE
 507                         Type [] t_args = TypeManager.GetGenericArguments (method);
 508                         if (TypeManager.IsGenericType (method.DeclaringType)) {
 509                                 Type t = MutateGenericType (method.DeclaringType);
 510                                 if (t != method.DeclaringType) {
 511                                         method = (MethodInfo) TypeManager.DropGenericMethodArguments (method);
 512                                         if (method.Module == Module.Builder)
 513                                                 method = TypeBuilder.GetMethod (t, method);
 514                                         else
 515                                                 method = (MethodInfo) MethodInfo.GetMethodFromHandle (method.MethodHandle, t.TypeHandle);
 516                                 }
 517                         }
 518
 519                         if (t_args == null || t_args.Length == 0)
 520                                 return method;
 521
 522                         for (int i = 0; i < t_args.Length; ++i)
 523                                 t_args [i] = MutateType (t_args [i]);
 524
 525                         return method.GetGenericMethodDefinition ().MakeGenericMethod (t_args);
 526 #else
 527                         throw new NotSupportedException ();
 528 #endif
 529                 }
 530
 531                 public ConstructorInfo MutateConstructor (ConstructorInfo ctor)
 532                 {
 533 #if GMCS_SOURCE
 534                         if (TypeManager.IsGenericType (ctor.DeclaringType)) {
 535                                 Type t = MutateGenericType (ctor.DeclaringType);
 536                                 if (t != ctor.DeclaringType) {
 537                                         ctor = (ConstructorInfo) TypeManager.DropGenericMethodArguments (ctor);
 538                                         if (ctor.Module == Module.Builder)
 539                                                 return TypeBuilder.GetConstructor (t, ctor);
 540
 541                                         return (ConstructorInfo) ConstructorInfo.GetMethodFromHandle (ctor.MethodHandle, t.TypeHandle);
 542                                 }
 543                         }
 544 #endif
 545                         return ctor;
 546                 }
 547
 548                 public FieldInfo MutateField (FieldInfo field)
 549                 {
 550 #if GMCS_SOURCE
 551                         if (TypeManager.IsGenericType (field.DeclaringType)) {
 552                                 Type t = MutateGenericType (field.DeclaringType);
 553                                 if (t != field.DeclaringType) {
 554                                         field = TypeManager.DropGenericTypeArguments (field.DeclaringType).GetField (field.Name, TypeManager.AllMembers);
 555                                         if (field.Module == Module.Builder)
 556                                                 return TypeBuilder.GetField (t, field);
 557
 558                                         return FieldInfo.GetFieldFromHandle (field.FieldHandle, t.TypeHandle);
 559                                 }
 560                         }
 561 #endif
 562                         return field;
 563                 }
 564
 565 #if GMCS_SOURCE
 566                 protected Type MutateArrayType (Type array)
 567                 {
 568                         Type element = TypeManager.GetElementType (array);
 569                         if (element.IsArray) {
 570                                 element = MutateArrayType (element);
 571                         } else if (TypeManager.IsGenericParameter (element)) {
 572                                 element = MutateGenericArgument (element);
 573                         } else if (TypeManager.IsGenericType (element)) {
 574                                 element = MutateGenericType (element);
 575                         } else {
 576                                 return array;
 577                         }
 578
 579                         int rank = array.GetArrayRank ();
 580                         if (rank == 1)
 581                                 return element.MakeArrayType ();
 582
 583                         return element.MakeArrayType (rank);
 584                 }
 585
 586                 protected Type MutateGenericType (Type type)
 587                 {
 588                         Type [] t_args = TypeManager.GetTypeArguments (type);
 589                         if (t_args == null || t_args.Length == 0)
 590                                 return type;
 591
 592                         for (int i = 0; i < t_args.Length; ++i)
 593                                 t_args [i] = MutateType (t_args [i]);
 594
 595                         return TypeManager.DropGenericTypeArguments (type).MakeGenericType (t_args);
 596                 }
 597 #endif
 598
 599                 //
 600                 // Changes method generic argument (MVAR) to type generic argument (VAR)
 601                 //
 602                 public Type MutateGenericArgument (Type type)
 603                 {
 604                         if (CurrentTypeParameters != null) {
 605                                 TypeParameter tp = TypeParameter.FindTypeParameter (CurrentTypeParameters, type.Name);
 606                                 if (tp != null)
 607                                         return tp.Type;
 608                         }
 609
 610                         return type;
 611                 }
 612
 613                 public ArrayList ReferencesFromChildrenBlock {
 614                         get { return children_references; }
 615                 }
 616
 617                 public static void Reset ()
 618                 {
 619                         unique_id = 0;
 620                 }
 621         }
 622
 623         public abstract class HoistedVariable
 624         {
 625                 class ExpressionTreeProxy : Expression
 626                 {
 627                         readonly HoistedVariable hv;
 628
 629                         public ExpressionTreeProxy (HoistedVariable hv)
 630                         {
 631                                 this.hv = hv;
 632                         }
 633
 634                         public override Expression CreateExpressionTree (ResolveContext ec)
 635                         {
 636                                 throw new NotSupportedException ("ET");
 637                         }
 638
 639                         public override Expression DoResolve (ResolveContext ec)
 640                         {
 641                                 eclass = ExprClass.Value;
 642                                 type = TypeManager.expression_type_expr.Type;
 643                                 return this;
 644                         }
 645
 646                         public override void Emit (EmitContext ec)
 647                         {
 648                                 ResolveContext rc = new ResolveContext (ec.MemberContext);
 649                                 Expression e = hv.GetFieldExpression (ec).CreateExpressionTree (rc);
 650                                 // This should never fail
 651                                 e = e.Resolve (rc);
 652                                 if (e != null)
 653                                         e.Emit (ec);
 654                         }
 655                 }
 656
 657                 protected readonly AnonymousMethodStorey storey;
 658                 protected Field field;
 659                 Hashtable cached_inner_access; // TODO: Hashtable is too heavyweight
 660                 FieldExpr cached_outer_access;
 661
 662                 protected HoistedVariable (AnonymousMethodStorey storey, string name, Type type)
 663                         : this (storey, storey.AddCapturedVariable (name, type))
 664                 {
 665                 }
 666
 667                 protected HoistedVariable (AnonymousMethodStorey storey, Field field)
 668                 {
 669                         this.storey = storey;
 670                         this.field = field;
 671                 }
 672
 673                 public void AddressOf (EmitContext ec, AddressOp mode)
 674                 {
 675                         GetFieldExpression (ec).AddressOf (ec, mode);
 676                 }
 677
 678                 public Expression CreateExpressionTree (ResolveContext ec)
 679                 {
 680                         return new ExpressionTreeProxy (this);
 681                 }
 682
 683                 public void Emit (EmitContext ec)
 684                 {
 685                         GetFieldExpression (ec).Emit (ec);
 686                 }
 687
 688                 //
 689                 // Creates field access expression for hoisted variable
 690                 //
 691                 protected FieldExpr GetFieldExpression (EmitContext ec)
 692                 {
 693                         if (ec.CurrentAnonymousMethod == null || ec.CurrentAnonymousMethod.Storey == null) {
 694                                 if (cached_outer_access != null)
 695                                         return cached_outer_access;
 696
 697                                 //
 698                                 // When setting top-level hoisted variable in generic storey
 699                                 // change storey generic types to method generic types (VAR -> MVAR)
 700                                 //
 701                                 cached_outer_access = storey.MemberName.IsGeneric ?
 702                                         new FieldExpr (field.FieldBuilder, storey.Instance.Type, field.Location) :
 703                                         new FieldExpr (field.FieldBuilder, field.Location);
 704
 705                                 cached_outer_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 706                                 return cached_outer_access;
 707                         }
 708
 709                         FieldExpr inner_access;
 710                         if (cached_inner_access != null) {
 711                                 inner_access = (FieldExpr) cached_inner_access [ec.CurrentAnonymousMethod];
 712                         } else {
 713                                 inner_access = null;
 714                                 cached_inner_access = new Hashtable (4);
 715                         }
 716
 717                         if (inner_access == null) {
 718                                 inner_access = field.Parent.MemberName.IsGeneric ?
 719                                         new FieldExpr (field.FieldBuilder, field.Parent.CurrentType, field.Location) :
 720                                         new FieldExpr (field.FieldBuilder, field.Location);
 721
 722                                 inner_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 723                                 cached_inner_access.Add (ec.CurrentAnonymousMethod, inner_access);
 724                         }
 725
 726                         return inner_access;
 727                 }
 728
 729                 public abstract void EmitSymbolInfo ();
 730
 731                 public void Emit (EmitContext ec, bool leave_copy)
 732                 {
 733                         GetFieldExpression (ec).Emit (ec, leave_copy);
 734                 }
 735
 736                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 737                 {
 738                         GetFieldExpression (ec).EmitAssign (ec, source, leave_copy, false);
 739                 }
 740         }
 741
 742         class HoistedParameter : HoistedVariable
 743         {
 744                 sealed class HoistedFieldAssign : Assign
 745                 {
 746                         public HoistedFieldAssign (Expression target, Expression source)
 747                                 : base (target, source, source.Location)
 748                         {
 749                         }
 750
 751                         protected override Expression ResolveConversions (ResolveContext ec)
 752                         {
 753                                 //
 754                                 // Implicit conversion check fails for hoisted type arguments
 755                                 // as they are of different types (!!0 x !0)
 756                                 //
 757                                 return this;
 758                         }
 759                 }
 760
 761                 readonly ParameterReference parameter;
 762
 763                 public HoistedParameter (AnonymousMethodStorey scope, ParameterReference par)
 764                         : base (scope, par.Name, par.Type)
 765                 {
 766                         this.parameter = par;
 767                 }
 768
 769                 public HoistedParameter (HoistedParameter hp, string name)
 770                         : base (hp.storey, name, hp.parameter.Type)
 771                 {
 772                         this.parameter = hp.parameter;
 773                 }
 774
 775                 public void EmitHoistingAssignment (EmitContext ec)
 776                 {
 777                         //
 778                         // Remove hoisted redirection to emit assignment from original parameter
 779                         //
 780                         HoistedVariable temp = parameter.Parameter.HoistedVariableReference;
 781                         parameter.Parameter.HoistedVariableReference = null;
 782
 783                         Assign a = new HoistedFieldAssign (GetFieldExpression (ec), parameter);
 784                         if (a.Resolve (new ResolveContext (ec.MemberContext)) != null)
 785                                 a.EmitStatement (ec);
 786
 787                         parameter.Parameter.HoistedVariableReference = temp;
 788                 }
 789
 790                 public override void EmitSymbolInfo ()
 791                 {
 792                         SymbolWriter.DefineCapturedParameter (storey.ID, field.Name, field.Name);
 793                 }
 794
 795                 public Field Field {
 796                         get { return field; }
 797                 }
 798         }
 799
 800         class HoistedLocalVariable : HoistedVariable
 801         {
 802                 readonly string name;
 803
 804                 public HoistedLocalVariable (AnonymousMethodStorey scope, LocalInfo local, string name)
 805                         : base (scope, name, local.VariableType)
 806                 {
 807                         this.name = local.Name;
 808                 }
 809
 810                 public override void EmitSymbolInfo ()
 811                 {
 812                         SymbolWriter.DefineCapturedLocal (storey.ID, name, field.Name);
 813                 }
 814         }
 815
 816         public class HoistedThis : HoistedVariable
 817         {
 818                 public HoistedThis (AnonymousMethodStorey storey, Field field)
 819                         : base (storey, field)
 820                 {
 821                 }
 822
 823                 public void EmitHoistingAssignment (EmitContext ec)
 824                 {
 825                         SimpleAssign a = new SimpleAssign (GetFieldExpression (ec), new CompilerGeneratedThis (ec.CurrentType, field.Location));
 826                         if (a.Resolve (new ResolveContext (ec.MemberContext)) != null)
 827                                 a.EmitStatement (ec);
 828                 }
 829
 830                 public override void EmitSymbolInfo ()
 831                 {
 832                         SymbolWriter.DefineCapturedThis (storey.ID, field.Name);
 833                 }
 834
 835                 public Field Field {
 836                         get { return field; }
 837                 }
 838         }
 839
 840         //
 841         // Anonymous method expression as created by parser
 842         //
 843         public class AnonymousMethodExpression : Expression
 844         {
 845                 ListDictionary compatibles;
 846                 public ToplevelBlock Block;
 847
 848                 public AnonymousMethodExpression (Location loc)
 849                 {
 850                         this.loc = loc;
 851                         this.compatibles = new ListDictionary ();
 852                 }
 853
 854                 public override string ExprClassName {
 855                         get {
 856                                 return "anonymous method";
 857                         }
 858                 }
 859
 860                 public virtual bool HasExplicitParameters {
 861                         get {
 862                                 return Parameters != ParametersCompiled.Undefined;
 863                         }
 864                 }
 865
 866                 public ParametersCompiled Parameters {
 867                         get { return Block.Parameters; }
 868                 }
 869
 870                 //
 871                 // Returns true if the body of lambda expression can be implicitly
 872                 // converted to the delegate of type `delegate_type'
 873                 //
 874                 public bool ImplicitStandardConversionExists (ResolveContext ec, Type delegate_type)
 875                 {
 876                         using (ec.With (ResolveContext.Options.InferReturnType, false)) {
 877                                 using (ec.Set (ResolveContext.Options.ProbingMode)) {
 878                                         return Compatible (ec, delegate_type) != null;
 879                                 }
 880                         }
 881                 }
 882
 883                 protected Type CompatibleChecks (ResolveContext ec, Type delegate_type)
 884                 {
 885                         if (TypeManager.IsDelegateType (delegate_type))
 886                                 return delegate_type;
 887
 888                         if (TypeManager.DropGenericTypeArguments (delegate_type) == TypeManager.expression_type) {
 889                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 890                                 if (TypeManager.IsDelegateType (delegate_type))
 891                                         return delegate_type;
 892
 893                                 ec.Report.Error (835, loc, "Cannot convert `{0}' to an expression tree of non-delegate type `{1}'",
 894                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 895                                 return null;
 896                         }
 897
 898                         ec.Report.Error (1660, loc, "Cannot convert `{0}' to non-delegate type `{1}'",
 899                                       GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 900                         return null;
 901                 }
 902
 903                 protected bool VerifyExplicitParameters (ResolveContext ec, Type delegate_type, AParametersCollection parameters)
 904                 {
 905                         if (VerifyParameterCompatibility (ec, delegate_type, parameters, ec.IsInProbingMode))
 906                                 return true;
 907
 908                         if (!ec.IsInProbingMode)
 909                                 ec.Report.Error (1661, loc,
 910                                         "Cannot convert `{0}' to delegate type `{1}' since there is a parameter mismatch",
 911                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 912
 913                         return false;
 914                 }
 915
 916                 protected bool VerifyParameterCompatibility (ResolveContext ec, Type delegate_type, AParametersCollection invoke_pd, bool ignore_errors)
 917                 {
 918                         if (Parameters.Count != invoke_pd.Count) {
 919                                 if (ignore_errors)
 920                                         return false;
 921
 922                                 ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 923                                               TypeManager.CSharpName (delegate_type), Parameters.Count.ToString ());
 924                                 return false;
 925                         }
 926
 927                         bool has_implicit_parameters = !HasExplicitParameters;
 928                         bool error = false;
 929
 930                         for (int i = 0; i < Parameters.Count; ++i) {
 931                                 Parameter.Modifier p_mod = invoke_pd.FixedParameters [i].ModFlags;
 932                                 if (Parameters.FixedParameters [i].ModFlags != p_mod && p_mod != Parameter.Modifier.PARAMS) {
 933                                         if (ignore_errors)
 934                                                 return false;
 935
 936                                         if (p_mod == Parameter.Modifier.NONE)
 937                                                 ec.Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 938                                                               (i + 1).ToString (), Parameter.GetModifierSignature (Parameters.FixedParameters [i].ModFlags));
 939                                         else
 940                                                 ec.Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 941                                                               (i+1).ToString (), Parameter.GetModifierSignature (p_mod));
 942                                         error = true;
 943                                 }
 944
 945                                 if (has_implicit_parameters)
 946                                         continue;
 947
 948                                 Type type = invoke_pd.Types [i];
 949
 950                                 // We assume that generic parameters are always inflated
 951                                 if (TypeManager.IsGenericParameter (type))
 952                                         continue;
 953
 954                                 if (TypeManager.HasElementType (type) && TypeManager.IsGenericParameter (TypeManager.GetElementType (type)))
 955                                         continue;
 956
 957                                 if (invoke_pd.Types [i] != Parameters.Types [i]) {
 958                                         if (ignore_errors)
 959                                                 return false;
 960
 961                                         ec.Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 962                                                       (i+1).ToString (),
 963                                                       TypeManager.CSharpName (Parameters.Types [i]),
 964                                                       TypeManager.CSharpName (invoke_pd.Types [i]));
 965                                         error = true;
 966                                 }
 967                         }
 968
 969                         return !error;
 970                 }
 971
 972                 //
 973                 // Infers type arguments based on explicit arguments
 974                 //
 975                 public bool ExplicitTypeInference (ResolveContext ec, TypeInferenceContext type_inference, Type delegate_type)
 976                 {
 977                         if (!HasExplicitParameters)
 978                                 return false;
 979
 980                         if (!TypeManager.IsDelegateType (delegate_type)) {
 981                                 if (TypeManager.DropGenericTypeArguments (delegate_type) != TypeManager.expression_type)
 982                                         return false;
 983
 984                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 985                                 if (!TypeManager.IsDelegateType (delegate_type))
 986                                         return false;
 987                         }
 988
 989                         AParametersCollection d_params = TypeManager.GetDelegateParameters (ec, delegate_type);
 990                         if (d_params.Count != Parameters.Count)
 991                                 return false;
 992
 993                         for (int i = 0; i < Parameters.Count; ++i) {
 994                                 Type itype = d_params.Types [i];
 995                                 if (!TypeManager.IsGenericParameter (itype)) {
 996                                         if (!TypeManager.HasElementType (itype))
 997                                                 continue;
 998
 999                                         if (!TypeManager.IsGenericParameter (TypeManager.GetElementType (itype)))
1000                                             continue;
1001                                 }
1002                                 type_inference.ExactInference (Parameters.Types [i], itype);
1003                         }
1004                         return true;
1005                 }
1006
1007                 public Type InferReturnType (ResolveContext ec, TypeInferenceContext tic, Type delegate_type)
1008                 {
1009                         AnonymousMethodBody am;
1010                         using (ec.Set (ResolveContext.Options.ProbingMode | ResolveContext.Options.InferReturnType)) {
1011                                 am = CompatibleMethod (ec, tic, InternalType.Arglist, delegate_type);
1012                         }
1013
1014                         if (am == null)
1015                                 return null;
1016
1017                         return am.ReturnType;
1018                 }
1019
1020                 //
1021                 // Returns AnonymousMethod container if this anonymous method
1022                 // expression can be implicitly converted to the delegate type `delegate_type'
1023                 //
1024                 public Expression Compatible (ResolveContext ec, Type type)
1025                 {
1026                         Expression am = (Expression) compatibles [type];
1027                         if (am != null)
1028                                 return am;
1029
1030                         Type delegate_type = CompatibleChecks (ec, type);
1031                         if (delegate_type == null)
1032                                 return null;
1033
1034                         //
1035                         // At this point its the first time we know the return type that is
1036                         // needed for the anonymous method.  We create the method here.
1037                         //
1038
1039                         MethodInfo invoke_mb = Delegate.GetInvokeMethod (ec.Compiler,
1040                                 ec.CurrentType, delegate_type);
1041                         Type return_type = TypeManager.TypeToCoreType (invoke_mb.ReturnType);
1042
1043 #if MS_COMPATIBLE
1044                         Type[] g_args = delegate_type.GetGenericArguments ();
1045                         if (return_type.IsGenericParameter)
1046                                 return_type = g_args [return_type.GenericParameterPosition];
1047 #endif
1048
1049                         //
1050                         // Second: the return type of the delegate must be compatible with
1051                         // the anonymous type.   Instead of doing a pass to examine the block
1052                         // we satisfy the rule by setting the return type on the EmitContext
1053                         // to be the delegate type return type.
1054                         //
1055
1056                         try {
1057                                 int errors = ec.Report.Errors;
1058                                 am = CompatibleMethod (ec, null, return_type, delegate_type);
1059                                 if (am != null && delegate_type != type && errors == ec.Report.Errors)
1060                                         am = CreateExpressionTree (ec, delegate_type);
1061
1062                                 if (!ec.IsInProbingMode)
1063                                         compatibles.Add (type, am == null ? EmptyExpression.Null : am);
1064
1065                                 return am;
1066                         } catch (CompletionResult){
1067                                 throw;
1068                         } catch (Exception e) {
1069                                 throw new InternalErrorException (e, loc);
1070                         }
1071                 }
1072
1073                 protected virtual Expression CreateExpressionTree (ResolveContext ec, Type delegate_type)
1074                 {
1075                         return CreateExpressionTree (ec);
1076                 }
1077
1078                 public override Expression CreateExpressionTree (ResolveContext ec)
1079                 {
1080                         ec.Report.Error (1946, loc, "An anonymous method cannot be converted to an expression tree");
1081                         return null;
1082                 }
1083
1084                 protected virtual ParametersCompiled ResolveParameters (ResolveContext ec, TypeInferenceContext tic, Type delegate_type)
1085                 {
1086                         AParametersCollection delegate_parameters = TypeManager.GetDelegateParameters (ec, delegate_type);
1087
1088                         if (Parameters == ParametersCompiled.Undefined) {
1089                                 //
1090                                 // We provide a set of inaccessible parameters
1091                                 //
1092                                 Parameter[] fixedpars = new Parameter[delegate_parameters.Count];
1093
1094                                 for (int i = 0; i < delegate_parameters.Count; i++) {
1095                                         Parameter.Modifier i_mod = delegate_parameters.FixedParameters [i].ModFlags;
1096                                         if (i_mod == Parameter.Modifier.OUT) {
1097                                                 ec.Report.Error (1688, loc, "Cannot convert anonymous " +
1098                                                                   "method block without a parameter list " +
1099                                                                   "to delegate type `{0}' because it has " +
1100                                                                   "one or more `out' parameters.",
1101                                                                   TypeManager.CSharpName (delegate_type));
1102                                                 return null;
1103                                         }
1104                                         fixedpars[i] = new Parameter (
1105                                                 null, null,
1106                                                 delegate_parameters.FixedParameters [i].ModFlags, null, loc);
1107                                 }
1108
1109                                 return ParametersCompiled.CreateFullyResolved (fixedpars, delegate_parameters.Types);
1110                         }
1111
1112                         if (!VerifyExplicitParameters (ec, delegate_type, delegate_parameters)) {
1113                                 return null;
1114                         }
1115
1116                         return Parameters;
1117                 }
1118
1119                 public override Expression DoResolve (ResolveContext ec)
1120                 {
1121                         if (ec.HasSet (ResolveContext.Options.ConstantScope)) {
1122                                 ec.Report.Error (1706, loc, "Anonymous methods and lambda expressions cannot be used in the current context");
1123                                 return null;
1124                         }
1125
1126                         //
1127                         // Set class type, set type
1128                         //
1129
1130                         eclass = ExprClass.Value;
1131
1132                         //
1133                         // This hack means `The type is not accessible
1134                         // anywhere', we depend on special conversion
1135                         // rules.
1136                         //
1137                         type = InternalType.AnonymousMethod;
1138
1139                         if ((Parameters != null) && !Parameters.Resolve (ec))
1140                                 return null;
1141
1142                         // FIXME: The emitted code isn't very careful about reachability
1143                         // so, ensure we have a 'ret' at the end
1144                         BlockContext bc = ec as BlockContext;
1145                         if (bc != null && bc.CurrentBranching != null && bc.CurrentBranching.CurrentUsageVector.IsUnreachable)
1146                                 bc.NeedReturnLabel ();
1147
1148                         return this;
1149                 }
1150
1151                 public override void Emit (EmitContext ec)
1152                 {
1153                         // nothing, as we only exist to not do anything.
1154                 }
1155
1156                 public static void Error_AddressOfCapturedVar (ResolveContext ec, IVariableReference var, Location loc)
1157                 {
1158                         ec.Report.Error (1686, loc,
1159                                 "Local variable or parameter `{0}' cannot have their address taken and be used inside an anonymous method or lambda expression",
1160                                 var.Name);
1161                 }
1162
1163                 public override string GetSignatureForError ()
1164                 {
1165                         return ExprClassName;
1166                 }
1167
1168                 protected AnonymousMethodBody CompatibleMethod (ResolveContext ec, TypeInferenceContext tic, Type return_type, Type delegate_type)
1169                 {
1170                         ParametersCompiled p = ResolveParameters (ec, tic, delegate_type);
1171                         if (p == null)
1172                                 return null;
1173
1174                         ToplevelBlock b = ec.IsInProbingMode ? (ToplevelBlock) Block.PerformClone () : Block;
1175
1176                         AnonymousMethodBody anonymous = CompatibleMethodFactory (return_type, delegate_type, p, b);
1177                         if (!anonymous.Compatible (ec))
1178                                 return null;
1179
1180                         return anonymous;
1181                 }
1182
1183                 protected virtual AnonymousMethodBody CompatibleMethodFactory (Type return_type, Type delegate_type, ParametersCompiled p, ToplevelBlock b)
1184                 {
1185                         return new AnonymousMethodBody (p, b, return_type, delegate_type, loc);
1186                 }
1187
1188                 protected override void CloneTo (CloneContext clonectx, Expression t)
1189                 {
1190                         AnonymousMethodExpression target = (AnonymousMethodExpression) t;
1191
1192                         target.Block = (ToplevelBlock) clonectx.LookupBlock (Block);
1193                 }
1194         }
1195
1196         //
1197         // Abstract expression for any block which requires variables hoisting
1198         //
1199         public abstract class AnonymousExpression : Expression
1200         {
1201                 protected class AnonymousMethodMethod : Method
1202                 {
1203                         public readonly AnonymousExpression AnonymousMethod;
1204                         public readonly AnonymousMethodStorey Storey;
1205                         readonly string RealName;
1206
1207                         public AnonymousMethodMethod (DeclSpace parent, AnonymousExpression am, AnonymousMethodStorey storey,
1208                                                           GenericMethod generic, TypeExpr return_type,
1209                                                           int mod, string real_name, MemberName name,
1210                                                           ParametersCompiled parameters)
1211                                 : base (parent, generic, return_type, mod | Modifiers.COMPILER_GENERATED,
1212                                                 name, parameters, null)
1213                         {
1214                                 this.AnonymousMethod = am;
1215                                 this.Storey = storey;
1216                                 this.RealName = real_name;
1217
1218                                 Parent.PartialContainer.AddMethod (this);
1219                                 Block = am.Block;
1220                         }
1221
1222                         public override EmitContext CreateEmitContext (ILGenerator ig)
1223                         {
1224                                 EmitContext ec = new EmitContext (this, ig, ReturnType);
1225                                 ec.CurrentAnonymousMethod = AnonymousMethod;
1226                                 if (AnonymousMethod.return_label != null) {
1227                                         ec.HasReturnLabel = true;
1228                                         ec.ReturnLabel = (Label) AnonymousMethod.return_label;
1229                                 }
1230
1231                                 return ec;
1232                         }
1233
1234                         protected override bool ResolveMemberType ()
1235                         {
1236                                 if (!base.ResolveMemberType ())
1237                                         return false;
1238
1239                                 if (Storey != null && Storey.IsGeneric) {
1240                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1241                                         if (gstorey != null) {
1242                                                 if (!Parameters.IsEmpty) {
1243                                                         Type [] ptypes = Parameters.Types;
1244                                                         for (int i = 0; i < ptypes.Length; ++i)
1245                                                                 ptypes [i] = gstorey.MutateType (ptypes [i]);
1246                                                 }
1247
1248                                                 member_type = gstorey.MutateType (member_type);
1249                                         }
1250                                 }
1251
1252                                 return true;
1253                         }
1254
1255                         public override void Emit ()
1256                         {
1257                                 //
1258                                 // Before emitting any code we have to change all MVAR references to VAR
1259                                 // when the method is of generic type and has hoisted variables
1260                                 //
1261                                 if (Storey == Parent && Storey.IsGeneric) {
1262                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1263                                         if (gstorey != null) {
1264                                                 block.MutateHoistedGenericType (gstorey);
1265                                         }
1266                                 }
1267
1268                                 if (MethodBuilder == null) {
1269                                         Define ();
1270                                 }
1271
1272                                 base.Emit ();
1273                         }
1274
1275                         public override void EmitExtraSymbolInfo (SourceMethod source)
1276                         {
1277                                 source.SetRealMethodName (RealName);
1278                         }
1279                 }
1280
1281                 //
1282                 // The block that makes up the body for the anonymous method
1283                 //
1284                 protected readonly ToplevelBlock Block;
1285
1286                 public Type ReturnType;
1287
1288                 object return_label;
1289
1290                 protected AnonymousExpression (ToplevelBlock block, Type return_type, Location loc)
1291                 {
1292                         this.ReturnType = return_type;
1293                         this.Block = block;
1294                         this.loc = loc;
1295                 }
1296
1297                 public abstract string ContainerType { get; }
1298                 public abstract bool IsIterator { get; }
1299                 public abstract AnonymousMethodStorey Storey { get; }
1300
1301                 public bool Compatible (ResolveContext ec)
1302                 {
1303                         // TODO: Implement clone
1304                         BlockContext aec = new BlockContext (ec.MemberContext, Block, ReturnType);
1305                         aec.CurrentAnonymousMethod = this;
1306
1307                         IDisposable aec_dispose = null;
1308                         ResolveContext.Options flags = 0;
1309                         if (ec.HasSet (ResolveContext.Options.InferReturnType)) {
1310                                 flags |= ResolveContext.Options.InferReturnType;
1311                                 aec.ReturnTypeInference = new TypeInferenceContext ();
1312                         }
1313
1314                         if (ec.IsInProbingMode)
1315                                 flags |= ResolveContext.Options.ProbingMode;
1316
1317                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
1318                                 flags |= ResolveContext.Options.FieldInitializerScope;
1319
1320                         if (ec.IsUnsafe)
1321                                 flags |= ResolveContext.Options.UnsafeScope;
1322
1323                         if (ec.HasSet (ResolveContext.Options.CheckedScope))
1324                                 flags |= ResolveContext.Options.CheckedScope;
1325
1326                         // HACK: Flag with 0 cannot be set
1327                         if (flags != 0)
1328                                 aec_dispose = aec.Set (flags);
1329
1330                         bool res = Block.Resolve (ec.CurrentBranching, aec, Block.Parameters, null);
1331
1332                         if (aec.HasReturnLabel)
1333                                 return_label = aec.ReturnLabel;
1334
1335                         if (ec.HasSet (ResolveContext.Options.InferReturnType)) {
1336                                 aec.ReturnTypeInference.FixAllTypes (ec);
1337                                 ReturnType = aec.ReturnTypeInference.InferredTypeArguments [0];
1338                         }
1339
1340                         if (aec_dispose != null) {
1341                                 aec_dispose.Dispose ();
1342                         }
1343
1344                         return res;
1345                 }
1346
1347                 public void SetHasThisAccess ()
1348                 {
1349                         Block.HasCapturedThis = true;
1350                         ExplicitBlock b = Block.Parent.Explicit;
1351
1352                         while (b != null) {
1353                                 if (b.HasCapturedThis)
1354                                         return;
1355
1356                                 b.HasCapturedThis = true;
1357                                 b = b.Parent == null ? null : b.Parent.Explicit;
1358                         }
1359                 }
1360         }
1361
1362         public class AnonymousMethodBody : AnonymousExpression
1363         {
1364                 protected readonly ParametersCompiled parameters;
1365                 AnonymousMethodStorey storey;
1366
1367                 AnonymousMethodMethod method;
1368                 Field am_cache;
1369                 string block_name;
1370
1371                 static int unique_id;
1372
1373                 public AnonymousMethodBody (ParametersCompiled parameters,
1374                                         ToplevelBlock block, Type return_type, Type delegate_type,
1375                                         Location loc)
1376                         : base (block, return_type, loc)
1377                 {
1378                         this.type = delegate_type;
1379                         this.parameters = parameters;
1380                 }
1381
1382                 public override string ContainerType {
1383                         get { return "anonymous method"; }
1384                 }
1385
1386                 public override AnonymousMethodStorey Storey {
1387                         get { return storey; }
1388                 }
1389
1390                 public override bool IsIterator {
1391                         get { return false; }
1392                 }
1393
1394                 public override Expression CreateExpressionTree (ResolveContext ec)
1395                 {
1396                         ec.Report.Error (1945, loc, "An expression tree cannot contain an anonymous method expression");
1397                         return null;
1398                 }
1399
1400                 bool Define (ResolveContext ec)
1401                 {
1402                         if (!Block.Resolved && !Compatible (ec))
1403                                 return false;
1404
1405                         if (block_name == null) {
1406                                 MemberCore mc = (MemberCore) ec.MemberContext;
1407                                 block_name = mc.MemberName.Basename;
1408                         }
1409
1410                         return true;
1411                 }
1412
1413                 //
1414                 // Creates a host for the anonymous method
1415                 //
1416                 AnonymousMethodMethod DoCreateMethodHost (EmitContext ec)
1417                 {
1418                         //
1419                         // Anonymous method body can be converted to
1420                         //
1421                         // 1, an instance method in current scope when only `this' is hoisted
1422                         // 2, a static method in current scope when neither `this' nor any variable is hoisted
1423                         // 3, an instance method in compiler generated storey when any hoisted variable exists
1424                         //
1425
1426                         int modifiers;
1427                         if (Block.HasCapturedVariable || Block.HasCapturedThis) {
1428                                 storey = FindBestMethodStorey ();
1429                                 modifiers = storey != null ? Modifiers.INTERNAL : Modifiers.PRIVATE;
1430                         } else {
1431                                 if (ec.CurrentAnonymousMethod != null)
1432                                         storey = ec.CurrentAnonymousMethod.Storey;
1433
1434                                 modifiers = Modifiers.STATIC | Modifiers.PRIVATE;
1435                         }
1436
1437                         TypeContainer parent = storey != null ? storey : ec.CurrentTypeDefinition;
1438
1439                         MemberCore mc = ec.MemberContext as MemberCore;
1440                         string name = CompilerGeneratedClass.MakeName (parent != storey ? block_name : null,
1441                                 "m", null, unique_id++);
1442
1443                         MemberName member_name;
1444                         GenericMethod generic_method;
1445                         if (storey == null && mc.MemberName.TypeArguments != null) {
1446                                 member_name = new MemberName (name, mc.MemberName.TypeArguments.Clone (), Location);
1447
1448                                 generic_method = new GenericMethod (parent.NamespaceEntry, parent, member_name,
1449                                         new TypeExpression (ReturnType, Location), parameters);
1450
1451                                 ArrayList list = new ArrayList ();
1452                                 foreach (TypeParameter tparam in ec.CurrentTypeParameters) {
1453                                         if (tparam.Constraints != null)
1454                                                 list.Add (tparam.Constraints.Clone ());
1455                                 }
1456                                 generic_method.SetParameterInfo (list);
1457                         } else {
1458                                 member_name = new MemberName (name, Location);
1459                                 generic_method = null;
1460                         }
1461
1462                         string real_name = String.Format (
1463                                 "{0}~{1}{2}", mc.GetSignatureForError (), GetSignatureForError (),
1464                                 parameters.GetSignatureForError ());
1465
1466                         return new AnonymousMethodMethod (parent,
1467                                 this, storey, generic_method, new TypeExpression (ReturnType, Location), modifiers,
1468                                 real_name, member_name, parameters);
1469                 }
1470
1471                 public override Expression DoResolve (ResolveContext ec)
1472                 {
1473                         if (eclass == ExprClass.Invalid) {
1474                                 if (!Define (ec))
1475                                         return null;
1476                         }
1477
1478                         eclass = ExprClass.Value;
1479                         return this;
1480                 }
1481
1482                 public override void Emit (EmitContext ec)
1483                 {
1484                         //
1485                         // Use same anonymous method implementation for scenarios where same
1486                         // code is used from multiple blocks, e.g. field initializers
1487                         //
1488                         if (method == null) {
1489                                 //
1490                                 // Delay an anonymous method definition to avoid emitting unused code
1491                                 // for unreachable blocks or expression trees
1492                                 //
1493                                 method = DoCreateMethodHost (ec);
1494                                 method.Define ();
1495                         }
1496
1497                         bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
1498                         if (is_static && am_cache == null) {
1499                                 //
1500                                 // Creates a field cache to store delegate instance if it's not generic
1501                                 //
1502                                 if (!method.MemberName.IsGeneric) {
1503                                         TypeContainer parent = method.Parent.PartialContainer;
1504                                         int id = parent.Fields == null ? 0 : parent.Fields.Count;
1505                                         am_cache = new Field (parent, new TypeExpression (type, loc),
1506                                                 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
1507                                                 new MemberName (CompilerGeneratedClass.MakeName (null, "f", "am$cache", id), loc), null);
1508                                         am_cache.Define ();
1509                                         parent.AddField (am_cache);
1510                                 } else {
1511                                         // TODO: Implement caching of generated generic static methods
1512                                         //
1513                                         // Idea:
1514                                         //
1515                                         // Some extra class is needed to capture variable generic type
1516                                         // arguments. Maybe we could re-use anonymous types, with a unique
1517                                         // anonymous method id, but they are quite heavy.
1518                                         //
1519                                         // Consider : "() => typeof(T);"
1520                                         //
1521                                         // We need something like
1522                                         // static class Wrap<Tn, Tm, DelegateType> {
1523                                         //              public static DelegateType cache;
1524                                         // }
1525                                         //
1526                                         // We then specialize local variable to capture all generic parameters
1527                                         // and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
1528                                         //
1529                                 }
1530                         }
1531
1532                         ILGenerator ig = ec.ig;
1533                         Label l_initialized = ig.DefineLabel ();
1534
1535                         if (am_cache != null) {
1536                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1537                                 ig.Emit (OpCodes.Brtrue_S, l_initialized);
1538                         }
1539
1540                         //
1541                         // Load method delegate implementation
1542                         //
1543
1544                         if (is_static) {
1545                                 ig.Emit (OpCodes.Ldnull);
1546                         } else if (storey != null) {
1547                                 Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (new ResolveContext (ec.MemberContext));
1548                                 if (e != null)
1549                                         e.Emit (ec);
1550                         } else {
1551                                 ig.Emit (OpCodes.Ldarg_0);
1552                         }
1553
1554                         MethodInfo delegate_method = method.MethodBuilder;
1555                         if (storey != null && storey.MemberName.IsGeneric) {
1556                                 Type t = storey.Instance.Type;
1557
1558                                 //
1559                                 // Mutate anonymous method instance type if we are in nested
1560                                 // hoisted generic anonymous method storey
1561                                 //
1562                                 if (ec.CurrentAnonymousMethod != null &&
1563                                         ec.CurrentAnonymousMethod.Storey != null &&
1564                                         ec.CurrentAnonymousMethod.Storey.IsGeneric) {
1565                                         t = storey.GetGenericStorey ().MutateType (t);
1566                                 }
1567
1568 #if GMCS_SOURCE
1569                                 delegate_method = TypeBuilder.GetMethod (t, delegate_method);
1570 #else
1571                                 throw new NotSupportedException ();
1572 #endif
1573                         }
1574
1575                         ig.Emit (OpCodes.Ldftn, delegate_method);
1576
1577                         ConstructorInfo constructor_method = Delegate.GetConstructor (RootContext.ToplevelTypes.Compiler, ec.CurrentType, type);
1578 #if MS_COMPATIBLE
1579             if (type.IsGenericType && type is TypeBuilder)
1580                 constructor_method = TypeBuilder.GetConstructor (type, constructor_method);
1581 #endif
1582                         ig.Emit (OpCodes.Newobj, constructor_method);
1583
1584                         if (am_cache != null) {
1585                                 ig.Emit (OpCodes.Stsfld, am_cache.FieldBuilder);
1586                                 ig.MarkLabel (l_initialized);
1587                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1588                         }
1589                 }
1590
1591                 //
1592                 // Look for the best storey for this anonymous method
1593                 //
1594                 AnonymousMethodStorey FindBestMethodStorey ()
1595                 {
1596                         //
1597                         // Use the nearest parent block which has a storey
1598                         //
1599                         for (Block b = Block.Parent; b != null; b = b.Parent) {
1600                                 AnonymousMethodStorey s = b.Explicit.AnonymousMethodStorey;
1601                                 if (s != null)
1602                                         return s;
1603                         }
1604
1605                         return null;
1606                 }
1607
1608                 public override string GetSignatureForError ()
1609                 {
1610                         return TypeManager.CSharpName (type);
1611                 }
1612
1613                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1614                 {
1615                         type = storey.MutateType (type);
1616                 }
1617
1618                 public static void Reset ()
1619                 {
1620                         unique_id = 0;
1621                 }
1622         }
1623
1624         //
1625         // Anonymous type container
1626         //
1627         public class AnonymousTypeClass : CompilerGeneratedClass
1628         {
1629                 sealed class AnonymousParameters : ParametersCompiled
1630                 {
1631                         public AnonymousParameters (params Parameter[] parameters)
1632                                 : base (parameters)
1633                         {
1634                         }
1635
1636                         protected override void ErrorDuplicateName (Parameter p, Report Report)
1637                         {
1638                                 Report.Error (833, p.Location, "`{0}': An anonymous type cannot have multiple properties with the same name",
1639                                         p.Name);
1640                         }
1641                 }
1642
1643                 static int types_counter;
1644                 public const string ClassNamePrefix = "<>__AnonType";
1645                 public const string SignatureForError = "anonymous type";
1646
1647                 readonly ArrayList parameters;
1648
1649                 private AnonymousTypeClass (DeclSpace parent, MemberName name, ArrayList parameters, Location loc)
1650                         : base (parent, name, (RootContext.EvalMode ? Modifiers.PUBLIC : 0) | Modifiers.SEALED)
1651                 {
1652                         this.parameters = parameters;
1653                 }
1654
1655                 public static AnonymousTypeClass Create (CompilerContext ctx, TypeContainer parent, ArrayList parameters, Location loc)
1656                 {
1657                         string name = ClassNamePrefix + types_counter++;
1658
1659                         SimpleName [] t_args = new SimpleName [parameters.Count];
1660                         TypeParameterName [] t_params = new TypeParameterName [parameters.Count];
1661                         Parameter [] ctor_params = new Parameter [parameters.Count];
1662                         for (int i = 0; i < parameters.Count; ++i) {
1663                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1664
1665                                 t_args [i] = new SimpleName ("<" + p.Name + ">__T", p.Location);
1666                                 t_params [i] = new TypeParameterName (t_args [i].Name, null, p.Location);
1667                                 ctor_params [i] = new Parameter (t_args [i], p.Name, 0, null, p.Location);
1668                         }
1669
1670                         //
1671                         // Create generic anonymous type host with generic arguments
1672                         // named upon properties names
1673                         //
1674                         AnonymousTypeClass a_type = new AnonymousTypeClass (parent.NamespaceEntry.SlaveDeclSpace,
1675                                 new MemberName (name, new TypeArguments (t_params), loc), parameters, loc);
1676
1677                         if (parameters.Count > 0)
1678                                 a_type.SetParameterInfo (null);
1679
1680                         Constructor c = new Constructor (a_type, name, Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
1681                                 null, new AnonymousParameters (ctor_params), null, loc);
1682                         c.Block = new ToplevelBlock (ctx, c.Parameters, loc);
1683
1684                         //
1685                         // Create fields and contructor body with field initialization
1686                         //
1687                         bool error = false;
1688                         for (int i = 0; i < parameters.Count; ++i) {
1689                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1690
1691                                 Field f = new Field (a_type, t_args [i], Modifiers.PRIVATE | Modifiers.READONLY,
1692                                         new MemberName ("<" + p.Name + ">", p.Location), null);
1693
1694                                 if (!a_type.AddField (f)) {
1695                                         error = true;
1696                                         continue;
1697                                 }
1698
1699                                 c.Block.AddStatement (new StatementExpression (
1700                                         new SimpleAssign (new MemberAccess (new This (p.Location), f.Name),
1701                                                 c.Block.GetParameterReference (p.Name, p.Location))));
1702
1703                                 ToplevelBlock get_block = new ToplevelBlock (ctx, p.Location);
1704                                 get_block.AddStatement (new Return (
1705                                         new MemberAccess (new This (p.Location), f.Name), p.Location));
1706                                 Accessor get_accessor = new Accessor (get_block, 0, null, null, p.Location);
1707                                 Property prop = new Property (a_type, t_args [i], Modifiers.PUBLIC,
1708                                         new MemberName (p.Name, p.Location), null, get_accessor, null, false);
1709                                 a_type.AddProperty (prop);
1710                         }
1711
1712                         if (error)
1713                                 return null;
1714
1715                         a_type.AddConstructor (c);
1716                         return a_type;
1717                 }
1718
1719                 public static void Reset ()
1720                 {
1721                         types_counter = 0;
1722                 }
1723
1724                 protected override bool AddToContainer (MemberCore symbol, string name)
1725                 {
1726                         MemberCore mc = (MemberCore) defined_names [name];
1727
1728                         if (mc == null) {
1729                                 defined_names.Add (name, symbol);
1730                                 return true;
1731                         }
1732
1733                         Report.SymbolRelatedToPreviousError (mc);
1734                         return false;
1735                 }
1736
1737                 void DefineOverrides ()
1738                 {
1739                         Location loc = Location;
1740
1741                         Method equals = new Method (this, null, TypeManager.system_boolean_expr,
1742                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("Equals", loc),
1743                                 Mono.CSharp.ParametersCompiled.CreateFullyResolved (new Parameter (null, "obj", 0, null, loc), TypeManager.object_type), null);
1744
1745                         Method tostring = new Method (this, null, TypeManager.system_string_expr,
1746                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("ToString", loc),
1747                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1748
1749                         ToplevelBlock equals_block = new ToplevelBlock (Compiler, equals.Parameters, loc);
1750                         TypeExpr current_type;
1751                         if (IsGeneric)
1752                                 current_type = new GenericTypeExpr (this, loc);
1753                         else
1754                                 current_type = new TypeExpression (TypeBuilder, loc);
1755
1756                         equals_block.AddVariable (current_type, "other", loc);
1757                         LocalVariableReference other_variable = new LocalVariableReference (equals_block, "other", loc);
1758
1759                         MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
1760                                 new QualifiedAliasMember ("global", "System", loc), "Collections", loc), "Generic", loc);
1761
1762                         Expression rs_equals = null;
1763                         Expression string_concat = new StringConstant ("{", loc);
1764                         Expression rs_hashcode = new IntConstant (-2128831035, loc);
1765                         for (int i = 0; i < parameters.Count; ++i) {
1766                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1767                                 Field f = (Field) Fields [i];
1768
1769                                 MemberAccess equality_comparer = new MemberAccess (new MemberAccess (
1770                                         system_collections_generic, "EqualityComparer",
1771                                                 new TypeArguments (new SimpleName (TypeParameters [i].Name, loc)), loc),
1772                                                 "Default", loc);
1773
1774                                 Arguments arguments_equal = new Arguments (2);
1775                                 arguments_equal.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1776                                 arguments_equal.Add (new Argument (new MemberAccess (other_variable, f.Name)));
1777
1778                                 Expression field_equal = new Invocation (new MemberAccess (equality_comparer,
1779                                         "Equals", loc), arguments_equal);
1780
1781                                 Arguments arguments_hashcode = new Arguments (1);
1782                                 arguments_hashcode.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1783                                 Expression field_hashcode = new Invocation (new MemberAccess (equality_comparer,
1784                                         "GetHashCode", loc), arguments_hashcode);
1785
1786                                 IntConstant FNV_prime = new IntConstant (16777619, loc);
1787                                 rs_hashcode = new Binary (Binary.Operator.Multiply,
1788                                         new Binary (Binary.Operator.ExclusiveOr, rs_hashcode, field_hashcode),
1789                                         FNV_prime);
1790
1791                                 Expression field_to_string = new Conditional (new Binary (Binary.Operator.Inequality,
1792                                         new MemberAccess (new This (f.Location), f.Name), new NullLiteral (loc)),
1793                                         new Invocation (new MemberAccess (
1794                                                 new MemberAccess (new This (f.Location), f.Name), "ToString"), null),
1795                                         new StringConstant (string.Empty, loc));
1796
1797                                 if (rs_equals == null) {
1798                                         rs_equals = field_equal;
1799                                         string_concat = new Binary (Binary.Operator.Addition,
1800                                                 string_concat,
1801                                                 new Binary (Binary.Operator.Addition,
1802                                                         new StringConstant (" " + p.Name + " = ", loc),
1803                                                         field_to_string));
1804                                         continue;
1805                                 }
1806
1807                                 //
1808                                 // Implementation of ToString () body using string concatenation
1809                                 //
1810                                 string_concat = new Binary (Binary.Operator.Addition,
1811                                         new Binary (Binary.Operator.Addition,
1812                                                 string_concat,
1813                                                 new StringConstant (", " + p.Name + " = ", loc)),
1814                                         field_to_string);
1815
1816                                 rs_equals = new Binary (Binary.Operator.LogicalAnd, rs_equals, field_equal);
1817                         }
1818
1819                         string_concat = new Binary (Binary.Operator.Addition,
1820                                 string_concat,
1821                                 new StringConstant (" }", loc));
1822
1823                         //
1824                         // Equals (object obj) override
1825                         //
1826                         LocalVariableReference other_variable_assign = new LocalVariableReference (equals_block, "other", loc);
1827                         equals_block.AddStatement (new StatementExpression (
1828                                 new SimpleAssign (other_variable_assign,
1829                                         new As (equals_block.GetParameterReference ("obj", loc),
1830                                                 current_type, loc), loc)));
1831
1832                         Expression equals_test = new Binary (Binary.Operator.Inequality, other_variable, new NullLiteral (loc));
1833                         if (rs_equals != null)
1834                                 equals_test = new Binary (Binary.Operator.LogicalAnd, equals_test, rs_equals);
1835                         equals_block.AddStatement (new Return (equals_test, loc));
1836
1837                         equals.Block = equals_block;
1838                         equals.Define ();
1839                         AddMethod (equals);
1840
1841                         //
1842                         // GetHashCode () override
1843                         //
1844                         Method hashcode = new Method (this, null, TypeManager.system_int32_expr,
1845                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN,
1846                                 new MemberName ("GetHashCode", loc),
1847                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1848
1849                         //
1850                         // Modified FNV with good avalanche behavior and uniform
1851                         // distribution with larger hash sizes.
1852                         //
1853                         // const int FNV_prime = 16777619;
1854                         // int hash = (int) 2166136261;
1855                         // foreach (int d in data)
1856                         //     hash = (hash ^ d) * FNV_prime;
1857                         // hash += hash << 13;
1858                         // hash ^= hash >> 7;
1859                         // hash += hash << 3;
1860                         // hash ^= hash >> 17;
1861                         // hash += hash << 5;
1862
1863                         ToplevelBlock hashcode_top = new ToplevelBlock (Compiler, loc);
1864                         Block hashcode_block = new Block (hashcode_top);
1865                         hashcode_top.AddStatement (new Unchecked (hashcode_block));
1866
1867                         hashcode_block.AddVariable (TypeManager.system_int32_expr, "hash", loc);
1868                         LocalVariableReference hash_variable = new LocalVariableReference (hashcode_block, "hash", loc);
1869                         LocalVariableReference hash_variable_assign = new LocalVariableReference (hashcode_block, "hash", loc);
1870                         hashcode_block.AddStatement (new StatementExpression (
1871                                 new SimpleAssign (hash_variable_assign, rs_hashcode)));
1872
1873                         hashcode_block.AddStatement (new StatementExpression (
1874                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1875                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (13, loc)))));
1876                         hashcode_block.AddStatement (new StatementExpression (
1877                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1878                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (7, loc)))));
1879                         hashcode_block.AddStatement (new StatementExpression (
1880                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1881                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (3, loc)))));
1882                         hashcode_block.AddStatement (new StatementExpression (
1883                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1884                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (17, loc)))));
1885                         hashcode_block.AddStatement (new StatementExpression (
1886                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1887                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (5, loc)))));
1888
1889                         hashcode_block.AddStatement (new Return (hash_variable, loc));
1890                         hashcode.Block = hashcode_top;
1891                         hashcode.Define ();
1892                         AddMethod (hashcode);
1893
1894                         //
1895                         // ToString () override
1896                         //
1897
1898                         ToplevelBlock tostring_block = new ToplevelBlock (Compiler, loc);
1899                         tostring_block.AddStatement (new Return (string_concat, loc));
1900                         tostring.Block = tostring_block;
1901                         tostring.Define ();
1902                         AddMethod (tostring);
1903                 }
1904
1905                 public override bool Define ()
1906                 {
1907                         if (!base.Define ())
1908                                 return false;
1909
1910                         DefineOverrides ();
1911                         return true;
1912                 }
1913
1914                 public override string GetSignatureForError ()
1915                 {
1916                         return SignatureForError;
1917                 }
1918
1919                 public ArrayList Parameters {
1920                         get {
1921                                 return parameters;
1922                         }
1923                 }
1924         }
1925 }