mcs/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.Generic;
  15 using System.Reflection;
  16 using System.Reflection.Emit;
  17
  18 namespace Mono.CSharp {
  19
  20         public abstract class CompilerGeneratedClass : Class
  21         {
  22                 protected CompilerGeneratedClass (DeclSpace parent, MemberName name, Modifiers mod)
  23                         : base (parent.NamespaceEntry, parent, name, mod | Modifiers.COMPILER_GENERATED, null)
  24                 {
  25                 }
  26
  27                 protected void CheckMembersDefined ()
  28                 {
  29                         if (HasMembersDefined)
  30                                 throw new InternalErrorException ("Helper class already defined!");
  31                 }
  32
  33                 protected static MemberName MakeMemberName (MemberBase host, string name, int unique_id, TypeParameter[] tparams, Location loc)
  34                 {
  35                         string host_name = host == null ? null : host.Name;
  36                         string tname = MakeName (host_name, "c", name, unique_id);
  37                         TypeArguments args = null;
  38                         if (tparams != null) {
  39                                 args = new TypeArguments ();
  40                                 foreach (TypeParameter tparam in tparams)
  41                                         args.Add (new TypeParameterName (tparam.Name, null, loc));
  42                         }
  43
  44                         return new MemberName (tname, args, loc);
  45                 }
  46
  47                 public static string MakeName (string host, string typePrefix, string name, int id)
  48                 {
  49                         return "<" + host + ">" + typePrefix + "__" + name + id.ToString ("X");
  50                 }
  51         }
  52
  53         public class HoistedStoreyClass : CompilerGeneratedClass
  54         {
  55                 public sealed class HoistedField : Field
  56                 {
  57                         public HoistedField (HoistedStoreyClass parent, FullNamedExpression type, Modifiers mod, string name,
  58                                   Attributes attrs, Location loc)
  59                                 : base (parent, type, mod, new MemberName (name, loc), attrs)
  60                         {
  61                         }
  62
  63                         protected override bool ResolveMemberType ()
  64                         {
  65                                 if (!base.ResolveMemberType ())
  66                                         return false;
  67
  68                                 HoistedStoreyClass parent = ((HoistedStoreyClass) Parent).GetGenericStorey ();
  69                                 if (parent != null && parent.Mutator != null)
  70                                         member_type = parent.Mutator.Mutate (MemberType);
  71
  72                                 return true;
  73                         }
  74                 }
  75
  76                 protected TypeParameterMutator mutator;
  77
  78                 public HoistedStoreyClass (DeclSpace parent, MemberName name, TypeParameter[] tparams, Modifiers mod)
  79                         : base (parent, name, mod | Modifiers.PRIVATE)
  80                 {
  81                         if (tparams != null) {
  82                                 type_params = new TypeParameter[tparams.Length];
  83                                 for (int i = 0; i < type_params.Length; ++i) {
  84                                         type_params[i] = tparams[i].CreateHoistedCopy (this, spec);
  85                                 }
  86                         }
  87                 }
  88
  89                 #region Properties
  90
  91                 public TypeParameterMutator Mutator {
  92                         get {
  93                                 return mutator;
  94                         }
  95                         set {
  96                                 mutator = value;
  97                         }
  98                 }
  99
 100                 #endregion
 101
 102                 public HoistedStoreyClass GetGenericStorey ()
 103                 {
 104                         DeclSpace storey = this;
 105                         while (storey != null && storey.CurrentTypeParameters == null)
 106                                 storey = storey.Parent;
 107
 108                         return storey as HoistedStoreyClass;
 109                 }
 110         }
 111
 112
 113         //
 114         // Anonymous method storey is created when an anonymous method uses
 115         // variable or parameter from outer scope. They are then hoisted to
 116         // anonymous method storey (captured)
 117         //
 118         public class AnonymousMethodStorey : HoistedStoreyClass
 119         {
 120                 struct StoreyFieldPair
 121                 {
 122                         public readonly AnonymousMethodStorey Storey;
 123                         public readonly Field Field;
 124
 125                         public StoreyFieldPair (AnonymousMethodStorey storey, Field field)
 126                         {
 127                                 this.Storey = storey;
 128                                 this.Field = field;
 129                         }
 130                 }
 131
 132                 //
 133                 // Needed to delay hoisted _this_ initialization. When an anonymous
 134                 // method is used inside ctor and _this_ is hoisted, base ctor has to
 135                 // be called first, otherwise _this_ will be initialized with
 136                 // uninitialized value.
 137                 //
 138                 sealed class ThisInitializer : Statement
 139                 {
 140                         readonly HoistedThis hoisted_this;
 141
 142                         public ThisInitializer (HoistedThis hoisted_this)
 143                         {
 144                                 this.hoisted_this = hoisted_this;
 145                         }
 146
 147                         protected override void DoEmit (EmitContext ec)
 148                         {
 149                                 hoisted_this.EmitHoistingAssignment (ec);
 150                         }
 151
 152                         protected override void CloneTo (CloneContext clonectx, Statement target)
 153                         {
 154                                 // Nothing to clone
 155                         }
 156                 }
 157
 158                 // Unique storey ID
 159                 public readonly int ID;
 160                 static int unique_id;
 161
 162                 public readonly Block OriginalSourceBlock;
 163
 164                 // A list of StoreyFieldPair with local field keeping parent storey instance
 165                 List<StoreyFieldPair> used_parent_storeys;
 166                 List<ExplicitBlock> children_references;
 167
 168                 // A list of hoisted parameters
 169                 protected List<HoistedParameter> hoisted_params;
 170                 protected List<HoistedVariable> hoisted_locals;
 171
 172                 // Hoisted this
 173                 protected HoistedThis hoisted_this;
 174
 175                 // Local variable which holds this storey instance
 176                 public LocalTemporary Instance;
 177
 178                 public AnonymousMethodStorey (Block block, TypeContainer parent, MemberBase host, TypeParameter[] tparams, string name)
 179                         : base (parent, MakeMemberName (host, name, unique_id, tparams, block.StartLocation),
 180                                 tparams, Modifiers.SEALED)
 181                 {
 182                         Parent = parent;
 183                         OriginalSourceBlock = block;
 184                         ID = unique_id++;
 185                 }
 186
 187                 public void AddCapturedThisField (EmitContext ec)
 188                 {
 189                         TypeExpr type_expr = new TypeExpression (ec.CurrentType, Location);
 190                         Field f = AddCompilerGeneratedField ("<>f__this", type_expr);
 191                         f.Define ();
 192                         hoisted_this = new HoistedThis (this, f);
 193
 194                         // Inflated type instance has to be updated manually
 195                         if (Instance.Type is InflatedTypeSpec) {
 196                                 var inflator = new TypeParameterInflator (Instance.Type, TypeParameterSpec.EmptyTypes, TypeSpec.EmptyTypes);
 197                                 Instance.Type.MemberCache.AddMember (f.Spec.InflateMember (inflator));
 198
 199                                 inflator = new TypeParameterInflator (f.Parent.CurrentType, TypeParameterSpec.EmptyTypes, TypeSpec.EmptyTypes);
 200                                 f.Parent.CurrentType.MemberCache.AddMember (f.Spec.InflateMember (inflator));
 201                         }
 202                 }
 203
 204                 public Field AddCapturedVariable (string name, TypeSpec type)
 205                 {
 206                         CheckMembersDefined ();
 207
 208                         FullNamedExpression field_type = new TypeExpression (type, Location);
 209                         if (!IsGeneric)
 210                                 return AddCompilerGeneratedField (name, field_type);
 211
 212                         const Modifiers mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 213                         Field f = new HoistedField (this, field_type, mod, name, null, Location);
 214                         AddField (f);
 215                         return f;
 216                 }
 217
 218                 protected Field AddCompilerGeneratedField (string name, FullNamedExpression type)
 219                 {
 220                         const Modifiers mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 221                         Field f = new Field (this, type, mod, new MemberName (name, Location), null);
 222                         AddField (f);
 223                         return f;
 224                 }
 225
 226                 //
 227                 // Creates a link between hoisted variable block and the anonymous method storey
 228                 //
 229                 // An anonymous method can reference variables from any outer block, but they are
 230                 // hoisted in their own ExplicitBlock. When more than one block is referenced we
 231                 // need to create another link between those variable storeys
 232                 //
 233                 public void AddReferenceFromChildrenBlock (ExplicitBlock block)
 234                 {
 235                         if (children_references == null)
 236                                 children_references = new List<ExplicitBlock> ();
 237
 238                         if (!children_references.Contains (block))
 239                                 children_references.Add (block);
 240                 }
 241
 242                 public void AddParentStoreyReference (EmitContext ec, AnonymousMethodStorey storey)
 243                 {
 244                         CheckMembersDefined ();
 245
 246                         if (used_parent_storeys == null)
 247                                 used_parent_storeys = new List<StoreyFieldPair> ();
 248                         else if (used_parent_storeys.Exists (i => i.Storey == storey))
 249                                 return;
 250
 251                         TypeExpr type_expr = storey.CreateStoreyTypeExpression (ec);
 252                         Field f = AddCompilerGeneratedField ("<>f__ref$" + storey.ID, type_expr);
 253                         used_parent_storeys.Add (new StoreyFieldPair (storey, f));
 254                 }
 255
 256                 public void CaptureLocalVariable (ResolveContext ec, LocalVariable local_info)
 257                 {
 258                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 259                         if (ec.CurrentBlock.Explicit != local_info.Block.Explicit)
 260                                 AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 261
 262                         if (local_info.HoistedVariant != null)
 263                                 return;
 264
 265                         HoistedVariable var = new HoistedLocalVariable (this, local_info, GetVariableMangledName (local_info));
 266                         local_info.HoistedVariant = var;
 267
 268                         if (hoisted_locals == null)
 269                                 hoisted_locals = new List<HoistedVariable> ();
 270
 271                         hoisted_locals.Add (var);
 272                 }
 273
 274                 public void CaptureParameter (ResolveContext ec, ParameterReference param_ref)
 275                 {
 276                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 277                         AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 278
 279                         if (param_ref.GetHoistedVariable (ec) != null)
 280                                 return;
 281
 282                         if (hoisted_params == null)
 283                                 hoisted_params = new List<HoistedParameter> (2);
 284
 285                         var expr = new HoistedParameter (this, param_ref);
 286                         param_ref.Parameter.HoistedVariant = expr;
 287                         hoisted_params.Add (expr);
 288                 }
 289
 290                 TypeExpr CreateStoreyTypeExpression (EmitContext ec)
 291                 {
 292                         //
 293                         // Create an instance of storey type
 294                         //
 295                         TypeExpr storey_type_expr;
 296                         if (CurrentTypeParameters != null) {
 297                                 //
 298                                 // Use current method type parameter (MVAR) for top level storey only. All
 299                                 // nested storeys use class type parameter (VAR)
 300                                 //
 301                                 TypeParameter[] tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
 302                                         ec.CurrentAnonymousMethod.Storey.TypeParameters :
 303                                         ec.CurrentTypeParameters;
 304
 305                                 TypeArguments targs = new TypeArguments ();
 306
 307                                 //
 308                                 // Use type parameter name instead of resolved type parameter
 309                                 // specification to resolve to correctly nested type parameters
 310                                 //
 311                                 for (int i = 0; i < tparams.Length; ++i)
 312                                         targs.Add (new SimpleName (tparams [i].Name, Location)); //  new TypeParameterExpr (tparams[i], Location));
 313
 314                                 storey_type_expr = new GenericTypeExpr (Definition, targs, Location);
 315                         } else {
 316                                 storey_type_expr = new TypeExpression (CurrentType, Location);
 317                         }
 318
 319                         return storey_type_expr;
 320                 }
 321
 322                 public void SetNestedStoryParent (AnonymousMethodStorey parentStorey)
 323                 {
 324                         Parent = parentStorey;
 325                         type_params = null;
 326                         spec.IsGeneric = false;
 327                         spec.DeclaringType = parentStorey.CurrentType;
 328                         MemberName.TypeArguments = null;
 329                 }
 330
 331                 protected override bool DoResolveTypeParameters ()
 332                 {
 333                         // Although any storey can have type parameters they are all clones of method type
 334                         // parameters therefore have to mutate MVAR references in any of cloned constraints
 335                         if (type_params != null) {
 336                                 for (int i = 0; i < type_params.Length; ++i) {
 337                                         var spec = type_params[i].Type;
 338                                         spec.BaseType = mutator.Mutate (spec.BaseType);
 339                                         if (spec.InterfacesDefined != null) {
 340                                                 var mutated = new TypeSpec[spec.InterfacesDefined.Length];
 341                                                 for (int ii = 0; ii < mutated.Length; ++ii) {
 342                                                         mutated[ii] = mutator.Mutate (spec.InterfacesDefined[ii]);
 343                                                 }
 344
 345                                                 spec.InterfacesDefined = mutated;
 346                                         }
 347
 348                                         if (spec.TypeArguments != null) {
 349                                                 spec.TypeArguments = mutator.Mutate (spec.TypeArguments);
 350                                         }
 351                                 }
 352                         }
 353
 354                         return true;
 355                 }
 356
 357                 //
 358                 // Initializes all hoisted variables
 359                 //
 360                 public void EmitStoreyInstantiation (EmitContext ec, ExplicitBlock block)
 361                 {
 362                         // There can be only one instance variable for each storey type
 363                         if (Instance != null)
 364                                 throw new InternalErrorException ();
 365
 366                         SymbolWriter.OpenCompilerGeneratedBlock (ec);
 367
 368                         //
 369                         // Create an instance of a storey
 370                         //
 371                         var storey_type_expr = CreateStoreyTypeExpression (ec);
 372
 373                         ResolveContext rc = new ResolveContext (ec.MemberContext);
 374                         rc.CurrentBlock = block;
 375                         Expression e = new New (storey_type_expr, null, Location).Resolve (rc);
 376                         e.Emit (ec);
 377
 378                         Instance = new LocalTemporary (storey_type_expr.Type);
 379                         Instance.Store (ec);
 380
 381                         EmitHoistedFieldsInitialization (rc, ec);
 382
 383                         SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
 384                         SymbolWriter.CloseCompilerGeneratedBlock (ec);
 385                 }
 386
 387                 void EmitHoistedFieldsInitialization (ResolveContext rc, EmitContext ec)
 388                 {
 389                         //
 390                         // Initialize all storey reference fields by using local or hoisted variables
 391                         //
 392                         if (used_parent_storeys != null) {
 393                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 394                                         //
 395                                         // Get instance expression of storey field
 396                                         //
 397                                         Expression instace_expr = GetStoreyInstanceExpression (ec);
 398                                         var fs = sf.Field.Spec;
 399                                         if (TypeManager.IsGenericType (instace_expr.Type))
 400                                                 fs = MemberCache.GetMember (instace_expr.Type, fs);
 401
 402                                         FieldExpr f_set_expr = new FieldExpr (fs, Location);
 403                                         f_set_expr.InstanceExpression = instace_expr;
 404
 405                                         SimpleAssign a = new SimpleAssign (f_set_expr, sf.Storey.GetStoreyInstanceExpression (ec));
 406                                         if (a.Resolve (rc) != null)
 407                                                 a.EmitStatement (ec);
 408                                 }
 409                         }
 410
 411                         //
 412                         // Define hoisted `this' in top-level storey only
 413                         //
 414                         if (OriginalSourceBlock.Explicit.HasCapturedThis && !(Parent is AnonymousMethodStorey)) {
 415                                 AddCapturedThisField (ec);
 416                                 rc.CurrentBlock.AddScopeStatement (new ThisInitializer (hoisted_this));
 417                         }
 418
 419                         //
 420                         // Setting currect anonymous method to null blocks any further variable hoisting
 421                         //
 422                         AnonymousExpression ae = ec.CurrentAnonymousMethod;
 423                         ec.CurrentAnonymousMethod = null;
 424
 425                         if (hoisted_params != null) {
 426                                 EmitHoistedParameters (ec, hoisted_params);
 427                         }
 428
 429                         ec.CurrentAnonymousMethod = ae;
 430                 }
 431
 432                 protected virtual void EmitHoistedParameters (EmitContext ec, IList<HoistedParameter> hoisted)
 433                 {
 434                         foreach (HoistedParameter hp in hoisted) {
 435                                 hp.EmitHoistingAssignment (ec);
 436                         }
 437                 }
 438
 439                 public override void EmitType ()
 440                 {
 441                         SymbolWriter.DefineAnonymousScope (ID);
 442
 443                         if (hoisted_this != null)
 444                                 hoisted_this.EmitSymbolInfo ();
 445
 446                         if (hoisted_locals != null) {
 447                                 foreach (HoistedVariable local in hoisted_locals)
 448                                         local.EmitSymbolInfo ();
 449                         }
 450
 451                         if (hoisted_params != null) {
 452                                 foreach (HoistedParameter param in hoisted_params)
 453                                         param.EmitSymbolInfo ();
 454                         }
 455
 456                         if (used_parent_storeys != null) {
 457                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 458                                         SymbolWriter.DefineCapturedScope (ID, sf.Storey.ID, sf.Field.Name);
 459                                 }
 460                         }
 461
 462                         base.EmitType ();
 463                 }
 464
 465                 //
 466                 // Returns a field which holds referenced storey instance
 467                 //
 468                 Field GetReferencedStoreyField (AnonymousMethodStorey storey)
 469                 {
 470                         if (used_parent_storeys == null)
 471                                 return null;
 472
 473                         foreach (StoreyFieldPair sf in used_parent_storeys) {
 474                                 if (sf.Storey == storey)
 475                                         return sf.Field;
 476                         }
 477
 478                         return null;
 479                 }
 480
 481                 //
 482                 // Creates storey instance expression regardless of currect IP
 483                 //
 484                 public Expression GetStoreyInstanceExpression (EmitContext ec)
 485                 {
 486                         AnonymousExpression am = ec.CurrentAnonymousMethod;
 487
 488                         //
 489                         // Access from original block -> storey
 490                         //
 491                         if (am == null)
 492                                 return Instance;
 493
 494                         //
 495                         // Access from anonymous method implemented as a static -> storey
 496                         //
 497                         if (am.Storey == null)
 498                                 return Instance;
 499
 500                         Field f = am.Storey.GetReferencedStoreyField (this);
 501                         if (f == null) {
 502                                 if (am.Storey == this) {
 503                                         //
 504                                         // Access inside of same storey (S -> S)
 505                                         //
 506                                         return new CompilerGeneratedThis (CurrentType, Location);
 507                                 }
 508                                 //
 509                                 // External field access
 510                                 //
 511                                 return Instance;
 512                         }
 513
 514                         //
 515                         // Storey was cached to local field
 516                         //
 517                         FieldExpr f_ind = new FieldExpr (f, Location);
 518                         f_ind.InstanceExpression = new CompilerGeneratedThis (CurrentType, Location);
 519                         return f_ind;
 520                 }
 521
 522                 protected virtual string GetVariableMangledName (LocalVariable local_info)
 523                 {
 524                         //
 525                         // No need to mangle anonymous method hoisted variables cause they
 526                         // are hoisted in their own scopes
 527                         //
 528                         return local_info.Name;
 529                 }
 530
 531                 public HoistedThis HoistedThis {
 532                         get { return hoisted_this; }
 533                 }
 534
 535                 public IList<ExplicitBlock> ReferencesFromChildrenBlock {
 536                         get { return children_references; }
 537                 }
 538
 539                 public static void Reset ()
 540                 {
 541                         unique_id = 0;
 542                 }
 543         }
 544
 545         public abstract class HoistedVariable
 546         {
 547                 //
 548                 // Hoisted version of variable references used in expression
 549                 // tree has to be delayed until we know its location. The variable
 550                 // doesn't know its location until all stories are calculated
 551                 //
 552                 class ExpressionTreeVariableReference : Expression
 553                 {
 554                         readonly HoistedVariable hv;
 555
 556                         public ExpressionTreeVariableReference (HoistedVariable hv)
 557                         {
 558                                 this.hv = hv;
 559                         }
 560
 561                         public override Expression CreateExpressionTree (ResolveContext ec)
 562                         {
 563                                 throw new NotSupportedException ("ET");
 564                         }
 565
 566                         protected override Expression DoResolve (ResolveContext ec)
 567                         {
 568                                 eclass = ExprClass.Value;
 569                                 type = TypeManager.expression_type_expr.Type;
 570                                 return this;
 571                         }
 572
 573                         public override void Emit (EmitContext ec)
 574                         {
 575                                 ResolveContext rc = new ResolveContext (ec.MemberContext);
 576                                 Expression e = hv.GetFieldExpression (ec).CreateExpressionTree (rc);
 577                                 // This should never fail
 578                                 e = e.Resolve (rc);
 579                                 if (e != null)
 580                                         e.Emit (ec);
 581                         }
 582                 }
 583
 584                 protected readonly AnonymousMethodStorey storey;
 585                 protected Field field;
 586                 Dictionary<AnonymousExpression, FieldExpr> cached_inner_access; // TODO: Hashtable is too heavyweight
 587                 FieldExpr cached_outer_access;
 588
 589                 protected HoistedVariable (AnonymousMethodStorey storey, string name, TypeSpec type)
 590                         : this (storey, storey.AddCapturedVariable (name, type))
 591                 {
 592                 }
 593
 594                 protected HoistedVariable (AnonymousMethodStorey storey, Field field)
 595                 {
 596                         this.storey = storey;
 597                         this.field = field;
 598                 }
 599
 600                 public void AddressOf (EmitContext ec, AddressOp mode)
 601                 {
 602                         GetFieldExpression (ec).AddressOf (ec, mode);
 603                 }
 604
 605                 public Expression CreateExpressionTree ()
 606                 {
 607                         return new ExpressionTreeVariableReference (this);
 608                 }
 609
 610                 public void Emit (EmitContext ec)
 611                 {
 612                         GetFieldExpression (ec).Emit (ec);
 613                 }
 614
 615                 //
 616                 // Creates field access expression for hoisted variable
 617                 //
 618                 protected virtual FieldExpr GetFieldExpression (EmitContext ec)
 619                 {
 620                         if (ec.CurrentAnonymousMethod == null || ec.CurrentAnonymousMethod.Storey == null) {
 621                                 if (cached_outer_access != null)
 622                                         return cached_outer_access;
 623
 624                                 //
 625                                 // When setting top-level hoisted variable in generic storey
 626                                 // change storey generic types to method generic types (VAR -> MVAR)
 627                                 //
 628                                 if (storey.Instance.Type.IsGenericOrParentIsGeneric) {
 629                                         var fs = MemberCache.GetMember (storey.Instance.Type, field.Spec);
 630                                         cached_outer_access = new FieldExpr (fs, field.Location);
 631                                 } else {
 632                                         cached_outer_access = new FieldExpr (field, field.Location);
 633                                 }
 634
 635                                 cached_outer_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 636                                 return cached_outer_access;
 637                         }
 638
 639                         FieldExpr inner_access;
 640                         if (cached_inner_access != null) {
 641                                 if (!cached_inner_access.TryGetValue (ec.CurrentAnonymousMethod, out inner_access))
 642                                         inner_access = null;
 643                         } else {
 644                                 inner_access = null;
 645                                 cached_inner_access = new Dictionary<AnonymousExpression, FieldExpr> (4);
 646                         }
 647
 648                         if (inner_access == null) {
 649                                 if (field.Parent.IsGeneric) {
 650                                         var fs = MemberCache.GetMember (field.Parent.CurrentType, field.Spec);
 651                                         inner_access = new FieldExpr (fs, field.Location);
 652                                 } else {
 653                                         inner_access = new FieldExpr (field, field.Location);
 654                                 }
 655
 656                                 inner_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 657                                 cached_inner_access.Add (ec.CurrentAnonymousMethod, inner_access);
 658                         }
 659
 660                         return inner_access;
 661                 }
 662
 663                 public abstract void EmitSymbolInfo ();
 664
 665                 public void Emit (EmitContext ec, bool leave_copy)
 666                 {
 667                         GetFieldExpression (ec).Emit (ec, leave_copy);
 668                 }
 669
 670                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 671                 {
 672                         GetFieldExpression (ec).EmitAssign (ec, source, leave_copy, false);
 673                 }
 674         }
 675
 676         public class HoistedParameter : HoistedVariable
 677         {
 678                 sealed class HoistedFieldAssign : Assign
 679                 {
 680                         public HoistedFieldAssign (Expression target, Expression source)
 681                                 : base (target, source, source.Location)
 682                         {
 683                         }
 684
 685                         protected override Expression ResolveConversions (ResolveContext ec)
 686                         {
 687                                 //
 688                                 // Implicit conversion check fails for hoisted type arguments
 689                                 // as they are of different types (!!0 x !0)
 690                                 //
 691                                 return this;
 692                         }
 693                 }
 694
 695                 readonly ParameterReference parameter;
 696
 697                 public HoistedParameter (AnonymousMethodStorey scope, ParameterReference par)
 698                         : base (scope, par.Name, par.Type)
 699                 {
 700                         this.parameter = par;
 701                 }
 702
 703                 public HoistedParameter (HoistedParameter hp, string name)
 704                         : base (hp.storey, name, hp.parameter.Type)
 705                 {
 706                         this.parameter = hp.parameter;
 707                 }
 708
 709                 public void EmitHoistingAssignment (EmitContext ec)
 710                 {
 711                         //
 712                         // Remove hoisted redirection to emit assignment from original parameter
 713                         //
 714                         HoistedVariable temp = parameter.Parameter.HoistedVariant;
 715                         parameter.Parameter.HoistedVariant = null;
 716
 717                         Assign a = new HoistedFieldAssign (GetFieldExpression (ec), parameter);
 718                         if (a.Resolve (new ResolveContext (ec.MemberContext)) != null)
 719                                 a.EmitStatement (ec);
 720
 721                         parameter.Parameter.HoistedVariant = temp;
 722                 }
 723
 724                 public override void EmitSymbolInfo ()
 725                 {
 726                         SymbolWriter.DefineCapturedParameter (storey.ID, field.Name, field.Name);
 727                 }
 728
 729                 public Field Field {
 730                         get { return field; }
 731                 }
 732         }
 733
 734         class HoistedLocalVariable : HoistedVariable
 735         {
 736                 readonly string name;
 737
 738                 public HoistedLocalVariable (AnonymousMethodStorey scope, LocalVariable local, string name)
 739                         : base (scope, name, local.Type)
 740                 {
 741                         this.name = local.Name;
 742                 }
 743
 744                 public override void EmitSymbolInfo ()
 745                 {
 746                         SymbolWriter.DefineCapturedLocal (storey.ID, name, field.Name);
 747                 }
 748         }
 749
 750         public class HoistedThis : HoistedVariable
 751         {
 752                 public HoistedThis (AnonymousMethodStorey storey, Field field)
 753                         : base (storey, field)
 754                 {
 755                 }
 756
 757                 public void EmitHoistingAssignment (EmitContext ec)
 758                 {
 759                         SimpleAssign a = new SimpleAssign (GetFieldExpression (ec), new CompilerGeneratedThis (ec.CurrentType, field.Location));
 760                         if (a.Resolve (new ResolveContext (ec.MemberContext)) != null)
 761                                 a.EmitStatement (ec);
 762                 }
 763
 764                 public override void EmitSymbolInfo ()
 765                 {
 766                         SymbolWriter.DefineCapturedThis (storey.ID, field.Name);
 767                 }
 768
 769                 public Field Field {
 770                         get { return field; }
 771                 }
 772         }
 773
 774         //
 775         // Anonymous method expression as created by parser
 776         //
 777         public class AnonymousMethodExpression : Expression
 778         {
 779                 //
 780                 // Special conversion for nested expression tree lambdas
 781                 //
 782                 class Quote : ShimExpression
 783                 {
 784                         public Quote (Expression expr)
 785                                 : base (expr)
 786                         {
 787                         }
 788
 789                         public override Expression CreateExpressionTree (ResolveContext ec)
 790                         {
 791                                 var args = new Arguments (1);
 792                                 args.Add (new Argument (expr.CreateExpressionTree (ec)));
 793                                 return CreateExpressionFactoryCall (ec, "Quote", args);
 794                         }
 795
 796                         protected override Expression DoResolve (ResolveContext rc)
 797                         {
 798                                 expr = expr.Resolve (rc);
 799                                 if (expr == null)
 800                                         return null;
 801
 802                                 eclass = expr.eclass;
 803                                 type = expr.Type;
 804                                 return this;
 805                         }
 806                 }
 807
 808                 Dictionary<TypeSpec, Expression> compatibles;
 809                 public ParametersBlock Block;
 810
 811                 public AnonymousMethodExpression (Location loc)
 812                 {
 813                         this.loc = loc;
 814                         this.compatibles = new Dictionary<TypeSpec, Expression> ();
 815                 }
 816
 817                 public override string ExprClassName {
 818                         get {
 819                                 return "anonymous method";
 820                         }
 821                 }
 822
 823                 public virtual bool HasExplicitParameters {
 824                         get {
 825                                 return Parameters != ParametersCompiled.Undefined;
 826                         }
 827                 }
 828
 829                 public ParametersCompiled Parameters {
 830                         get { return Block.Parameters; }
 831                 }
 832
 833                 //
 834                 // Returns true if the body of lambda expression can be implicitly
 835                 // converted to the delegate of type `delegate_type'
 836                 //
 837                 public bool ImplicitStandardConversionExists (ResolveContext ec, TypeSpec delegate_type)
 838                 {
 839                         using (ec.With (ResolveContext.Options.InferReturnType, false)) {
 840                                 using (ec.Set (ResolveContext.Options.ProbingMode)) {
 841                                         return Compatible (ec, delegate_type) != null;
 842                                 }
 843                         }
 844                 }
 845
 846                 TypeSpec CompatibleChecks (ResolveContext ec, TypeSpec delegate_type)
 847                 {
 848                         if (delegate_type.IsDelegate)
 849                                 return delegate_type;
 850
 851                         if (delegate_type.IsGeneric && delegate_type.GetDefinition () == TypeManager.expression_type) {
 852                                 delegate_type = delegate_type.TypeArguments [0];
 853                                 if (delegate_type.IsDelegate)
 854                                         return delegate_type;
 855
 856                                 ec.Report.Error (835, loc, "Cannot convert `{0}' to an expression tree of non-delegate type `{1}'",
 857                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 858                                 return null;
 859                         }
 860
 861                         ec.Report.Error (1660, loc, "Cannot convert `{0}' to non-delegate type `{1}'",
 862                                       GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 863                         return null;
 864                 }
 865
 866                 protected bool VerifyExplicitParameters (ResolveContext ec, TypeSpec delegate_type, AParametersCollection parameters)
 867                 {
 868                         if (VerifyParameterCompatibility (ec, delegate_type, parameters, ec.IsInProbingMode))
 869                                 return true;
 870
 871                         if (!ec.IsInProbingMode)
 872                                 ec.Report.Error (1661, loc,
 873                                         "Cannot convert `{0}' to delegate type `{1}' since there is a parameter mismatch",
 874                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 875
 876                         return false;
 877                 }
 878
 879                 protected bool VerifyParameterCompatibility (ResolveContext ec, TypeSpec delegate_type, AParametersCollection invoke_pd, bool ignore_errors)
 880                 {
 881                         if (Parameters.Count != invoke_pd.Count) {
 882                                 if (ignore_errors)
 883                                         return false;
 884
 885                                 ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 886                                               TypeManager.CSharpName (delegate_type), Parameters.Count.ToString ());
 887                                 return false;
 888                         }
 889
 890                         bool has_implicit_parameters = !HasExplicitParameters;
 891                         bool error = false;
 892
 893                         for (int i = 0; i < Parameters.Count; ++i) {
 894                                 Parameter.Modifier p_mod = invoke_pd.FixedParameters [i].ModFlags;
 895                                 if (Parameters.FixedParameters [i].ModFlags != p_mod && p_mod != Parameter.Modifier.PARAMS) {
 896                                         if (ignore_errors)
 897                                                 return false;
 898
 899                                         if (p_mod == Parameter.Modifier.NONE)
 900                                                 ec.Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 901                                                               (i + 1).ToString (), Parameter.GetModifierSignature (Parameters.FixedParameters [i].ModFlags));
 902                                         else
 903                                                 ec.Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 904                                                               (i+1).ToString (), Parameter.GetModifierSignature (p_mod));
 905                                         error = true;
 906                                 }
 907
 908                                 if (has_implicit_parameters)
 909                                         continue;
 910
 911                                 TypeSpec type = invoke_pd.Types [i];
 912
 913                                 // We assume that generic parameters are always inflated
 914                                 if (TypeManager.IsGenericParameter (type))
 915                                         continue;
 916
 917                                 if (TypeManager.HasElementType (type) && TypeManager.IsGenericParameter (TypeManager.GetElementType (type)))
 918                                         continue;
 919
 920                                 if (!TypeSpecComparer.IsEqual (invoke_pd.Types [i], Parameters.Types [i])) {
 921                                         if (ignore_errors)
 922                                                 return false;
 923
 924                                         ec.Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 925                                                       (i+1).ToString (),
 926                                                       TypeManager.CSharpName (Parameters.Types [i]),
 927                                                       TypeManager.CSharpName (invoke_pd.Types [i]));
 928                                         error = true;
 929                                 }
 930                         }
 931
 932                         return !error;
 933                 }
 934
 935                 //
 936                 // Infers type arguments based on explicit arguments
 937                 //
 938                 public bool ExplicitTypeInference (ResolveContext ec, TypeInferenceContext type_inference, TypeSpec delegate_type)
 939                 {
 940                         if (!HasExplicitParameters)
 941                                 return false;
 942
 943                         if (!delegate_type.IsDelegate) {
 944                                 if (delegate_type.GetDefinition () != TypeManager.expression_type)
 945                                         return false;
 946
 947                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 948                                 if (!delegate_type.IsDelegate)
 949                                         return false;
 950                         }
 951
 952                         AParametersCollection d_params = Delegate.GetParameters (ec.Compiler, delegate_type);
 953                         if (d_params.Count != Parameters.Count)
 954                                 return false;
 955
 956                         for (int i = 0; i < Parameters.Count; ++i) {
 957                                 TypeSpec itype = d_params.Types [i];
 958                                 if (!TypeManager.IsGenericParameter (itype)) {
 959                                         if (!TypeManager.HasElementType (itype))
 960                                                 continue;
 961
 962                                         if (!TypeManager.IsGenericParameter (TypeManager.GetElementType (itype)))
 963                                             continue;
 964                                 }
 965                                 type_inference.ExactInference (Parameters.Types [i], itype);
 966                         }
 967                         return true;
 968                 }
 969
 970                 public TypeSpec InferReturnType (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type)
 971                 {
 972                         Expression expr;
 973                         AnonymousExpression am;
 974
 975                         if (compatibles.TryGetValue (delegate_type, out expr)) {
 976                                 am = expr as AnonymousExpression;
 977                                 return am == null ? null : am.ReturnType;
 978                         }
 979
 980                         using (ec.Set (ResolveContext.Options.ProbingMode | ResolveContext.Options.InferReturnType)) {
 981                                 am = CompatibleMethodBody (ec, tic, InternalType.Arglist, delegate_type);
 982                                 if (am != null)
 983                                         am = am.Compatible (ec);
 984                         }
 985
 986                         if (am == null)
 987                                 return null;
 988
 989 //                      compatibles.Add (delegate_type, am);
 990                         return am.ReturnType;
 991                 }
 992
 993                 //
 994                 // Returns AnonymousMethod container if this anonymous method
 995                 // expression can be implicitly converted to the delegate type `delegate_type'
 996                 //
 997                 public Expression Compatible (ResolveContext ec, TypeSpec type)
 998                 {
 999                         Expression am;
1000                         if (compatibles.TryGetValue (type, out am))
1001                                 return am;
1002
1003                         TypeSpec delegate_type = CompatibleChecks (ec, type);
1004                         if (delegate_type == null)
1005                                 return null;
1006
1007                         //
1008                         // At this point its the first time we know the return type that is
1009                         // needed for the anonymous method.  We create the method here.
1010                         //
1011
1012                         var invoke_mb = Delegate.GetInvokeMethod (ec.Compiler, delegate_type);
1013                         TypeSpec return_type = invoke_mb.ReturnType;
1014
1015                         //
1016                         // Second: the return type of the delegate must be compatible with
1017                         // the anonymous type.   Instead of doing a pass to examine the block
1018                         // we satisfy the rule by setting the return type on the EmitContext
1019                         // to be the delegate type return type.
1020                         //
1021
1022                         var body = CompatibleMethodBody (ec, null, return_type, delegate_type);
1023                         if (body == null)
1024                                 return null;
1025
1026                         bool etree_conversion = delegate_type != type;
1027
1028                         try {
1029                                 if (etree_conversion) {
1030                                         if (ec.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
1031                                                 //
1032                                                 // Nested expression tree lambda use same scope as parent
1033                                                 // lambda, this also means no variable capturing between this
1034                                                 // and parent scope
1035                                                 //
1036                                                 am = body.Compatible (ec, ec.CurrentAnonymousMethod);
1037
1038                                                 //
1039                                                 // Quote nested expression tree
1040                                                 //
1041                                                 if (am != null)
1042                                                         am = new Quote (am);
1043                                         } else {
1044                                                 int errors = ec.Report.Errors;
1045
1046                                                 using (ec.Set (ResolveContext.Options.ExpressionTreeConversion)) {
1047                                                         am = body.Compatible (ec);
1048                                                 }
1049
1050                                                 //
1051                                                 // Rewrite expressions into expression tree when targeting Expression<T>
1052                                                 //
1053                                                 if (am != null && errors == ec.Report.Errors)
1054                                                         am = CreateExpressionTree (ec, delegate_type);
1055                                         }
1056                                 } else {
1057                                         am = body.Compatible (ec);
1058                                 }
1059                         } catch (CompletionResult) {
1060                                 throw;
1061                         } catch (Exception e) {
1062                                 throw new InternalErrorException (e, loc);
1063                         }
1064
1065                         if (!ec.IsInProbingMode) {
1066                                 compatibles.Add (type, am ?? EmptyExpression.Null);
1067                         }
1068
1069                         return am;
1070                 }
1071
1072                 protected virtual Expression CreateExpressionTree (ResolveContext ec, TypeSpec delegate_type)
1073                 {
1074                         return CreateExpressionTree (ec);
1075                 }
1076
1077                 public override Expression CreateExpressionTree (ResolveContext ec)
1078                 {
1079                         ec.Report.Error (1946, loc, "An anonymous method cannot be converted to an expression tree");
1080                         return null;
1081                 }
1082
1083                 protected virtual ParametersCompiled ResolveParameters (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type)
1084                 {
1085                         var delegate_parameters = Delegate.GetParameters (ec.Compiler, delegate_type);
1086
1087                         if (Parameters == ParametersCompiled.Undefined) {
1088                                 //
1089                                 // We provide a set of inaccessible parameters
1090                                 //
1091                                 Parameter[] fixedpars = new Parameter[delegate_parameters.Count];
1092
1093                                 for (int i = 0; i < delegate_parameters.Count; i++) {
1094                                         Parameter.Modifier i_mod = delegate_parameters.FixedParameters [i].ModFlags;
1095                                         if (i_mod == Parameter.Modifier.OUT) {
1096                                                 if (!ec.IsInProbingMode) {
1097                                                         ec.Report.Error (1688, loc,
1098                                                                 "Cannot convert anonymous method block without a parameter list to delegate type `{0}' because it has one or more `out' parameters",
1099                                                                 delegate_type.GetSignatureForError ());
1100                                                 }
1101
1102                                                 return null;
1103                                         }
1104                                         fixedpars[i] = new Parameter (
1105                                                 new TypeExpression (delegate_parameters.Types [i], loc), 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                 protected 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 (!DoResolveParameters (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                 protected virtual bool DoResolveParameters (ResolveContext rc)
1152                 {
1153                         return Parameters.Resolve (rc);
1154                 }
1155
1156                 public override void Emit (EmitContext ec)
1157                 {
1158                         // nothing, as we only exist to not do anything.
1159                 }
1160
1161                 public static void Error_AddressOfCapturedVar (ResolveContext ec, IVariableReference var, Location loc)
1162                 {
1163                         ec.Report.Error (1686, loc,
1164                                 "Local variable or parameter `{0}' cannot have their address taken and be used inside an anonymous method or lambda expression",
1165                                 var.Name);
1166                 }
1167
1168                 public override string GetSignatureForError ()
1169                 {
1170                         return ExprClassName;
1171                 }
1172
1173                 AnonymousMethodBody CompatibleMethodBody (ResolveContext ec, TypeInferenceContext tic, TypeSpec return_type, TypeSpec delegate_type)
1174                 {
1175                         ParametersCompiled p = ResolveParameters (ec, tic, delegate_type);
1176                         if (p == null)
1177                                 return null;
1178
1179                         ParametersBlock b = ec.IsInProbingMode ? (ParametersBlock) Block.PerformClone () : Block;
1180
1181                         return CompatibleMethodFactory (return_type, delegate_type, p, b);
1182
1183                 }
1184
1185                 protected virtual AnonymousMethodBody CompatibleMethodFactory (TypeSpec return_type, TypeSpec delegate_type, ParametersCompiled p, ParametersBlock b)
1186                 {
1187                         return new AnonymousMethodBody (p, b, return_type, delegate_type, loc);
1188                 }
1189
1190                 protected override void CloneTo (CloneContext clonectx, Expression t)
1191                 {
1192                         AnonymousMethodExpression target = (AnonymousMethodExpression) t;
1193
1194                         target.Block = (ParametersBlock) clonectx.LookupBlock (Block);
1195                 }
1196         }
1197
1198         //
1199         // Abstract expression for any block which requires variables hoisting
1200         //
1201         public abstract class AnonymousExpression : Expression
1202         {
1203                 protected class AnonymousMethodMethod : Method
1204                 {
1205                         public readonly AnonymousExpression AnonymousMethod;
1206                         public readonly AnonymousMethodStorey Storey;
1207                         readonly string RealName;
1208
1209                         public AnonymousMethodMethod (DeclSpace parent, AnonymousExpression am, AnonymousMethodStorey storey,
1210                                                           GenericMethod generic, TypeExpr return_type,
1211                                                           Modifiers mod, string real_name, MemberName name,
1212                                                           ParametersCompiled parameters)
1213                                 : base (parent, generic, return_type, mod | Modifiers.COMPILER_GENERATED,
1214                                                 name, parameters, null)
1215                         {
1216                                 this.AnonymousMethod = am;
1217                                 this.Storey = storey;
1218                                 this.RealName = real_name;
1219
1220                                 Parent.PartialContainer.AddMethod (this);
1221                                 Block = new ToplevelBlock (am.block, parameters);
1222                         }
1223
1224                         public override EmitContext CreateEmitContext (ILGenerator ig)
1225                         {
1226                                 EmitContext ec = new EmitContext (this, ig, ReturnType);
1227                                 ec.CurrentAnonymousMethod = AnonymousMethod;
1228                                 if (AnonymousMethod.return_label != null) {
1229                                         ec.HasReturnLabel = true;
1230                                         ec.ReturnLabel = (Label) AnonymousMethod.return_label;
1231                                 }
1232
1233                                 return ec;
1234                         }
1235
1236                         protected override void DefineTypeParameters ()
1237                         {
1238                                 // Type parameters were cloned
1239                         }
1240
1241                         protected override bool ResolveMemberType ()
1242                         {
1243                                 if (!base.ResolveMemberType ())
1244                                         return false;
1245
1246                                 if (Storey != null && Storey.Mutator != null) {
1247                                         if (!parameters.IsEmpty) {
1248                                                 var mutated = Storey.Mutator.Mutate (parameters.Types);
1249                                                 if (mutated != parameters.Types)
1250                                                         parameters = ParametersCompiled.CreateFullyResolved ((Parameter[]) parameters.FixedParameters, mutated);
1251                                         }
1252
1253                                         member_type = Storey.Mutator.Mutate (member_type);
1254                                 }
1255
1256                                 return true;
1257                         }
1258
1259                         public override void Emit ()
1260                         {
1261                                 if (MethodBuilder == null) {
1262                                         Define ();
1263                                 }
1264
1265                                 base.Emit ();
1266                         }
1267
1268                         public override void EmitExtraSymbolInfo (SourceMethod source)
1269                         {
1270                                 source.SetRealMethodName (RealName);
1271                         }
1272                 }
1273
1274                 protected ParametersBlock block;
1275
1276                 public TypeSpec ReturnType;
1277
1278                 object return_label;
1279
1280                 protected AnonymousExpression (ParametersBlock block, TypeSpec return_type, Location loc)
1281                 {
1282                         this.ReturnType = return_type;
1283                         this.block = block;
1284                         this.loc = loc;
1285                 }
1286
1287                 public abstract string ContainerType { get; }
1288                 public abstract bool IsIterator { get; }
1289                 public abstract AnonymousMethodStorey Storey { get; }
1290
1291                 public AnonymousExpression Compatible (ResolveContext ec)
1292                 {
1293                         return Compatible (ec, this);
1294                 }
1295
1296                 public AnonymousExpression Compatible (ResolveContext ec, AnonymousExpression ae)
1297                 {
1298                         if (block.Resolved)
1299                                 return this;
1300
1301                         // TODO: Implement clone
1302                         BlockContext aec = new BlockContext (ec, block, ReturnType);
1303                         aec.CurrentAnonymousMethod = ae;
1304
1305                         ResolveContext.Options flags = 0;
1306
1307                         var am = this as AnonymousMethodBody;
1308
1309                         if (ec.HasSet (ResolveContext.Options.InferReturnType) && am != null) {
1310                                 am.ReturnTypeInference = new TypeInferenceContext ();
1311                         }
1312
1313                         if (ec.IsInProbingMode)
1314                                 flags |= ResolveContext.Options.ProbingMode;
1315
1316                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
1317                                 flags |= ResolveContext.Options.FieldInitializerScope;
1318
1319                         if (ec.HasSet (ResolveContext.Options.ExpressionTreeConversion))
1320                                 flags |= ResolveContext.Options.ExpressionTreeConversion;
1321
1322                         aec.Set (flags);
1323
1324                         var errors = ec.Report.Errors;
1325
1326                         bool res = Block.Resolve (ec.CurrentBranching, aec, null);
1327
1328                         if (aec.HasReturnLabel)
1329                                 return_label = aec.ReturnLabel;
1330
1331                         if (am != null && am.ReturnTypeInference != null) {
1332                                 am.ReturnTypeInference.FixAllTypes (ec);
1333                                 ReturnType = am.ReturnTypeInference.InferredTypeArguments [0];
1334                                 am.ReturnTypeInference = null;
1335                         }
1336
1337                         if (res && errors != ec.Report.Errors)
1338                                 return null;
1339
1340                         return res ? this : null;
1341                 }
1342
1343                 public void SetHasThisAccess ()
1344                 {
1345                         ExplicitBlock b = block;
1346                         do {
1347                                 if (b.HasCapturedThis)
1348                                         return;
1349
1350                                 b.HasCapturedThis = true;
1351                                 b = b.Parent == null ? null : b.Parent.Explicit;
1352                         } while (b != null);
1353                 }
1354
1355                 //
1356                 // The block that makes up the body for the anonymous method
1357                 //
1358                 public ParametersBlock Block {
1359                         get {
1360                                 return block;
1361                         }
1362                 }
1363
1364         }
1365
1366         public class AnonymousMethodBody : AnonymousExpression
1367         {
1368                 protected readonly ParametersCompiled parameters;
1369                 AnonymousMethodStorey storey;
1370
1371                 AnonymousMethodMethod method;
1372                 Field am_cache;
1373                 string block_name;
1374                 TypeInferenceContext return_inference;
1375
1376                 static int unique_id;
1377
1378                 public AnonymousMethodBody (ParametersCompiled parameters,
1379                                         ParametersBlock block, TypeSpec return_type, TypeSpec delegate_type,
1380                                         Location loc)
1381                         : base (block, return_type, loc)
1382                 {
1383                         this.type = delegate_type;
1384                         this.parameters = parameters;
1385                 }
1386
1387                 #region Properties
1388
1389                 public override string ContainerType {
1390                         get { return "anonymous method"; }
1391                 }
1392
1393                 public override bool IsIterator {
1394                         get { return false; }
1395                 }
1396
1397                 public TypeInferenceContext ReturnTypeInference {
1398                         get {
1399                                 return return_inference;
1400                         }
1401                         set {
1402                                 return_inference = value;
1403                         }
1404                 }
1405
1406                 public override AnonymousMethodStorey Storey {
1407                         get { return storey; }
1408                 }
1409
1410                 #endregion
1411
1412                 public override Expression CreateExpressionTree (ResolveContext ec)
1413                 {
1414                         ec.Report.Error (1945, loc, "An expression tree cannot contain an anonymous method expression");
1415                         return null;
1416                 }
1417
1418                 bool Define (ResolveContext ec)
1419                 {
1420                         if (!Block.Resolved && Compatible (ec) == null)
1421                                 return false;
1422
1423                         if (block_name == null) {
1424                                 MemberCore mc = (MemberCore) ec.MemberContext;
1425                                 block_name = mc.MemberName.Basename;
1426                         }
1427
1428                         return true;
1429                 }
1430
1431                 //
1432                 // Creates a host for the anonymous method
1433                 //
1434                 AnonymousMethodMethod DoCreateMethodHost (EmitContext ec)
1435                 {
1436                         //
1437                         // Anonymous method body can be converted to
1438                         //
1439                         // 1, an instance method in current scope when only `this' is hoisted
1440                         // 2, a static method in current scope when neither `this' nor any variable is hoisted
1441                         // 3, an instance method in compiler generated storey when any hoisted variable exists
1442                         //
1443
1444                         Modifiers modifiers;
1445                         if (Block.HasCapturedVariable || Block.HasCapturedThis) {
1446                                 storey = FindBestMethodStorey ();
1447                                 modifiers = storey != null ? Modifiers.INTERNAL : Modifiers.PRIVATE;
1448                         } else {
1449                                 if (ec.CurrentAnonymousMethod != null)
1450                                         storey = ec.CurrentAnonymousMethod.Storey;
1451
1452                                 modifiers = Modifiers.STATIC | Modifiers.PRIVATE;
1453                         }
1454
1455                         TypeContainer parent = storey != null ? storey : ec.CurrentTypeDefinition.Parent.PartialContainer;
1456
1457                         MemberCore mc = ec.MemberContext as MemberCore;
1458                         string name = CompilerGeneratedClass.MakeName (parent != storey ? block_name : null,
1459                                 "m", null, unique_id++);
1460
1461                         MemberName member_name;
1462                         GenericMethod generic_method;
1463                         if (storey == null && mc.MemberName.TypeArguments != null) {
1464                                 member_name = new MemberName (name, mc.MemberName.TypeArguments.Clone (), Location);
1465
1466                                 var hoisted_tparams = ec.CurrentTypeParameters;
1467                                 var type_params = new TypeParameter[hoisted_tparams.Length];
1468                                 for (int i = 0; i < type_params.Length; ++i) {
1469                                         type_params[i] = hoisted_tparams[i].CreateHoistedCopy (null, null);
1470                                 }
1471
1472                                 generic_method = new GenericMethod (parent.NamespaceEntry, parent, member_name, type_params,
1473                                         new TypeExpression (ReturnType, Location), parameters);
1474                         } else {
1475                                 member_name = new MemberName (name, Location);
1476                                 generic_method = null;
1477                         }
1478
1479                         string real_name = String.Format (
1480                                 "{0}~{1}{2}", mc.GetSignatureForError (), GetSignatureForError (),
1481                                 parameters.GetSignatureForError ());
1482
1483                         return new AnonymousMethodMethod (parent,
1484                                 this, storey, generic_method, new TypeExpression (ReturnType, Location), modifiers,
1485                                 real_name, member_name, parameters);
1486                 }
1487
1488                 protected override Expression DoResolve (ResolveContext ec)
1489                 {
1490                         if (!Define (ec))
1491                                 return null;
1492
1493                         eclass = ExprClass.Value;
1494                         return this;
1495                 }
1496
1497                 public override void Emit (EmitContext ec)
1498                 {
1499                         //
1500                         // Use same anonymous method implementation for scenarios where same
1501                         // code is used from multiple blocks, e.g. field initializers
1502                         //
1503                         if (method == null) {
1504                                 //
1505                                 // Delay an anonymous method definition to avoid emitting unused code
1506                                 // for unreachable blocks or expression trees
1507                                 //
1508                                 method = DoCreateMethodHost (ec);
1509                                 method.Define ();
1510                         }
1511
1512                         bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
1513                         if (is_static && am_cache == null) {
1514                                 //
1515                                 // Creates a field cache to store delegate instance if it's not generic
1516                                 //
1517                                 if (!method.MemberName.IsGeneric) {
1518                                         TypeContainer parent = method.Parent.PartialContainer;
1519                                         int id = parent.Fields == null ? 0 : parent.Fields.Count;
1520                                         var cache_type = storey != null && storey.Mutator != null ? storey.Mutator.Mutate (type) : type;
1521
1522                                         am_cache = new Field (parent, new TypeExpression (cache_type, loc),
1523                                                 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
1524                                                 new MemberName (CompilerGeneratedClass.MakeName (null, "f", "am$cache", id), loc), null);
1525                                         am_cache.Define ();
1526                                         parent.AddField (am_cache);
1527                                 } else {
1528                                         // TODO: Implement caching of generated generic static methods
1529                                         //
1530                                         // Idea:
1531                                         //
1532                                         // Some extra class is needed to capture variable generic type
1533                                         // arguments. Maybe we could re-use anonymous types, with a unique
1534                                         // anonymous method id, but they are quite heavy.
1535                                         //
1536                                         // Consider : "() => typeof(T);"
1537                                         //
1538                                         // We need something like
1539                                         // static class Wrap<Tn, Tm, DelegateType> {
1540                                         //              public static DelegateType cache;
1541                                         // }
1542                                         //
1543                                         // We then specialize local variable to capture all generic parameters
1544                                         // and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
1545                                         //
1546                                 }
1547                         }
1548
1549                         Label l_initialized = ec.DefineLabel ();
1550
1551                         if (am_cache != null) {
1552                                 ec.Emit (OpCodes.Ldsfld, am_cache.Spec);
1553                                 ec.Emit (OpCodes.Brtrue_S, l_initialized);
1554                         }
1555
1556                         //
1557                         // Load method delegate implementation
1558                         //
1559
1560                         if (is_static) {
1561                                 ec.Emit (OpCodes.Ldnull);
1562                         } else if (storey != null) {
1563                                 Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (new ResolveContext (ec.MemberContext));
1564                                 if (e != null)
1565                                         e.Emit (ec);
1566                         } else {
1567                                 ec.Emit (OpCodes.Ldarg_0);
1568                         }
1569
1570                         var delegate_method = method.Spec;
1571                         if (storey != null && storey.MemberName.IsGeneric) {
1572                                 TypeSpec t = storey.Instance.Type;
1573
1574                                 //
1575                                 // Mutate anonymous method instance type if we are in nested
1576                                 // hoisted generic anonymous method storey
1577                                 //
1578                                 if (ec.CurrentAnonymousMethod != null &&
1579                                         ec.CurrentAnonymousMethod.Storey != null &&
1580                                         ec.CurrentAnonymousMethod.Storey.Mutator != null) {
1581                                         t = storey.Mutator.Mutate (t);
1582                                 }
1583
1584                                 ec.Emit (OpCodes.Ldftn, TypeBuilder.GetMethod (t.GetMetaInfo (), (MethodInfo) delegate_method.GetMetaInfo ()));
1585                         } else {
1586                                 ec.Emit (OpCodes.Ldftn, delegate_method);
1587                         }
1588
1589                         var constructor_method = Delegate.GetConstructor (ec.MemberContext.Compiler, ec.CurrentType, type);
1590                         ec.Emit (OpCodes.Newobj, constructor_method);
1591
1592                         if (am_cache != null) {
1593                                 ec.Emit (OpCodes.Stsfld, am_cache.Spec);
1594                                 ec.MarkLabel (l_initialized);
1595                                 ec.Emit (OpCodes.Ldsfld, am_cache.Spec);
1596                         }
1597                 }
1598
1599                 //
1600                 // Look for the best storey for this anonymous method
1601                 //
1602                 AnonymousMethodStorey FindBestMethodStorey ()
1603                 {
1604                         //
1605                         // Use the nearest parent block which has a storey
1606                         //
1607                         for (Block b = Block.Parent; b != null; b = b.Parent) {
1608                                 AnonymousMethodStorey s = b.Explicit.AnonymousMethodStorey;
1609                                 if (s != null)
1610                                         return s;
1611                         }
1612
1613                         return null;
1614                 }
1615
1616                 public override string GetSignatureForError ()
1617                 {
1618                         return TypeManager.CSharpName (type);
1619                 }
1620
1621                 public static void Reset ()
1622                 {
1623                         unique_id = 0;
1624                 }
1625         }
1626
1627         //
1628         // Anonymous type container
1629         //
1630         public class AnonymousTypeClass : CompilerGeneratedClass
1631         {
1632                 // TODO: Merge with AnonymousTypeParameter
1633                 public class GeneratedParameter : Parameter
1634                 {
1635                         public GeneratedParameter (FullNamedExpression type, AnonymousTypeParameter p)
1636                                 : base (type, p.Name, Modifier.NONE, null, p.Location)
1637                         {
1638                         }
1639                 }
1640
1641                 static int types_counter;
1642                 public const string ClassNamePrefix = "<>__AnonType";
1643                 public const string SignatureForError = "anonymous type";
1644
1645                 readonly IList<AnonymousTypeParameter> parameters;
1646
1647                 private AnonymousTypeClass (DeclSpace parent, MemberName name, IList<AnonymousTypeParameter> parameters, Location loc)
1648                         : base (parent, name, (RootContext.EvalMode ? Modifiers.PUBLIC : 0) | Modifiers.SEALED)
1649                 {
1650                         this.parameters = parameters;
1651                 }
1652
1653                 public static AnonymousTypeClass Create (CompilerContext ctx, TypeContainer parent, IList<AnonymousTypeParameter> parameters, Location loc)
1654                 {
1655                         string name = ClassNamePrefix + types_counter++;
1656
1657                         ParametersCompiled all_parameters;
1658                         TypeParameterName[] t_params;
1659                         SimpleName[] t_args;
1660
1661                         if (parameters.Count == 0) {
1662                                 all_parameters = ParametersCompiled.EmptyReadOnlyParameters;
1663                                 t_params = new TypeParameterName[0];
1664                                 t_args = null;
1665                         } else {
1666                                 t_args = new SimpleName[parameters.Count];
1667                                 t_params = new TypeParameterName[parameters.Count];
1668                                 Parameter[] ctor_params = new Parameter[parameters.Count];
1669                                 for (int i = 0; i < parameters.Count; ++i) {
1670                                         AnonymousTypeParameter p = parameters[i];
1671
1672                                         t_args[i] = new SimpleName ("<" + p.Name + ">__T", p.Location);
1673                                         t_params[i] = new TypeParameterName (t_args[i].Name, null, p.Location);
1674                                         ctor_params[i] = new GeneratedParameter (t_args[i], p);
1675                                 }
1676
1677                                 all_parameters = new ParametersCompiled (ctor_params);
1678                         }
1679
1680                         //
1681                         // Create generic anonymous type host with generic arguments
1682                         // named upon properties names
1683                         //
1684                         AnonymousTypeClass a_type = new AnonymousTypeClass (parent.NamespaceEntry.SlaveDeclSpace,
1685                                 new MemberName (name, new TypeArguments (t_params), loc), parameters, loc);
1686
1687                         if (parameters.Count > 0)
1688                                 a_type.SetParameterInfo (null);
1689
1690                         Constructor c = new Constructor (a_type, name, Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
1691                                 null, all_parameters, null, loc);
1692                         c.Block = new ToplevelBlock (ctx, c.ParameterInfo, loc);
1693
1694                         //
1695                         // Create fields and contructor body with field initialization
1696                         //
1697                         bool error = false;
1698                         for (int i = 0; i < parameters.Count; ++i) {
1699                                 AnonymousTypeParameter p = parameters [i];
1700
1701                                 Field f = new Field (a_type, t_args [i], Modifiers.PRIVATE | Modifiers.READONLY,
1702                                         new MemberName ("<" + p.Name + ">", p.Location), null);
1703
1704                                 if (!a_type.AddField (f)) {
1705                                         error = true;
1706                                         continue;
1707                                 }
1708
1709                                 c.Block.AddStatement (new StatementExpression (
1710                                         new SimpleAssign (new MemberAccess (new This (p.Location), f.Name),
1711                                                 c.Block.GetParameterReference (i, p.Location))));
1712
1713                                 ToplevelBlock get_block = new ToplevelBlock (ctx, p.Location);
1714                                 get_block.AddStatement (new Return (
1715                                         new MemberAccess (new This (p.Location), f.Name), p.Location));
1716
1717                                 Property prop = new Property (a_type, t_args [i], Modifiers.PUBLIC,
1718                                         new MemberName (p.Name, p.Location), null);
1719                                 prop.Get = new Property.GetMethod (prop, 0, null, p.Location);
1720                                 prop.Get.Block = get_block;
1721                                 a_type.AddProperty (prop);
1722                         }
1723
1724                         if (error)
1725                                 return null;
1726
1727                         a_type.AddConstructor (c);
1728                         return a_type;
1729                 }
1730
1731                 public static void Reset ()
1732                 {
1733                         types_counter = 0;
1734                 }
1735
1736                 protected override bool AddToContainer (MemberCore symbol, string name)
1737                 {
1738                         MemberCore mc = GetDefinition (name);
1739
1740                         if (mc == null) {
1741                                 defined_names.Add (name, symbol);
1742                                 return true;
1743                         }
1744
1745                         Report.SymbolRelatedToPreviousError (mc);
1746                         return false;
1747                 }
1748
1749                 protected override bool DoDefineMembers ()
1750                 {
1751                         if (!base.DoDefineMembers ())
1752                                 return false;
1753
1754                         Location loc = Location;
1755
1756                         var equals_parameters = ParametersCompiled.CreateFullyResolved (
1757                                 new Parameter (new TypeExpression (TypeManager.object_type, loc), "obj", 0, null, loc), TypeManager.object_type);
1758
1759                         Method equals = new Method (this, null, new TypeExpression (TypeManager.bool_type, loc),
1760                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("Equals", loc),
1761                                 equals_parameters, null);
1762
1763                         equals_parameters[0].Resolve (equals, 0);
1764
1765                         Method tostring = new Method (this, null, new TypeExpression (TypeManager.string_type, loc),
1766                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("ToString", loc),
1767                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1768
1769                         ToplevelBlock equals_block = new ToplevelBlock (Compiler, equals.ParameterInfo, loc);
1770
1771                         TypeExpr current_type;
1772                         if (type_params != null) {
1773                                 var targs = new TypeArguments ();
1774                                 foreach (var type_param in type_params)
1775                                         targs.Add (new TypeParameterExpr (type_param, type_param.Location));
1776
1777                                 current_type = new GenericTypeExpr (Definition, targs, loc);
1778                         } else {
1779                                 current_type = new TypeExpression (Definition, loc);
1780                         }
1781
1782                         var li_other = LocalVariable.CreateCompilerGenerated (CurrentType, equals_block, loc);
1783                         equals_block.AddStatement (new BlockVariableDeclaration (new TypeExpression (li_other.Type, loc), li_other));
1784                         var other_variable = new LocalVariableReference (li_other, loc);
1785
1786                         MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
1787                                 new QualifiedAliasMember ("global", "System", loc), "Collections", loc), "Generic", loc);
1788
1789                         Expression rs_equals = null;
1790                         Expression string_concat = new StringConstant ("{", loc);
1791                         Expression rs_hashcode = new IntConstant (-2128831035, loc);
1792                         for (int i = 0; i < parameters.Count; ++i) {
1793                                 var p = parameters [i];
1794                                 var f = Fields [i];
1795
1796                                 MemberAccess equality_comparer = new MemberAccess (new MemberAccess (
1797                                         system_collections_generic, "EqualityComparer",
1798                                                 new TypeArguments (new SimpleName (CurrentTypeParameters [i].Name, loc)), loc),
1799                                                 "Default", loc);
1800
1801                                 Arguments arguments_equal = new Arguments (2);
1802                                 arguments_equal.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1803                                 arguments_equal.Add (new Argument (new MemberAccess (other_variable, f.Name)));
1804
1805                                 Expression field_equal = new Invocation (new MemberAccess (equality_comparer,
1806                                         "Equals", loc), arguments_equal);
1807
1808                                 Arguments arguments_hashcode = new Arguments (1);
1809                                 arguments_hashcode.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1810                                 Expression field_hashcode = new Invocation (new MemberAccess (equality_comparer,
1811                                         "GetHashCode", loc), arguments_hashcode);
1812
1813                                 IntConstant FNV_prime = new IntConstant (16777619, loc);
1814                                 rs_hashcode = new Binary (Binary.Operator.Multiply,
1815                                         new Binary (Binary.Operator.ExclusiveOr, rs_hashcode, field_hashcode, loc),
1816                                         FNV_prime, loc);
1817
1818                                 Expression field_to_string = new Conditional (new BooleanExpression (new Binary (Binary.Operator.Inequality,
1819                                         new MemberAccess (new This (f.Location), f.Name), new NullLiteral (loc), loc)),
1820                                         new Invocation (new MemberAccess (
1821                                                 new MemberAccess (new This (f.Location), f.Name), "ToString"), null),
1822                                         new StringConstant (string.Empty, loc), loc);
1823
1824                                 if (rs_equals == null) {
1825                                         rs_equals = field_equal;
1826                                         string_concat = new Binary (Binary.Operator.Addition,
1827                                                 string_concat,
1828                                                 new Binary (Binary.Operator.Addition,
1829                                                         new StringConstant (" " + p.Name + " = ", loc),
1830                                                         field_to_string,
1831                                                         loc),
1832                                                 loc);
1833                                         continue;
1834                                 }
1835
1836                                 //
1837                                 // Implementation of ToString () body using string concatenation
1838                                 //
1839                                 string_concat = new Binary (Binary.Operator.Addition,
1840                                         new Binary (Binary.Operator.Addition,
1841                                                 string_concat,
1842                                                 new StringConstant (", " + p.Name + " = ", loc),
1843                                                 loc),
1844                                         field_to_string,
1845                                         loc);
1846
1847                                 rs_equals = new Binary (Binary.Operator.LogicalAnd, rs_equals, field_equal, loc);
1848                         }
1849
1850                         string_concat = new Binary (Binary.Operator.Addition,
1851                                 string_concat,
1852                                 new StringConstant (" }", loc),
1853                                 loc);
1854
1855                         //
1856                         // Equals (object obj) override
1857                         //
1858                         var other_variable_assign = new TemporaryVariableReference (li_other, loc);
1859                         equals_block.AddStatement (new StatementExpression (
1860                                 new SimpleAssign (other_variable_assign,
1861                                         new As (equals_block.GetParameterReference (0, loc),
1862                                                 current_type, loc), loc)));
1863
1864                         Expression equals_test = new Binary (Binary.Operator.Inequality, other_variable, new NullLiteral (loc), loc);
1865                         if (rs_equals != null)
1866                                 equals_test = new Binary (Binary.Operator.LogicalAnd, equals_test, rs_equals, loc);
1867                         equals_block.AddStatement (new Return (equals_test, loc));
1868
1869                         equals.Block = equals_block;
1870                         equals.Define ();
1871                         AddMethod (equals);
1872
1873                         //
1874                         // GetHashCode () override
1875                         //
1876                         Method hashcode = new Method (this, null, new TypeExpression (TypeManager.int32_type, loc),
1877                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN,
1878                                 new MemberName ("GetHashCode", loc),
1879                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1880
1881                         //
1882                         // Modified FNV with good avalanche behavior and uniform
1883                         // distribution with larger hash sizes.
1884                         //
1885                         // const int FNV_prime = 16777619;
1886                         // int hash = (int) 2166136261;
1887                         // foreach (int d in data)
1888                         //     hash = (hash ^ d) * FNV_prime;
1889                         // hash += hash << 13;
1890                         // hash ^= hash >> 7;
1891                         // hash += hash << 3;
1892                         // hash ^= hash >> 17;
1893                         // hash += hash << 5;
1894
1895                         ToplevelBlock hashcode_top = new ToplevelBlock (Compiler, loc);
1896                         Block hashcode_block = new Block (hashcode_top, loc, loc);
1897                         hashcode_top.AddStatement (new Unchecked (hashcode_block, loc));
1898
1899                         var li_hash = LocalVariable.CreateCompilerGenerated (TypeManager.int32_type, hashcode_top, loc);
1900                         hashcode_block.AddStatement (new BlockVariableDeclaration (new TypeExpression (li_hash.Type, loc), li_hash));
1901                         LocalVariableReference hash_variable_assign = new LocalVariableReference (li_hash, loc);
1902                         hashcode_block.AddStatement (new StatementExpression (
1903                                 new SimpleAssign (hash_variable_assign, rs_hashcode)));
1904
1905                         var hash_variable = new LocalVariableReference (li_hash, loc);
1906                         hashcode_block.AddStatement (new StatementExpression (
1907                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1908                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (13, loc), loc), loc)));
1909                         hashcode_block.AddStatement (new StatementExpression (
1910                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1911                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (7, loc), loc), loc)));
1912                         hashcode_block.AddStatement (new StatementExpression (
1913                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1914                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (3, loc), loc), loc)));
1915                         hashcode_block.AddStatement (new StatementExpression (
1916                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1917                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (17, loc), loc), loc)));
1918                         hashcode_block.AddStatement (new StatementExpression (
1919                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1920                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (5, loc), loc), loc)));
1921
1922                         hashcode_block.AddStatement (new Return (hash_variable, loc));
1923                         hashcode.Block = hashcode_top;
1924                         hashcode.Define ();
1925                         AddMethod (hashcode);
1926
1927                         //
1928                         // ToString () override
1929                         //
1930
1931                         ToplevelBlock tostring_block = new ToplevelBlock (Compiler, loc);
1932                         tostring_block.AddStatement (new Return (string_concat, loc));
1933                         tostring.Block = tostring_block;
1934                         tostring.Define ();
1935                         AddMethod (tostring);
1936
1937                         return true;
1938                 }
1939
1940                 public override string GetSignatureForError ()
1941                 {
1942                         return SignatureForError;
1943                 }
1944
1945                 public IList<AnonymousTypeParameter> Parameters {
1946                         get {
1947                                 return parameters;
1948                         }
1949                 }
1950         }
1951 }