mcs/mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 //
  12
  13 namespace Mono.CSharp {
  14         using System;
  15         using System.Collections;
  16         using System.Diagnostics;
  17         using System.Reflection;
  18         using System.Reflection.Emit;
  19         using System.Text;
  20
  21         /// <remarks>
  22         ///   The ExprClass class contains the is used to pass the
  23         ///   classification of an expression (value, variable, namespace,
  24         ///   type, method group, property access, event access, indexer access,
  25         ///   nothing).
  26         /// </remarks>
  27         public enum ExprClass : byte {
  28                 Invalid,
  29
  30                 Value,
  31                 Variable,
  32                 Namespace,
  33                 Type,
  34                 MethodGroup,
  35                 PropertyAccess,
  36                 EventAccess,
  37                 IndexerAccess,
  38                 Nothing,
  39         }
  40
  41         /// <remarks>
  42         ///   This is used to tell Resolve in which types of expressions we're
  43         ///   interested.
  44         /// </remarks>
  45         [Flags]
  46         public enum ResolveFlags {
  47                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  48                 VariableOrValue         = 1,
  49
  50                 // Returns a type expression.
  51                 Type                    = 2,
  52
  53                 // Returns a method group.
  54                 MethodGroup             = 4,
  55
  56                 // Mask of all the expression class flags.
  57                 MaskExprClass           = 7,
  58
  59                 // Disable control flow analysis while resolving the expression.
  60                 // This is used when resolving the instance expression of a field expression.
  61                 DisableFlowAnalysis     = 8,
  62
  63                 // Set if this is resolving the first part of a MemberAccess.
  64                 Intermediate            = 16,
  65
  66                 // Disable control flow analysis _of struct_ while resolving the expression.
  67                 // This is used when resolving the instance expression of a field expression.
  68                 DisableStructFlowAnalysis       = 32,
  69
  70         }
  71
  72         //
  73         // This is just as a hint to AddressOf of what will be done with the
  74         // address.
  75         [Flags]
  76         public enum AddressOp {
  77                 Store = 1,
  78                 Load  = 2,
  79                 LoadStore = 3
  80         };
  81
  82         /// <summary>
  83         ///   This interface is implemented by variables
  84         /// </summary>
  85         public interface IMemoryLocation {
  86                 /// <summary>
  87                 ///   The AddressOf method should generate code that loads
  88                 ///   the address of the object and leaves it on the stack.
  89                 ///
  90                 ///   The `mode' argument is used to notify the expression
  91                 ///   of whether this will be used to read from the address or
  92                 ///   write to the address.
  93                 ///
  94                 ///   This is just a hint that can be used to provide good error
  95                 ///   reporting, and should have no other side effects.
  96                 /// </summary>
  97                 void AddressOf (EmitContext ec, AddressOp mode);
  98         }
  99
 100         /// <summary>
 101         ///   This interface is implemented by variables
 102         /// </summary>
 103         public interface IVariable {
 104                 VariableInfo VariableInfo {
 105                         get;
 106                 }
 107
 108                 bool VerifyFixed ();
 109         }
 110
 111         /// <remarks>
 112         ///   Base class for expressions
 113         /// </remarks>
 114         public abstract class Expression {
 115                 public ExprClass eclass;
 116                 protected Type type;
 117                 protected Location loc;
 118
 119                 public Type Type {
 120                         get { return type; }
 121                         set { type = value; }
 122                 }
 123
 124                 public virtual Location Location {
 125                         get { return loc; }
 126                 }
 127
 128                 /// <summary>
 129                 ///   Utility wrapper routine for Error, just to beautify the code
 130                 /// </summary>
 131                 public void Error (int error, string s)
 132                 {
 133                         Report.Error (error, loc, s);
 134                 }
 135
 136                 // Not nice but we have broken hierarchy.
 137                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 138                 {
 139                 }
 140
 141                 public virtual bool GetAttributableValue (Type value_type, out object value)
 142                 {
 143                         Attribute.Error_AttributeArgumentNotValid (loc);
 144                         value = null;
 145                         return false;
 146                 }
 147
 148                 public virtual string GetSignatureForError ()
 149                 {
 150                         return TypeManager.CSharpName (type);
 151                 }
 152
 153                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 154                 {
 155                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 156
 157                         must_do_cs1540_check = false; // by default we do not check for this
 158
 159                         if (ma == MethodAttributes.Public)
 160                                 return true;
 161
 162                         //
 163                         // If only accessible to the current class or children
 164                         //
 165                         if (ma == MethodAttributes.Private)
 166                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 167                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 168
 169                         if (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 170                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 171                                         return true;
 172                         } else {
 173                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 174                                         return false;
 175                         }
 176
 177                         // Family and FamANDAssem require that we derive.
 178                         // FamORAssem requires that we derive if in different assemblies.
 179                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 180                                 return false;
 181
 182                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 183                                 must_do_cs1540_check = true;
 184
 185                         return true;
 186                 }
 187
 188                 public virtual bool IsNull {
 189                         get {
 190                                 return false;
 191                         }
 192                 }
 193
 194                 /// <summary>
 195                 ///   Performs semantic analysis on the Expression
 196                 /// </summary>
 197                 ///
 198                 /// <remarks>
 199                 ///   The Resolve method is invoked to perform the semantic analysis
 200                 ///   on the node.
 201                 ///
 202                 ///   The return value is an expression (it can be the
 203                 ///   same expression in some cases) or a new
 204                 ///   expression that better represents this node.
 205                 ///
 206                 ///   For example, optimizations of Unary (LiteralInt)
 207                 ///   would return a new LiteralInt with a negated
 208                 ///   value.
 209                 ///
 210                 ///   If there is an error during semantic analysis,
 211                 ///   then an error should be reported (using Report)
 212                 ///   and a null value should be returned.
 213                 ///
 214                 ///   There are two side effects expected from calling
 215                 ///   Resolve(): the the field variable "eclass" should
 216                 ///   be set to any value of the enumeration
 217                 ///   `ExprClass' and the type variable should be set
 218                 ///   to a valid type (this is the type of the
 219                 ///   expression).
 220                 /// </remarks>
 221                 public abstract Expression DoResolve (EmitContext ec);
 222
 223                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 224                 {
 225                         return null;
 226                 }
 227
 228                 //
 229                 // This is used if the expression should be resolved as a type or namespace name.
 230                 // the default implementation fails.
 231                 //
 232                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 233                 {
 234                         if (!silent) {
 235                                 Expression e = this;
 236                                 EmitContext ec = rc as EmitContext;
 237                                 if (ec != null)
 238                                         e = e.Resolve (ec);
 239                                 if (e != null)
 240                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 241                         }
 242                         return null;
 243                 }
 244
 245                 //
 246                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 247                 // same name exists or as a keyword when no type was found
 248                 //
 249                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 250                 {
 251                         return ResolveAsTypeTerminal (rc, silent);
 252                 }
 253
 254                 //
 255                 // This is used to resolve the expression as a type, a null
 256                 // value will be returned if the expression is not a type
 257                 // reference
 258                 //
 259                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 260                 {
 261                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 262                         if (te == null)
 263                                 return null;
 264
 265                         if (!silent) { // && !(te is TypeParameterExpr)) {
 266                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 267                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 268                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 269                                 }
 270                         }
 271
 272                         // Constrains don't need to be checked for overrides
 273                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 274                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 275                                 te.loc = loc;
 276                                 return te;
 277                         }
 278
 279                         ConstructedType ct = te as ConstructedType;
 280                         if ((ct != null) && !ct.CheckConstraints (ec))
 281                                 return null;
 282
 283                         return te;
 284                 }
 285
 286                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 287                 {
 288                         int errors = Report.Errors;
 289
 290                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 291
 292                         if (fne == null)
 293                                 return null;
 294
 295                         if (fne.eclass != ExprClass.Type) {
 296                                 if (!silent && errors == Report.Errors)
 297                                         fne.Error_UnexpectedKind (null, "type", loc);
 298                                 return null;
 299                         }
 300
 301                         TypeExpr te = fne as TypeExpr;
 302
 303                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 304                                 Report.SymbolRelatedToPreviousError (te.Type);
 305                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 306                                 return null;
 307                         }
 308
 309                         te.loc = loc;
 310                         return te;
 311                 }
 312
 313                 public static void ErrorIsInaccesible (Location loc, string name)
 314                 {
 315                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 316                 }
 317
 318                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 319                 {
 320                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 321                                 + " The qualifier must be of type `{2}' or derived from it",
 322                                 TypeManager.GetFullNameSignature (m),
 323                                 TypeManager.CSharpName (qualifier),
 324                                 TypeManager.CSharpName (container));
 325
 326                 }
 327
 328                 public static void Error_InvalidExpressionStatement (Location loc)
 329                 {
 330                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 331                                        "expressions can be used as a statement");
 332                 }
 333
 334                 public void Error_InvalidExpressionStatement ()
 335                 {
 336                         Error_InvalidExpressionStatement (loc);
 337                 }
 338
 339                 protected void Error_CannotAssign (string to, string roContext)
 340                 {
 341                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 342                                 to, roContext);
 343                 }
 344
 345                 public static void Error_VoidInvalidInTheContext (Location loc)
 346                 {
 347                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 348                 }
 349
 350                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 351                 {
 352                         // The error was already reported as CS1660
 353                         if (type == TypeManager.anonymous_method_type)
 354                                 return;
 355
 356                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 357 #if GMCS_SOURCE
 358                                 string sig1 = type.DeclaringMethod == null ?
 359                                         TypeManager.CSharpName (type.DeclaringType) :
 360                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 361                                 string sig2 = target.DeclaringMethod == null ?
 362                                         TypeManager.CSharpName (target.DeclaringType) :
 363                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 364                                 Report.ExtraInformation (loc,
 365                                         String.Format (
 366                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 367                                                 Type.Name, sig1, sig2));
 368 #endif
 369                         } else if (Type.FullName == target.FullName){
 370                                 Report.ExtraInformation (loc,
 371                                         String.Format (
 372                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 373                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 374                         }
 375
 376                         if (expl) {
 377                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 378                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 379                                 return;
 380                         }
 381
 382                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 383                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 384
 385                         if (b ||
 386                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 387                             Convert.ExplicitUnsafe (e, target) != null ||
 388                             (ec != null && Convert.ExplicitUserConversion (ec, this, target, Location.Null) != null))
 389                         {
 390                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 391                                               "An explicit conversion exists (are you missing a cast?)",
 392                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 393                                 return;
 394                         }
 395
 396                         if (Type != TypeManager.string_type && this is Constant && !(this is EmptyConstantCast)) {
 397                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 398                                         ((Constant)(this)).GetValue ().ToString (), TypeManager.CSharpName (target));
 399                                 return;
 400                         }
 401
 402                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 403                                 TypeManager.CSharpName (type),
 404                                 TypeManager.CSharpName (target));
 405                 }
 406
 407                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 408                 {
 409                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 410                                 name);
 411                 }
 412
 413                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 414                 {
 415                         Error_TypeDoesNotContainDefinition (loc, type, name);
 416                 }
 417
 418                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 419                 {
 420                         Report.SymbolRelatedToPreviousError (type);
 421                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 422                                 TypeManager.CSharpName (type), name);
 423                 }
 424
 425                 protected static void Error_ValueAssignment (Location loc)
 426                 {
 427                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 428                 }
 429
 430                 ResolveFlags ExprClassToResolveFlags
 431                 {
 432                         get {
 433                                 switch (eclass) {
 434                                         case ExprClass.Type:
 435                                         case ExprClass.Namespace:
 436                                                 return ResolveFlags.Type;
 437
 438                                         case ExprClass.MethodGroup:
 439                                                 return ResolveFlags.MethodGroup;
 440
 441                                         case ExprClass.Value:
 442                                         case ExprClass.Variable:
 443                                         case ExprClass.PropertyAccess:
 444                                         case ExprClass.EventAccess:
 445                                         case ExprClass.IndexerAccess:
 446                                                 return ResolveFlags.VariableOrValue;
 447
 448                                         default:
 449                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 450                                 }
 451                         }
 452                 }
 453
 454                 /// <summary>
 455                 ///   Resolves an expression and performs semantic analysis on it.
 456                 /// </summary>
 457                 ///
 458                 /// <remarks>
 459                 ///   Currently Resolve wraps DoResolve to perform sanity
 460                 ///   checking and assertion checking on what we expect from Resolve.
 461                 /// </remarks>
 462                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 463                 {
 464                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 465                                 return ResolveAsTypeStep (ec, false);
 466
 467                         bool do_flow_analysis = ec.DoFlowAnalysis;
 468                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 469                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 470                                 do_flow_analysis = false;
 471                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 472                                 omit_struct_analysis = true;
 473
 474                         Expression e;
 475                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 476                                 if (this is SimpleName) {
 477                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 478                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 479                                 } else {
 480                                         e = DoResolve (ec);
 481                                 }
 482                         }
 483
 484                         if (e == null)
 485                                 return null;
 486
 487                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 488                                 e.Error_UnexpectedKind (flags, loc);
 489                                 return null;
 490                         }
 491
 492                         if (e.type == null && !(e is Namespace)) {
 493                                 throw new Exception (
 494                                         "Expression " + e.GetType () +
 495                                         " did not set its type after Resolve\n" +
 496                                         "called from: " + this.GetType ());
 497                         }
 498
 499                         return e;
 500                 }
 501
 502                 /// <summary>
 503                 ///   Resolves an expression and performs semantic analysis on it.
 504                 /// </summary>
 505                 public Expression Resolve (EmitContext ec)
 506                 {
 507                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 508
 509                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 510                                 ((MethodGroupExpr) e).ReportUsageError ();
 511                                 return null;
 512                         }
 513                         return e;
 514                 }
 515
 516                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 517                 {
 518                         Expression e = Resolve (ec);
 519                         if (e == null)
 520                                 return null;
 521
 522                         Constant c = e as Constant;
 523                         if (c != null)
 524                                 return c;
 525
 526                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 527                         return null;
 528                 }
 529
 530                 /// <summary>
 531                 ///   Resolves an expression for LValue assignment
 532                 /// </summary>
 533                 ///
 534                 /// <remarks>
 535                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 536                 ///   checking and assertion checking on what we expect from Resolve
 537                 /// </remarks>
 538                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 539                 {
 540                         int errors = Report.Errors;
 541                         bool out_access = right_side == EmptyExpression.OutAccess;
 542
 543                         Expression e = DoResolveLValue (ec, right_side);
 544
 545                         if (e != null && out_access && !(e is IMemoryLocation)) {
 546                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 547                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 548
 549                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 550                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 551                                 e = null;
 552                         }
 553
 554                         if (e == null) {
 555                                 if (errors == Report.Errors) {
 556                                         if (out_access)
 557                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 558                                         else
 559                                                 Error_ValueAssignment (loc);
 560                                 }
 561                                 return null;
 562                         }
 563
 564                         if (e.eclass == ExprClass.Invalid)
 565                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 566
 567                         if (e.eclass == ExprClass.MethodGroup) {
 568                                 ((MethodGroupExpr) e).ReportUsageError ();
 569                                 return null;
 570                         }
 571
 572                         if ((e.type == null) && !(e is ConstructedType))
 573                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 574
 575                         return e;
 576                 }
 577
 578                 /// <summary>
 579                 ///   Emits the code for the expression
 580                 /// </summary>
 581                 ///
 582                 /// <remarks>
 583                 ///   The Emit method is invoked to generate the code
 584                 ///   for the expression.
 585                 /// </remarks>
 586                 public abstract void Emit (EmitContext ec);
 587
 588                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 589                 {
 590                         Emit (ec);
 591                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 592                 }
 593
 594                 public virtual void EmitSideEffect (EmitContext ec)
 595                 {
 596                         Emit (ec);
 597                         ec.ig.Emit (OpCodes.Pop);
 598                 }
 599
 600                 /// <summary>
 601                 ///   Protected constructor.  Only derivate types should
 602                 ///   be able to be created
 603                 /// </summary>
 604
 605                 protected Expression ()
 606                 {
 607                         eclass = ExprClass.Invalid;
 608                         type = null;
 609                 }
 610
 611                 /// <summary>
 612                 ///   Returns a fully formed expression after a MemberLookup
 613                 /// </summary>
 614                 ///
 615                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 616                 {
 617                         if (mi is EventInfo)
 618                                 return new EventExpr ((EventInfo) mi, loc);
 619                         else if (mi is FieldInfo) {
 620                                 FieldInfo fi = (FieldInfo) mi;
 621                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 622                                         return new ConstantExpr (fi, loc);
 623                                 return new FieldExpr (fi, loc);
 624                         } else if (mi is PropertyInfo)
 625                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 626                         else if (mi is Type) {
 627                                 return new TypeExpression ((System.Type) mi, loc);
 628                         }
 629
 630                         return null;
 631                 }
 632
 633                 protected static ArrayList almost_matched_members = new ArrayList (4);
 634
 635                 //
 636                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 637                 //
 638                 // This code could use some optimizations, but we need to do some
 639                 // measurements.  For example, we could use a delegate to `flag' when
 640                 // something can not any longer be a method-group (because it is something
 641                 // else).
 642                 //
 643                 // Return values:
 644                 //     If the return value is an Array, then it is an array of
 645                 //     MethodBases
 646                 //
 647                 //     If the return value is an MemberInfo, it is anything, but a Method
 648                 //
 649                 //     null on error.
 650                 //
 651                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 652                 // the arguments here and have MemberLookup return only the methods that
 653                 // match the argument count/type, unlike we are doing now (we delay this
 654                 // decision).
 655                 //
 656                 // This is so we can catch correctly attempts to invoke instance methods
 657                 // from a static body (scan for error 120 in ResolveSimpleName).
 658                 //
 659                 //
 660                 // FIXME: Potential optimization, have a static ArrayList
 661                 //
 662
 663                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 664                                                        MemberTypes mt, BindingFlags bf, Location loc)
 665                 {
 666                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 667                 }
 668
 669                 //
 670                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 671                 // `qualifier_type' or null to lookup members in the current class.
 672                 //
 673
 674                 public static Expression MemberLookup (Type container_type,
 675                                                        Type qualifier_type, Type queried_type,
 676                                                        string name, MemberTypes mt,
 677                                                        BindingFlags bf, Location loc)
 678                 {
 679                         almost_matched_members.Clear ();
 680
 681                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 682                                                                      queried_type, mt, bf, name, almost_matched_members);
 683
 684                         if (mi == null)
 685                                 return null;
 686
 687                         if (mi.Length > 1) {
 688                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 689                                 ArrayList methods = new ArrayList (2);
 690                                 ArrayList non_methods = null;
 691
 692                                 foreach (MemberInfo m in mi) {
 693                                         if (m is MethodBase) {
 694                                                 methods.Add (m);
 695                                                 continue;
 696                                         }
 697
 698                                         if (non_methods == null) {
 699                                                 non_methods = new ArrayList (2);
 700                                                 non_methods.Add (m);
 701                                                 continue;
 702                                         }
 703
 704                                         foreach (MemberInfo n_m in non_methods) {
 705                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 706                                                         continue;
 707
 708                                                 Report.SymbolRelatedToPreviousError (m);
 709                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 710                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 711                                                 return null;
 712                                         }
 713                                 }
 714
 715                                 if (methods.Count == 0)
 716                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 717
 718                                 if (non_methods != null) {
 719                                         MethodBase method = (MethodBase) methods [0];
 720                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 721                                         if (method.DeclaringType == non_method.DeclaringType) {
 722                                                 // Cannot happen with C# code, but is valid in IL
 723                                                 Report.SymbolRelatedToPreviousError (method);
 724                                                 Report.SymbolRelatedToPreviousError (non_method);
 725                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 726                                                               TypeManager.GetFullNameSignature (non_method),
 727                                                               TypeManager.CSharpSignature (method));
 728                                                 return null;
 729                                         }
 730
 731                                         if (is_interface) {
 732                                                 Report.SymbolRelatedToPreviousError (method);
 733                                                 Report.SymbolRelatedToPreviousError (non_method);
 734                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 735                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 736                                         }
 737                                 }
 738
 739                                 return new MethodGroupExpr (methods, queried_type, loc);
 740                         }
 741
 742                         if (mi [0] is MethodBase)
 743                                 return new MethodGroupExpr (mi, queried_type, loc);
 744
 745                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 746                 }
 747
 748                 public const MemberTypes AllMemberTypes =
 749                         MemberTypes.Constructor |
 750                         MemberTypes.Event       |
 751                         MemberTypes.Field       |
 752                         MemberTypes.Method      |
 753                         MemberTypes.NestedType  |
 754                         MemberTypes.Property;
 755
 756                 public const BindingFlags AllBindingFlags =
 757                         BindingFlags.Public |
 758                         BindingFlags.Static |
 759                         BindingFlags.Instance;
 760
 761                 public static Expression MemberLookup (Type container_type, Type queried_type,
 762                                                        string name, Location loc)
 763                 {
 764                         return MemberLookup (container_type, null, queried_type, name,
 765                                              AllMemberTypes, AllBindingFlags, loc);
 766                 }
 767
 768                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 769                                                        Type queried_type, string name, Location loc)
 770                 {
 771                         return MemberLookup (container_type, qualifier_type, queried_type,
 772                                              name, AllMemberTypes, AllBindingFlags, loc);
 773                 }
 774
 775                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 776                                                        string name, Location loc)
 777                 {
 778                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 779                                              MemberTypes.Method, AllBindingFlags, loc);
 780                 }
 781
 782                 /// <summary>
 783                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 784                 ///   to find a final definition.  If the final definition is not found, we
 785                 ///   look for private members and display a useful debugging message if we
 786                 ///   find it.
 787                 /// </summary>
 788                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 789                                                             Type queried_type, string name,
 790                                                             MemberTypes mt, BindingFlags bf,
 791                                                             Location loc)
 792                 {
 793                         Expression e;
 794
 795                         int errors = Report.Errors;
 796
 797                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 798
 799                         if (e != null || errors != Report.Errors)
 800                                 return e;
 801
 802                         // No errors were reported by MemberLookup, but there was an error.
 803                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 804                                         name, null, mt, bf);
 805                 }
 806
 807                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 808                                                        Type queried_type, string name, string class_name,
 809                                                            MemberTypes mt, BindingFlags bf)
 810                 {
 811                         if (almost_matched_members.Count != 0) {
 812                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 813                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 814                                         for (int j = 0; j < i; ++j) {
 815                                                 if (m == almost_matched_members [j]) {
 816                                                         m = null;
 817                                                         break;
 818                                                 }
 819                                         }
 820                                         if (m == null)
 821                                                 continue;
 822
 823                                         Type declaring_type = m.DeclaringType;
 824
 825                                         Report.SymbolRelatedToPreviousError (m);
 826                                         if (qualifier_type == null) {
 827                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 828                                                               TypeManager.CSharpName (m.DeclaringType),
 829                                                               TypeManager.CSharpName (container_type));
 830
 831                                         } else if (qualifier_type != container_type &&
 832                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 833                                                 // Although a derived class can access protected members of
 834                                                 // its base class it cannot do so through an instance of the
 835                                                 // base class (CS1540).  If the qualifier_type is a base of the
 836                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 837                                                 // then we are in this situation.
 838                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 839                                         } else {
 840                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 841                                         }
 842                                 }
 843                                 almost_matched_members.Clear ();
 844                                 return null;
 845                         }
 846
 847                         MemberInfo[] lookup = null;
 848                         if (queried_type == null) {
 849                                 class_name = "global::";
 850                         } else {
 851                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 852                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 853                                         name, null);
 854
 855                                 if (lookup != null) {
 856                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 857                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 858                                         return Error_MemberLookupFailed (lookup);
 859                                 }
 860
 861                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 862                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 863                                         name, null);
 864                         }
 865
 866                         if (lookup == null) {
 867                                 if (class_name != null) {
 868                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 869                                                 name);
 870                                 } else {
 871                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 872                                 }
 873                                 return null;
 874                         }
 875
 876                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 877                                                       AllMemberTypes, AllBindingFlags |
 878                                                       BindingFlags.NonPublic, name, null) == null) {
 879                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 880                                         Type t = (Type) lookup [0];
 881
 882                                         Report.Error (305, loc,
 883                                                       "Using the generic type `{0}' " +
 884                                                       "requires {1} type arguments",
 885                                                       TypeManager.CSharpName (t),
 886                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 887                                         return null;
 888                                 }
 889                         }
 890
 891                         return Error_MemberLookupFailed (lookup);
 892                 }
 893
 894                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 895                 {
 896                         for (int i = 0; i < members.Length; ++i) {
 897                                 if (!(members [i] is MethodBase))
 898                                         return null;
 899                         }
 900
 901                         // By default propagate the closest candidates upwards
 902                         return new MethodGroupExpr (members, type, loc);
 903                 }
 904
 905                 protected virtual void Error_NegativeArrayIndex (Location loc)
 906                 {
 907                         throw new NotImplementedException ();
 908                 }
 909
 910                 /// <summary>
 911                 ///   Returns an expression that can be used to invoke operator true
 912                 ///   on the expression if it exists.
 913                 /// </summary>
 914                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 915                 {
 916                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 917                 }
 918
 919                 /// <summary>
 920                 ///   Returns an expression that can be used to invoke operator false
 921                 ///   on the expression if it exists.
 922                 /// </summary>
 923                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 924                 {
 925                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 926                 }
 927
 928                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 929                 {
 930                         MethodGroupExpr operator_group;
 931                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 932                         if (operator_group == null)
 933                                 return null;
 934
 935                         ArrayList arguments = new ArrayList (1);
 936                         arguments.Add (new Argument (e, Argument.AType.Expression));
 937                         operator_group = operator_group.OverloadResolve (
 938                                 ec, ref arguments, false, loc);
 939
 940                         if (operator_group == null)
 941                                 return null;
 942
 943                         return new UserOperatorCall (operator_group, arguments, null, loc);
 944                 }
 945
 946                 /// <summary>
 947                 ///   Resolves the expression `e' into a boolean expression: either through
 948                 ///   an implicit conversion, or through an `operator true' invocation
 949                 /// </summary>
 950                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 951                 {
 952                         e = e.Resolve (ec);
 953                         if (e == null)
 954                                 return null;
 955
 956                         if (e.Type == TypeManager.bool_type)
 957                                 return e;
 958
 959                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 960
 961                         if (converted != null)
 962                                 return converted;
 963
 964                         //
 965                         // If no implicit conversion to bool exists, try using `operator true'
 966                         //
 967                         converted = Expression.GetOperatorTrue (ec, e, loc);
 968                         if (converted == null){
 969                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 970                                 return null;
 971                         }
 972                         return converted;
 973                 }
 974
 975                 public virtual string ExprClassName
 976                 {
 977                         get {
 978                                 switch (eclass){
 979                                         case ExprClass.Invalid:
 980                                                 return "Invalid";
 981                                         case ExprClass.Value:
 982                                                 return "value";
 983                                         case ExprClass.Variable:
 984                                                 return "variable";
 985                                         case ExprClass.Namespace:
 986                                                 return "namespace";
 987                                         case ExprClass.Type:
 988                                                 return "type";
 989                                         case ExprClass.MethodGroup:
 990                                                 return "method group";
 991                                         case ExprClass.PropertyAccess:
 992                                                 return "property access";
 993                                         case ExprClass.EventAccess:
 994                                                 return "event access";
 995                                         case ExprClass.IndexerAccess:
 996                                                 return "indexer access";
 997                                         case ExprClass.Nothing:
 998                                                 return "null";
 999                                 }
1000                                 throw new Exception ("Should not happen");
1001                         }
1002                 }
1003
1004                 /// <summary>
1005                 ///   Reports that we were expecting `expr' to be of class `expected'
1006                 /// </summary>
1007                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1008                 {
1009                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1010                 }
1011
1012                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1013                 {
1014                         string name = GetSignatureForError ();
1015                         if (ds != null)
1016                                 name = ds.GetSignatureForError () + '.' + name;
1017
1018                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1019                               name, was, expected);
1020                 }
1021
1022                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1023                 {
1024                         string [] valid = new string [4];
1025                         int count = 0;
1026
1027                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1028                                 valid [count++] = "variable";
1029                                 valid [count++] = "value";
1030                         }
1031
1032                         if ((flags & ResolveFlags.Type) != 0)
1033                                 valid [count++] = "type";
1034
1035                         if ((flags & ResolveFlags.MethodGroup) != 0)
1036                                 valid [count++] = "method group";
1037
1038                         if (count == 0)
1039                                 valid [count++] = "unknown";
1040
1041                         StringBuilder sb = new StringBuilder (valid [0]);
1042                         for (int i = 1; i < count - 1; i++) {
1043                                 sb.Append ("', `");
1044                                 sb.Append (valid [i]);
1045                         }
1046                         if (count > 1) {
1047                                 sb.Append ("' or `");
1048                                 sb.Append (valid [count - 1]);
1049                         }
1050
1051                         Report.Error (119, loc,
1052                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1053                 }
1054
1055                 public static void UnsafeError (Location loc)
1056                 {
1057                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1058                 }
1059
1060                 //
1061                 // Load the object from the pointer.
1062                 //
1063                 public static void LoadFromPtr (ILGenerator ig, Type t)
1064                 {
1065                         if (t == TypeManager.int32_type)
1066                                 ig.Emit (OpCodes.Ldind_I4);
1067                         else if (t == TypeManager.uint32_type)
1068                                 ig.Emit (OpCodes.Ldind_U4);
1069                         else if (t == TypeManager.short_type)
1070                                 ig.Emit (OpCodes.Ldind_I2);
1071                         else if (t == TypeManager.ushort_type)
1072                                 ig.Emit (OpCodes.Ldind_U2);
1073                         else if (t == TypeManager.char_type)
1074                                 ig.Emit (OpCodes.Ldind_U2);
1075                         else if (t == TypeManager.byte_type)
1076                                 ig.Emit (OpCodes.Ldind_U1);
1077                         else if (t == TypeManager.sbyte_type)
1078                                 ig.Emit (OpCodes.Ldind_I1);
1079                         else if (t == TypeManager.uint64_type)
1080                                 ig.Emit (OpCodes.Ldind_I8);
1081                         else if (t == TypeManager.int64_type)
1082                                 ig.Emit (OpCodes.Ldind_I8);
1083                         else if (t == TypeManager.float_type)
1084                                 ig.Emit (OpCodes.Ldind_R4);
1085                         else if (t == TypeManager.double_type)
1086                                 ig.Emit (OpCodes.Ldind_R8);
1087                         else if (t == TypeManager.bool_type)
1088                                 ig.Emit (OpCodes.Ldind_I1);
1089                         else if (t == TypeManager.intptr_type)
1090                                 ig.Emit (OpCodes.Ldind_I);
1091                         else if (TypeManager.IsEnumType (t)) {
1092                                 if (t == TypeManager.enum_type)
1093                                         ig.Emit (OpCodes.Ldind_Ref);
1094                                 else
1095                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1096                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1097                                 ig.Emit (OpCodes.Ldobj, t);
1098                         else if (t.IsPointer)
1099                                 ig.Emit (OpCodes.Ldind_I);
1100                         else
1101                                 ig.Emit (OpCodes.Ldind_Ref);
1102                 }
1103
1104                 //
1105                 // The stack contains the pointer and the value of type `type'
1106                 //
1107                 public static void StoreFromPtr (ILGenerator ig, Type type)
1108                 {
1109                         if (TypeManager.IsEnumType (type))
1110                                 type = TypeManager.GetEnumUnderlyingType (type);
1111                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1112                                 ig.Emit (OpCodes.Stind_I4);
1113                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1114                                 ig.Emit (OpCodes.Stind_I8);
1115                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1116                                  type == TypeManager.ushort_type)
1117                                 ig.Emit (OpCodes.Stind_I2);
1118                         else if (type == TypeManager.float_type)
1119                                 ig.Emit (OpCodes.Stind_R4);
1120                         else if (type == TypeManager.double_type)
1121                                 ig.Emit (OpCodes.Stind_R8);
1122                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1123                                  type == TypeManager.bool_type)
1124                                 ig.Emit (OpCodes.Stind_I1);
1125                         else if (type == TypeManager.intptr_type)
1126                                 ig.Emit (OpCodes.Stind_I);
1127                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1128                                 ig.Emit (OpCodes.Stobj, type);
1129                         else
1130                                 ig.Emit (OpCodes.Stind_Ref);
1131                 }
1132
1133                 //
1134                 // Returns the size of type `t' if known, otherwise, 0
1135                 //
1136                 public static int GetTypeSize (Type t)
1137                 {
1138                         t = TypeManager.TypeToCoreType (t);
1139                         if (t == TypeManager.int32_type ||
1140                             t == TypeManager.uint32_type ||
1141                             t == TypeManager.float_type)
1142                                 return 4;
1143                         else if (t == TypeManager.int64_type ||
1144                                  t == TypeManager.uint64_type ||
1145                                  t == TypeManager.double_type)
1146                                 return 8;
1147                         else if (t == TypeManager.byte_type ||
1148                                  t == TypeManager.sbyte_type ||
1149                                  t == TypeManager.bool_type)
1150                                 return 1;
1151                         else if (t == TypeManager.short_type ||
1152                                  t == TypeManager.char_type ||
1153                                  t == TypeManager.ushort_type)
1154                                 return 2;
1155                         else if (t == TypeManager.decimal_type)
1156                                 return 16;
1157                         else
1158                                 return 0;
1159                 }
1160
1161                 protected void Error_CannotCallAbstractBase (string name)
1162                 {
1163                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1164                 }
1165
1166                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1167                 {
1168                         Report.SymbolRelatedToPreviousError (type);
1169                         if (ec.CurrentInitializerVariable != null) {
1170                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1171                                         GetSignatureForError ());
1172                         } else {
1173                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1174                                         GetSignatureForError ());
1175                         }
1176                 }
1177
1178                 //
1179                 // Converts `source' to an int, uint, long or ulong.
1180                 //
1181                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1182                 {
1183                         Expression converted;
1184
1185                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1186                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1187                                 if (converted == null)
1188                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1189                                 if (converted == null)
1190                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1191                                 if (converted == null)
1192                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1193
1194                                 if (converted == null) {
1195                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1196                                         return null;
1197                                 }
1198                         }
1199
1200                         //
1201                         // Only positive constants are allowed at compile time
1202                         //
1203                         Constant c = converted as Constant;
1204                         if (c != null) {
1205                                 if (c.IsNegative) {
1206                                         Error_NegativeArrayIndex (source.loc);
1207                                 }
1208                                 return c;
1209                         }
1210
1211                         return new ArrayIndexCast (converted).Resolve (ec);
1212                 }
1213
1214                 //
1215                 // Derived classes implement this method by cloning the fields that
1216                 // could become altered during the Resolve stage
1217                 //
1218                 // Only expressions that are created for the parser need to implement
1219                 // this.
1220                 //
1221                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1222                 {
1223                         throw new NotImplementedException (
1224                                 String.Format (
1225                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1226                 }
1227
1228                 //
1229                 // Clones an expression created by the parser.
1230                 //
1231                 // We only support expressions created by the parser so far, not
1232                 // expressions that have been resolved (many more classes would need
1233                 // to implement CloneTo).
1234                 //
1235                 // This infrastructure is here merely for Lambda expressions which
1236                 // compile the same code using different type values for the same
1237                 // arguments to find the correct overload
1238                 //
1239                 public Expression Clone (CloneContext clonectx)
1240                 {
1241                         Expression cloned = (Expression) MemberwiseClone ();
1242                         CloneTo (clonectx, cloned);
1243
1244                         return cloned;
1245                 }
1246
1247                 public virtual Expression CreateExpressionTree (EmitContext ec)
1248                 {
1249                         throw new NotImplementedException (
1250                                 "Expression tree conversion not implemented for " + GetType ());
1251                 }
1252
1253                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1254                 {
1255                         return CreateExpressionFactoryCall (name, null, args, loc);
1256                 }
1257
1258                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1259                 {
1260                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1261                 }
1262
1263                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1264                 {
1265                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1266                 }
1267
1268                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1269                 {
1270                         TypeExpr texpr = TypeManager.expression_type_expr;
1271                         if (texpr == null) {
1272                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1273                                 if (t == null)
1274                                         return null;
1275
1276                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1277                         }
1278
1279                         return texpr;
1280                 }
1281         }
1282
1283         /// <summary>
1284         ///   This is just a base class for expressions that can
1285         ///   appear on statements (invocations, object creation,
1286         ///   assignments, post/pre increment and decrement).  The idea
1287         ///   being that they would support an extra Emition interface that
1288         ///   does not leave a result on the stack.
1289         /// </summary>
1290         public abstract class ExpressionStatement : Expression {
1291
1292                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1293                 {
1294                         Expression e = Resolve (ec);
1295                         if (e == null)
1296                                 return null;
1297
1298                         ExpressionStatement es = e as ExpressionStatement;
1299                         if (es == null)
1300                                 Error_InvalidExpressionStatement ();
1301
1302                         return es;
1303                 }
1304
1305                 /// <summary>
1306                 ///   Requests the expression to be emitted in a `statement'
1307                 ///   context.  This means that no new value is left on the
1308                 ///   stack after invoking this method (constrasted with
1309                 ///   Emit that will always leave a value on the stack).
1310                 /// </summary>
1311                 public abstract void EmitStatement (EmitContext ec);
1312
1313                 public override void EmitSideEffect (EmitContext ec)
1314                 {
1315                         EmitStatement (ec);
1316                 }
1317         }
1318
1319         /// <summary>
1320         ///   This kind of cast is used to encapsulate the child
1321         ///   whose type is child.Type into an expression that is
1322         ///   reported to return "return_type".  This is used to encapsulate
1323         ///   expressions which have compatible types, but need to be dealt
1324         ///   at higher levels with.
1325         ///
1326         ///   For example, a "byte" expression could be encapsulated in one
1327         ///   of these as an "unsigned int".  The type for the expression
1328         ///   would be "unsigned int".
1329         ///
1330         /// </summary>
1331         public abstract class TypeCast : Expression
1332         {
1333                 protected Expression child;
1334
1335                 protected TypeCast (Expression child, Type return_type)
1336                 {
1337                         eclass = child.eclass;
1338                         loc = child.Location;
1339                         type = return_type;
1340                         this.child = child;
1341                 }
1342
1343                 public override Expression CreateExpressionTree (EmitContext ec)
1344                 {
1345                         ArrayList args = new ArrayList (2);
1346                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1347                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1348                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1349                 }
1350
1351                 public override Expression DoResolve (EmitContext ec)
1352                 {
1353                         // This should never be invoked, we are born in fully
1354                         // initialized state.
1355
1356                         return this;
1357                 }
1358
1359                 public override void Emit (EmitContext ec)
1360                 {
1361                         child.Emit (ec);
1362                 }
1363
1364                 public override bool GetAttributableValue (Type value_type, out object value)
1365                 {
1366                         return child.GetAttributableValue (value_type, out value);
1367                 }
1368
1369                 protected override void CloneTo (CloneContext clonectx, Expression t)
1370                 {
1371                         TypeCast target = (TypeCast) t;
1372
1373                         target.child = child.Clone (clonectx);
1374                 }
1375         }
1376
1377         public class EmptyCast : TypeCast {
1378                 EmptyCast (Expression child, Type target_type)
1379                         : base (child, target_type)
1380                 {
1381                 }
1382
1383                 public static Expression Create (Expression child, Type type)
1384                 {
1385                         Constant c = child as Constant;
1386                         if (c != null)
1387                                 return new EmptyConstantCast (c, type);
1388
1389                         return new EmptyCast (child, type);
1390                 }
1391
1392                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1393                 {
1394                         child.EmitBranchable (ec, label, on_true);
1395                 }
1396
1397                 public override void EmitSideEffect (EmitContext ec)
1398                 {
1399                         child.EmitSideEffect (ec);
1400                 }
1401
1402         }
1403
1404         /// <summary>
1405         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1406         /// </summary>
1407         public class OperatorCast : TypeCast {
1408                 MethodInfo conversion_operator;
1409                 bool find_explicit;
1410
1411                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1412
1413                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1414                         : base (child, target_type)
1415                 {
1416                         this.find_explicit = find_explicit;
1417                 }
1418
1419                 // Returns the implicit operator that converts from
1420                 // 'child.Type' to our target type (type)
1421                 MethodInfo GetConversionOperator (bool find_explicit)
1422                 {
1423                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1424
1425                         MemberInfo [] mi;
1426
1427                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1428                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1429
1430                         if (mi == null){
1431                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1432                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1433                         }
1434
1435                         foreach (MethodInfo oper in mi) {
1436                                 ParameterData pd = TypeManager.GetParameterData (oper);
1437
1438                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1439                                         return oper;
1440                         }
1441
1442                         return null;
1443
1444
1445                 }
1446                 public override void Emit (EmitContext ec)
1447                 {
1448                         ILGenerator ig = ec.ig;
1449
1450                         child.Emit (ec);
1451                         conversion_operator = GetConversionOperator (find_explicit);
1452
1453                         if (conversion_operator == null)
1454                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1455
1456                         ig.Emit (OpCodes.Call, conversion_operator);
1457                 }
1458
1459         }
1460
1461         /// <summary>
1462         ///     This is a numeric cast to a Decimal
1463         /// </summary>
1464         public class CastToDecimal : TypeCast {
1465                 MethodInfo conversion_operator;
1466
1467                 public CastToDecimal (Expression child)
1468                         : this (child, false)
1469                 {
1470                 }
1471
1472                 public CastToDecimal (Expression child, bool find_explicit)
1473                         : base (child, TypeManager.decimal_type)
1474                 {
1475                         conversion_operator = GetConversionOperator (find_explicit);
1476
1477                         if (conversion_operator == null)
1478                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1479                 }
1480
1481                 // Returns the implicit operator that converts from
1482                 // 'child.Type' to System.Decimal.
1483                 MethodInfo GetConversionOperator (bool find_explicit)
1484                 {
1485                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1486
1487                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1488                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1489
1490                         foreach (MethodInfo oper in mi) {
1491                                 ParameterData pd = TypeManager.GetParameterData (oper);
1492
1493                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1494                                         return oper;
1495                         }
1496
1497                         return null;
1498                 }
1499                 public override void Emit (EmitContext ec)
1500                 {
1501                         ILGenerator ig = ec.ig;
1502                         child.Emit (ec);
1503
1504                         ig.Emit (OpCodes.Call, conversion_operator);
1505                 }
1506         }
1507
1508         /// <summary>
1509         ///     This is an explicit numeric cast from a Decimal
1510         /// </summary>
1511         public class CastFromDecimal : TypeCast
1512         {
1513                 static IDictionary operators;
1514
1515                 public CastFromDecimal (Expression child, Type return_type)
1516                         : base (child, return_type)
1517                 {
1518                         if (child.Type != TypeManager.decimal_type)
1519                                 throw new InternalErrorException (
1520                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1521                 }
1522
1523                 // Returns the explicit operator that converts from an
1524                 // express of type System.Decimal to 'type'.
1525                 public Expression Resolve ()
1526                 {
1527                         if (operators == null) {
1528                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1529                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1530                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1531
1532                                 operators = new System.Collections.Specialized.HybridDictionary ();
1533                                 foreach (MethodInfo oper in all_oper) {
1534                                         ParameterData pd = TypeManager.GetParameterData (oper);
1535                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1536                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1537                                 }
1538                         }
1539
1540                         return operators.Contains (type) ? this : null;
1541                 }
1542
1543                 public override void Emit (EmitContext ec)
1544                 {
1545                         ILGenerator ig = ec.ig;
1546                         child.Emit (ec);
1547
1548                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1549                 }
1550         }
1551
1552
1553         //
1554         // Constant specialization of EmptyCast.
1555         // We need to special case this since an empty cast of
1556         // a constant is still a constant.
1557         //
1558         public class EmptyConstantCast : Constant
1559         {
1560                 public readonly Constant child;
1561
1562                 public EmptyConstantCast(Constant child, Type type)
1563                         : base (child.Location)
1564                 {
1565                         eclass = child.eclass;
1566                         this.child = child;
1567                         this.type = type;
1568                 }
1569
1570                 public override string AsString ()
1571                 {
1572                         return child.AsString ();
1573                 }
1574
1575                 public override object GetValue ()
1576                 {
1577                         return child.GetValue ();
1578                 }
1579
1580                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1581                 {
1582                         // FIXME: check that 'type' can be converted to 'target_type' first
1583                         return child.ConvertExplicitly (in_checked_context, target_type);
1584                 }
1585
1586                 public override Expression CreateExpressionTree (EmitContext ec)
1587                 {
1588                         ArrayList args = new ArrayList (2);
1589                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1590                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1591                         return CreateExpressionFactoryCall ("Convert", args);
1592                 }
1593
1594                 public override Constant Increment ()
1595                 {
1596                         return child.Increment ();
1597                 }
1598
1599                 public override bool IsDefaultValue {
1600                         get { return child.IsDefaultValue; }
1601                 }
1602
1603                 public override bool IsNegative {
1604                         get { return child.IsNegative; }
1605                 }
1606
1607                 public override bool IsNull {
1608                         get { return child.IsNull; }
1609                 }
1610
1611                 public override bool IsZeroInteger {
1612                         get { return child.IsZeroInteger; }
1613                 }
1614
1615                 public override void Emit (EmitContext ec)
1616                 {
1617                         child.Emit (ec);
1618                 }
1619
1620                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1621                 {
1622                         child.EmitBranchable (ec, label, on_true);
1623                 }
1624
1625                 public override void EmitSideEffect (EmitContext ec)
1626                 {
1627                         child.EmitSideEffect (ec);
1628                 }
1629
1630                 public override Constant ConvertImplicitly (Type target_type)
1631                 {
1632                         // FIXME: Do we need to check user conversions?
1633                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1634                                 return null;
1635                         return child.ConvertImplicitly (target_type);
1636                 }
1637         }
1638
1639
1640         /// <summary>
1641         ///  This class is used to wrap literals which belong inside Enums
1642         /// </summary>
1643         public class EnumConstant : Constant {
1644                 public Constant Child;
1645
1646                 public EnumConstant (Constant child, Type enum_type):
1647                         base (child.Location)
1648                 {
1649                         eclass = child.eclass;
1650                         this.Child = child;
1651                         type = enum_type;
1652                 }
1653
1654                 public override Expression DoResolve (EmitContext ec)
1655                 {
1656                         // This should never be invoked, we are born in fully
1657                         // initialized state.
1658
1659                         return this;
1660                 }
1661
1662                 public override void Emit (EmitContext ec)
1663                 {
1664                         Child.Emit (ec);
1665                 }
1666
1667                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1668                 {
1669                         Child.EmitBranchable (ec, label, on_true);
1670                 }
1671
1672                 public override void EmitSideEffect (EmitContext ec)
1673                 {
1674                         Child.EmitSideEffect (ec);
1675                 }
1676
1677                 public override bool GetAttributableValue (Type value_type, out object value)
1678                 {
1679                         value = GetTypedValue ();
1680                         return true;
1681                 }
1682
1683                 public override string GetSignatureForError()
1684                 {
1685                         return TypeManager.CSharpName (Type);
1686                 }
1687
1688                 public override object GetValue ()
1689                 {
1690                         return Child.GetValue ();
1691                 }
1692
1693                 public override object GetTypedValue ()
1694                 {
1695                         // FIXME: runtime is not ready to work with just emited enums
1696                         if (!RootContext.StdLib) {
1697                                 return Child.GetValue ();
1698                         }
1699
1700                         return System.Enum.ToObject (type, Child.GetValue ());
1701                 }
1702
1703                 public override string AsString ()
1704                 {
1705                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1706                 }
1707
1708                 public override Constant Increment()
1709                 {
1710                         return new EnumConstant (Child.Increment (), type);
1711                 }
1712
1713                 public override bool IsDefaultValue {
1714                         get {
1715                                 return Child.IsDefaultValue;
1716                         }
1717                 }
1718
1719                 public override bool IsZeroInteger {
1720                         get { return Child.IsZeroInteger; }
1721                 }
1722
1723                 public override bool IsNegative {
1724                         get {
1725                                 return Child.IsNegative;
1726                         }
1727                 }
1728
1729                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1730                 {
1731                         if (Child.Type == target_type)
1732                                 return Child;
1733
1734                         return Child.ConvertExplicitly (in_checked_context, target_type);
1735                 }
1736
1737                 public override Constant ConvertImplicitly (Type type)
1738                 {
1739                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1740                         type = TypeManager.DropGenericTypeArguments (type);
1741
1742                         if (this_type == type) {
1743                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1744                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1745                                         return this;
1746
1747                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1748                                 if (type.UnderlyingSystemType != child_type)
1749                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1750                                 return this;
1751                         }
1752
1753                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1754                                 return null;
1755                         }
1756
1757                         return Child.ConvertImplicitly(type);
1758                 }
1759
1760         }
1761
1762         /// <summary>
1763         ///   This kind of cast is used to encapsulate Value Types in objects.
1764         ///
1765         ///   The effect of it is to box the value type emitted by the previous
1766         ///   operation.
1767         /// </summary>
1768         public class BoxedCast : TypeCast {
1769
1770                 public BoxedCast (Expression expr, Type target_type)
1771                         : base (expr, target_type)
1772                 {
1773                         eclass = ExprClass.Value;
1774                 }
1775
1776                 public override Expression DoResolve (EmitContext ec)
1777                 {
1778                         // This should never be invoked, we are born in fully
1779                         // initialized state.
1780
1781                         return this;
1782                 }
1783
1784                 public override void Emit (EmitContext ec)
1785                 {
1786                         base.Emit (ec);
1787
1788                         ec.ig.Emit (OpCodes.Box, child.Type);
1789                 }
1790
1791                 public override void EmitSideEffect (EmitContext ec)
1792                 {
1793                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1794                         // so, we need to emit the box+pop instructions in most cases
1795                         if (child.Type.IsValueType &&
1796                             (type == TypeManager.object_type || type == TypeManager.value_type))
1797                                 child.EmitSideEffect (ec);
1798                         else
1799                                 base.EmitSideEffect (ec);
1800                 }
1801         }
1802
1803         public class UnboxCast : TypeCast {
1804                 public UnboxCast (Expression expr, Type return_type)
1805                         : base (expr, return_type)
1806                 {
1807                 }
1808
1809                 public override Expression DoResolve (EmitContext ec)
1810                 {
1811                         // This should never be invoked, we are born in fully
1812                         // initialized state.
1813
1814                         return this;
1815                 }
1816
1817                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1818                 {
1819                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1820                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1821                         return base.DoResolveLValue (ec, right_side);
1822                 }
1823
1824                 public override void Emit (EmitContext ec)
1825                 {
1826                         Type t = type;
1827                         ILGenerator ig = ec.ig;
1828
1829                         base.Emit (ec);
1830 #if GMCS_SOURCE
1831                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1832                                 ig.Emit (OpCodes.Unbox_Any, t);
1833                         else
1834 #endif
1835                         {
1836                                 ig.Emit (OpCodes.Unbox, t);
1837
1838                                 LoadFromPtr (ig, t);
1839                         }
1840                 }
1841         }
1842
1843         /// <summary>
1844         ///   This is used to perform explicit numeric conversions.
1845         ///
1846         ///   Explicit numeric conversions might trigger exceptions in a checked
1847         ///   context, so they should generate the conv.ovf opcodes instead of
1848         ///   conv opcodes.
1849         /// </summary>
1850         public class ConvCast : TypeCast {
1851                 public enum Mode : byte {
1852                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1853                         U1_I1, U1_CH,
1854                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1855                         U2_I1, U2_U1, U2_I2, U2_CH,
1856                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1857                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1858                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1859                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1860                         CH_I1, CH_U1, CH_I2,
1861                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1862                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1863                 }
1864
1865                 Mode mode;
1866
1867                 public ConvCast (Expression child, Type return_type, Mode m)
1868                         : base (child, return_type)
1869                 {
1870                         mode = m;
1871                 }
1872
1873                 public override Expression DoResolve (EmitContext ec)
1874                 {
1875                         // This should never be invoked, we are born in fully
1876                         // initialized state.
1877
1878                         return this;
1879                 }
1880
1881                 public override string ToString ()
1882                 {
1883                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1884                 }
1885
1886                 public override void Emit (EmitContext ec)
1887                 {
1888                         ILGenerator ig = ec.ig;
1889
1890                         base.Emit (ec);
1891
1892                         if (ec.CheckState){
1893                                 switch (mode){
1894                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1895                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1896                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1897                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1898                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1899
1900                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1901                                 case Mode.U1_CH: /* nothing */ break;
1902
1903                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1904                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1905                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1906                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1907                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1908                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1909
1910                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1911                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1912                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1913                                 case Mode.U2_CH: /* nothing */ break;
1914
1915                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1916                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1917                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1918                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1919                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1920                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1921                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1922
1923                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1924                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1925                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1926                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1927                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1928                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1929
1930                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1931                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1932                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1933                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1934                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1935                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1936                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1937                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1938
1939                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1940                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1941                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1942                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1943                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1944                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1945                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1946                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1947
1948                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1949                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1950                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1951
1952                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1953                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1954                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1955                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1956                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1957                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1958                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1959                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1960                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1961
1962                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1963                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1964                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1965                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1966                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1967                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1968                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1969                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1970                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1971                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1972                                 }
1973                         } else {
1974                                 switch (mode){
1975                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1976                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1977                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1978                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1979                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1980
1981                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1982                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1983
1984                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1985                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1986                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1987                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1988                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1989                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1990
1991                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1992                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1993                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1994                                 case Mode.U2_CH: /* nothing */ break;
1995
1996                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1997                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1998                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1999                                 case Mode.I4_U4: /* nothing */ break;
2000                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2001                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2002                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2003
2004                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2005                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2006                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2007                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2008                                 case Mode.U4_I4: /* nothing */ break;
2009                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2010
2011                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2012                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2013                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2014                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2015                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2016                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2017                                 case Mode.I8_U8: /* nothing */ break;
2018                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2019
2020                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2021                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2022                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2023                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2024                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2025                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2026                                 case Mode.U8_I8: /* nothing */ break;
2027                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2028
2029                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2030                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2031                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2032
2033                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2034                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2035                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2036                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2037                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2038                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2039                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2040                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2041                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2042
2043                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2044                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2045                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2046                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2047                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2048                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2049                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2050                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2051                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2052                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2053                                 }
2054                         }
2055                 }
2056         }
2057
2058         public class OpcodeCast : TypeCast {
2059                 OpCode op, op2;
2060                 bool second_valid;
2061
2062                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2063                         : base (child, return_type)
2064
2065                 {
2066                         this.op = op;
2067                         second_valid = false;
2068                 }
2069
2070                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
2071                         : base (child, return_type)
2072
2073                 {
2074                         this.op = op;
2075                         this.op2 = op2;
2076                         second_valid = true;
2077                 }
2078
2079                 public override Expression DoResolve (EmitContext ec)
2080                 {
2081                         // This should never be invoked, we are born in fully
2082                         // initialized state.
2083
2084                         return this;
2085                 }
2086
2087                 public override void Emit (EmitContext ec)
2088                 {
2089                         base.Emit (ec);
2090                         ec.ig.Emit (op);
2091
2092                         if (second_valid)
2093                                 ec.ig.Emit (op2);
2094                 }
2095
2096                 public Type UnderlyingType {
2097                         get { return child.Type; }
2098                 }
2099         }
2100
2101         /// <summary>
2102         ///   This kind of cast is used to encapsulate a child and cast it
2103         ///   to the class requested
2104         /// </summary>
2105         public class ClassCast : TypeCast {
2106                 public ClassCast (Expression child, Type return_type)
2107                         : base (child, return_type)
2108
2109                 {
2110                 }
2111
2112                 public override Expression DoResolve (EmitContext ec)
2113                 {
2114                         // This should never be invoked, we are born in fully
2115                         // initialized state.
2116
2117                         return this;
2118                 }
2119
2120                 public override void Emit (EmitContext ec)
2121                 {
2122                         base.Emit (ec);
2123
2124                         if (TypeManager.IsGenericParameter (child.Type))
2125                                 ec.ig.Emit (OpCodes.Box, child.Type);
2126
2127 #if GMCS_SOURCE
2128                         if (type.IsGenericParameter)
2129                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2130                         else
2131 #endif
2132                                 ec.ig.Emit (OpCodes.Castclass, type);
2133                 }
2134         }
2135
2136         //
2137         // Used when resolved expression has different representations for
2138         // expression trees and emit phase
2139         //
2140         public class ReducedExpression : Expression
2141         {
2142                 class ReducedConstantExpression : Constant
2143                 {
2144                         readonly Constant expr;
2145                         readonly Expression orig_expr;
2146
2147                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2148                                 : base (expr.Location)
2149                         {
2150                                 this.expr = expr;
2151                                 this.orig_expr = orig_expr;
2152                                 eclass = expr.eclass;
2153                                 type = expr.Type;
2154                         }
2155
2156                         public override string AsString ()
2157                         {
2158                                 return expr.AsString ();
2159                         }
2160
2161                         public override Expression CreateExpressionTree (EmitContext ec)
2162                         {
2163                                 return orig_expr.CreateExpressionTree (ec);
2164                         }
2165
2166                         public override object GetValue ()
2167                         {
2168                                 return expr.GetValue ();
2169                         }
2170
2171                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2172                         {
2173                                 throw new NotImplementedException ();
2174                         }
2175
2176                         public override Expression DoResolve (EmitContext ec)
2177                         {
2178                                 return this;
2179                         }
2180
2181                         public override Constant Increment ()
2182                         {
2183                                 throw new NotImplementedException ();
2184                         }
2185
2186                         public override bool IsDefaultValue {
2187                                 get {
2188                                         return expr.IsDefaultValue;
2189                                 }
2190                         }
2191
2192                         public override bool IsNegative {
2193                                 get {
2194                                         return expr.IsNegative;
2195                                 }
2196                         }
2197
2198                         public override void Emit (EmitContext ec)
2199                         {
2200                                 expr.Emit (ec);
2201                         }
2202                 }
2203
2204                 readonly Expression expr, orig_expr;
2205
2206                 private ReducedExpression (Expression expr, Expression orig_expr)
2207                 {
2208                         this.expr = expr;
2209                         this.orig_expr = orig_expr;
2210                         this.loc = orig_expr.Location;
2211                 }
2212
2213                 public static Expression Create (Constant expr, Expression original_expr)
2214                 {
2215                         return new ReducedConstantExpression (expr, original_expr);
2216                 }
2217
2218                 public static Expression Create (Expression expr, Expression original_expr)
2219                 {
2220                         Constant c = expr as Constant;
2221                         if (c != null)
2222                                 return Create (c, original_expr);
2223
2224                         return new ReducedExpression (expr, original_expr);
2225                 }
2226
2227                 public override Expression CreateExpressionTree (EmitContext ec)
2228                 {
2229                         return orig_expr.CreateExpressionTree (ec);
2230                 }
2231
2232                 public override Expression DoResolve (EmitContext ec)
2233                 {
2234                         eclass = expr.eclass;
2235                         type = expr.Type;
2236                         return this;
2237                 }
2238
2239                 public override void Emit (EmitContext ec)
2240                 {
2241                         expr.Emit (ec);
2242                 }
2243
2244                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2245                 {
2246                         expr.EmitBranchable (ec, target, on_true);
2247                 }
2248         }
2249
2250         //
2251         // Unresolved type name expressions
2252         //
2253         public abstract class ATypeNameExpression : FullNamedExpression
2254         {
2255                 public readonly string Name;
2256                 protected TypeArguments targs;
2257
2258                 protected ATypeNameExpression (string name, Location l)
2259                 {
2260                         Name = name;
2261                         loc = l;
2262                 }
2263
2264                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2265                 {
2266                         Name = name;
2267                         this.targs = targs;
2268                         loc = l;
2269                 }
2270
2271                 public bool HasTypeArguments {
2272                         get {
2273                                 return targs != null;
2274                         }
2275                 }
2276
2277                 public override string GetSignatureForError ()
2278                 {
2279                         if (targs != null) {
2280                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2281                                         targs.GetSignatureForError () + ">";
2282                         }
2283
2284                         return Name;
2285                 }
2286         }
2287
2288         /// <summary>
2289         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2290         ///   of a dotted-name.
2291         /// </summary>
2292         public class SimpleName : ATypeNameExpression {
2293                 bool in_transit;
2294
2295                 public SimpleName (string name, Location l)
2296                         : base (name, l)
2297                 {
2298                 }
2299
2300                 public SimpleName (string name, TypeArguments args, Location l)
2301                         : base (name, args, l)
2302                 {
2303                 }
2304
2305                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2306                         : base (name, l)
2307                 {
2308                         targs = new TypeArguments (l);
2309                         foreach (TypeParameter type_param in type_params)
2310                                 targs.Add (new TypeParameterExpr (type_param, l));
2311                 }
2312
2313                 public static string RemoveGenericArity (string name)
2314                 {
2315                         int start = 0;
2316                         StringBuilder sb = null;
2317                         do {
2318                                 int pos = name.IndexOf ('`', start);
2319                                 if (pos < 0) {
2320                                         if (start == 0)
2321                                                 return name;
2322
2323                                         sb.Append (name.Substring (start));
2324                                         break;
2325                                 }
2326
2327                                 if (sb == null)
2328                                         sb = new StringBuilder ();
2329                                 sb.Append (name.Substring (start, pos-start));
2330
2331                                 pos++;
2332                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2333                                         pos++;
2334
2335                                 start = pos;
2336                         } while (start < name.Length);
2337
2338                         return sb.ToString ();
2339                 }
2340
2341                 public SimpleName GetMethodGroup ()
2342                 {
2343                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2344                 }
2345
2346                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2347                 {
2348                         if (ec.IsInFieldInitializer)
2349                                 Report.Error (236, l,
2350                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2351                                         name);
2352                         else
2353                                 Report.Error (
2354                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2355                                         name);
2356                 }
2357
2358                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2359                 {
2360                         return resolved_to != null && resolved_to.Type != null &&
2361                                 resolved_to.Type.Name == Name &&
2362                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2363                 }
2364
2365                 public override Expression DoResolve (EmitContext ec)
2366                 {
2367                         return SimpleNameResolve (ec, null, false);
2368                 }
2369
2370                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2371                 {
2372                         return SimpleNameResolve (ec, right_side, false);
2373                 }
2374
2375
2376                 public Expression DoResolve (EmitContext ec, bool intermediate)
2377                 {
2378                         return SimpleNameResolve (ec, null, intermediate);
2379                 }
2380
2381                 static bool IsNestedChild (Type t, Type parent)
2382                 {
2383                         while (parent != null) {
2384                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2385                                         return true;
2386
2387                                 parent = parent.BaseType;
2388                         }
2389
2390                         return false;
2391                 }
2392
2393                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2394                 {
2395                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2396                                 return null;
2397
2398                         DeclSpace ds = ec.DeclContainer;
2399                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2400                                 ds = ds.Parent;
2401
2402                         if (ds == null)
2403                                 return null;
2404
2405                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2406
2407                         int arg_count = targs != null ? targs.Count : 0;
2408
2409                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2410                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2411                                         TypeArguments new_args = new TypeArguments (loc);
2412                                         foreach (TypeParameter param in ds.TypeParameters)
2413                                                 new_args.Add (new TypeParameterExpr (param, loc));
2414
2415                                         if (targs != null)
2416                                                 new_args.Add (targs);
2417
2418                                         return new ConstructedType (t, new_args, loc);
2419                                 }
2420                         }
2421
2422                         return null;
2423                 }
2424
2425                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2426                 {
2427                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2428                         if (fne != null)
2429                                 return fne.ResolveAsTypeStep (ec, silent);
2430
2431                         int errors = Report.Errors;
2432                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2433
2434                         if (fne != null) {
2435                                 if (fne.Type == null)
2436                                         return fne;
2437
2438                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2439                                 if (nested != null)
2440                                         return nested.ResolveAsTypeStep (ec, false);
2441
2442                                 if (targs != null) {
2443                                         ConstructedType ct = new ConstructedType (fne, targs, loc);
2444                                         return ct.ResolveAsTypeStep (ec, false);
2445                                 }
2446
2447                                 return fne;
2448                         }
2449
2450                         if (silent || errors != Report.Errors)
2451                                 return null;
2452
2453                         Error_TypeOrNamespaceNotFound (ec);
2454                         return null;
2455                 }
2456
2457                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2458                 {
2459                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2460                         if (mc != null) {
2461                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2462                                 return;
2463                         }
2464
2465                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2466                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2467                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2468                                 Type type = a.GetType (fullname);
2469                                 if (type != null) {
2470                                         Report.SymbolRelatedToPreviousError (type);
2471                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2472                                         return;
2473                                 }
2474                         }
2475
2476                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2477                         if (t != null) {
2478                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2479                                 return;
2480                         }
2481
2482                         if (targs != null) {
2483                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2484                                 if (retval != null) {
2485                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2486                                         return;
2487                                 }
2488                         }
2489
2490                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2491                 }
2492
2493                 // TODO: I am still not convinced about this. If someone else will need it
2494                 // implement this as virtual property in MemberCore hierarchy
2495                 public static string GetMemberType (MemberCore mc)
2496                 {
2497                         if (mc is Property)
2498                                 return "property";
2499                         if (mc is Indexer)
2500                                 return "indexer";
2501                         if (mc is FieldBase)
2502                                 return "field";
2503                         if (mc is MethodCore)
2504                                 return "method";
2505                         if (mc is EnumMember)
2506                                 return "enum";
2507                         if (mc is Event)
2508                                 return "event";
2509
2510                         return "type";
2511                 }
2512
2513                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2514                 {
2515                         if (in_transit)
2516                                 return null;
2517
2518                         in_transit = true;
2519                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2520                         in_transit = false;
2521
2522                         if (e == null)
2523                                 return null;
2524
2525                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2526                                 return e;
2527
2528                         return null;
2529                 }
2530
2531                 /// <remarks>
2532                 ///   7.5.2: Simple Names.
2533                 ///
2534                 ///   Local Variables and Parameters are handled at
2535                 ///   parse time, so they never occur as SimpleNames.
2536                 ///
2537                 ///   The `intermediate' flag is used by MemberAccess only
2538                 ///   and it is used to inform us that it is ok for us to
2539                 ///   avoid the static check, because MemberAccess might end
2540                 ///   up resolving the Name as a Type name and the access as
2541                 ///   a static type access.
2542                 ///
2543                 ///   ie: Type Type; .... { Type.GetType (""); }
2544                 ///
2545                 ///   Type is both an instance variable and a Type;  Type.GetType
2546                 ///   is the static method not an instance method of type.
2547                 /// </remarks>
2548                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2549                 {
2550                         Expression e = null;
2551
2552                         //
2553                         // Stage 1: Performed by the parser (binding to locals or parameters).
2554                         //
2555                         Block current_block = ec.CurrentBlock;
2556                         if (current_block != null){
2557                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2558                                 if (vi != null){
2559                                         if (targs != null) {
2560                                                 Report.Error (307, loc,
2561                                                               "The variable `{0}' cannot be used with type arguments",
2562                                                               Name);
2563                                                 return null;
2564                                         }
2565
2566                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2567                                         if (right_side != null) {
2568                                                 return var.ResolveLValue (ec, right_side, loc);
2569                                         } else {
2570                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2571                                                 if (intermediate)
2572                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2573                                                 return var.Resolve (ec, rf);
2574                                         }
2575                                 }
2576
2577                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2578                                 if (pref != null) {
2579                                         if (targs != null) {
2580                                                 Report.Error (307, loc,
2581                                                               "The variable `{0}' cannot be used with type arguments",
2582                                                               Name);
2583                                                 return null;
2584                                         }
2585
2586                                         if (right_side != null)
2587                                                 return pref.ResolveLValue (ec, right_side, loc);
2588                                         else
2589                                                 return pref.Resolve (ec);
2590                                 }
2591
2592                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2593                                 if (expr != null) {
2594                                         if (right_side != null)
2595                                                 return expr.ResolveLValue (ec, right_side, loc);
2596                                         return expr.Resolve (ec);
2597                                 }
2598                         }
2599
2600                         //
2601                         // Stage 2: Lookup members
2602                         //
2603
2604                         Type almost_matched_type = null;
2605                         ArrayList almost_matched = null;
2606                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2607                                 // either RootDeclSpace or GenericMethod
2608                                 if (lookup_ds.TypeBuilder == null)
2609                                         continue;
2610
2611                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2612                                 if (e != null) {
2613                                         if (e is PropertyExpr) {
2614                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2615                                                 // it doesn't know which accessor to check permissions against
2616                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2617                                                         break;
2618                                         } else if (e is EventExpr) {
2619                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2620                                                         break;
2621                                         } else {
2622                                                 break;
2623                                         }
2624                                         e = null;
2625                                 }
2626
2627                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2628                                         almost_matched_type = lookup_ds.TypeBuilder;
2629                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2630                                 }
2631                         }
2632
2633                         if (e == null) {
2634                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2635                                         almost_matched_type = ec.ContainerType;
2636                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2637                                 }
2638                                 e = ResolveAsTypeStep (ec, true);
2639                         }
2640
2641                         if (e == null) {
2642                                 if (current_block != null) {
2643                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2644                                         if (ikv != null) {
2645                                                 LocalInfo li = ikv as LocalInfo;
2646                                                 // Supress CS0219 warning
2647                                                 if (li != null)
2648                                                         li.Used = true;
2649
2650                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2651                                                 return null;
2652                                         }
2653                                 }
2654
2655                                 if (almost_matched != null)
2656                                         almost_matched_members = almost_matched;
2657                                 if (almost_matched_type == null)
2658                                         almost_matched_type = ec.ContainerType;
2659                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2660                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2661                                 return null;
2662                         }
2663
2664                         if (e is TypeExpr) {
2665                                 if (targs == null)
2666                                         return e;
2667
2668                                 ConstructedType ct = new ConstructedType (
2669                                         e.Type, targs, loc);
2670                                 return ct.ResolveAsTypeStep (ec, false);
2671                         }
2672
2673                         if (e is MemberExpr) {
2674                                 MemberExpr me = (MemberExpr) e;
2675
2676                                 Expression left;
2677                                 if (me.IsInstance) {
2678                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2679                                                 //
2680                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2681                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2682                                                 // and each predicate is true if the MethodGroupExpr contains
2683                                                 // at least one of that kind of method.
2684                                                 //
2685
2686                                                 if (!me.IsStatic &&
2687                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2688                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2689                                                         return null;
2690                                                 }
2691
2692                                                 //
2693                                                 // Pass the buck to MemberAccess and Invocation.
2694                                                 //
2695                                                 left = EmptyExpression.Null;
2696                                         } else {
2697                                                 left = ec.GetThis (loc);
2698                                         }
2699                                 } else {
2700                                         left = new TypeExpression (ec.ContainerType, loc);
2701                                 }
2702
2703                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2704                                 if (me == null)
2705                                         return null;
2706
2707                                 if (targs != null) {
2708                                         targs.Resolve (ec);
2709                                         me.SetTypeArguments (targs);
2710                                 }
2711
2712                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2713                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2714                                     me.InstanceExpression.Type != me.DeclaringType &&
2715                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2716                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2717                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2718                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2719                                         return null;
2720                                 }
2721
2722                                 return (right_side != null)
2723                                         ? me.DoResolveLValue (ec, right_side)
2724                                         : me.DoResolve (ec);
2725                         }
2726
2727                         return e;
2728                 }
2729
2730                 protected override void CloneTo (CloneContext clonectx, Expression target)
2731                 {
2732                         // CloneTo: Nothing, we do not keep any state on this expression
2733                 }
2734         }
2735
2736         /// <summary>
2737         ///   Represents a namespace or a type.  The name of the class was inspired by
2738         ///   section 10.8.1 (Fully Qualified Names).
2739         /// </summary>
2740         public abstract class FullNamedExpression : Expression {
2741                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2742                 {
2743                         return this;
2744                 }
2745
2746                 public override void Emit (EmitContext ec)
2747                 {
2748                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2749                                 GetSignatureForError ());
2750                 }
2751         }
2752
2753         /// <summary>
2754         ///   Expression that evaluates to a type
2755         /// </summary>
2756         public abstract class TypeExpr : FullNamedExpression {
2757                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2758                 {
2759                         TypeExpr t = DoResolveAsTypeStep (ec);
2760                         if (t == null)
2761                                 return null;
2762
2763                         eclass = ExprClass.Type;
2764                         return t;
2765                 }
2766
2767                 override public Expression DoResolve (EmitContext ec)
2768                 {
2769                         return ResolveAsTypeTerminal (ec, false);
2770                 }
2771
2772                 public virtual bool CheckAccessLevel (DeclSpace ds)
2773                 {
2774                         return ds.CheckAccessLevel (Type);
2775                 }
2776
2777                 public virtual bool AsAccessible (DeclSpace ds)
2778                 {
2779                         return ds.IsAccessibleAs (Type);
2780                 }
2781
2782                 public virtual bool IsClass {
2783                         get { return Type.IsClass; }
2784                 }
2785
2786                 public virtual bool IsValueType {
2787                         get { return Type.IsValueType; }
2788                 }
2789
2790                 public virtual bool IsInterface {
2791                         get { return Type.IsInterface; }
2792                 }
2793
2794                 public virtual bool IsSealed {
2795                         get { return Type.IsSealed; }
2796                 }
2797
2798                 public virtual bool CanInheritFrom ()
2799                 {
2800                         if (Type == TypeManager.enum_type ||
2801                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2802                             Type == TypeManager.multicast_delegate_type ||
2803                             Type == TypeManager.delegate_type ||
2804                             Type == TypeManager.array_type)
2805                                 return false;
2806
2807                         return true;
2808                 }
2809
2810                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2811
2812                 public override bool Equals (object obj)
2813                 {
2814                         TypeExpr tobj = obj as TypeExpr;
2815                         if (tobj == null)
2816                                 return false;
2817
2818                         return Type == tobj.Type;
2819                 }
2820
2821                 public override int GetHashCode ()
2822                 {
2823                         return Type.GetHashCode ();
2824                 }
2825         }
2826
2827         /// <summary>
2828         ///   Fully resolved Expression that already evaluated to a type
2829         /// </summary>
2830         public class TypeExpression : TypeExpr {
2831                 public TypeExpression (Type t, Location l)
2832                 {
2833                         Type = t;
2834                         eclass = ExprClass.Type;
2835                         loc = l;
2836                 }
2837
2838                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2839                 {
2840                         return this;
2841                 }
2842
2843                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2844                 {
2845                         return this;
2846                 }
2847         }
2848
2849         /// <summary>
2850         ///   Used to create types from a fully qualified name.  These are just used
2851         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2852         ///   classified as a type.
2853         /// </summary>
2854         public sealed class TypeLookupExpression : TypeExpr {
2855                 readonly string name;
2856
2857                 public TypeLookupExpression (string name)
2858                 {
2859                         this.name = name;
2860                         eclass = ExprClass.Type;
2861                 }
2862
2863                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2864                 {
2865                         // It's null for corlib compilation only
2866                         if (type == null)
2867                                 return DoResolveAsTypeStep (ec);
2868
2869                         return this;
2870                 }
2871
2872                 private class UnexpectedType
2873                 {
2874                 }
2875
2876                 // This performes recursive type lookup, providing support for generic types.
2877                 // For example, given the type:
2878                 //
2879                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2880                 //
2881                 // The types will be checked in the following order:
2882                 //                                                                             _
2883                 // System                                                                       |
2884                 // System.Collections                                                           |
2885                 // System.Collections.Generic                                                   |
2886                 //                        _                                                     |
2887                 //     System              | recursive call 1                                   |
2888                 //     System.Int32       _|                                                    | main method call
2889                 //                        _                                                     |
2890                 //     System              | recursive call 2                                   |
2891                 //     System.String      _|                                                    |
2892                 //                                                                              |
2893                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2894                 //
2895                 private Type TypeLookup (IResolveContext ec, string name)
2896                 {
2897                         int index = 0;
2898                         int dot = 0;
2899                         bool done = false;
2900                         FullNamedExpression resolved = null;
2901                         Type type = null;
2902                         Type recursive_type = null;
2903                         while (index < name.Length) {
2904                                 if (name[index] == '[') {
2905                                         int open = index;
2906                                         int braces = 1;
2907                                         do {
2908                                                 index++;
2909                                                 if (name[index] == '[')
2910                                                         braces++;
2911                                                 else if (name[index] == ']')
2912                                                         braces--;
2913                                         } while (braces > 0);
2914                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2915                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2916                                                 return recursive_type;
2917                                 }
2918                                 else {
2919                                         if (name[index] == ',')
2920                                                 done = true;
2921                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2922                                                 string substring = name.Substring(dot, index - dot);
2923
2924                                                 if (resolved == null)
2925                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2926                                                 else if (resolved is Namespace)
2927                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2928                                                 else if (type != null)
2929                                                         type = TypeManager.GetNestedType (type, substring);
2930                                                 else
2931                                                         return null;
2932
2933                                                 if (resolved == null)
2934                                                         return null;
2935                                                 else if (type == null && resolved is TypeExpr)
2936                                                         type = resolved.Type;
2937
2938                                                 dot = index + 1;
2939                                         }
2940                                 }
2941                                 index++;
2942                         }
2943                         if (name[0] != '[') {
2944                                 string substring = name.Substring(dot, index - dot);
2945
2946                                 if (type != null)
2947                                         return TypeManager.GetNestedType (type, substring);
2948
2949                                 if (resolved != null) {
2950                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2951                                         if (resolved is TypeExpr)
2952                                                 return resolved.Type;
2953
2954                                         if (resolved == null)
2955                                                 return null;
2956
2957                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2958                                         return typeof (UnexpectedType);
2959                                 }
2960                                 else
2961                                         return null;
2962                         }
2963                         else
2964                                 return recursive_type;
2965                         }
2966
2967                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2968                 {
2969                         Type t = TypeLookup (ec, name);
2970                         if (t == null) {
2971                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2972                                 return null;
2973                         }
2974                         if (t == typeof(UnexpectedType))
2975                                 return null;
2976                         type = t;
2977                         return this;
2978                 }
2979
2980                 protected override void CloneTo (CloneContext clonectx, Expression target)
2981                 {
2982                         // CloneTo: Nothing, we do not keep any state on this expression
2983                 }
2984
2985                 public override string GetSignatureForError ()
2986                 {
2987                         if (type == null)
2988                                 return TypeManager.CSharpName (name);
2989
2990                         return base.GetSignatureForError ();
2991                 }
2992         }
2993
2994         /// <summary>
2995         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2996         ///   See 14.5.11.
2997         /// </summary>
2998         public class UnboundTypeExpression : TypeExpr
2999         {
3000                 MemberName name;
3001
3002                 public UnboundTypeExpression (MemberName name, Location l)
3003                 {
3004                         this.name = name;
3005                         loc = l;
3006                 }
3007
3008                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3009                 {
3010                         Expression expr;
3011                         if (name.Left != null) {
3012                                 Expression lexpr = name.Left.GetTypeExpression ();
3013                                 expr = new MemberAccess (lexpr, name.Basename);
3014                         } else {
3015                                 expr = new SimpleName (name.Basename, loc);
3016                         }
3017
3018                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
3019                         if (fne == null)
3020                                 return null;
3021
3022                         type = fne.Type;
3023                         return new TypeExpression (type, loc);
3024                 }
3025         }
3026
3027         /// <summary>
3028         ///   This class denotes an expression which evaluates to a member
3029         ///   of a struct or a class.
3030         /// </summary>
3031         public abstract class MemberExpr : Expression
3032         {
3033                 protected bool is_base;
3034
3035                 /// <summary>
3036                 ///   The name of this member.
3037                 /// </summary>
3038                 public abstract string Name {
3039                         get;
3040                 }
3041
3042                 //
3043                 // When base.member is used
3044                 //
3045                 public bool IsBase {
3046                         get { return is_base; }
3047                         set { is_base = value; }
3048                 }
3049
3050                 /// <summary>
3051                 ///   Whether this is an instance member.
3052                 /// </summary>
3053                 public abstract bool IsInstance {
3054                         get;
3055                 }
3056
3057                 /// <summary>
3058                 ///   Whether this is a static member.
3059                 /// </summary>
3060                 public abstract bool IsStatic {
3061                         get;
3062                 }
3063
3064                 /// <summary>
3065                 ///   The type which declares this member.
3066                 /// </summary>
3067                 public abstract Type DeclaringType {
3068                         get;
3069                 }
3070
3071                 /// <summary>
3072                 ///   The instance expression associated with this member, if it's a
3073                 ///   non-static member.
3074                 /// </summary>
3075                 public Expression InstanceExpression;
3076
3077                 public static void error176 (Location loc, string name)
3078                 {
3079                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3080                                       "with an instance reference, qualify it with a type name instead", name);
3081                 }
3082
3083                 // TODO: possible optimalization
3084                 // Cache resolved constant result in FieldBuilder <-> expression map
3085                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3086                                                                SimpleName original)
3087                 {
3088                         //
3089                         // Precondition:
3090                         //   original == null || original.Resolve (...) ==> left
3091                         //
3092
3093                         if (left is TypeExpr) {
3094                                 left = left.ResolveAsTypeTerminal (ec, true);
3095                                 if (left == null)
3096                                         return null;
3097
3098                                 if (!IsStatic) {
3099                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3100                                         return null;
3101                                 }
3102
3103                                 return this;
3104                         }
3105
3106                         if (!IsInstance) {
3107                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3108                                         return this;
3109
3110                                 return ResolveExtensionMemberAccess (left);
3111                         }
3112
3113                         InstanceExpression = left;
3114                         return this;
3115                 }
3116
3117                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3118                 {
3119                         error176 (loc, GetSignatureForError ());
3120                         return this;
3121                 }
3122
3123                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3124                 {
3125                         if (IsStatic)
3126                                 return;
3127
3128                         if (InstanceExpression == EmptyExpression.Null) {
3129                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3130                                 return;
3131                         }
3132
3133                         if (InstanceExpression.Type.IsValueType) {
3134                                 if (InstanceExpression is IMemoryLocation) {
3135                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3136                                 } else {
3137                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3138                                         InstanceExpression.Emit (ec);
3139                                         t.Store (ec);
3140                                         t.AddressOf (ec, AddressOp.Store);
3141                                 }
3142                         } else
3143                                 InstanceExpression.Emit (ec);
3144
3145                         if (prepare_for_load)
3146                                 ec.ig.Emit (OpCodes.Dup);
3147                 }
3148
3149                 public virtual void SetTypeArguments (TypeArguments ta)
3150                 {
3151                         // TODO: need to get correct member type
3152                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3153                                 GetSignatureForError ());
3154                 }
3155         }
3156
3157         ///
3158         /// Represents group of extension methods
3159         ///
3160         public class ExtensionMethodGroupExpr : MethodGroupExpr
3161         {
3162                 readonly NamespaceEntry namespace_entry;
3163                 public Expression ExtensionExpression;
3164                 Argument extension_argument;
3165
3166                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3167                         : base (list, extensionType, l)
3168                 {
3169                         this.namespace_entry = n;
3170                 }
3171
3172                 public override bool IsStatic {
3173                         get { return true; }
3174                 }
3175
3176                 public bool IsTopLevel {
3177                         get { return namespace_entry == null; }
3178                 }
3179
3180                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3181                 {
3182                         if (arguments == null)
3183                                 arguments = new ArrayList (1);
3184                         arguments.Insert (0, extension_argument);
3185                         base.EmitArguments (ec, arguments);
3186                 }
3187
3188                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3189                 {
3190                         if (arguments == null)
3191                                 arguments = new ArrayList (1);
3192                         arguments.Insert (0, extension_argument);
3193                         base.EmitCall (ec, arguments);
3194                 }
3195
3196                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3197                 {
3198                         if (arguments == null)
3199                                 arguments = new ArrayList (1);
3200
3201                         arguments.Insert (0, new Argument (ExtensionExpression));
3202                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3203
3204                         // Store resolved argument and restore original arguments
3205                         if (mg != null)
3206                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3207                         arguments.RemoveAt (0);
3208
3209                         return mg;
3210                 }
3211
3212                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3213                 {
3214                         // Use normal resolve rules
3215                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3216                         if (mg != null)
3217                                 return mg;
3218
3219                         if (ns == null)
3220                                 return null;
3221
3222                         // Search continues
3223                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3224                         if (e == null)
3225                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3226
3227                         e.ExtensionExpression = ExtensionExpression;
3228                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3229                 }
3230         }
3231
3232         /// <summary>
3233         ///   MethodGroupExpr represents a group of method candidates which
3234         ///   can be resolved to the best method overload
3235         /// </summary>
3236         public class MethodGroupExpr : MemberExpr
3237         {
3238                 public interface IErrorHandler
3239                 {
3240                         bool NoExactMatch (EmitContext ec, MethodBase method);
3241                 }
3242
3243                 public IErrorHandler CustomErrorHandler;
3244                 public MethodBase [] Methods;
3245                 MethodBase best_candidate;
3246                 // TODO: make private
3247                 public TypeArguments type_arguments;
3248                 bool identical_type_name;
3249                 Type delegate_type;
3250
3251                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3252                         : this (type, l)
3253                 {
3254                         Methods = new MethodBase [mi.Length];
3255                         mi.CopyTo (Methods, 0);
3256                 }
3257
3258                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3259                         : this (type, l)
3260                 {
3261                         try {
3262                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3263                         } catch {
3264                                 foreach (MemberInfo m in list){
3265                                         if (!(m is MethodBase)){
3266                                                 Console.WriteLine ("Name " + m.Name);
3267                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3268                                         }
3269                                 }
3270                                 throw;
3271                         }
3272
3273
3274                 }
3275
3276                 protected MethodGroupExpr (Type type, Location loc)
3277                 {
3278                         this.loc = loc;
3279                         eclass = ExprClass.MethodGroup;
3280                         this.type = type;
3281                 }
3282
3283                 public override Type DeclaringType {
3284                         get {
3285                                 //
3286                                 // We assume that the top-level type is in the end
3287                                 //
3288                                 return Methods [Methods.Length - 1].DeclaringType;
3289                                 //return Methods [0].DeclaringType;
3290                         }
3291                 }
3292
3293                 public Type DelegateType {
3294                         set {
3295                                 delegate_type = value;
3296                         }
3297                 }
3298
3299                 public bool IdenticalTypeName {
3300                         get {
3301                                 return identical_type_name;
3302                         }
3303
3304                         set {
3305                                 identical_type_name = value;
3306                         }
3307                 }
3308
3309                 public override string GetSignatureForError ()
3310                 {
3311                         if (best_candidate != null)
3312                                 return TypeManager.CSharpSignature (best_candidate);
3313
3314                         return TypeManager.CSharpSignature (Methods [0]);
3315                 }
3316
3317                 public override string Name {
3318                         get {
3319                                 return Methods [0].Name;
3320                         }
3321                 }
3322
3323                 public override bool IsInstance {
3324                         get {
3325                                 if (best_candidate != null)
3326                                         return !best_candidate.IsStatic;
3327
3328                                 foreach (MethodBase mb in Methods)
3329                                         if (!mb.IsStatic)
3330                                                 return true;
3331
3332                                 return false;
3333                         }
3334                 }
3335
3336                 public override bool IsStatic {
3337                         get {
3338                                 if (best_candidate != null)
3339                                         return best_candidate.IsStatic;
3340
3341                                 foreach (MethodBase mb in Methods)
3342                                         if (mb.IsStatic)
3343                                                 return true;
3344
3345                                 return false;
3346                         }
3347                 }
3348
3349                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3350                 {
3351                         return (ConstructorInfo)mg.best_candidate;
3352                 }
3353
3354                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3355                 {
3356                         return (MethodInfo)mg.best_candidate;
3357                 }
3358
3359                 //
3360                 //  7.4.3.3  Better conversion from expression
3361                 //  Returns :   1    if a->p is better,
3362                 //              2    if a->q is better,
3363                 //              0 if neither is better
3364                 //
3365                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3366                 {
3367                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3368                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3369                                 //
3370                                 // Uwrap delegate from Expression<T>
3371                                 //
3372                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3373                                         p = TypeManager.GetTypeArguments (p) [0];
3374                                         q = TypeManager.GetTypeArguments (q) [0];
3375                                 }
3376                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3377                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3378                         } else {
3379                                 if (argument_type == p)
3380                                         return 1;
3381
3382                                 if (argument_type == q)
3383                                         return 2;
3384                         }
3385
3386                         return BetterTypeConversion (ec, p, q);
3387                 }
3388
3389                 //
3390                 // 7.4.3.4  Better conversion from type
3391                 //
3392                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3393                 {
3394                         if (p == null || q == null)
3395                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3396
3397                         if (p == TypeManager.int32_type) {
3398                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3399                                         return 1;
3400                         } else if (p == TypeManager.int64_type) {
3401                                 if (q == TypeManager.uint64_type)
3402                                         return 1;
3403                         } else if (p == TypeManager.sbyte_type) {
3404                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3405                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3406                                         return 1;
3407                         } else if (p == TypeManager.short_type) {
3408                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3409                                         q == TypeManager.uint64_type)
3410                                         return 1;
3411                         }
3412
3413                         if (q == TypeManager.int32_type) {
3414                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3415                                         return 2;
3416                         } if (q == TypeManager.int64_type) {
3417                                 if (p == TypeManager.uint64_type)
3418                                         return 2;
3419                         } else if (q == TypeManager.sbyte_type) {
3420                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3421                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3422                                         return 2;
3423                         } if (q == TypeManager.short_type) {
3424                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3425                                         p == TypeManager.uint64_type)
3426                                         return 2;
3427                         }
3428
3429                         // TODO: this is expensive
3430                         Expression p_tmp = new EmptyExpression (p);
3431                         Expression q_tmp = new EmptyExpression (q);
3432
3433                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3434                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3435
3436                         if (p_to_q && !q_to_p)
3437                                 return 1;
3438
3439                         if (q_to_p && !p_to_q)
3440                                 return 2;
3441
3442                         return 0;
3443                 }
3444
3445                 /// <summary>
3446                 ///   Determines "Better function" between candidate
3447                 ///   and the current best match
3448                 /// </summary>
3449                 /// <remarks>
3450                 ///    Returns a boolean indicating :
3451                 ///     false if candidate ain't better
3452                 ///     true  if candidate is better than the current best match
3453                 /// </remarks>
3454                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3455                         MethodBase candidate, bool candidate_params,
3456                         MethodBase best, bool best_params)
3457                 {
3458                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3459                         ParameterData best_pd = TypeManager.GetParameterData (best);
3460
3461                         bool better_at_least_one = false;
3462                         bool same = true;
3463                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3464                         {
3465                                 Argument a = (Argument) args [j];
3466
3467                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3468                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3469
3470                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3471                                 {
3472                                         ct = TypeManager.GetElementType (ct);
3473                                         --c_idx;
3474                                 }
3475
3476                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3477                                 {
3478                                         bt = TypeManager.GetElementType (bt);
3479                                         --b_idx;
3480                                 }
3481
3482                                 if (ct.Equals (bt))
3483                                         continue;
3484
3485                                 same = false;
3486                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3487
3488                                 // for each argument, the conversion to 'ct' should be no worse than
3489                                 // the conversion to 'bt'.
3490                                 if (result == 2)
3491                                         return false;
3492
3493                                 // for at least one argument, the conversion to 'ct' should be better than
3494                                 // the conversion to 'bt'.
3495                                 if (result != 0)
3496                                         better_at_least_one = true;
3497                         }
3498
3499                         if (better_at_least_one)
3500                                 return true;
3501
3502                         //
3503                         // This handles the case
3504                         //
3505                         //   Add (float f1, float f2, float f3);
3506                         //   Add (params decimal [] foo);
3507                         //
3508                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3509                         // first candidate would've chosen as better.
3510                         //
3511                         if (!same)
3512                                 return false;
3513
3514                         //
3515                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3516                         //
3517                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3518                                 return true;
3519                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3520                                 return false;
3521
3522                         //
3523                         // This handles the following cases:
3524                         //
3525                         //   Trim () is better than Trim (params char[] chars)
3526                         //   Concat (string s1, string s2, string s3) is better than
3527                         //     Concat (string s1, params string [] srest)
3528                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3529                         //
3530                         if (!candidate_params && best_params)
3531                                 return true;
3532                         if (candidate_params && !best_params)
3533                                 return false;
3534
3535                         int candidate_param_count = candidate_pd.Count;
3536                         int best_param_count = best_pd.Count;
3537
3538                         if (candidate_param_count != best_param_count)
3539                                 // can only happen if (candidate_params && best_params)
3540                                 return candidate_param_count > best_param_count;
3541
3542                         //
3543                         // now, both methods have the same number of parameters, and the parameters have the same types
3544                         // Pick the "more specific" signature
3545                         //
3546
3547                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3548                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3549
3550                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3551                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3552
3553                         bool specific_at_least_once = false;
3554                         for (int j = 0; j < candidate_param_count; ++j)
3555                         {
3556                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3557                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3558                                 if (ct.Equals (bt))
3559                                         continue;
3560                                 Type specific = MoreSpecific (ct, bt);
3561                                 if (specific == bt)
3562                                         return false;
3563                                 if (specific == ct)
3564                                         specific_at_least_once = true;
3565                         }
3566
3567                         if (specific_at_least_once)
3568                                 return true;
3569
3570                         // FIXME: handle lifted operators
3571                         // ...
3572
3573                         return false;
3574                 }
3575
3576                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3577                 {
3578                         if (!IsStatic)
3579                                 return base.ResolveExtensionMemberAccess (left);
3580
3581                         //
3582                         // When left side is an expression and at least one candidate method is
3583                         // static, it can be extension method
3584                         //
3585                         InstanceExpression = left;
3586                         return this;
3587                 }
3588
3589                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3590                                                                 SimpleName original)
3591                 {
3592                         if (!(left is TypeExpr) &&
3593                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3594                                 IdenticalTypeName = true;
3595
3596                         return base.ResolveMemberAccess (ec, left, loc, original);
3597                 }
3598
3599                 public override Expression CreateExpressionTree (EmitContext ec)
3600                 {
3601                         if (best_candidate.IsConstructor)
3602                                 return new TypeOfConstructorInfo (best_candidate, loc);
3603
3604                         return new TypeOfMethodInfo (best_candidate, loc);
3605                 }
3606
3607                 override public Expression DoResolve (EmitContext ec)
3608                 {
3609                         if (InstanceExpression != null) {
3610                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3611                                 if (InstanceExpression == null)
3612                                         return null;
3613                         }
3614
3615                         return this;
3616                 }
3617
3618                 public void ReportUsageError ()
3619                 {
3620                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3621                                       Name + "()' is referenced without parentheses");
3622                 }
3623
3624                 override public void Emit (EmitContext ec)
3625                 {
3626                         ReportUsageError ();
3627                 }
3628
3629                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3630                 {
3631                         Invocation.EmitArguments (ec, arguments, false, null);
3632                 }
3633
3634                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3635                 {
3636                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3637                 }
3638
3639                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3640                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3641                 {
3642                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3643                                 Report.SymbolRelatedToPreviousError (method);
3644                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3645                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3646                                                 TypeManager.CSharpSignature (method));
3647                                         return;
3648                                 }
3649                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3650                                           TypeManager.CSharpSignature (method));
3651                         } else if (delegate_type == null) {
3652                                 Report.SymbolRelatedToPreviousError (method);
3653                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3654                                                   TypeManager.CSharpSignature (method));
3655                         } else
3656                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3657                                         TypeManager.CSharpName (delegate_type));
3658
3659                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3660
3661                         string index = (idx + 1).ToString ();
3662                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3663                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3664                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3665                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3666                                                 index, Parameter.GetModifierSignature (a.Modifier));
3667                                 else
3668                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3669                                                 index, Parameter.GetModifierSignature (mod));
3670                         } else {
3671                                 string p1 = a.GetSignatureForError ();
3672                                 string p2 = TypeManager.CSharpName (paramType);
3673
3674                                 if (p1 == p2) {
3675                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3676                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3677                                         Report.SymbolRelatedToPreviousError (paramType);
3678                                 }
3679                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3680                         }
3681                 }
3682
3683                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3684                 {
3685                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3686                                 Name, TypeManager.CSharpName (target));
3687                 }
3688
3689                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3690                 {
3691                         return parameters.Count;
3692                 }
3693
3694                 public static bool IsAncestralType (Type first_type, Type second_type)
3695                 {
3696                         return first_type != second_type &&
3697                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3698                                 TypeManager.ImplementsInterface (second_type, first_type));
3699                 }
3700
3701                 ///
3702                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3703                 /// to the given set of arguments
3704                 /// A return value rates candidate method compatibility,
3705                 /// 0 = the best, int.MaxValue = the worst
3706                 ///
3707                 public int IsApplicable (EmitContext ec,
3708                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3709                 {
3710                         MethodBase candidate = method;
3711
3712                         ParameterData pd = TypeManager.GetParameterData (candidate);
3713                         int param_count = GetApplicableParametersCount (candidate, pd);
3714
3715                         if (arg_count != param_count) {
3716                                 if (!pd.HasParams)
3717                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3718                                 if (arg_count < param_count - 1)
3719                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3720                         }
3721
3722 #if GMCS_SOURCE
3723                         //
3724                         // 1. Handle generic method using type arguments when specified or type inference
3725                         //
3726                         if (TypeManager.IsGenericMethod (candidate)) {
3727                                 if (type_arguments != null) {
3728                                         Type [] g_args = candidate.GetGenericArguments ();
3729                                         if (g_args.Length != type_arguments.Count)
3730                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3731
3732                                         // TODO: Don't create new method, create Parameters only
3733                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3734                                         candidate = method;
3735                                         pd = TypeManager.GetParameterData (candidate);
3736                                 } else {
3737                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3738                                         if (score != 0)
3739                                                 return score - 20000;
3740
3741                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3742                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3743                                                         TypeManager.CSharpSignature (candidate));
3744
3745                                         pd = TypeManager.GetParameterData (candidate);
3746                                 }
3747                         } else {
3748                                 if (type_arguments != null)
3749                                         return int.MaxValue - 15000;
3750                         }
3751 #endif
3752
3753                         //
3754                         // 2. Each argument has to be implicitly convertible to method parameter
3755                         //
3756                         method = candidate;
3757                         Parameter.Modifier p_mod = 0;
3758                         Type pt = null;
3759                         for (int i = 0; i < arg_count; i++) {
3760                                 Argument a = (Argument) arguments [i];
3761                                 Parameter.Modifier a_mod = a.Modifier &
3762                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3763
3764                                 if (p_mod != Parameter.Modifier.PARAMS) {
3765                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3766
3767                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3768                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3769                                                         continue;
3770
3771                                                 p_mod = 0;
3772                                         }
3773
3774                                         pt = pd.ParameterType (i);
3775                                 } else {
3776                                         params_expanded_form = true;
3777                                 }
3778
3779                                 int score = 1;
3780                                 if (!params_expanded_form)
3781                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3782
3783                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3784                                         // It can be applicable in expanded form
3785                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3786                                         if (score == 0)
3787                                                 params_expanded_form = true;
3788                                 }
3789
3790                                 if (score != 0) {
3791                                         if (params_expanded_form)
3792                                                 ++score;
3793                                         return (arg_count - i) * 2 + score;
3794                                 }
3795                         }
3796
3797                         if (arg_count != param_count)
3798                                 params_expanded_form = true;
3799
3800                         return 0;
3801                 }
3802
3803                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3804                 {
3805                         //
3806                         // Types have to be identical when ref or out modifer is used
3807                         //
3808                         if (arg_mod != 0 || param_mod != 0) {
3809                                 if (TypeManager.HasElementType (parameter))
3810                                         parameter = parameter.GetElementType ();
3811
3812                                 Type a_type = argument.Type;
3813                                 if (TypeManager.HasElementType (a_type))
3814                                         a_type = a_type.GetElementType ();
3815
3816                                 if (a_type != parameter)
3817                                         return 2;
3818
3819                                 return 0;
3820                         }
3821
3822                         // FIXME: Kill this abomination (EmitContext.TempEc)
3823                         EmitContext prevec = EmitContext.TempEc;
3824                         EmitContext.TempEc = ec;
3825                         try {
3826                                 if (delegate_type != null ?
3827                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3828                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3829                                         return 2;
3830
3831                                 if (arg_mod != param_mod)
3832                                         return 1;
3833
3834                         } finally {
3835                                 EmitContext.TempEc = prevec;
3836                         }
3837
3838                         return 0;
3839                 }
3840
3841                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3842                 {
3843                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3844                                 return false;
3845
3846                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3847                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3848
3849                         if (cand_pd.Count != base_pd.Count)
3850                                 return false;
3851
3852                         for (int j = 0; j < cand_pd.Count; ++j)
3853                         {
3854                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3855                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3856                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3857                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3858
3859                                 if (cm != bm || ct != bt)
3860                                         return false;
3861                         }
3862
3863                         return true;
3864                 }
3865
3866                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3867                 {
3868                         MemberInfo [] miset;
3869                         MethodGroupExpr union;
3870
3871                         if (mg1 == null) {
3872                                 if (mg2 == null)
3873                                         return null;
3874                                 return (MethodGroupExpr) mg2;
3875                         } else {
3876                                 if (mg2 == null)
3877                                         return (MethodGroupExpr) mg1;
3878                         }
3879
3880                         MethodGroupExpr left_set = null, right_set = null;
3881                         int length1 = 0, length2 = 0;
3882
3883                         left_set = (MethodGroupExpr) mg1;
3884                         length1 = left_set.Methods.Length;
3885
3886                         right_set = (MethodGroupExpr) mg2;
3887                         length2 = right_set.Methods.Length;
3888
3889                         ArrayList common = new ArrayList ();
3890
3891                         foreach (MethodBase r in right_set.Methods){
3892                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3893                                         common.Add (r);
3894                         }
3895
3896                         miset = new MemberInfo [length1 + length2 - common.Count];
3897                         left_set.Methods.CopyTo (miset, 0);
3898
3899                         int k = length1;
3900
3901                         foreach (MethodBase r in right_set.Methods) {
3902                                 if (!common.Contains (r))
3903                                         miset [k++] = r;
3904                         }
3905
3906                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3907
3908                         return union;
3909                 }
3910
3911                 static Type MoreSpecific (Type p, Type q)
3912                 {
3913                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3914                                 return q;
3915                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3916                                 return p;
3917
3918                         if (TypeManager.HasElementType (p))
3919                         {
3920                                 Type pe = TypeManager.GetElementType (p);
3921                                 Type qe = TypeManager.GetElementType (q);
3922                                 Type specific = MoreSpecific (pe, qe);
3923                                 if (specific == pe)
3924                                         return p;
3925                                 if (specific == qe)
3926                                         return q;
3927                         }
3928                         else if (TypeManager.IsGenericType (p))
3929                         {
3930                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3931                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3932
3933                                 bool p_specific_at_least_once = false;
3934                                 bool q_specific_at_least_once = false;
3935
3936                                 for (int i = 0; i < pargs.Length; i++)
3937                                 {
3938                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3939                                         if (specific == pargs [i])
3940                                                 p_specific_at_least_once = true;
3941                                         if (specific == qargs [i])
3942                                                 q_specific_at_least_once = true;
3943                                 }
3944
3945                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3946                                         return p;
3947                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3948                                         return q;
3949                         }
3950
3951                         return null;
3952                 }
3953
3954                 /// <summary>
3955                 ///   Find the Applicable Function Members (7.4.2.1)
3956                 ///
3957                 ///   me: Method Group expression with the members to select.
3958                 ///       it might contain constructors or methods (or anything
3959                 ///       that maps to a method).
3960                 ///
3961                 ///   Arguments: ArrayList containing resolved Argument objects.
3962                 ///
3963                 ///   loc: The location if we want an error to be reported, or a Null
3964                 ///        location for "probing" purposes.
3965                 ///
3966                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3967                 ///            that is the best match of me on Arguments.
3968                 ///
3969                 /// </summary>
3970                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
3971                         bool may_fail, Location loc)
3972                 {
3973                         bool method_params = false;
3974                         Type applicable_type = null;
3975                         int arg_count = 0;
3976                         ArrayList candidates = new ArrayList (2);
3977                         ArrayList candidate_overrides = null;
3978
3979                         //
3980                         // Used to keep a map between the candidate
3981                         // and whether it is being considered in its
3982                         // normal or expanded form
3983                         //
3984                         // false is normal form, true is expanded form
3985                         //
3986                         Hashtable candidate_to_form = null;
3987
3988                         if (Arguments != null)
3989                                 arg_count = Arguments.Count;
3990
3991                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3992                                 if (!may_fail)
3993                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3994                                 return null;
3995                         }
3996
3997                         int nmethods = Methods.Length;
3998
3999                         if (!IsBase) {
4000                                 //
4001                                 // Methods marked 'override' don't take part in 'applicable_type'
4002                                 // computation, nor in the actual overload resolution.
4003                                 // However, they still need to be emitted instead of a base virtual method.
4004                                 // So, we salt them away into the 'candidate_overrides' array.
4005                                 //
4006                                 // In case of reflected methods, we replace each overriding method with
4007                                 // its corresponding base virtual method.  This is to improve compatibility
4008                                 // with non-C# libraries which change the visibility of overrides (#75636)
4009                                 //
4010                                 int j = 0;
4011                                 for (int i = 0; i < Methods.Length; ++i) {
4012                                         MethodBase m = Methods [i];
4013                                         if (TypeManager.IsOverride (m)) {
4014                                                 if (candidate_overrides == null)
4015                                                         candidate_overrides = new ArrayList ();
4016                                                 candidate_overrides.Add (m);
4017                                                 m = TypeManager.TryGetBaseDefinition (m);
4018                                         }
4019                                         if (m != null)
4020                                                 Methods [j++] = m;
4021                                 }
4022                                 nmethods = j;
4023                         }
4024
4025                         //
4026                         // Enable message recording, it's used mainly by lambda expressions
4027                         //
4028                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4029                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4030
4031                         //
4032                         // First we construct the set of applicable methods
4033                         //
4034                         bool is_sorted = true;
4035                         int best_candidate_rate = int.MaxValue;
4036                         for (int i = 0; i < nmethods; i++) {
4037                                 Type decl_type = Methods [i].DeclaringType;
4038
4039                                 //
4040                                 // If we have already found an applicable method
4041                                 // we eliminate all base types (Section 14.5.5.1)
4042                                 //
4043                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4044                                         continue;
4045
4046                                 //
4047                                 // Check if candidate is applicable (section 14.4.2.1)
4048                                 //
4049                                 bool params_expanded_form = false;
4050                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4051
4052                                 if (candidate_rate < best_candidate_rate) {
4053                                         best_candidate_rate = candidate_rate;
4054                                         best_candidate = Methods [i];
4055                                 }
4056
4057                                 if (params_expanded_form) {
4058                                         if (candidate_to_form == null)
4059                                                 candidate_to_form = new PtrHashtable ();
4060                                         MethodBase candidate = Methods [i];
4061                                         candidate_to_form [candidate] = candidate;
4062                                 }
4063
4064                                 if (candidate_rate != 0) {
4065                                         if (msg_recorder != null)
4066                                                 msg_recorder.EndSession ();
4067                                         continue;
4068                                 }
4069
4070                                 msg_recorder = null;
4071                                 candidates.Add (Methods [i]);
4072
4073                                 if (applicable_type == null)
4074                                         applicable_type = decl_type;
4075                                 else if (applicable_type != decl_type) {
4076                                         is_sorted = false;
4077                                         if (IsAncestralType (applicable_type, decl_type))
4078                                                 applicable_type = decl_type;
4079                                 }
4080                         }
4081
4082                         Report.SetMessageRecorder (prev_recorder);
4083                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4084                                 return null;
4085
4086                         int candidate_top = candidates.Count;
4087
4088                         if (applicable_type == null) {
4089                                 //
4090                                 // When we found a top level method which does not match and it's
4091                                 // not an extension method. We start extension methods lookup from here
4092                                 //
4093                                 if (InstanceExpression != null) {
4094                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4095                                         if (ex_method_lookup != null) {
4096                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4097                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4098                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4099                                         }
4100                                 }
4101
4102                                 if (may_fail)
4103                                         return null;
4104
4105                                 //
4106                                 // Okay so we have failed to find exact match so we
4107                                 // return error info about the closest match
4108                                 //
4109                                 if (best_candidate != null) {
4110                                         if (CustomErrorHandler != null) {
4111                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4112                                                         return null;
4113                                         }
4114
4115                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4116                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4117                                         if (arg_count == pd.Count || pd.HasParams) {
4118                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4119                                                         if (type_arguments == null) {
4120                                                                 Report.Error (411, loc,
4121                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4122                                                                         "the usage. Try specifying the type arguments explicitly",
4123                                                                         TypeManager.CSharpSignature (best_candidate));
4124                                                                 return null;
4125                                                         }
4126
4127                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4128                                                         if (type_arguments.Count != g_args.Length) {
4129                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4130                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4131                                                                         TypeManager.CSharpSignature (best_candidate),
4132                                                                         g_args.Length.ToString ());
4133                                                                 return null;
4134                                                         }
4135                                                 } else {
4136                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4137                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4138                                                                 return null;
4139                                                         }
4140                                                 }
4141
4142                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4143                                                         return null;
4144                                         }
4145                                 }
4146
4147                                 if (almost_matched_members.Count != 0) {
4148                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4149                                         null, MemberTypes.Constructor, AllBindingFlags);
4150                                         return null;
4151                                 }
4152
4153                                 //
4154                                 // We failed to find any method with correct argument count
4155                                 //
4156                                 if (Name == ConstructorInfo.ConstructorName) {
4157                                         Report.SymbolRelatedToPreviousError (type);
4158                                         Report.Error (1729, loc,
4159                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4160                                                 TypeManager.CSharpName (type), arg_count);
4161                                 } else {
4162                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4163                                                 Name, arg_count.ToString ());
4164                                 }
4165
4166                                 return null;
4167                         }
4168
4169                         if (!is_sorted) {
4170                                 //
4171                                 // At this point, applicable_type is _one_ of the most derived types
4172                                 // in the set of types containing the methods in this MethodGroup.
4173                                 // Filter the candidates so that they only contain methods from the
4174                                 // most derived types.
4175                                 //
4176
4177                                 int finalized = 0; // Number of finalized candidates
4178
4179                                 do {
4180                                         // Invariant: applicable_type is a most derived type
4181
4182                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4183                                         // eliminating all it's base types.  At the same time, we'll also move
4184                                         // every unrelated type to the end of the array, and pick the next
4185                                         // 'applicable_type'.
4186
4187                                         Type next_applicable_type = null;
4188                                         int j = finalized; // where to put the next finalized candidate
4189                                         int k = finalized; // where to put the next undiscarded candidate
4190                                         for (int i = finalized; i < candidate_top; ++i) {
4191                                                 MethodBase candidate = (MethodBase) candidates [i];
4192                                                 Type decl_type = candidate.DeclaringType;
4193
4194                                                 if (decl_type == applicable_type) {
4195                                                         candidates [k++] = candidates [j];
4196                                                         candidates [j++] = candidates [i];
4197                                                         continue;
4198                                                 }
4199
4200                                                 if (IsAncestralType (decl_type, applicable_type))
4201                                                         continue;
4202
4203                                                 if (next_applicable_type != null &&
4204                                                         IsAncestralType (decl_type, next_applicable_type))
4205                                                         continue;
4206
4207                                                 candidates [k++] = candidates [i];
4208
4209                                                 if (next_applicable_type == null ||
4210                                                         IsAncestralType (next_applicable_type, decl_type))
4211                                                         next_applicable_type = decl_type;
4212                                         }
4213
4214                                         applicable_type = next_applicable_type;
4215                                         finalized = j;
4216                                         candidate_top = k;
4217                                 } while (applicable_type != null);
4218                         }
4219
4220                         //
4221                         // Now we actually find the best method
4222                         //
4223
4224                         best_candidate = (MethodBase) candidates [0];
4225                         if (delegate_type == null)
4226                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4227
4228                         for (int ix = 1; ix < candidate_top; ix++) {
4229                                 MethodBase candidate = (MethodBase) candidates [ix];
4230
4231                                 if (candidate == best_candidate)
4232                                         continue;
4233
4234                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4235
4236                                 if (BetterFunction (ec, Arguments, arg_count,
4237                                         candidate, cand_params,
4238                                         best_candidate, method_params)) {
4239                                         best_candidate = candidate;
4240                                         method_params = cand_params;
4241                                 }
4242                         }
4243                         //
4244                         // Now check that there are no ambiguities i.e the selected method
4245                         // should be better than all the others
4246                         //
4247                         MethodBase ambiguous = null;
4248                         for (int ix = 1; ix < candidate_top; ix++) {
4249                                 MethodBase candidate = (MethodBase) candidates [ix];
4250
4251                                 if (candidate == best_candidate)
4252                                         continue;
4253
4254                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4255                                 if (!BetterFunction (ec, Arguments, arg_count,
4256                                         best_candidate, method_params,
4257                                         candidate, cand_params))
4258                                 {
4259                                         if (!may_fail)
4260                                                 Report.SymbolRelatedToPreviousError (candidate);
4261                                         ambiguous = candidate;
4262                                 }
4263                         }
4264
4265                         if (ambiguous != null) {
4266                                 Report.SymbolRelatedToPreviousError (best_candidate);
4267                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4268                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4269                                 return this;
4270                         }
4271
4272                         //
4273                         // If the method is a virtual function, pick an override closer to the LHS type.
4274                         //
4275                         if (!IsBase && best_candidate.IsVirtual) {
4276                                 if (TypeManager.IsOverride (best_candidate))
4277                                         throw new InternalErrorException (
4278                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4279
4280                                 if (candidate_overrides != null) {
4281                                         Type[] gen_args = null;
4282                                         bool gen_override = false;
4283                                         if (TypeManager.IsGenericMethod (best_candidate))
4284                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4285
4286                                         foreach (MethodBase candidate in candidate_overrides) {
4287                                                 if (TypeManager.IsGenericMethod (candidate)) {
4288                                                         if (gen_args == null)
4289                                                                 continue;
4290
4291                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4292                                                                 continue;
4293                                                 } else {
4294                                                         if (gen_args != null)
4295                                                                 continue;
4296                                                 }
4297
4298                                                 if (IsOverride (candidate, best_candidate)) {
4299                                                         gen_override = true;
4300                                                         best_candidate = candidate;
4301                                                 }
4302                                         }
4303
4304                                         if (gen_override && gen_args != null) {
4305 #if GMCS_SOURCE
4306                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4307 #endif
4308                                         }
4309                                 }
4310                         }
4311
4312                         //
4313                         // And now check if the arguments are all
4314                         // compatible, perform conversions if
4315                         // necessary etc. and return if everything is
4316                         // all right
4317                         //
4318                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4319                                 method_params, may_fail, loc))
4320                                 return null;
4321
4322                         if (best_candidate == null)
4323                                 return null;
4324
4325                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4326 #if GMCS_SOURCE
4327                         if (the_method.IsGenericMethodDefinition &&
4328                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4329                                 return null;
4330 #endif
4331
4332                         IMethodData data = TypeManager.GetMethod (the_method);
4333                         if (data != null)
4334                                 data.SetMemberIsUsed ();
4335
4336                         return this;
4337                 }
4338
4339                 public override void SetTypeArguments (TypeArguments ta)
4340                 {
4341                         type_arguments = ta;
4342                 }
4343
4344                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4345                                                           int arg_count, MethodBase method,
4346                                                           bool chose_params_expanded,
4347                                                           bool may_fail, Location loc)
4348                 {
4349                         ParameterData pd = TypeManager.GetParameterData (method);
4350
4351                         int errors = Report.Errors;
4352                         Parameter.Modifier p_mod = 0;
4353                         Type pt = null;
4354                         int a_idx = 0, a_pos = 0;
4355                         Argument a = null;
4356                         ArrayList params_initializers = null;
4357
4358                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4359                                 a = (Argument) arguments [a_idx];
4360                                 if (p_mod != Parameter.Modifier.PARAMS) {
4361                                         p_mod = pd.ParameterModifier (a_idx);
4362                                         pt = pd.ParameterType (a_idx);
4363
4364                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4365                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4366                                                         break;
4367                                                 continue;
4368                                         }
4369
4370                                         if (pt.IsPointer && !ec.InUnsafe) {
4371                                                 if (may_fail)
4372                                                         return false;
4373
4374                                                 UnsafeError (loc);
4375                                         }
4376
4377                                         if (p_mod == Parameter.Modifier.PARAMS) {
4378                                                 if (chose_params_expanded) {
4379                                                         params_initializers = new ArrayList (arg_count - a_idx);
4380                                                         pt = TypeManager.GetElementType (pt);
4381                                                 }
4382                                         } else if (p_mod != 0) {
4383                                                 pt = TypeManager.GetElementType (pt);
4384                                         }
4385                                 }
4386
4387                                 //
4388                                 // Types have to be identical when ref or out modifer is used
4389                                 //
4390                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4391                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4392                                                 break;
4393
4394                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4395                                                 break;
4396
4397                                         continue;
4398                                 }
4399
4400                                 Expression conv;
4401                                 if (TypeManager.IsEqual (a.Type, pt)) {
4402                                         conv = a.Expr;
4403                                 } else {
4404                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4405                                         if (conv == null)
4406                                                 break;
4407                                 }
4408
4409                                 //
4410                                 // Convert params arguments to an array initializer
4411                                 //
4412                                 if (params_initializers != null) {
4413                                         params_initializers.Add (conv);
4414                                         arguments.RemoveAt (a_idx--);
4415                                         --arg_count;
4416                                         continue;
4417                                 }
4418
4419                                 // Update the argument with the implicit conversion
4420                                 a.Expr = conv;
4421                         }
4422
4423                         //
4424                         // Fill not provided arguments required by params modifier
4425                         //
4426                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4427                                 if (arguments == null)
4428                                         arguments = new ArrayList (1);
4429
4430                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4431                                 pt = TypeManager.GetElementType (pt);
4432                                 params_initializers = new ArrayList (0);
4433                         }
4434
4435                         if (a_idx == arg_count) {
4436                                 //
4437                                 // Append an array argument with all params arguments
4438                                 //
4439                                 if (params_initializers != null) {
4440                                         arguments.Add (new Argument (
4441                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4442                                                 params_initializers, loc).Resolve (ec)));
4443                                 }
4444                                 return true;
4445                         }
4446
4447                         if (!may_fail && Report.Errors == errors) {
4448                                 if (CustomErrorHandler != null)
4449                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4450                                 else
4451                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4452                         }
4453                         return false;
4454                 }
4455         }
4456
4457         public class ConstantExpr : MemberExpr
4458         {
4459                 FieldInfo constant;
4460
4461                 public ConstantExpr (FieldInfo constant, Location loc)
4462                 {
4463                         this.constant = constant;
4464                         this.loc = loc;
4465                 }
4466
4467                 public override string Name {
4468                         get { throw new NotImplementedException (); }
4469                 }
4470
4471                 public override bool IsInstance {
4472                         get { return !IsStatic; }
4473                 }
4474
4475                 public override bool IsStatic {
4476                         get { return constant.IsStatic; }
4477                 }
4478
4479                 public override Type DeclaringType {
4480                         get { return constant.DeclaringType; }
4481                 }
4482
4483                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4484                 {
4485                         constant = TypeManager.GetGenericFieldDefinition (constant);
4486
4487                         IConstant ic = TypeManager.GetConstant (constant);
4488                         if (ic == null) {
4489                                 if (constant.IsLiteral) {
4490                                         ic = new ExternalConstant (constant);
4491                                 } else {
4492                                         ic = ExternalConstant.CreateDecimal (constant);
4493                                         // HACK: decimal field was not resolved as constant
4494                                         if (ic == null)
4495                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4496                                 }
4497                                 TypeManager.RegisterConstant (constant, ic);
4498                         }
4499
4500                         return base.ResolveMemberAccess (ec, left, loc, original);
4501                 }
4502
4503                 public override Expression CreateExpressionTree (EmitContext ec)
4504                 {
4505                         throw new NotSupportedException ();
4506                 }
4507
4508                 public override Expression DoResolve (EmitContext ec)
4509                 {
4510                         IConstant ic = TypeManager.GetConstant (constant);
4511                         if (ic.ResolveValue ()) {
4512                                 if (!ec.IsInObsoleteScope)
4513                                         ic.CheckObsoleteness (loc);
4514                         }
4515
4516                         return ic.CreateConstantReference (loc);
4517                 }
4518
4519                 public override void Emit (EmitContext ec)
4520                 {
4521                         throw new NotSupportedException ();
4522                 }
4523
4524                 public override string GetSignatureForError ()
4525                 {
4526                         return TypeManager.GetFullNameSignature (constant);
4527                 }
4528         }
4529
4530         /// <summary>
4531         ///   Fully resolved expression that evaluates to a Field
4532         /// </summary>
4533         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4534                 public readonly FieldInfo FieldInfo;
4535                 VariableInfo variable_info;
4536
4537                 LocalTemporary temp;
4538                 bool prepared;
4539                 bool in_initializer;
4540
4541                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4542                         this (fi, l)
4543                 {
4544                         this.in_initializer = in_initializer;
4545                 }
4546
4547                 public FieldExpr (FieldInfo fi, Location l)
4548                 {
4549                         FieldInfo = fi;
4550                         eclass = ExprClass.Variable;
4551                         type = TypeManager.TypeToCoreType (fi.FieldType);
4552                         loc = l;
4553                 }
4554
4555                 public override string Name {
4556                         get {
4557                                 return FieldInfo.Name;
4558                         }
4559                 }
4560
4561                 public override bool IsInstance {
4562                         get {
4563                                 return !FieldInfo.IsStatic;
4564                         }
4565                 }
4566
4567                 public override bool IsStatic {
4568                         get {
4569                                 return FieldInfo.IsStatic;
4570                         }
4571                 }
4572
4573                 public override Type DeclaringType {
4574                         get {
4575                                 return FieldInfo.DeclaringType;
4576                         }
4577                 }
4578
4579                 public override string GetSignatureForError ()
4580                 {
4581                         return TypeManager.GetFullNameSignature (FieldInfo);
4582                 }
4583
4584                 public VariableInfo VariableInfo {
4585                         get {
4586                                 return variable_info;
4587                         }
4588                 }
4589
4590                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4591                                                                 SimpleName original)
4592                 {
4593                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4594                         Type t = fi.FieldType;
4595
4596                         if (t.IsPointer && !ec.InUnsafe) {
4597                                 UnsafeError (loc);
4598                         }
4599
4600                         return base.ResolveMemberAccess (ec, left, loc, original);
4601                 }
4602
4603                 public override Expression CreateExpressionTree (EmitContext ec)
4604                 {
4605                         Expression instance;
4606                         if (InstanceExpression == null) {
4607                                 instance = new NullLiteral (loc);
4608                         } else {
4609                                 instance = InstanceExpression.CreateExpressionTree (ec);
4610                         }
4611
4612                         ArrayList args = new ArrayList (2);
4613                         args.Add (new Argument (instance));
4614                         args.Add (new Argument (CreateTypeOfExpression ()));
4615                         return CreateExpressionFactoryCall ("Field", args);
4616                 }
4617
4618                 public Expression CreateTypeOfExpression ()
4619                 {
4620                         return new TypeOfField (FieldInfo, loc);
4621                 }
4622
4623                 override public Expression DoResolve (EmitContext ec)
4624                 {
4625                         return DoResolve (ec, false, false);
4626                 }
4627
4628                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4629                 {
4630                         if (!FieldInfo.IsStatic){
4631                                 if (InstanceExpression == null){
4632                                         //
4633                                         // This can happen when referencing an instance field using
4634                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4635                                         //
4636                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4637                                         return null;
4638                                 }
4639
4640                                 // Resolve the field's instance expression while flow analysis is turned
4641                                 // off: when accessing a field "a.b", we must check whether the field
4642                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4643
4644                                 if (lvalue_instance) {
4645                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4646                                                 Expression right_side =
4647                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4648                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4649                                         }
4650                                 } else {
4651                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4652                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4653                                 }
4654
4655                                 if (InstanceExpression == null)
4656                                         return null;
4657
4658                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4659                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4660                                 }
4661                         }
4662
4663                         if (!in_initializer && !ec.IsInFieldInitializer) {
4664                                 ObsoleteAttribute oa;
4665                                 FieldBase f = TypeManager.GetField (FieldInfo);
4666                                 if (f != null) {
4667                                         if (!ec.IsInObsoleteScope)
4668                                                 f.CheckObsoleteness (loc);
4669
4670                                         // To be sure that type is external because we do not register generated fields
4671                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4672                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4673                                         if (oa != null)
4674                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4675                                 }
4676                         }
4677
4678                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4679                         if (am != null){
4680                                 if (!FieldInfo.IsStatic){
4681                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4682                                                 Report.Error (1673, loc,
4683                                                 "Anonymous methods inside structs cannot access instance members of `{0}'. Consider copying `{0}' to a local variable outside the anonymous method and using the local instead",
4684                                                         "this");
4685                                                 return null;
4686                                         }
4687                                 }
4688                         }
4689
4690                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4691                         if (fb != null) {
4692                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4693                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4694                                 }
4695
4696                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4697                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4698                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4699                                                 TypeManager.GetFullNameSignature (FieldInfo));
4700                                 }
4701
4702                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4703                         }
4704
4705                         // If the instance expression is a local variable or parameter.
4706                         IVariable var = InstanceExpression as IVariable;
4707                         if ((var == null) || (var.VariableInfo == null))
4708                                 return this;
4709
4710                         VariableInfo vi = var.VariableInfo;
4711                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4712                                 return null;
4713
4714                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4715                         return this;
4716                 }
4717
4718                 static readonly int [] codes = {
4719                         191,    // instance, write access
4720                         192,    // instance, out access
4721                         198,    // static, write access
4722                         199,    // static, out access
4723                         1648,   // member of value instance, write access
4724                         1649,   // member of value instance, out access
4725                         1650,   // member of value static, write access
4726                         1651    // member of value static, out access
4727                 };
4728
4729                 static readonly string [] msgs = {
4730                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4731                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4732                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4733                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4734                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4735                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4736                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4737                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4738                 };
4739
4740                 // The return value is always null.  Returning a value simplifies calling code.
4741                 Expression Report_AssignToReadonly (Expression right_side)
4742                 {
4743                         int i = 0;
4744                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4745                                 i += 1;
4746                         if (IsStatic)
4747                                 i += 2;
4748                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4749                                 i += 4;
4750                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4751
4752                         return null;
4753                 }
4754
4755                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4756                 {
4757                         IVariable var = InstanceExpression as IVariable;
4758                         if ((var != null) && (var.VariableInfo != null))
4759                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4760
4761                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4762                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4763
4764                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4765
4766                         if (e == null)
4767                                 return null;
4768
4769                         FieldBase fb = TypeManager.GetField (FieldInfo);
4770                         if (fb != null)
4771                                 fb.SetAssigned ();
4772
4773                         if (FieldInfo.IsInitOnly) {
4774                                 // InitOnly fields can only be assigned in constructors or initializers
4775                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4776                                         return Report_AssignToReadonly (right_side);
4777
4778                                 if (ec.IsConstructor) {
4779                                         Type ctype = ec.TypeContainer.CurrentType;
4780                                         if (ctype == null)
4781                                                 ctype = ec.ContainerType;
4782
4783                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4784                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4785                                                 return Report_AssignToReadonly (right_side);
4786                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4787                                         if (IsStatic && !ec.IsStatic)
4788                                                 return Report_AssignToReadonly (right_side);
4789                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4790                                         if (!IsStatic && !(InstanceExpression is This))
4791                                                 return Report_AssignToReadonly (right_side);
4792                                 }
4793                         }
4794
4795                         if (right_side == EmptyExpression.OutAccess &&
4796                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4797                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4798                                 Report.Warning (197, 1, loc,
4799                                                 "Passing `{0}' as ref or out or taking its address may cause a runtime exception because it is a field of a marshal-by-reference class",
4800                                                 GetSignatureForError ());
4801                         }
4802
4803                         return this;
4804                 }
4805
4806                 bool is_marshal_by_ref ()
4807                 {
4808                         return !IsStatic && Type.IsValueType && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
4809                 }
4810
4811                 public override void CheckMarshalByRefAccess (EmitContext ec)
4812                 {
4813                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
4814                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4815                                 Report.Warning (1690, 1, loc, "Cannot call methods, properties, or indexers on `{0}' because it is a value type member of a marshal-by-reference class",
4816                                                 GetSignatureForError ());
4817                         }
4818                 }
4819
4820                 public bool VerifyFixed ()
4821                 {
4822                         IVariable variable = InstanceExpression as IVariable;
4823                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4824                         // We defer the InstanceExpression check after the variable check to avoid a
4825                         // separate null check on InstanceExpression.
4826                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4827                 }
4828
4829                 public override int GetHashCode ()
4830                 {
4831                         return FieldInfo.GetHashCode ();
4832                 }
4833
4834                 public override bool Equals (object obj)
4835                 {
4836                         FieldExpr fe = obj as FieldExpr;
4837                         if (fe == null)
4838                                 return false;
4839
4840                         if (FieldInfo != fe.FieldInfo)
4841                                 return false;
4842
4843                         if (InstanceExpression == null || fe.InstanceExpression == null)
4844                                 return true;
4845
4846                         return InstanceExpression.Equals (fe.InstanceExpression);
4847                 }
4848
4849                 public void Emit (EmitContext ec, bool leave_copy)
4850                 {
4851                         ILGenerator ig = ec.ig;
4852                         bool is_volatile = false;
4853
4854                         FieldBase f = TypeManager.GetField (FieldInfo);
4855                         if (f != null){
4856                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4857                                         is_volatile = true;
4858
4859                                 f.SetMemberIsUsed ();
4860                         }
4861
4862                         if (FieldInfo.IsStatic){
4863                                 if (is_volatile)
4864                                         ig.Emit (OpCodes.Volatile);
4865
4866                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4867                         } else {
4868                                 if (!prepared)
4869                                         EmitInstance (ec, false);
4870
4871                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4872                                 if (ff != null) {
4873                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4874                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4875                                 } else {
4876                                         if (is_volatile)
4877                                                 ig.Emit (OpCodes.Volatile);
4878
4879                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4880                                 }
4881                         }
4882
4883                         if (leave_copy) {
4884                                 ec.ig.Emit (OpCodes.Dup);
4885                                 if (!FieldInfo.IsStatic) {
4886                                         temp = new LocalTemporary (this.Type);
4887                                         temp.Store (ec);
4888                                 }
4889                         }
4890                 }
4891
4892                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4893                 {
4894                         FieldAttributes fa = FieldInfo.Attributes;
4895                         bool is_static = (fa & FieldAttributes.Static) != 0;
4896                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4897                         ILGenerator ig = ec.ig;
4898
4899                         if (is_readonly && !ec.IsConstructor){
4900                                 Report_AssignToReadonly (source);
4901                                 return;
4902                         }
4903
4904                         //
4905                         // String concatenation creates a new string instance
4906                         //
4907                         prepared = prepare_for_load && !(source is StringConcat);
4908                         EmitInstance (ec, prepared);
4909
4910                         source.Emit (ec);
4911                         if (leave_copy) {
4912                                 ec.ig.Emit (OpCodes.Dup);
4913                                 if (!FieldInfo.IsStatic) {
4914                                         temp = new LocalTemporary (this.Type);
4915                                         temp.Store (ec);
4916                                 }
4917                         }
4918
4919                         FieldBase f = TypeManager.GetField (FieldInfo);
4920                         if (f != null){
4921                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4922                                         ig.Emit (OpCodes.Volatile);
4923
4924                                 f.SetAssigned ();
4925                         }
4926
4927                         if (is_static)
4928                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4929                         else
4930                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4931
4932                         if (temp != null) {
4933                                 temp.Emit (ec);
4934                                 temp.Release (ec);
4935                         }
4936                 }
4937
4938                 public override void Emit (EmitContext ec)
4939                 {
4940                         Emit (ec, false);
4941                 }
4942
4943                 public override void EmitSideEffect (EmitContext ec)
4944                 {
4945                         FieldBase f = TypeManager.GetField (FieldInfo);
4946                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
4947
4948                         if (is_volatile || is_marshal_by_ref ())
4949                                 base.EmitSideEffect (ec);
4950                 }
4951
4952                 public void AddressOf (EmitContext ec, AddressOp mode)
4953                 {
4954                         ILGenerator ig = ec.ig;
4955
4956                         FieldBase f = TypeManager.GetField (FieldInfo);
4957                         if (f != null){
4958                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4959                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4960                                                         f.GetSignatureForError ());
4961                                 }
4962
4963                                 if ((mode & AddressOp.Store) != 0)
4964                                         f.SetAssigned ();
4965                                 if ((mode & AddressOp.Load) != 0)
4966                                         f.SetMemberIsUsed ();
4967                         }
4968
4969                         //
4970                         // Handle initonly fields specially: make a copy and then
4971                         // get the address of the copy.
4972                         //
4973                         bool need_copy;
4974                         if (FieldInfo.IsInitOnly){
4975                                 need_copy = true;
4976                                 if (ec.IsConstructor){
4977                                         if (FieldInfo.IsStatic){
4978                                                 if (ec.IsStatic)
4979                                                         need_copy = false;
4980                                         } else
4981                                                 need_copy = false;
4982                                 }
4983                         } else
4984                                 need_copy = false;
4985
4986                         if (need_copy){
4987                                 LocalBuilder local;
4988                                 Emit (ec);
4989                                 local = ig.DeclareLocal (type);
4990                                 ig.Emit (OpCodes.Stloc, local);
4991                                 ig.Emit (OpCodes.Ldloca, local);
4992                                 return;
4993                         }
4994
4995
4996                         if (FieldInfo.IsStatic){
4997                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
4998                         } else {
4999                                 if (!prepared)
5000                                         EmitInstance (ec, false);
5001                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
5002                         }
5003                 }
5004         }
5005
5006
5007         /// <summary>
5008         ///   Expression that evaluates to a Property.  The Assign class
5009         ///   might set the `Value' expression if we are in an assignment.
5010         ///
5011         ///   This is not an LValue because we need to re-write the expression, we
5012         ///   can not take data from the stack and store it.
5013         /// </summary>
5014         public class PropertyExpr : MemberExpr, IAssignMethod {
5015                 public readonly PropertyInfo PropertyInfo;
5016                 MethodInfo getter, setter;
5017                 bool is_static;
5018
5019                 bool resolved;
5020
5021                 LocalTemporary temp;
5022                 bool prepared;
5023
5024                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5025                 {
5026                         PropertyInfo = pi;
5027                         eclass = ExprClass.PropertyAccess;
5028                         is_static = false;
5029                         loc = l;
5030
5031                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5032
5033                         ResolveAccessors (container_type);
5034                 }
5035
5036                 public override string Name {
5037                         get {
5038                                 return PropertyInfo.Name;
5039                         }
5040                 }
5041
5042                 public override bool IsInstance {
5043                         get {
5044                                 return !is_static;
5045                         }
5046                 }
5047
5048                 public override bool IsStatic {
5049                         get {
5050                                 return is_static;
5051                         }
5052                 }
5053
5054                 public override Expression CreateExpressionTree (EmitContext ec)
5055                 {
5056                         if (IsSingleDimensionalArrayLength ()) {
5057                                 ArrayList args = new ArrayList (1);
5058                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5059                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5060                         }
5061
5062                         // TODO: it's waiting for PropertyExpr refactoring
5063                         //ArrayList args = new ArrayList (2);
5064                         //args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5065                         //args.Add (getter expression);
5066                         //return CreateExpressionFactoryCall ("Property", args);
5067                         return base.CreateExpressionTree (ec);
5068                 }
5069
5070                 public Expression CreateSetterTypeOfExpression ()
5071                 {
5072                         return new TypeOfMethodInfo (setter, loc);
5073                 }
5074
5075                 public override Type DeclaringType {
5076                         get {
5077                                 return PropertyInfo.DeclaringType;
5078                         }
5079                 }
5080
5081                 public override string GetSignatureForError ()
5082                 {
5083                         return TypeManager.GetFullNameSignature (PropertyInfo);
5084                 }
5085
5086                 void FindAccessors (Type invocation_type)
5087                 {
5088                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5089                                 BindingFlags.Static | BindingFlags.Instance |
5090                                 BindingFlags.DeclaredOnly;
5091
5092                         Type current = PropertyInfo.DeclaringType;
5093                         for (; current != null; current = current.BaseType) {
5094                                 MemberInfo[] group = TypeManager.MemberLookup (
5095                                         invocation_type, invocation_type, current,
5096                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5097
5098                                 if (group == null)
5099                                         continue;
5100
5101                                 if (group.Length != 1)
5102                                         // Oooops, can this ever happen ?
5103                                         return;
5104
5105                                 PropertyInfo pi = (PropertyInfo) group [0];
5106
5107                                 if (getter == null)
5108                                         getter = pi.GetGetMethod (true);
5109
5110                                 if (setter == null)
5111                                         setter = pi.GetSetMethod (true);
5112
5113                                 MethodInfo accessor = getter != null ? getter : setter;
5114
5115                                 if (!accessor.IsVirtual)
5116                                         return;
5117                         }
5118                 }
5119
5120                 //
5121                 // We also perform the permission checking here, as the PropertyInfo does not
5122                 // hold the information for the accessibility of its setter/getter
5123                 //
5124                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5125                 void ResolveAccessors (Type container_type)
5126                 {
5127                         FindAccessors (container_type);
5128
5129                         if (getter != null) {
5130                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5131                                 IMethodData md = TypeManager.GetMethod (the_getter);
5132                                 if (md != null)
5133                                         md.SetMemberIsUsed ();
5134
5135                                 is_static = getter.IsStatic;
5136                         }
5137
5138                         if (setter != null) {
5139                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5140                                 IMethodData md = TypeManager.GetMethod (the_setter);
5141                                 if (md != null)
5142                                         md.SetMemberIsUsed ();
5143
5144                                 is_static = setter.IsStatic;
5145                         }
5146                 }
5147
5148                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5149                 {
5150                         if (is_static) {
5151                                 InstanceExpression = null;
5152                                 return true;
5153                         }
5154
5155                         if (InstanceExpression == null) {
5156                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5157                                 return false;
5158                         }
5159
5160                         InstanceExpression = InstanceExpression.DoResolve (ec);
5161                         if (lvalue_instance && InstanceExpression != null)
5162                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5163
5164                         if (InstanceExpression == null)
5165                                 return false;
5166
5167                         InstanceExpression.CheckMarshalByRefAccess (ec);
5168
5169                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5170                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5171                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5172                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5173                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5174                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5175                                 return false;
5176                         }
5177
5178                         return true;
5179                 }
5180
5181                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5182                 {
5183                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5184                         if (mi is MethodBuilder) {
5185                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5186                                 return;
5187                         }
5188
5189                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5190                         sig.Append ('.');
5191                         ParameterData iparams = TypeManager.GetParameterData (mi);
5192                         sig.Append (getter ? "get_" : "set_");
5193                         sig.Append (Name);
5194                         sig.Append (iparams.GetSignatureForError ());
5195
5196                         Report.SymbolRelatedToPreviousError (mi);
5197                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5198                                 Name, sig.ToString ());
5199                 }
5200
5201                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5202                 {
5203                         bool dummy;
5204                         MethodInfo accessor = lvalue ? setter : getter;
5205                         if (accessor == null && lvalue)
5206                                 accessor = getter;
5207                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5208                 }
5209
5210                 bool IsSingleDimensionalArrayLength ()
5211                 {
5212                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5213                                 return false;
5214
5215                         string t_name = InstanceExpression.Type.Name;
5216                         int t_name_len = t_name.Length;
5217                         return t_name_len > 2 && t_name [t_name_len - 2] == '[' && t_name [t_name_len - 3] != ']';
5218                 }
5219
5220                 override public Expression DoResolve (EmitContext ec)
5221                 {
5222                         if (resolved)
5223                                 return this;
5224
5225                         if (getter != null){
5226                                 if (TypeManager.GetParameterData (getter).Count != 0){
5227                                         Error_PropertyNotFound (getter, true);
5228                                         return null;
5229                                 }
5230                         }
5231
5232                         if (getter == null){
5233                                 //
5234                                 // The following condition happens if the PropertyExpr was
5235                                 // created, but is invalid (ie, the property is inaccessible),
5236                                 // and we did not want to embed the knowledge about this in
5237                                 // the caller routine.  This only avoids double error reporting.
5238                                 //
5239                                 if (setter == null)
5240                                         return null;
5241
5242                                 if (InstanceExpression != EmptyExpression.Null) {
5243                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5244                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5245                                         return null;
5246                                 }
5247                         }
5248
5249                         bool must_do_cs1540_check = false;
5250                         if (getter != null &&
5251                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5252                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5253                                 if (pm != null && pm.HasCustomAccessModifier) {
5254                                         Report.SymbolRelatedToPreviousError (pm);
5255                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5256                                                 TypeManager.CSharpSignature (getter));
5257                                 }
5258                                 else {
5259                                         Report.SymbolRelatedToPreviousError (getter);
5260                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5261                                 }
5262                                 return null;
5263                         }
5264
5265                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5266                                 return null;
5267
5268                         //
5269                         // Only base will allow this invocation to happen.
5270                         //
5271                         if (IsBase && getter.IsAbstract) {
5272                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5273                                 return null;
5274                         }
5275
5276                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5277                                 UnsafeError (loc);
5278                                 return null;
5279                         }
5280
5281                         resolved = true;
5282
5283                         return this;
5284                 }
5285
5286                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5287                 {
5288                         if (right_side == EmptyExpression.OutAccess) {
5289                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5290                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5291                                             PropertyInfo.Name);
5292                                 } else {
5293                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5294                                               GetSignatureForError ());
5295                                 }
5296                                 return null;
5297                         }
5298
5299                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5300                                 Error_CannotModifyIntermediateExpressionValue (ec);
5301                         }
5302
5303                         if (setter == null){
5304                                 //
5305                                 // The following condition happens if the PropertyExpr was
5306                                 // created, but is invalid (ie, the property is inaccessible),
5307                                 // and we did not want to embed the knowledge about this in
5308                                 // the caller routine.  This only avoids double error reporting.
5309                                 //
5310                                 if (getter == null)
5311                                         return null;
5312                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5313                                               GetSignatureForError ());
5314                                 return null;
5315                         }
5316
5317                         if (TypeManager.GetParameterData (setter).Count != 1){
5318                                 Error_PropertyNotFound (setter, false);
5319                                 return null;
5320                         }
5321
5322                         bool must_do_cs1540_check;
5323                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5324                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5325                                 if (pm != null && pm.HasCustomAccessModifier) {
5326                                         Report.SymbolRelatedToPreviousError (pm);
5327                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5328                                                 TypeManager.CSharpSignature (setter));
5329                                 }
5330                                 else {
5331                                         Report.SymbolRelatedToPreviousError (setter);
5332                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5333                                 }
5334                                 return null;
5335                         }
5336
5337                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5338                                 return null;
5339
5340                         //
5341                         // Only base will allow this invocation to happen.
5342                         //
5343                         if (IsBase && setter.IsAbstract){
5344                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5345                                 return null;
5346                         }
5347
5348                         return this;
5349                 }
5350
5351                 public override void Emit (EmitContext ec)
5352                 {
5353                         Emit (ec, false);
5354                 }
5355
5356                 public void Emit (EmitContext ec, bool leave_copy)
5357                 {
5358                         //
5359                         // Special case: length of single dimension array property is turned into ldlen
5360                         //
5361                         if (IsSingleDimensionalArrayLength ()) {
5362                                 if (!prepared)
5363                                         EmitInstance (ec, false);
5364                                 ec.ig.Emit (OpCodes.Ldlen);
5365                                 ec.ig.Emit (OpCodes.Conv_I4);
5366                                 return;
5367                         }
5368
5369                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5370
5371                         if (leave_copy) {
5372                                 ec.ig.Emit (OpCodes.Dup);
5373                                 if (!is_static) {
5374                                         temp = new LocalTemporary (this.Type);
5375                                         temp.Store (ec);
5376                                 }
5377                         }
5378                 }
5379
5380                 //
5381                 // Implements the IAssignMethod interface for assignments
5382                 //
5383                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5384                 {
5385                         Expression my_source = source;
5386
5387                         if (prepare_for_load) {
5388                                 if (source is StringConcat)
5389                                         EmitInstance (ec, false);
5390                                 else
5391                                         prepared = true;
5392
5393                                 source.Emit (ec);
5394
5395                                 prepared = true;
5396                                 if (leave_copy) {
5397                                         ec.ig.Emit (OpCodes.Dup);
5398                                         if (!is_static) {
5399                                                 temp = new LocalTemporary (this.Type);
5400                                                 temp.Store (ec);
5401                                         }
5402                                 }
5403                         } else if (leave_copy) {
5404                                 source.Emit (ec);
5405                                 temp = new LocalTemporary (this.Type);
5406                                 temp.Store (ec);
5407                                 my_source = temp;
5408                         }
5409
5410                         ArrayList args = new ArrayList (1);
5411                         args.Add (new Argument (my_source, Argument.AType.Expression));
5412
5413                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5414
5415                         if (temp != null) {
5416                                 temp.Emit (ec);
5417                                 temp.Release (ec);
5418                         }
5419                 }
5420         }
5421
5422         /// <summary>
5423         ///   Fully resolved expression that evaluates to an Event
5424         /// </summary>
5425         public class EventExpr : MemberExpr {
5426                 public readonly EventInfo EventInfo;
5427
5428                 bool is_static;
5429                 MethodInfo add_accessor, remove_accessor;
5430
5431                 public EventExpr (EventInfo ei, Location loc)
5432                 {
5433                         EventInfo = ei;
5434                         this.loc = loc;
5435                         eclass = ExprClass.EventAccess;
5436
5437                         add_accessor = TypeManager.GetAddMethod (ei);
5438                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5439                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5440                                 is_static = true;
5441
5442                         if (EventInfo is MyEventBuilder){
5443                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5444                                 type = eb.EventType;
5445                                 eb.SetUsed ();
5446                         } else
5447                                 type = EventInfo.EventHandlerType;
5448                 }
5449
5450                 public override string Name {
5451                         get {
5452                                 return EventInfo.Name;
5453                         }
5454                 }
5455
5456                 public override bool IsInstance {
5457                         get {
5458                                 return !is_static;
5459                         }
5460                 }
5461
5462                 public override bool IsStatic {
5463                         get {
5464                                 return is_static;
5465                         }
5466                 }
5467
5468                 public override Type DeclaringType {
5469                         get {
5470                                 return EventInfo.DeclaringType;
5471                         }
5472                 }
5473
5474                 void Error_AssignmentEventOnly ()
5475                 {
5476                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5477                                 GetSignatureForError ());
5478                 }
5479
5480                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5481                                                                 SimpleName original)
5482                 {
5483                         //
5484                         // If the event is local to this class, we transform ourselves into a FieldExpr
5485                         //
5486
5487                         if (EventInfo.DeclaringType == ec.ContainerType ||
5488                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5489                                 EventField mi = TypeManager.GetEventField (EventInfo);
5490
5491                                 if (mi != null) {
5492                                         if (!ec.IsInObsoleteScope)
5493                                                 mi.CheckObsoleteness (loc);
5494
5495                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5496                                                 Error_AssignmentEventOnly ();
5497
5498                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5499
5500                                         InstanceExpression = null;
5501
5502                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5503                                 }
5504                         }
5505
5506                         if (left is This && !ec.IsInCompoundAssignment)
5507                                 Error_AssignmentEventOnly ();
5508
5509                         return base.ResolveMemberAccess (ec, left, loc, original);
5510                 }
5511
5512
5513                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5514                 {
5515                         if (is_static) {
5516                                 InstanceExpression = null;
5517                                 return true;
5518                         }
5519
5520                         if (InstanceExpression == null) {
5521                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5522                                 return false;
5523                         }
5524
5525                         InstanceExpression = InstanceExpression.DoResolve (ec);
5526                         if (InstanceExpression == null)
5527                                 return false;
5528
5529                         if (IsBase && add_accessor.IsAbstract) {
5530                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5531                                 return false;
5532                         }
5533
5534                         //
5535                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5536                         // However, in the Event case, we reported a CS0122 instead.
5537                         //
5538                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5539                             InstanceExpression.Type != ec.ContainerType &&
5540                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5541                                 Report.SymbolRelatedToPreviousError (EventInfo);
5542                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5543                                 return false;
5544                         }
5545
5546                         return true;
5547                 }
5548
5549                 public bool IsAccessibleFrom (Type invocation_type)
5550                 {
5551                         bool dummy;
5552                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5553                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5554                 }
5555
5556                 public override Expression CreateExpressionTree (EmitContext ec)
5557                 {
5558                         throw new NotSupportedException ();
5559                 }
5560
5561                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5562                 {
5563                         return DoResolve (ec);
5564                 }
5565
5566                 public override Expression DoResolve (EmitContext ec)
5567                 {
5568                         bool must_do_cs1540_check;
5569                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5570                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5571                                 Report.SymbolRelatedToPreviousError (EventInfo);
5572                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5573                                 return null;
5574                         }
5575
5576                         if (!InstanceResolve (ec, must_do_cs1540_check))
5577                                 return null;
5578
5579                         return this;
5580                 }
5581
5582                 public override void Emit (EmitContext ec)
5583                 {
5584                         Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5585                                       "(except on the defining type)", GetSignatureForError ());
5586                 }
5587
5588                 public override string GetSignatureForError ()
5589                 {
5590                         return TypeManager.CSharpSignature (EventInfo);
5591                 }
5592
5593                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5594                 {
5595                         BinaryDelegate source_del = source as BinaryDelegate;
5596                         if (source_del == null) {
5597                                 Emit (ec);
5598                                 return;
5599                         }
5600                         Expression handler = source_del.Right;
5601
5602                         Argument arg = new Argument (handler, Argument.AType.Expression);
5603                         ArrayList args = new ArrayList ();
5604
5605                         args.Add (arg);
5606
5607                         if (source_del.IsAddition)
5608                                 Invocation.EmitCall (
5609                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5610                         else
5611                                 Invocation.EmitCall (
5612                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5613                 }
5614         }
5615
5616         public class TemporaryVariable : Expression, IMemoryLocation
5617         {
5618                 LocalInfo li;
5619                 Variable var;
5620
5621                 public TemporaryVariable (Type type, Location loc)
5622                 {
5623                         this.type = type;
5624                         this.loc = loc;
5625                         eclass = ExprClass.Value;
5626                 }
5627
5628                 public override Expression DoResolve (EmitContext ec)
5629                 {
5630                         if (li != null)
5631                                 return this;
5632
5633                         TypeExpr te = new TypeExpression (type, loc);
5634                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5635                         if (!li.Resolve (ec))
5636                                 return null;
5637
5638                         if (ec.MustCaptureVariable (li)) {
5639                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5640                                 var = scope.AddLocal (li);
5641                                 type = var.Type;
5642                         }
5643
5644                         return this;
5645                 }
5646
5647                 public Variable Variable {
5648                         get { return var != null ? var : li.Variable; }
5649                 }
5650
5651                 public override void Emit (EmitContext ec)
5652                 {
5653                         Variable.EmitInstance (ec);
5654                         Variable.Emit (ec);
5655                 }
5656
5657                 public void EmitLoadAddress (EmitContext ec)
5658                 {
5659                         Variable.EmitInstance (ec);
5660                         Variable.EmitAddressOf (ec);
5661                 }
5662
5663                 public void Store (EmitContext ec, Expression right_side)
5664                 {
5665                         Variable.EmitInstance (ec);
5666                         right_side.Emit (ec);
5667                         Variable.EmitAssign (ec);
5668                 }
5669
5670                 public void EmitThis (EmitContext ec)
5671                 {
5672                         Variable.EmitInstance (ec);
5673                 }
5674
5675                 public void EmitStore (EmitContext ec)
5676                 {
5677                         Variable.EmitAssign (ec);
5678                 }
5679
5680                 public void AddressOf (EmitContext ec, AddressOp mode)
5681                 {
5682                         EmitLoadAddress (ec);
5683                 }
5684         }
5685
5686         ///
5687         /// Handles `var' contextual keyword; var becomes a keyword only
5688         /// if no type called var exists in a variable scope
5689         ///
5690         public class VarExpr : SimpleName
5691         {
5692                 // Used for error reporting only
5693                 ArrayList initializer;
5694
5695                 public VarExpr (Location loc)
5696                         : base ("var", loc)
5697                 {
5698                 }
5699
5700                 public ArrayList VariableInitializer {
5701                         set {
5702                                 this.initializer = value;
5703                         }
5704                 }
5705
5706                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5707                 {
5708                         if (type != null)
5709                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5710
5711                         type = right_side.Type;
5712                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5713                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5714                                               right_side.GetSignatureForError ());
5715                                 return null;
5716                         }
5717
5718                         eclass = ExprClass.Variable;
5719                         return this;
5720                 }
5721
5722                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5723                 {
5724                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5725                 }
5726
5727                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5728                 {
5729                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5730                         if (te != null)
5731                                 return te;
5732
5733                         if (initializer == null)
5734                                 return null;
5735
5736                         if (initializer.Count > 1) {
5737                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5738                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5739                                 initializer = null;
5740                                 return null;
5741                         }
5742
5743                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5744                         if (variable_initializer == null) {
5745                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5746                                 return null;
5747                         }
5748
5749                         return null;
5750                 }
5751         }
5752 }