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                 TypeParameter,
  35                 MethodGroup,
  36                 PropertyAccess,
  37                 EventAccess,
  38                 IndexerAccess,
  39                 Nothing,
  40         }
  41
  42         /// <remarks>
  43         ///   This is used to tell Resolve in which types of expressions we're
  44         ///   interested.
  45         /// </remarks>
  46         [Flags]
  47         public enum ResolveFlags {
  48                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  49                 VariableOrValue         = 1,
  50
  51                 // Returns a type expression.
  52                 Type                    = 1 << 1,
  53
  54                 // Returns a method group.
  55                 MethodGroup             = 1 << 2,
  56
  57                 TypeParameter   = 1 << 3,
  58
  59                 // Mask of all the expression class flags.
  60                 MaskExprClass = VariableOrValue | Type | MethodGroup | TypeParameter,
  61
  62                 // Disable control flow analysis while resolving the expression.
  63                 // This is used when resolving the instance expression of a field expression.
  64                 DisableFlowAnalysis     = 1 << 10,
  65
  66                 // Set if this is resolving the first part of a MemberAccess.
  67                 Intermediate            = 1 << 11,
  68
  69                 // Disable control flow analysis _of struct_ while resolving the expression.
  70                 // This is used when resolving the instance expression of a field expression.
  71                 DisableStructFlowAnalysis       = 1 << 12,
  72
  73         }
  74
  75         //
  76         // This is just as a hint to AddressOf of what will be done with the
  77         // address.
  78         [Flags]
  79         public enum AddressOp {
  80                 Store = 1,
  81                 Load  = 2,
  82                 LoadStore = 3
  83         };
  84
  85         /// <summary>
  86         ///   This interface is implemented by variables
  87         /// </summary>
  88         public interface IMemoryLocation {
  89                 /// <summary>
  90                 ///   The AddressOf method should generate code that loads
  91                 ///   the address of the object and leaves it on the stack.
  92                 ///
  93                 ///   The `mode' argument is used to notify the expression
  94                 ///   of whether this will be used to read from the address or
  95                 ///   write to the address.
  96                 ///
  97                 ///   This is just a hint that can be used to provide good error
  98                 ///   reporting, and should have no other side effects.
  99                 /// </summary>
 100                 void AddressOf (EmitContext ec, AddressOp mode);
 101         }
 102
 103         //
 104         // An expressions resolved as a direct variable reference
 105         //
 106         public interface IVariableReference : IFixedExpression
 107         {
 108                 bool IsHoisted { get; }
 109                 string Name { get; }
 110                 VariableInfo VariableInfo { get; }
 111
 112                 void SetHasAddressTaken ();
 113         }
 114
 115         //
 116         // Implemented by an expression which could be or is always
 117         // fixed
 118         //
 119         public interface IFixedExpression
 120         {
 121                 bool IsFixed { get; }
 122         }
 123
 124         /// <remarks>
 125         ///   Base class for expressions
 126         /// </remarks>
 127         public abstract class Expression {
 128                 public ExprClass eclass;
 129                 protected Type type;
 130                 protected Location loc;
 131
 132                 public Type Type {
 133                         get { return type; }
 134                         set { type = value; }
 135                 }
 136
 137                 public virtual Location Location {
 138                         get { return loc; }
 139                 }
 140
 141                 /// <summary>
 142                 ///   Utility wrapper routine for Error, just to beautify the code
 143                 /// </summary>
 144                 public void Error (int error, string s)
 145                 {
 146                         Report.Error (error, loc, s);
 147                 }
 148
 149                 // Not nice but we have broken hierarchy.
 150                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 151                 {
 152                 }
 153
 154                 public virtual bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
 155                 {
 156                         Attribute.Error_AttributeArgumentNotValid (loc);
 157                         value = null;
 158                         return false;
 159                 }
 160
 161                 public virtual string GetSignatureForError ()
 162                 {
 163                         return TypeManager.CSharpName (type);
 164                 }
 165
 166                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 167                 {
 168                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 169
 170                         must_do_cs1540_check = false; // by default we do not check for this
 171
 172                         if (ma == MethodAttributes.Public)
 173                                 return true;
 174
 175                         //
 176                         // If only accessible to the current class or children
 177                         //
 178                         if (ma == MethodAttributes.Private)
 179                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 180                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 181
 182                         if (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 183                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 184                                         return true;
 185                         } else {
 186                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 187                                         return false;
 188                         }
 189
 190                         // Family and FamANDAssem require that we derive.
 191                         // FamORAssem requires that we derive if in different assemblies.
 192                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 193                                 return false;
 194
 195                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 196                                 must_do_cs1540_check = true;
 197
 198                         return true;
 199                 }
 200
 201                 public virtual bool IsNull {
 202                         get {
 203                                 return false;
 204                         }
 205                 }
 206
 207                 /// <summary>
 208                 ///   Performs semantic analysis on the Expression
 209                 /// </summary>
 210                 ///
 211                 /// <remarks>
 212                 ///   The Resolve method is invoked to perform the semantic analysis
 213                 ///   on the node.
 214                 ///
 215                 ///   The return value is an expression (it can be the
 216                 ///   same expression in some cases) or a new
 217                 ///   expression that better represents this node.
 218                 ///
 219                 ///   For example, optimizations of Unary (LiteralInt)
 220                 ///   would return a new LiteralInt with a negated
 221                 ///   value.
 222                 ///
 223                 ///   If there is an error during semantic analysis,
 224                 ///   then an error should be reported (using Report)
 225                 ///   and a null value should be returned.
 226                 ///
 227                 ///   There are two side effects expected from calling
 228                 ///   Resolve(): the the field variable "eclass" should
 229                 ///   be set to any value of the enumeration
 230                 ///   `ExprClass' and the type variable should be set
 231                 ///   to a valid type (this is the type of the
 232                 ///   expression).
 233                 /// </remarks>
 234                 public abstract Expression DoResolve (EmitContext ec);
 235
 236                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 237                 {
 238                         return null;
 239                 }
 240
 241                 //
 242                 // This is used if the expression should be resolved as a type or namespace name.
 243                 // the default implementation fails.
 244                 //
 245                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 246                 {
 247                         if (!silent) {
 248                                 Expression e = this;
 249                                 EmitContext ec = rc as EmitContext;
 250                                 if (ec != null)
 251                                         e = e.Resolve (ec);
 252                                 if (e != null)
 253                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 254                         }
 255                         return null;
 256                 }
 257
 258                 //
 259                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 260                 // same name exists or as a keyword when no type was found
 261                 //
 262                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 263                 {
 264                         return ResolveAsTypeTerminal (rc, silent);
 265                 }
 266
 267                 //
 268                 // This is used to resolve the expression as a type, a null
 269                 // value will be returned if the expression is not a type
 270                 // reference
 271                 //
 272                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 273                 {
 274                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 275                         if (te == null)
 276                                 return null;
 277
 278                         if (!silent) { // && !(te is TypeParameterExpr)) {
 279                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 280                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 281                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 282                                 }
 283                         }
 284
 285                         GenericTypeExpr ct = te as GenericTypeExpr;
 286                         if (ct != null) {
 287                                 // Skip constrains check for overrides and explicit implementations
 288                                 // TODO: they should use different overload
 289                                 GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 290                                 if (gm != null && ((gm.ModFlags & Modifiers.OVERRIDE) != 0 || gm.MemberName.Left != null)) {
 291                                         te.loc = loc;
 292                                         return te;
 293                                 }
 294
 295                                 // TODO: silent flag is ignored
 296                                 ct.CheckConstraints (ec);
 297                         }
 298
 299                         return te;
 300                 }
 301
 302                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 303                 {
 304                         int errors = Report.Errors;
 305
 306                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 307
 308                         if (fne == null)
 309                                 return null;
 310
 311                         TypeExpr te = fne as TypeExpr;
 312                         if (te == null) {
 313                                 if (!silent && errors == Report.Errors)
 314                                         fne.Error_UnexpectedKind (null, "type", loc);
 315                                 return null;
 316                         }
 317
 318                         if (!te.CheckAccessLevel (ec.GenericDeclContainer)) {
 319                                 Report.SymbolRelatedToPreviousError (te.Type);
 320                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 321                                 return null;
 322                         }
 323
 324                         te.loc = loc;
 325                         return te;
 326                 }
 327
 328                 public static void ErrorIsInaccesible (Location loc, string name)
 329                 {
 330                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 331                 }
 332
 333                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 334                 {
 335                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 336                                 + " The qualifier must be of type `{2}' or derived from it",
 337                                 TypeManager.GetFullNameSignature (m),
 338                                 TypeManager.CSharpName (qualifier),
 339                                 TypeManager.CSharpName (container));
 340
 341                 }
 342
 343                 public static void Error_InvalidExpressionStatement (Location loc)
 344                 {
 345                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 346                                        "expressions can be used as a statement");
 347                 }
 348
 349                 public void Error_InvalidExpressionStatement ()
 350                 {
 351                         Error_InvalidExpressionStatement (loc);
 352                 }
 353
 354                 protected void Error_CannotAssign (string to, string roContext)
 355                 {
 356                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 357                                 to, roContext);
 358                 }
 359
 360                 public static void Error_VoidInvalidInTheContext (Location loc)
 361                 {
 362                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 363                 }
 364
 365                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 366                 {
 367                         // The error was already reported as CS1660
 368                         if (type == TypeManager.anonymous_method_type)
 369                                 return;
 370
 371                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 372 #if GMCS_SOURCE
 373                                 string sig1 = type.DeclaringMethod == null ?
 374                                         TypeManager.CSharpName (type.DeclaringType) :
 375                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 376                                 string sig2 = target.DeclaringMethod == null ?
 377                                         TypeManager.CSharpName (target.DeclaringType) :
 378                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 379                                 Report.ExtraInformation (loc,
 380                                         String.Format (
 381                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 382                                                 Type.Name, sig1, sig2));
 383 #endif
 384                         } else if (Type.FullName == target.FullName){
 385                                 Report.ExtraInformation (loc,
 386                                         String.Format (
 387                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 388                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 389                         }
 390
 391                         if (expl) {
 392                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 393                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 394                                 return;
 395                         }
 396
 397                         Report.DisableReporting ();
 398                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 399                         Report.EnableReporting ();
 400
 401                         if (expl_exists) {
 402                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 403                                               "An explicit conversion exists (are you missing a cast?)",
 404                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 405                                 return;
 406                         }
 407
 408                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 409                                 TypeManager.CSharpName (type),
 410                                 TypeManager.CSharpName (target));
 411                 }
 412
 413                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (string name)
 414                 {
 415                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 416                 }
 417
 418                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 419                 {
 420                         Error_TypeDoesNotContainDefinition (loc, type, name);
 421                 }
 422
 423                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 424                 {
 425                         Report.SymbolRelatedToPreviousError (type);
 426                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 427                                 TypeManager.CSharpName (type), name);
 428                 }
 429
 430                 protected static void Error_ValueAssignment (Location loc)
 431                 {
 432                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 433                 }
 434
 435                 ResolveFlags ExprClassToResolveFlags
 436                 {
 437                         get {
 438                                 switch (eclass) {
 439                                 case ExprClass.Type:
 440                                 case ExprClass.Namespace:
 441                                         return ResolveFlags.Type;
 442
 443                                 case ExprClass.MethodGroup:
 444                                         return ResolveFlags.MethodGroup;
 445
 446                                 case ExprClass.TypeParameter:
 447                                         return ResolveFlags.TypeParameter;
 448
 449                                 case ExprClass.Value:
 450                                 case ExprClass.Variable:
 451                                 case ExprClass.PropertyAccess:
 452                                 case ExprClass.EventAccess:
 453                                 case ExprClass.IndexerAccess:
 454                                         return ResolveFlags.VariableOrValue;
 455
 456                                 default:
 457                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 458                                 }
 459                         }
 460                 }
 461
 462                 /// <summary>
 463                 ///   Resolves an expression and performs semantic analysis on it.
 464                 /// </summary>
 465                 ///
 466                 /// <remarks>
 467                 ///   Currently Resolve wraps DoResolve to perform sanity
 468                 ///   checking and assertion checking on what we expect from Resolve.
 469                 /// </remarks>
 470                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 471                 {
 472                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 473                                 return ResolveAsTypeStep (ec, false);
 474
 475                         bool do_flow_analysis = ec.DoFlowAnalysis;
 476                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 477                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 478                                 do_flow_analysis = false;
 479                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 480                                 omit_struct_analysis = true;
 481
 482                         Expression e;
 483                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 484                                 if (this is SimpleName) {
 485                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 486                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 487                                 } else {
 488                                         e = DoResolve (ec);
 489                                 }
 490                         }
 491
 492                         if (e == null)
 493                                 return null;
 494
 495                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 496                                 e.Error_UnexpectedKind (flags, loc);
 497                                 return null;
 498                         }
 499
 500                         if (e.type == null && !(e is Namespace)) {
 501                                 throw new Exception (
 502                                         "Expression " + e.GetType () +
 503                                         " did not set its type after Resolve\n" +
 504                                         "called from: " + this.GetType ());
 505                         }
 506
 507                         return e;
 508                 }
 509
 510                 /// <summary>
 511                 ///   Resolves an expression and performs semantic analysis on it.
 512                 /// </summary>
 513                 public Expression Resolve (EmitContext ec)
 514                 {
 515                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 516
 517                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 518                                 ((MethodGroupExpr) e).ReportUsageError ();
 519                                 return null;
 520                         }
 521                         return e;
 522                 }
 523
 524                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 525                 {
 526                         Expression e = Resolve (ec);
 527                         if (e == null)
 528                                 return null;
 529
 530                         Constant c = e as Constant;
 531                         if (c != null)
 532                                 return c;
 533
 534                         if (type != null && TypeManager.IsReferenceType (type))
 535                                 Const.Error_ConstantCanBeInitializedWithNullOnly (type, loc, mc.GetSignatureForError ());
 536                         else
 537                                 Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 538
 539                         return null;
 540                 }
 541
 542                 /// <summary>
 543                 ///   Resolves an expression for LValue assignment
 544                 /// </summary>
 545                 ///
 546                 /// <remarks>
 547                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 548                 ///   checking and assertion checking on what we expect from Resolve
 549                 /// </remarks>
 550                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 551                 {
 552                         int errors = Report.Errors;
 553                         bool out_access = right_side == EmptyExpression.OutAccess;
 554
 555                         Expression e = DoResolveLValue (ec, right_side);
 556
 557                         if (e != null && out_access && !(e is IMemoryLocation)) {
 558                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 559                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 560
 561                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 562                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 563                                 e = null;
 564                         }
 565
 566                         if (e == null) {
 567                                 if (errors == Report.Errors) {
 568                                         if (out_access)
 569                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 570                                         else
 571                                                 Error_ValueAssignment (loc);
 572                                 }
 573                                 return null;
 574                         }
 575
 576                         if (e.eclass == ExprClass.Invalid)
 577                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 578
 579                         if ((e.type == null) && !(e is GenericTypeExpr))
 580                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 581
 582                         return e;
 583                 }
 584
 585                 /// <summary>
 586                 ///   Emits the code for the expression
 587                 /// </summary>
 588                 ///
 589                 /// <remarks>
 590                 ///   The Emit method is invoked to generate the code
 591                 ///   for the expression.
 592                 /// </remarks>
 593                 public abstract void Emit (EmitContext ec);
 594
 595                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 596                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 597                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 598                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 599                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 600                 {
 601                         Emit (ec);
 602                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 603                 }
 604
 605                 // Emit this expression for its side effects, not for its value.
 606                 // The default implementation is to emit the value, and then throw it away.
 607                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 608                 public virtual void EmitSideEffect (EmitContext ec)
 609                 {
 610                         Emit (ec);
 611                         ec.ig.Emit (OpCodes.Pop);
 612                 }
 613
 614                 /// <summary>
 615                 ///   Protected constructor.  Only derivate types should
 616                 ///   be able to be created
 617                 /// </summary>
 618
 619                 protected Expression ()
 620                 {
 621                         eclass = ExprClass.Invalid;
 622                         type = null;
 623                 }
 624
 625                 /// <summary>
 626                 ///   Returns a fully formed expression after a MemberLookup
 627                 /// </summary>
 628                 ///
 629                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 630                 {
 631                         if (mi is EventInfo)
 632                                 return new EventExpr ((EventInfo) mi, loc);
 633                         else if (mi is FieldInfo) {
 634                                 FieldInfo fi = (FieldInfo) mi;
 635                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 636                                         return new ConstantExpr (fi, loc);
 637                                 return new FieldExpr (fi, loc);
 638                         } else if (mi is PropertyInfo)
 639                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 640                         else if (mi is Type) {
 641                                 return new TypeExpression ((System.Type) mi, loc);
 642                         }
 643
 644                         return null;
 645                 }
 646
 647                 // TODO: [Obsolete ("Can be removed")]
 648                 protected static ArrayList almost_matched_members = new ArrayList (4);
 649
 650                 //
 651                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 652                 //
 653                 // This code could use some optimizations, but we need to do some
 654                 // measurements.  For example, we could use a delegate to `flag' when
 655                 // something can not any longer be a method-group (because it is something
 656                 // else).
 657                 //
 658                 // Return values:
 659                 //     If the return value is an Array, then it is an array of
 660                 //     MethodBases
 661                 //
 662                 //     If the return value is an MemberInfo, it is anything, but a Method
 663                 //
 664                 //     null on error.
 665                 //
 666                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 667                 // the arguments here and have MemberLookup return only the methods that
 668                 // match the argument count/type, unlike we are doing now (we delay this
 669                 // decision).
 670                 //
 671                 // This is so we can catch correctly attempts to invoke instance methods
 672                 // from a static body (scan for error 120 in ResolveSimpleName).
 673                 //
 674                 //
 675                 // FIXME: Potential optimization, have a static ArrayList
 676                 //
 677
 678                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 679                                                        MemberTypes mt, BindingFlags bf, Location loc)
 680                 {
 681                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 682                 }
 683
 684                 //
 685                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 686                 // `qualifier_type' or null to lookup members in the current class.
 687                 //
 688
 689                 public static Expression MemberLookup (Type container_type,
 690                                                        Type qualifier_type, Type queried_type,
 691                                                        string name, MemberTypes mt,
 692                                                        BindingFlags bf, Location loc)
 693                 {
 694                         almost_matched_members.Clear ();
 695
 696                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 697                                                                      queried_type, mt, bf, name, almost_matched_members);
 698
 699                         if (mi == null)
 700                                 return null;
 701
 702                         if (mi.Length > 1) {
 703                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 704                                 ArrayList methods = new ArrayList (2);
 705                                 ArrayList non_methods = null;
 706
 707                                 foreach (MemberInfo m in mi) {
 708                                         if (m is MethodBase) {
 709                                                 methods.Add (m);
 710                                                 continue;
 711                                         }
 712
 713                                         if (non_methods == null) {
 714                                                 non_methods = new ArrayList (2);
 715                                                 non_methods.Add (m);
 716                                                 continue;
 717                                         }
 718
 719                                         foreach (MemberInfo n_m in non_methods) {
 720                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 721                                                         continue;
 722
 723                                                 Report.SymbolRelatedToPreviousError (m);
 724                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 725                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 726                                                 return null;
 727                                         }
 728                                 }
 729
 730                                 if (methods.Count == 0)
 731                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 732
 733                                 if (non_methods != null) {
 734                                         MethodBase method = (MethodBase) methods [0];
 735                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 736                                         if (method.DeclaringType == non_method.DeclaringType) {
 737                                                 // Cannot happen with C# code, but is valid in IL
 738                                                 Report.SymbolRelatedToPreviousError (method);
 739                                                 Report.SymbolRelatedToPreviousError (non_method);
 740                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 741                                                               TypeManager.GetFullNameSignature (non_method),
 742                                                               TypeManager.CSharpSignature (method));
 743                                                 return null;
 744                                         }
 745
 746                                         if (is_interface) {
 747                                                 Report.SymbolRelatedToPreviousError (method);
 748                                                 Report.SymbolRelatedToPreviousError (non_method);
 749                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 750                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 751                                         }
 752                                 }
 753
 754                                 return new MethodGroupExpr (methods, queried_type, loc);
 755                         }
 756
 757                         if (mi [0] is MethodBase)
 758                                 return new MethodGroupExpr (mi, queried_type, loc);
 759
 760                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 761                 }
 762
 763                 public const MemberTypes AllMemberTypes =
 764                         MemberTypes.Constructor |
 765                         MemberTypes.Event       |
 766                         MemberTypes.Field       |
 767                         MemberTypes.Method      |
 768                         MemberTypes.NestedType  |
 769                         MemberTypes.Property;
 770
 771                 public const BindingFlags AllBindingFlags =
 772                         BindingFlags.Public |
 773                         BindingFlags.Static |
 774                         BindingFlags.Instance;
 775
 776                 public static Expression MemberLookup (Type container_type, Type queried_type,
 777                                                        string name, Location loc)
 778                 {
 779                         return MemberLookup (container_type, null, queried_type, name,
 780                                              AllMemberTypes, AllBindingFlags, loc);
 781                 }
 782
 783                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 784                                                        Type queried_type, string name, Location loc)
 785                 {
 786                         return MemberLookup (container_type, qualifier_type, queried_type,
 787                                              name, AllMemberTypes, AllBindingFlags, loc);
 788                 }
 789
 790                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 791                                                        string name, Location loc)
 792                 {
 793                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 794                                              MemberTypes.Method, AllBindingFlags, loc);
 795                 }
 796
 797                 /// <summary>
 798                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 799                 ///   to find a final definition.  If the final definition is not found, we
 800                 ///   look for private members and display a useful debugging message if we
 801                 ///   find it.
 802                 /// </summary>
 803                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 804                                                             Type queried_type, string name,
 805                                                             MemberTypes mt, BindingFlags bf,
 806                                                             Location loc)
 807                 {
 808                         Expression e;
 809
 810                         int errors = Report.Errors;
 811                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 812
 813                         if (e != null || errors != Report.Errors)
 814                                 return e;
 815
 816                         // No errors were reported by MemberLookup, but there was an error.
 817                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 818                                         name, null, mt, bf);
 819                 }
 820
 821                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 822                                                        Type queried_type, string name, string class_name,
 823                                                            MemberTypes mt, BindingFlags bf)
 824                 {
 825                         MemberInfo[] lookup = null;
 826                         if (queried_type == null) {
 827                                 class_name = "global::";
 828                         } else {
 829                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 830                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 831                                         name, null);
 832
 833                                 if (lookup != null) {
 834                                         Expression e = Error_MemberLookupFailed (queried_type, lookup);
 835
 836                                         //
 837                                         // FIXME: This is still very wrong, it should be done inside
 838                                         // OverloadResolve to do correct arguments matching.
 839                                         // Requires MemberLookup accessiblity check removal
 840                                         //
 841                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 842                                                 MemberInfo mi = lookup[0];
 843                                                 Report.SymbolRelatedToPreviousError (mi);
 844                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 845                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 846                                                         // Although a derived class can access protected members of
 847                                                         // its base class it cannot do so through an instance of the
 848                                                         // base class (CS1540).  If the qualifier_type is a base of the
 849                                                         // ec.ContainerType and the lookup succeeds with the latter one,
 850                                                         // then we are in this situation.
 851                                                         Error_CannotAccessProtected (loc, mi, qualifier_type, container_type);
 852                                                 } else {
 853                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi));
 854                                                 }
 855                                         }
 856
 857                                         return e;
 858                                 }
 859
 860                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 861                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 862                                         name, null);
 863                         }
 864
 865                         if (lookup == null) {
 866                                 if (class_name != null) {
 867                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 868                                                 name);
 869                                 } else {
 870                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 871                                 }
 872                                 return null;
 873                         }
 874
 875                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 876                                                       AllMemberTypes, AllBindingFlags |
 877                                                       BindingFlags.NonPublic, name, null) == null) {
 878                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 879                                         Type t = (Type) lookup [0];
 880
 881                                         Report.Error (305, loc,
 882                                                       "Using the generic type `{0}' " +
 883                                                       "requires {1} type arguments",
 884                                                       TypeManager.CSharpName (t),
 885                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 886                                         return null;
 887                                 }
 888                         }
 889
 890                         return Error_MemberLookupFailed (queried_type, lookup);
 891                 }
 892
 893                 protected virtual Expression Error_MemberLookupFailed (Type type, MemberInfo[] members)
 894                 {
 895                         for (int i = 0; i < members.Length; ++i) {
 896                                 if (!(members [i] is MethodBase))
 897                                         return null;
 898                         }
 899
 900                         // By default propagate the closest candidates upwards
 901                         return new MethodGroupExpr (members, type, loc, true);
 902                 }
 903
 904                 protected virtual void Error_NegativeArrayIndex (Location loc)
 905                 {
 906                         throw new NotImplementedException ();
 907                 }
 908
 909                 protected void Error_PointerInsideExpressionTree ()
 910                 {
 911                         Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 912                 }
 913
 914                 /// <summary>
 915                 ///   Returns an expression that can be used to invoke operator true
 916                 ///   on the expression if it exists.
 917                 /// </summary>
 918                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 919                 {
 920                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 921                 }
 922
 923                 /// <summary>
 924                 ///   Returns an expression that can be used to invoke operator false
 925                 ///   on the expression if it exists.
 926                 /// </summary>
 927                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 928                 {
 929                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 930                 }
 931
 932                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 933                 {
 934                         MethodGroupExpr operator_group;
 935                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 936                         operator_group = MethodLookup (ec.ContainerType, e.Type, mname, loc) as MethodGroupExpr;
 937                         if (operator_group == null)
 938                                 return null;
 939
 940                         ArrayList arguments = new ArrayList (1);
 941                         arguments.Add (new Argument (e, Argument.AType.Expression));
 942                         operator_group = operator_group.OverloadResolve (
 943                                 ec, ref arguments, false, loc);
 944
 945                         if (operator_group == null)
 946                                 return null;
 947
 948                         return new UserOperatorCall (operator_group, arguments, null, loc);
 949                 }
 950
 951                 /// <summary>
 952                 ///   Resolves the expression `e' into a boolean expression: either through
 953                 ///   an implicit conversion, or through an `operator true' invocation
 954                 /// </summary>
 955                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 956                 {
 957                         e = e.Resolve (ec);
 958                         if (e == null)
 959                                 return null;
 960
 961                         if (e.Type == TypeManager.bool_type)
 962                                 return e;
 963
 964                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 965
 966                         if (converted != null)
 967                                 return converted;
 968
 969                         //
 970                         // If no implicit conversion to bool exists, try using `operator true'
 971                         //
 972                         converted = Expression.GetOperatorTrue (ec, e, loc);
 973                         if (converted == null){
 974                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 975                                 return null;
 976                         }
 977                         return converted;
 978                 }
 979
 980                 public virtual string ExprClassName
 981                 {
 982                         get {
 983                                 switch (eclass){
 984                                 case ExprClass.Invalid:
 985                                         return "Invalid";
 986                                 case ExprClass.Value:
 987                                         return "value";
 988                                 case ExprClass.Variable:
 989                                         return "variable";
 990                                 case ExprClass.Namespace:
 991                                         return "namespace";
 992                                 case ExprClass.Type:
 993                                         return "type";
 994                                 case ExprClass.MethodGroup:
 995                                         return "method group";
 996                                 case ExprClass.PropertyAccess:
 997                                         return "property access";
 998                                 case ExprClass.EventAccess:
 999                                         return "event access";
1000                                 case ExprClass.IndexerAccess:
1001                                         return "indexer access";
1002                                 case ExprClass.Nothing:
1003                                         return "null";
1004                                 case ExprClass.TypeParameter:
1005                                         return "type parameter";
1006                                 }
1007                                 throw new Exception ("Should not happen");
1008                         }
1009                 }
1010
1011                 /// <summary>
1012                 ///   Reports that we were expecting `expr' to be of class `expected'
1013                 /// </summary>
1014                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1015                 {
1016                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1017                 }
1018
1019                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1020                 {
1021                         string name = GetSignatureForError ();
1022                         if (ds != null)
1023                                 name = ds.GetSignatureForError () + '.' + name;
1024
1025                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1026                               name, was, expected);
1027                 }
1028
1029                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1030                 {
1031                         string [] valid = new string [4];
1032                         int count = 0;
1033
1034                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1035                                 valid [count++] = "variable";
1036                                 valid [count++] = "value";
1037                         }
1038
1039                         if ((flags & ResolveFlags.Type) != 0)
1040                                 valid [count++] = "type";
1041
1042                         if ((flags & ResolveFlags.MethodGroup) != 0)
1043                                 valid [count++] = "method group";
1044
1045                         if (count == 0)
1046                                 valid [count++] = "unknown";
1047
1048                         StringBuilder sb = new StringBuilder (valid [0]);
1049                         for (int i = 1; i < count - 1; i++) {
1050                                 sb.Append ("', `");
1051                                 sb.Append (valid [i]);
1052                         }
1053                         if (count > 1) {
1054                                 sb.Append ("' or `");
1055                                 sb.Append (valid [count - 1]);
1056                         }
1057
1058                         Report.Error (119, loc,
1059                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1060                 }
1061
1062                 public static void UnsafeError (Location loc)
1063                 {
1064                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1065                 }
1066
1067                 //
1068                 // Load the object from the pointer.
1069                 //
1070                 public static void LoadFromPtr (ILGenerator ig, Type t)
1071                 {
1072                         if (t == TypeManager.int32_type)
1073                                 ig.Emit (OpCodes.Ldind_I4);
1074                         else if (t == TypeManager.uint32_type)
1075                                 ig.Emit (OpCodes.Ldind_U4);
1076                         else if (t == TypeManager.short_type)
1077                                 ig.Emit (OpCodes.Ldind_I2);
1078                         else if (t == TypeManager.ushort_type)
1079                                 ig.Emit (OpCodes.Ldind_U2);
1080                         else if (t == TypeManager.char_type)
1081                                 ig.Emit (OpCodes.Ldind_U2);
1082                         else if (t == TypeManager.byte_type)
1083                                 ig.Emit (OpCodes.Ldind_U1);
1084                         else if (t == TypeManager.sbyte_type)
1085                                 ig.Emit (OpCodes.Ldind_I1);
1086                         else if (t == TypeManager.uint64_type)
1087                                 ig.Emit (OpCodes.Ldind_I8);
1088                         else if (t == TypeManager.int64_type)
1089                                 ig.Emit (OpCodes.Ldind_I8);
1090                         else if (t == TypeManager.float_type)
1091                                 ig.Emit (OpCodes.Ldind_R4);
1092                         else if (t == TypeManager.double_type)
1093                                 ig.Emit (OpCodes.Ldind_R8);
1094                         else if (t == TypeManager.bool_type)
1095                                 ig.Emit (OpCodes.Ldind_I1);
1096                         else if (t == TypeManager.intptr_type)
1097                                 ig.Emit (OpCodes.Ldind_I);
1098                         else if (TypeManager.IsEnumType (t)) {
1099                                 if (t == TypeManager.enum_type)
1100                                         ig.Emit (OpCodes.Ldind_Ref);
1101                                 else
1102                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1103                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1104                                 ig.Emit (OpCodes.Ldobj, t);
1105                         else if (t.IsPointer)
1106                                 ig.Emit (OpCodes.Ldind_I);
1107                         else
1108                                 ig.Emit (OpCodes.Ldind_Ref);
1109                 }
1110
1111                 //
1112                 // The stack contains the pointer and the value of type `type'
1113                 //
1114                 public static void StoreFromPtr (ILGenerator ig, Type type)
1115                 {
1116                         if (TypeManager.IsEnumType (type))
1117                                 type = TypeManager.GetEnumUnderlyingType (type);
1118                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1119                                 ig.Emit (OpCodes.Stind_I4);
1120                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1121                                 ig.Emit (OpCodes.Stind_I8);
1122                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1123                                  type == TypeManager.ushort_type)
1124                                 ig.Emit (OpCodes.Stind_I2);
1125                         else if (type == TypeManager.float_type)
1126                                 ig.Emit (OpCodes.Stind_R4);
1127                         else if (type == TypeManager.double_type)
1128                                 ig.Emit (OpCodes.Stind_R8);
1129                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1130                                  type == TypeManager.bool_type)
1131                                 ig.Emit (OpCodes.Stind_I1);
1132                         else if (type == TypeManager.intptr_type)
1133                                 ig.Emit (OpCodes.Stind_I);
1134                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1135                                 ig.Emit (OpCodes.Stobj, type);
1136                         else
1137                                 ig.Emit (OpCodes.Stind_Ref);
1138                 }
1139
1140                 //
1141                 // Returns the size of type `t' if known, otherwise, 0
1142                 //
1143                 public static int GetTypeSize (Type t)
1144                 {
1145                         t = TypeManager.TypeToCoreType (t);
1146                         if (t == TypeManager.int32_type ||
1147                             t == TypeManager.uint32_type ||
1148                             t == TypeManager.float_type)
1149                                 return 4;
1150                         else if (t == TypeManager.int64_type ||
1151                                  t == TypeManager.uint64_type ||
1152                                  t == TypeManager.double_type)
1153                                 return 8;
1154                         else if (t == TypeManager.byte_type ||
1155                                  t == TypeManager.sbyte_type ||
1156                                  t == TypeManager.bool_type)
1157                                 return 1;
1158                         else if (t == TypeManager.short_type ||
1159                                  t == TypeManager.char_type ||
1160                                  t == TypeManager.ushort_type)
1161                                 return 2;
1162                         else if (t == TypeManager.decimal_type)
1163                                 return 16;
1164                         else
1165                                 return 0;
1166                 }
1167
1168                 protected void Error_CannotCallAbstractBase (string name)
1169                 {
1170                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1171                 }
1172
1173                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1174                 {
1175                         Report.SymbolRelatedToPreviousError (type);
1176                         if (ec.CurrentInitializerVariable != null) {
1177                                 Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1178                                         TypeManager.CSharpName (type), GetSignatureForError ());
1179                         } else {
1180                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1181                                         GetSignatureForError ());
1182                         }
1183                 }
1184
1185                 public void Error_ExpressionCannotBeGeneric (Location loc)
1186                 {
1187                         Report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
1188                                 ExprClassName, GetSignatureForError ());
1189                 }
1190
1191                 //
1192                 // Converts `source' to an int, uint, long or ulong.
1193                 //
1194                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1195                 {
1196                         Expression converted;
1197
1198                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1199                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1200                                 if (converted == null)
1201                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1202                                 if (converted == null)
1203                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1204                                 if (converted == null)
1205                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1206
1207                                 if (converted == null) {
1208                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1209                                         return null;
1210                                 }
1211                         }
1212
1213                         //
1214                         // Only positive constants are allowed at compile time
1215                         //
1216                         Constant c = converted as Constant;
1217                         if (c != null) {
1218                                 if (c.IsNegative) {
1219                                         Error_NegativeArrayIndex (source.loc);
1220                                 }
1221                                 return c;
1222                         }
1223
1224                         return new ArrayIndexCast (converted).Resolve (ec);
1225                 }
1226
1227                 //
1228                 // Derived classes implement this method by cloning the fields that
1229                 // could become altered during the Resolve stage
1230                 //
1231                 // Only expressions that are created for the parser need to implement
1232                 // this.
1233                 //
1234                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1235                 {
1236                         throw new NotImplementedException (
1237                                 String.Format (
1238                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1239                 }
1240
1241                 //
1242                 // Clones an expression created by the parser.
1243                 //
1244                 // We only support expressions created by the parser so far, not
1245                 // expressions that have been resolved (many more classes would need
1246                 // to implement CloneTo).
1247                 //
1248                 // This infrastructure is here merely for Lambda expressions which
1249                 // compile the same code using different type values for the same
1250                 // arguments to find the correct overload
1251                 //
1252                 public Expression Clone (CloneContext clonectx)
1253                 {
1254                         Expression cloned = (Expression) MemberwiseClone ();
1255                         CloneTo (clonectx, cloned);
1256
1257                         return cloned;
1258                 }
1259
1260                 //
1261                 // Implementation of expression to expression tree conversion
1262                 //
1263                 public abstract Expression CreateExpressionTree (EmitContext ec);
1264
1265                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1266                 {
1267                         return CreateExpressionFactoryCall (name, null, args, loc);
1268                 }
1269
1270                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1271                 {
1272                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1273                 }
1274
1275                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1276                 {
1277                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1278                 }
1279
1280                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1281                 {
1282                         TypeExpr texpr = TypeManager.expression_type_expr;
1283                         if (texpr == null) {
1284                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1285                                 if (t == null)
1286                                         return null;
1287
1288                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1289                         }
1290
1291                         return texpr;
1292                 }
1293
1294                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1295                 {
1296                         // TODO: It should probably be type = storey.MutateType (type);
1297                 }
1298         }
1299
1300         /// <summary>
1301         ///   This is just a base class for expressions that can
1302         ///   appear on statements (invocations, object creation,
1303         ///   assignments, post/pre increment and decrement).  The idea
1304         ///   being that they would support an extra Emition interface that
1305         ///   does not leave a result on the stack.
1306         /// </summary>
1307         public abstract class ExpressionStatement : Expression {
1308
1309                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1310                 {
1311                         Expression e = Resolve (ec);
1312                         if (e == null)
1313                                 return null;
1314
1315                         ExpressionStatement es = e as ExpressionStatement;
1316                         if (es == null)
1317                                 Error_InvalidExpressionStatement ();
1318
1319                         return es;
1320                 }
1321
1322                 /// <summary>
1323                 ///   Requests the expression to be emitted in a `statement'
1324                 ///   context.  This means that no new value is left on the
1325                 ///   stack after invoking this method (constrasted with
1326                 ///   Emit that will always leave a value on the stack).
1327                 /// </summary>
1328                 public abstract void EmitStatement (EmitContext ec);
1329
1330                 public override void EmitSideEffect (EmitContext ec)
1331                 {
1332                         EmitStatement (ec);
1333                 }
1334         }
1335
1336         /// <summary>
1337         ///   This kind of cast is used to encapsulate the child
1338         ///   whose type is child.Type into an expression that is
1339         ///   reported to return "return_type".  This is used to encapsulate
1340         ///   expressions which have compatible types, but need to be dealt
1341         ///   at higher levels with.
1342         ///
1343         ///   For example, a "byte" expression could be encapsulated in one
1344         ///   of these as an "unsigned int".  The type for the expression
1345         ///   would be "unsigned int".
1346         ///
1347         /// </summary>
1348         public abstract class TypeCast : Expression
1349         {
1350                 protected readonly Expression child;
1351
1352                 protected TypeCast (Expression child, Type return_type)
1353                 {
1354                         eclass = child.eclass;
1355                         loc = child.Location;
1356                         type = return_type;
1357                         this.child = child;
1358                 }
1359
1360                 public override Expression CreateExpressionTree (EmitContext ec)
1361                 {
1362                         ArrayList args = new ArrayList (2);
1363                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1364                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1365
1366                         if (type.IsPointer || child.Type.IsPointer)
1367                                 Error_PointerInsideExpressionTree ();
1368
1369                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1370                 }
1371
1372                 public override Expression DoResolve (EmitContext ec)
1373                 {
1374                         // This should never be invoked, we are born in fully
1375                         // initialized state.
1376
1377                         return this;
1378                 }
1379
1380                 public override void Emit (EmitContext ec)
1381                 {
1382                         child.Emit (ec);
1383                 }
1384
1385                 public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
1386                 {
1387                         return child.GetAttributableValue (ec, value_type, out value);
1388                 }
1389
1390                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1391                 {
1392                         type = storey.MutateType (type);
1393                         child.MutateHoistedGenericType (storey);
1394                 }
1395
1396                 protected override void CloneTo (CloneContext clonectx, Expression t)
1397                 {
1398                         // Nothing to clone
1399                 }
1400
1401                 public override bool IsNull {
1402                         get { return child.IsNull; }
1403                 }
1404         }
1405
1406         public class EmptyCast : TypeCast {
1407                 EmptyCast (Expression child, Type target_type)
1408                         : base (child, target_type)
1409                 {
1410                 }
1411
1412                 public static Expression Create (Expression child, Type type)
1413                 {
1414                         Constant c = child as Constant;
1415                         if (c != null)
1416                                 return new EmptyConstantCast (c, type);
1417
1418                         EmptyCast e = child as EmptyCast;
1419                         if (e != null)
1420                                 return new EmptyCast (e.child, type);
1421
1422                         return new EmptyCast (child, type);
1423                 }
1424
1425                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1426                 {
1427                         child.EmitBranchable (ec, label, on_true);
1428                 }
1429
1430                 public override void EmitSideEffect (EmitContext ec)
1431                 {
1432                         child.EmitSideEffect (ec);
1433                 }
1434         }
1435
1436         //
1437         // Used for predefined class library user casts (no obsolete check, etc.)
1438         //
1439         public class OperatorCast : TypeCast {
1440                 MethodInfo conversion_operator;
1441
1442                 public OperatorCast (Expression child, Type target_type)
1443                         : this (child, target_type, false)
1444                 {
1445                 }
1446
1447                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1448                         : base (child, target_type)
1449                 {
1450                         conversion_operator = GetConversionOperator (find_explicit);
1451                         if (conversion_operator == null)
1452                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1453                 }
1454
1455                 // Returns the implicit operator that converts from
1456                 // 'child.Type' to our target type (type)
1457                 MethodInfo GetConversionOperator (bool find_explicit)
1458                 {
1459                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1460
1461                         MemberInfo [] mi;
1462
1463                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1464                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1465
1466                         if (mi == null){
1467                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1468                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1469                         }
1470
1471                         foreach (MethodInfo oper in mi) {
1472                                 AParametersCollection pd = TypeManager.GetParameterData (oper);
1473
1474                                 if (pd.Types [0] == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1475                                         return oper;
1476                         }
1477
1478                         return null;
1479                 }
1480
1481                 public override void Emit (EmitContext ec)
1482                 {
1483                         child.Emit (ec);
1484                         ec.ig.Emit (OpCodes.Call, conversion_operator);
1485                 }
1486         }
1487
1488         /// <summary>
1489         ///     This is a numeric cast to a Decimal
1490         /// </summary>
1491         public class CastToDecimal : OperatorCast {
1492                 public CastToDecimal (Expression child)
1493                         : this (child, false)
1494                 {
1495                 }
1496
1497                 public CastToDecimal (Expression child, bool find_explicit)
1498                         : base (child, TypeManager.decimal_type, find_explicit)
1499                 {
1500                 }
1501         }
1502
1503         /// <summary>
1504         ///     This is an explicit numeric cast from a Decimal
1505         /// </summary>
1506         public class CastFromDecimal : TypeCast
1507         {
1508                 static IDictionary operators;
1509
1510                 public CastFromDecimal (Expression child, Type return_type)
1511                         : base (child, return_type)
1512                 {
1513                         if (child.Type != TypeManager.decimal_type)
1514                                 throw new InternalErrorException (
1515                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1516                 }
1517
1518                 // Returns the explicit operator that converts from an
1519                 // express of type System.Decimal to 'type'.
1520                 public Expression Resolve ()
1521                 {
1522                         if (operators == null) {
1523                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1524                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1525                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1526
1527                                 operators = new System.Collections.Specialized.HybridDictionary ();
1528                                 foreach (MethodInfo oper in all_oper) {
1529                                         AParametersCollection pd = TypeManager.GetParameterData (oper);
1530                                         if (pd.Types [0] == TypeManager.decimal_type)
1531                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1532                                 }
1533                         }
1534
1535                         return operators.Contains (type) ? this : null;
1536                 }
1537
1538                 public override void Emit (EmitContext ec)
1539                 {
1540                         ILGenerator ig = ec.ig;
1541                         child.Emit (ec);
1542
1543                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1544                 }
1545         }
1546
1547
1548         //
1549         // Constant specialization of EmptyCast.
1550         // We need to special case this since an empty cast of
1551         // a constant is still a constant.
1552         //
1553         public class EmptyConstantCast : Constant
1554         {
1555                 public readonly Constant child;
1556
1557                 public EmptyConstantCast(Constant child, Type type)
1558                         : base (child.Location)
1559                 {
1560                         eclass = child.eclass;
1561                         this.child = child;
1562                         this.type = type;
1563                 }
1564
1565                 public override string AsString ()
1566                 {
1567                         return child.AsString ();
1568                 }
1569
1570                 public override object GetValue ()
1571                 {
1572                         return child.GetValue ();
1573                 }
1574
1575                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1576                 {
1577                         // FIXME: check that 'type' can be converted to 'target_type' first
1578                         return child.ConvertExplicitly (in_checked_context, target_type);
1579                 }
1580
1581                 public override Expression CreateExpressionTree (EmitContext ec)
1582                 {
1583                         ArrayList args = new ArrayList (2);
1584                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1585                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1586                         if (type.IsPointer)
1587                                 Error_PointerInsideExpressionTree ();
1588
1589                         return CreateExpressionFactoryCall ("Convert", args);
1590                 }
1591
1592                 public override Constant Increment ()
1593                 {
1594                         return child.Increment ();
1595                 }
1596
1597                 public override bool IsDefaultValue {
1598                         get { return child.IsDefaultValue; }
1599                 }
1600
1601                 public override bool IsNegative {
1602                         get { return child.IsNegative; }
1603                 }
1604
1605                 public override bool IsNull {
1606                         get { return child.IsNull; }
1607                 }
1608
1609                 public override bool IsZeroInteger {
1610                         get { return child.IsZeroInteger; }
1611                 }
1612
1613                 public override void Emit (EmitContext ec)
1614                 {
1615                         child.Emit (ec);
1616                 }
1617
1618                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1619                 {
1620                         child.EmitBranchable (ec, label, on_true);
1621                 }
1622
1623                 public override void EmitSideEffect (EmitContext ec)
1624                 {
1625                         child.EmitSideEffect (ec);
1626                 }
1627
1628                 public override Constant ConvertImplicitly (Type target_type)
1629                 {
1630                         // FIXME: Do we need to check user conversions?
1631                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1632                                 return null;
1633                         return child.ConvertImplicitly (target_type);
1634                 }
1635
1636                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1637                 {
1638                         child.MutateHoistedGenericType (storey);
1639                 }
1640         }
1641
1642
1643         /// <summary>
1644         ///  This class is used to wrap literals which belong inside Enums
1645         /// </summary>
1646         public class EnumConstant : Constant {
1647                 public Constant Child;
1648
1649                 public EnumConstant (Constant child, Type enum_type):
1650                         base (child.Location)
1651                 {
1652                         eclass = child.eclass;
1653                         this.Child = child;
1654                         type = enum_type;
1655                 }
1656
1657                 public override Expression DoResolve (EmitContext ec)
1658                 {
1659                         // This should never be invoked, we are born in fully
1660                         // initialized state.
1661
1662                         return this;
1663                 }
1664
1665                 public override void Emit (EmitContext ec)
1666                 {
1667                         Child.Emit (ec);
1668                 }
1669
1670                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1671                 {
1672                         Child.EmitBranchable (ec, label, on_true);
1673                 }
1674
1675                 public override void EmitSideEffect (EmitContext ec)
1676                 {
1677                         Child.EmitSideEffect (ec);
1678                 }
1679
1680                 public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
1681                 {
1682                         value = GetTypedValue ();
1683                         return true;
1684                 }
1685
1686                 public override string GetSignatureForError()
1687                 {
1688                         return TypeManager.CSharpName (Type);
1689                 }
1690
1691                 public override object GetValue ()
1692                 {
1693                         return Child.GetValue ();
1694                 }
1695
1696                 public override object GetTypedValue ()
1697                 {
1698                         // FIXME: runtime is not ready to work with just emited enums
1699                         if (!RootContext.StdLib) {
1700                                 return Child.GetValue ();
1701                         }
1702
1703 #if MS_COMPATIBLE
1704                         // Small workaround for big problem
1705                         // System.Enum.ToObject cannot be called on dynamic types
1706                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1707                         // because it does not properly support generics
1708                         //
1709                         // This works only sometimes
1710                         //
1711                         if (type.Module == CodeGen.Module.Builder)
1712                                 return Child.GetValue ();
1713 #endif
1714
1715                         return System.Enum.ToObject (type, Child.GetValue ());
1716                 }
1717
1718                 public override string AsString ()
1719                 {
1720                         return Child.AsString ();
1721                 }
1722
1723                 public override Constant Increment()
1724                 {
1725                         return new EnumConstant (Child.Increment (), type);
1726                 }
1727
1728                 public override bool IsDefaultValue {
1729                         get {
1730                                 return Child.IsDefaultValue;
1731                         }
1732                 }
1733
1734                 public override bool IsZeroInteger {
1735                         get { return Child.IsZeroInteger; }
1736                 }
1737
1738                 public override bool IsNegative {
1739                         get {
1740                                 return Child.IsNegative;
1741                         }
1742                 }
1743
1744                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1745                 {
1746                         if (Child.Type == target_type)
1747                                 return Child;
1748
1749                         return Child.ConvertExplicitly (in_checked_context, target_type);
1750                 }
1751
1752                 public override Constant ConvertImplicitly (Type type)
1753                 {
1754                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1755                         type = TypeManager.DropGenericTypeArguments (type);
1756
1757                         if (this_type == type) {
1758                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1759                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1760                                         return this;
1761
1762                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1763                                 if (type.UnderlyingSystemType != child_type)
1764                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1765                                 return this;
1766                         }
1767
1768                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1769                                 return null;
1770                         }
1771
1772                         return Child.ConvertImplicitly(type);
1773                 }
1774
1775         }
1776
1777         /// <summary>
1778         ///   This kind of cast is used to encapsulate Value Types in objects.
1779         ///
1780         ///   The effect of it is to box the value type emitted by the previous
1781         ///   operation.
1782         /// </summary>
1783         public class BoxedCast : TypeCast {
1784
1785                 public BoxedCast (Expression expr, Type target_type)
1786                         : base (expr, target_type)
1787                 {
1788                         eclass = ExprClass.Value;
1789                 }
1790
1791                 public override Expression DoResolve (EmitContext ec)
1792                 {
1793                         // This should never be invoked, we are born in fully
1794                         // initialized state.
1795
1796                         return this;
1797                 }
1798
1799                 public override void Emit (EmitContext ec)
1800                 {
1801                         base.Emit (ec);
1802
1803                         ec.ig.Emit (OpCodes.Box, child.Type);
1804                 }
1805
1806                 public override void EmitSideEffect (EmitContext ec)
1807                 {
1808                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1809                         // so, we need to emit the box+pop instructions in most cases
1810                         if (child.Type.IsValueType &&
1811                             (type == TypeManager.object_type || type == TypeManager.value_type))
1812                                 child.EmitSideEffect (ec);
1813                         else
1814                                 base.EmitSideEffect (ec);
1815                 }
1816         }
1817
1818         public class UnboxCast : TypeCast {
1819                 public UnboxCast (Expression expr, Type return_type)
1820                         : base (expr, return_type)
1821                 {
1822                 }
1823
1824                 public override Expression DoResolve (EmitContext ec)
1825                 {
1826                         // This should never be invoked, we are born in fully
1827                         // initialized state.
1828
1829                         return this;
1830                 }
1831
1832                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1833                 {
1834                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1835                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1836                         return base.DoResolveLValue (ec, right_side);
1837                 }
1838
1839                 public override void Emit (EmitContext ec)
1840                 {
1841                         ILGenerator ig = ec.ig;
1842
1843                         base.Emit (ec);
1844 #if GMCS_SOURCE
1845                         if (type.IsGenericParameter || type.IsGenericType && type.IsValueType)
1846                                 ig.Emit (OpCodes.Unbox_Any, type);
1847                         else
1848 #endif
1849                         {
1850                                 ig.Emit (OpCodes.Unbox, type);
1851
1852                                 LoadFromPtr (ig, type);
1853                         }
1854                 }
1855
1856                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1857                 {
1858                         type = storey.MutateType (type);
1859                         base.MutateHoistedGenericType (storey);
1860                 }
1861         }
1862
1863         /// <summary>
1864         ///   This is used to perform explicit numeric conversions.
1865         ///
1866         ///   Explicit numeric conversions might trigger exceptions in a checked
1867         ///   context, so they should generate the conv.ovf opcodes instead of
1868         ///   conv opcodes.
1869         /// </summary>
1870         public class ConvCast : TypeCast {
1871                 public enum Mode : byte {
1872                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1873                         U1_I1, U1_CH,
1874                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1875                         U2_I1, U2_U1, U2_I2, U2_CH,
1876                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1877                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1878                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1879                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1880                         CH_I1, CH_U1, CH_I2,
1881                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1882                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1883                 }
1884
1885                 Mode mode;
1886
1887                 public ConvCast (Expression child, Type return_type, Mode m)
1888                         : base (child, return_type)
1889                 {
1890                         mode = m;
1891                 }
1892
1893                 public override Expression DoResolve (EmitContext ec)
1894                 {
1895                         // This should never be invoked, we are born in fully
1896                         // initialized state.
1897
1898                         return this;
1899                 }
1900
1901                 public override string ToString ()
1902                 {
1903                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1904                 }
1905
1906                 public override void Emit (EmitContext ec)
1907                 {
1908                         ILGenerator ig = ec.ig;
1909
1910                         base.Emit (ec);
1911
1912                         if (ec.CheckState){
1913                                 switch (mode){
1914                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1915                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1916                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1917                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1918                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1919
1920                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1921                                 case Mode.U1_CH: /* nothing */ break;
1922
1923                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1924                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1925                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1926                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1927                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1928                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1929
1930                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1931                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1932                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1933                                 case Mode.U2_CH: /* nothing */ break;
1934
1935                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1936                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1937                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1938                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1939                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1940                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1941                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1942
1943                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1944                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1945                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1946                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1947                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1948                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1949
1950                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1951                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1952                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1953                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1954                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1955                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1956                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1957                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1958
1959                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1960                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1961                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1962                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1963                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1964                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1965                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1966                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1967
1968                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1969                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1970                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1971
1972                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1973                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1974                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1975                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1976                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1977                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1978                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1979                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1980                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1981
1982                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1983                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1984                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1985                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1986                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1987                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1988                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1989                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1990                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1991                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1992                                 }
1993                         } else {
1994                                 switch (mode){
1995                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1996                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1997                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1998                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1999                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
2000
2001                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
2002                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
2003
2004                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2005                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2006                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2007                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2008                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2009                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2010
2011                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2012                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2013                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2014                                 case Mode.U2_CH: /* nothing */ break;
2015
2016                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2017                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2018                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2019                                 case Mode.I4_U4: /* nothing */ break;
2020                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2021                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2022                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2023
2024                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2025                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2026                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2027                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2028                                 case Mode.U4_I4: /* nothing */ break;
2029                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2030
2031                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2032                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2033                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2034                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2035                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2036                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2037                                 case Mode.I8_U8: /* nothing */ break;
2038                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2039
2040                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2041                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2042                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2043                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2044                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2045                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2046                                 case Mode.U8_I8: /* nothing */ break;
2047                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2048
2049                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2050                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2051                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2052
2053                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2054                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2055                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2056                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2057                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2058                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2059                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2060                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2061                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2062
2063                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2064                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2065                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2066                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2067                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2068                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2069                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2070                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2071                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2072                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2073                                 }
2074                         }
2075                 }
2076         }
2077
2078         public class OpcodeCast : TypeCast {
2079                 readonly OpCode op;
2080
2081                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2082                         : base (child, return_type)
2083                 {
2084                         this.op = op;
2085                 }
2086
2087                 public override Expression DoResolve (EmitContext ec)
2088                 {
2089                         // This should never be invoked, we are born in fully
2090                         // initialized state.
2091
2092                         return this;
2093                 }
2094
2095                 public override void Emit (EmitContext ec)
2096                 {
2097                         base.Emit (ec);
2098                         ec.ig.Emit (op);
2099                 }
2100
2101                 public Type UnderlyingType {
2102                         get { return child.Type; }
2103                 }
2104         }
2105
2106         /// <summary>
2107         ///   This kind of cast is used to encapsulate a child and cast it
2108         ///   to the class requested
2109         /// </summary>
2110         public sealed class ClassCast : TypeCast {
2111                 Type child_generic_parameter;
2112
2113                 public ClassCast (Expression child, Type return_type)
2114                         : base (child, return_type)
2115
2116                 {
2117                         if (TypeManager.IsGenericParameter (child.Type))
2118                                 child_generic_parameter = child.Type;
2119                 }
2120
2121                 public override Expression DoResolve (EmitContext ec)
2122                 {
2123                         // This should never be invoked, we are born in fully
2124                         // initialized state.
2125
2126                         return this;
2127                 }
2128
2129                 public override void Emit (EmitContext ec)
2130                 {
2131                         base.Emit (ec);
2132
2133 #if GMCS_SOURCE
2134                         if (child_generic_parameter != null) {
2135                                 ec.ig.Emit (OpCodes.Box, child_generic_parameter);
2136                         }
2137
2138                         if (type.IsGenericParameter)
2139                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2140                         else if (child_generic_parameter == null)
2141 #endif
2142                                 ec.ig.Emit (OpCodes.Castclass, type);
2143                 }
2144
2145                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2146                 {
2147                         type = storey.MutateType (type);
2148                         if (child_generic_parameter != null)
2149                                 child_generic_parameter = storey.MutateGenericArgument (child_generic_parameter);
2150
2151                         base.MutateHoistedGenericType (storey);
2152                 }
2153         }
2154
2155         //
2156         // Created during resolving pahse when an expression is wrapped or constantified
2157         // and original expression can be used later (e.g. for expression trees)
2158         //
2159         public class ReducedExpression : Expression
2160         {
2161                 sealed class ReducedConstantExpression : EmptyConstantCast
2162                 {
2163                         readonly Expression orig_expr;
2164
2165                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2166                                 : base (expr, expr.Type)
2167                         {
2168                                 this.orig_expr = orig_expr;
2169                         }
2170
2171                         public override Constant ConvertImplicitly (Type target_type)
2172                         {
2173                                 Constant c = base.ConvertImplicitly (target_type);
2174                                 if (c != null)
2175                                         c = new ReducedConstantExpression (c, orig_expr);
2176                                 return c;
2177                         }
2178
2179                         public override Expression CreateExpressionTree (EmitContext ec)
2180                         {
2181                                 return orig_expr.CreateExpressionTree (ec);
2182                         }
2183
2184                         public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
2185                         {
2186                                 //
2187                                 // Even if resolved result is a constant original expression was not
2188                                 // and attribute accepts constants only
2189                                 //
2190                                 Attribute.Error_AttributeArgumentNotValid (orig_expr.Location);
2191                                 value = null;
2192                                 return false;
2193                         }
2194
2195                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2196                         {
2197                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2198                                 if (c != null)
2199                                         c = new ReducedConstantExpression (c, orig_expr);
2200                                 return c;
2201                         }
2202                 }
2203
2204                 sealed class ReducedExpressionStatement : ExpressionStatement
2205                 {
2206                         readonly Expression orig_expr;
2207                         readonly ExpressionStatement stm;
2208
2209                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2210                         {
2211                                 this.orig_expr = orig;
2212                                 this.stm = stm;
2213                                 this.loc = orig.Location;
2214                         }
2215
2216                         public override Expression CreateExpressionTree (EmitContext ec)
2217                         {
2218                                 return orig_expr.CreateExpressionTree (ec);
2219                         }
2220
2221                         public override Expression DoResolve (EmitContext ec)
2222                         {
2223                                 eclass = stm.eclass;
2224                                 type = stm.Type;
2225                                 return this;
2226                         }
2227
2228                         public override void Emit (EmitContext ec)
2229                         {
2230                                 stm.Emit (ec);
2231                         }
2232
2233                         public override void EmitStatement (EmitContext ec)
2234                         {
2235                                 stm.EmitStatement (ec);
2236                         }
2237
2238                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2239                         {
2240                                 stm.MutateHoistedGenericType (storey);
2241                         }
2242                 }
2243
2244                 readonly Expression expr, orig_expr;
2245
2246                 private ReducedExpression (Expression expr, Expression orig_expr)
2247                 {
2248                         this.expr = expr;
2249                         this.orig_expr = orig_expr;
2250                         this.loc = orig_expr.Location;
2251                 }
2252
2253                 public static Constant Create (Constant expr, Expression original_expr)
2254                 {
2255                         return new ReducedConstantExpression (expr, original_expr);
2256                 }
2257
2258                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2259                 {
2260                         return new ReducedExpressionStatement (s, orig);
2261                 }
2262
2263                 public static Expression Create (Expression expr, Expression original_expr)
2264                 {
2265                         Constant c = expr as Constant;
2266                         if (c != null)
2267                                 return Create (c, original_expr);
2268
2269                         ExpressionStatement s = expr as ExpressionStatement;
2270                         if (s != null)
2271                                 return Create (s, original_expr);
2272
2273                         return new ReducedExpression (expr, original_expr);
2274                 }
2275
2276                 public override Expression CreateExpressionTree (EmitContext ec)
2277                 {
2278                         return orig_expr.CreateExpressionTree (ec);
2279                 }
2280
2281                 public override Expression DoResolve (EmitContext ec)
2282                 {
2283                         eclass = expr.eclass;
2284                         type = expr.Type;
2285                         return this;
2286                 }
2287
2288                 public override void Emit (EmitContext ec)
2289                 {
2290                         expr.Emit (ec);
2291                 }
2292
2293                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2294                 {
2295                         expr.EmitBranchable (ec, target, on_true);
2296                 }
2297
2298                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2299                 {
2300                         expr.MutateHoistedGenericType (storey);
2301                 }
2302         }
2303
2304         //
2305         // Unresolved type name expressions
2306         //
2307         public abstract class ATypeNameExpression : FullNamedExpression
2308         {
2309                 public readonly string Name;
2310                 protected TypeArguments targs;
2311
2312                 protected ATypeNameExpression (string name, Location l)
2313                 {
2314                         Name = name;
2315                         loc = l;
2316                 }
2317
2318                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2319                 {
2320                         Name = name;
2321                         this.targs = targs;
2322                         loc = l;
2323                 }
2324
2325                 public bool HasTypeArguments {
2326                         get {
2327                                 return targs != null;
2328                         }
2329                 }
2330
2331                 public override string GetSignatureForError ()
2332                 {
2333                         if (targs != null) {
2334                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2335                                         targs.GetSignatureForError () + ">";
2336                         }
2337
2338                         return Name;
2339                 }
2340         }
2341
2342         /// <summary>
2343         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2344         ///   of a dotted-name.
2345         /// </summary>
2346         public class SimpleName : ATypeNameExpression {
2347                 bool in_transit;
2348
2349                 public SimpleName (string name, Location l)
2350                         : base (name, l)
2351                 {
2352                 }
2353
2354                 public SimpleName (string name, TypeArguments args, Location l)
2355                         : base (name, args, l)
2356                 {
2357                 }
2358
2359                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2360                         : base (name, l)
2361                 {
2362                         targs = new TypeArguments ();
2363                         foreach (TypeParameter type_param in type_params)
2364                                 targs.Add (new TypeParameterExpr (type_param, l));
2365                 }
2366
2367                 public static string RemoveGenericArity (string name)
2368                 {
2369                         int start = 0;
2370                         StringBuilder sb = null;
2371                         do {
2372                                 int pos = name.IndexOf ('`', start);
2373                                 if (pos < 0) {
2374                                         if (start == 0)
2375                                                 return name;
2376
2377                                         sb.Append (name.Substring (start));
2378                                         break;
2379                                 }
2380
2381                                 if (sb == null)
2382                                         sb = new StringBuilder ();
2383                                 sb.Append (name.Substring (start, pos-start));
2384
2385                                 pos++;
2386                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2387                                         pos++;
2388
2389                                 start = pos;
2390                         } while (start < name.Length);
2391
2392                         return sb.ToString ();
2393                 }
2394
2395                 public SimpleName GetMethodGroup ()
2396                 {
2397                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2398                 }
2399
2400                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2401                 {
2402                         if (ec.IsInFieldInitializer)
2403                                 Report.Error (236, l,
2404                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2405                                         name);
2406                         else
2407                                 Report.Error (120, l,
2408                                         "An object reference is required to access non-static member `{0}'",
2409                                         name);
2410                 }
2411
2412                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2413                 {
2414                         return resolved_to != null && resolved_to.Type != null &&
2415                                 resolved_to.Type.Name == Name &&
2416                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2417                 }
2418
2419                 public override Expression DoResolve (EmitContext ec)
2420                 {
2421                         return SimpleNameResolve (ec, null, false);
2422                 }
2423
2424                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2425                 {
2426                         return SimpleNameResolve (ec, right_side, false);
2427                 }
2428
2429
2430                 public Expression DoResolve (EmitContext ec, bool intermediate)
2431                 {
2432                         return SimpleNameResolve (ec, null, intermediate);
2433                 }
2434
2435                 static bool IsNestedChild (Type t, Type parent)
2436                 {
2437                         while (parent != null) {
2438                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2439                                         return true;
2440
2441                                 parent = parent.BaseType;
2442                         }
2443
2444                         return false;
2445                 }
2446
2447                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2448                 {
2449                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2450                                 return null;
2451
2452                         DeclSpace ds = ec.DeclContainer;
2453                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2454                                 ds = ds.Parent;
2455
2456                         if (ds == null)
2457                                 return null;
2458
2459                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2460
2461                         int arg_count = targs != null ? targs.Count : 0;
2462
2463                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2464                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2465                                         TypeArguments new_args = new TypeArguments ();
2466                                         foreach (TypeParameter param in ds.TypeParameters)
2467                                                 new_args.Add (new TypeParameterExpr (param, loc));
2468
2469                                         if (targs != null)
2470                                                 new_args.Add (targs);
2471
2472                                         return new GenericTypeExpr (t, new_args, loc);
2473                                 }
2474                         }
2475
2476                         return null;
2477                 }
2478
2479                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2480                 {
2481                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2482                         if (fne != null)
2483                                 return fne.ResolveAsTypeStep (ec, silent);
2484
2485                         int errors = Report.Errors;
2486                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2487
2488                         if (fne != null) {
2489                                 if (fne.Type == null)
2490                                         return fne;
2491
2492                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2493                                 if (nested != null)
2494                                         return nested.ResolveAsTypeStep (ec, false);
2495
2496                                 if (targs != null) {
2497                                         GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2498                                         return ct.ResolveAsTypeStep (ec, false);
2499                                 }
2500
2501                                 return fne;
2502                         }
2503
2504                         if (silent || errors != Report.Errors)
2505                                 return null;
2506
2507                         Error_TypeOrNamespaceNotFound (ec);
2508                         return null;
2509                 }
2510
2511                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2512                 {
2513                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2514                         if (mc != null) {
2515                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2516                                 return;
2517                         }
2518
2519                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2520                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2521                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2522                                 Type type = a.GetType (fullname);
2523                                 if (type != null) {
2524                                         Report.SymbolRelatedToPreviousError (type);
2525                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2526                                         return;
2527                                 }
2528                         }
2529
2530                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2531                         if (t != null) {
2532                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2533                                 return;
2534                         }
2535
2536                         if (targs != null) {
2537                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2538                                 if (retval != null) {
2539                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval, loc);
2540                                         return;
2541                                 }
2542                         }
2543
2544                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2545                 }
2546
2547                 // TODO: I am still not convinced about this. If someone else will need it
2548                 // implement this as virtual property in MemberCore hierarchy
2549                 public static string GetMemberType (MemberCore mc)
2550                 {
2551                         if (mc is Property)
2552                                 return "property";
2553                         if (mc is Indexer)
2554                                 return "indexer";
2555                         if (mc is FieldBase)
2556                                 return "field";
2557                         if (mc is MethodCore)
2558                                 return "method";
2559                         if (mc is EnumMember)
2560                                 return "enum";
2561                         if (mc is Event)
2562                                 return "event";
2563
2564                         return "type";
2565                 }
2566
2567                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2568                 {
2569                         if (in_transit)
2570                                 return null;
2571
2572                         in_transit = true;
2573                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2574                         in_transit = false;
2575
2576                         if (e == null)
2577                                 return null;
2578
2579                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2580                                 return e;
2581
2582                         return null;
2583                 }
2584
2585                 /// <remarks>
2586                 ///   7.5.2: Simple Names.
2587                 ///
2588                 ///   Local Variables and Parameters are handled at
2589                 ///   parse time, so they never occur as SimpleNames.
2590                 ///
2591                 ///   The `intermediate' flag is used by MemberAccess only
2592                 ///   and it is used to inform us that it is ok for us to
2593                 ///   avoid the static check, because MemberAccess might end
2594                 ///   up resolving the Name as a Type name and the access as
2595                 ///   a static type access.
2596                 ///
2597                 ///   ie: Type Type; .... { Type.GetType (""); }
2598                 ///
2599                 ///   Type is both an instance variable and a Type;  Type.GetType
2600                 ///   is the static method not an instance method of type.
2601                 /// </remarks>
2602                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2603                 {
2604                         Expression e = null;
2605
2606                         //
2607                         // Stage 1: Performed by the parser (binding to locals or parameters).
2608                         //
2609                         Block current_block = ec.CurrentBlock;
2610                         if (current_block != null){
2611                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2612                                 if (vi != null){
2613                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2614                                         if (right_side != null) {
2615                                                 return var.ResolveLValue (ec, right_side, loc);
2616                                         } else {
2617                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2618                                                 if (intermediate)
2619                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2620                                                 return var.Resolve (ec, rf);
2621                                         }
2622                                 }
2623
2624                                 Expression expr = current_block.Toplevel.GetParameterReference (Name, loc);
2625                                 if (expr == null)
2626                                         expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2627
2628                                 if (expr != null) {
2629                                         if (right_side != null)
2630                                                 return expr.ResolveLValue (ec, right_side, loc);
2631
2632                                         return expr.Resolve (ec);
2633                                 }
2634                         }
2635
2636                         //
2637                         // Stage 2: Lookup members
2638                         //
2639
2640                         Type almost_matched_type = null;
2641                         ArrayList almost_matched = null;
2642                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2643                                 // either RootDeclSpace or GenericMethod
2644                                 if (lookup_ds.TypeBuilder == null)
2645                                         continue;
2646
2647                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2648                                 if (e != null) {
2649                                         PropertyExpr pe = e as PropertyExpr;
2650                                         if (pe != null) {
2651                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2652
2653                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2654                                                 // it doesn't know which accessor to check permissions against
2655                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.ContainerType, right_side != null))
2656                                                         break;
2657                                         } else if (e is EventExpr) {
2658                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2659                                                         break;
2660                                         } else if (targs != null && e is TypeExpression) {
2661                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2662                                                 break;
2663                                         } else {
2664                                                 break;
2665                                         }
2666                                         e = null;
2667                                 }
2668
2669                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2670                                         almost_matched_type = lookup_ds.TypeBuilder;
2671                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2672                                 }
2673                         }
2674
2675                         if (e == null) {
2676                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2677                                         almost_matched_type = ec.ContainerType;
2678                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2679                                 }
2680                                 e = ResolveAsTypeStep (ec, true);
2681                         }
2682
2683                         if (e == null) {
2684                                 if (current_block != null) {
2685                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2686                                         if (ikv != null) {
2687                                                 LocalInfo li = ikv as LocalInfo;
2688                                                 // Supress CS0219 warning
2689                                                 if (li != null)
2690                                                         li.Used = true;
2691
2692                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2693                                                 return null;
2694                                         }
2695                                 }
2696
2697                                 if (RootContext.EvalMode){
2698                                         FieldInfo fi = Evaluator.LookupField (Name);
2699                                         if (fi != null)
2700                                                 return new FieldExpr (fi, loc).Resolve (ec);
2701                                 }
2702
2703                                 if (almost_matched != null)
2704                                         almost_matched_members = almost_matched;
2705                                 if (almost_matched_type == null)
2706                                         almost_matched_type = ec.ContainerType;
2707                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2708                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2709                                 return null;
2710                         }
2711
2712                         if (e is MemberExpr) {
2713                                 MemberExpr me = (MemberExpr) e;
2714
2715                                 Expression left;
2716                                 if (me.IsInstance) {
2717                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2718                                                 //
2719                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2720                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2721                                                 // and each predicate is true if the MethodGroupExpr contains
2722                                                 // at least one of that kind of method.
2723                                                 //
2724
2725                                                 if (!me.IsStatic &&
2726                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2727                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2728                                                         return null;
2729                                                 }
2730
2731                                                 //
2732                                                 // Pass the buck to MemberAccess and Invocation.
2733                                                 //
2734                                                 left = EmptyExpression.Null;
2735                                         } else {
2736                                                 left = ec.GetThis (loc);
2737                                         }
2738                                 } else {
2739                                         left = new TypeExpression (ec.ContainerType, loc);
2740                                 }
2741
2742                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2743                                 if (me == null)
2744                                         return null;
2745
2746                                 if (targs != null) {
2747                                         targs.Resolve (ec);
2748                                         me.SetTypeArguments (targs);
2749                                 }
2750
2751                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2752                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2753                                     me.InstanceExpression.Type != me.DeclaringType &&
2754                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2755                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2756                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2757                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2758                                         return null;
2759                                 }
2760
2761                                 return (right_side != null)
2762                                         ? me.DoResolveLValue (ec, right_side)
2763                                         : me.DoResolve (ec);
2764                         }
2765
2766                         return e;
2767                 }
2768         }
2769
2770         /// <summary>
2771         ///   Represents a namespace or a type.  The name of the class was inspired by
2772         ///   section 10.8.1 (Fully Qualified Names).
2773         /// </summary>
2774         public abstract class FullNamedExpression : Expression
2775         {
2776                 protected override void CloneTo (CloneContext clonectx, Expression target)
2777                 {
2778                         // Do nothing, most unresolved type expressions cannot be
2779                         // resolved to different type
2780                 }
2781
2782                 public override Expression CreateExpressionTree (EmitContext ec)
2783                 {
2784                         throw new NotSupportedException ("ET");
2785                 }
2786
2787                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2788                 {
2789                         throw new NotSupportedException ();
2790                 }
2791
2792                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2793                 {
2794                         return this;
2795                 }
2796
2797                 public override void Emit (EmitContext ec)
2798                 {
2799                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2800                                 GetSignatureForError ());
2801                 }
2802         }
2803
2804         /// <summary>
2805         ///   Expression that evaluates to a type
2806         /// </summary>
2807         public abstract class TypeExpr : FullNamedExpression {
2808                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2809                 {
2810                         TypeExpr t = DoResolveAsTypeStep (ec);
2811                         if (t == null)
2812                                 return null;
2813
2814                         eclass = ExprClass.Type;
2815                         return t;
2816                 }
2817
2818                 override public Expression DoResolve (EmitContext ec)
2819                 {
2820                         return ResolveAsTypeTerminal (ec, false);
2821                 }
2822
2823                 public virtual bool CheckAccessLevel (DeclSpace ds)
2824                 {
2825                         return ds.CheckAccessLevel (Type);
2826                 }
2827
2828                 public virtual bool AsAccessible (DeclSpace ds)
2829                 {
2830                         return ds.IsAccessibleAs (Type);
2831                 }
2832
2833                 public virtual bool IsClass {
2834                         get { return Type.IsClass; }
2835                 }
2836
2837                 public virtual bool IsValueType {
2838                         get { return Type.IsValueType; }
2839                 }
2840
2841                 public virtual bool IsInterface {
2842                         get { return Type.IsInterface; }
2843                 }
2844
2845                 public virtual bool IsSealed {
2846                         get { return Type.IsSealed; }
2847                 }
2848
2849                 public virtual bool CanInheritFrom ()
2850                 {
2851                         if (Type == TypeManager.enum_type ||
2852                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2853                             Type == TypeManager.multicast_delegate_type ||
2854                             Type == TypeManager.delegate_type ||
2855                             Type == TypeManager.array_type)
2856                                 return false;
2857
2858                         return true;
2859                 }
2860
2861                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2862
2863                 public override bool Equals (object obj)
2864                 {
2865                         TypeExpr tobj = obj as TypeExpr;
2866                         if (tobj == null)
2867                                 return false;
2868
2869                         return Type == tobj.Type;
2870                 }
2871
2872                 public override int GetHashCode ()
2873                 {
2874                         return Type.GetHashCode ();
2875                 }
2876
2877                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2878                 {
2879                         type = storey.MutateType (type);
2880                 }
2881         }
2882
2883         /// <summary>
2884         ///   Fully resolved Expression that already evaluated to a type
2885         /// </summary>
2886         public class TypeExpression : TypeExpr {
2887                 public TypeExpression (Type t, Location l)
2888                 {
2889                         Type = t;
2890                         eclass = ExprClass.Type;
2891                         loc = l;
2892                 }
2893
2894                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2895                 {
2896                         return this;
2897                 }
2898
2899                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2900                 {
2901                         return this;
2902                 }
2903         }
2904
2905         /// <summary>
2906         ///   Used to create types from a fully qualified name.  These are just used
2907         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2908         ///   classified as a type.
2909         /// </summary>
2910         public sealed class TypeLookupExpression : TypeExpr {
2911                 readonly string name;
2912
2913                 public TypeLookupExpression (string name)
2914                 {
2915                         this.name = name;
2916                         eclass = ExprClass.Type;
2917                 }
2918
2919                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2920                 {
2921                         // It's null for corlib compilation only
2922                         if (type == null)
2923                                 return DoResolveAsTypeStep (ec);
2924
2925                         return this;
2926                 }
2927
2928                 private class UnexpectedType
2929                 {
2930                 }
2931
2932                 // This performes recursive type lookup, providing support for generic types.
2933                 // For example, given the type:
2934                 //
2935                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2936                 //
2937                 // The types will be checked in the following order:
2938                 //                                                                             _
2939                 // System                                                                       |
2940                 // System.Collections                                                           |
2941                 // System.Collections.Generic                                                   |
2942                 //                        _                                                     |
2943                 //     System              | recursive call 1                                   |
2944                 //     System.Int32       _|                                                    | main method call
2945                 //                        _                                                     |
2946                 //     System              | recursive call 2                                   |
2947                 //     System.String      _|                                                    |
2948                 //                                                                              |
2949                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2950                 //
2951                 private Type TypeLookup (IResolveContext ec, string name)
2952                 {
2953                         int index = 0;
2954                         int dot = 0;
2955                         bool done = false;
2956                         FullNamedExpression resolved = null;
2957                         Type type = null;
2958                         Type recursive_type = null;
2959                         while (index < name.Length) {
2960                                 if (name[index] == '[') {
2961                                         int open = index;
2962                                         int braces = 1;
2963                                         do {
2964                                                 index++;
2965                                                 if (name[index] == '[')
2966                                                         braces++;
2967                                                 else if (name[index] == ']')
2968                                                         braces--;
2969                                         } while (braces > 0);
2970                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2971                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2972                                                 return recursive_type;
2973                                 }
2974                                 else {
2975                                         if (name[index] == ',')
2976                                                 done = true;
2977                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2978                                                 string substring = name.Substring(dot, index - dot);
2979
2980                                                 if (resolved == null)
2981                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2982                                                 else if (resolved is Namespace)
2983                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2984                                                 else if (type != null)
2985                                                         type = TypeManager.GetNestedType (type, substring);
2986                                                 else
2987                                                         return null;
2988
2989                                                 if (resolved == null)
2990                                                         return null;
2991                                                 else if (type == null && resolved is TypeExpr)
2992                                                         type = resolved.Type;
2993
2994                                                 dot = index + 1;
2995                                         }
2996                                 }
2997                                 index++;
2998                         }
2999                         if (name[0] != '[') {
3000                                 string substring = name.Substring(dot, index - dot);
3001
3002                                 if (type != null)
3003                                         return TypeManager.GetNestedType (type, substring);
3004
3005                                 if (resolved != null) {
3006                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
3007                                         if (resolved is TypeExpr)
3008                                                 return resolved.Type;
3009
3010                                         if (resolved == null)
3011                                                 return null;
3012
3013                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
3014                                         return typeof (UnexpectedType);
3015                                 }
3016                                 else
3017                                         return null;
3018                         }
3019                         else
3020                                 return recursive_type;
3021                         }
3022
3023                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3024                 {
3025                         Type t = TypeLookup (ec, name);
3026                         if (t == null) {
3027                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
3028                                 return null;
3029                         }
3030                         if (t == typeof(UnexpectedType))
3031                                 return null;
3032                         type = t;
3033                         return this;
3034                 }
3035
3036                 public override string GetSignatureForError ()
3037                 {
3038                         if (type == null)
3039                                 return TypeManager.CSharpName (name, null);
3040
3041                         return base.GetSignatureForError ();
3042                 }
3043         }
3044
3045         /// <summary>
3046         ///   This class denotes an expression which evaluates to a member
3047         ///   of a struct or a class.
3048         /// </summary>
3049         public abstract class MemberExpr : Expression
3050         {
3051                 protected bool is_base;
3052
3053                 /// <summary>
3054                 ///   The name of this member.
3055                 /// </summary>
3056                 public abstract string Name {
3057                         get;
3058                 }
3059
3060                 //
3061                 // When base.member is used
3062                 //
3063                 public bool IsBase {
3064                         get { return is_base; }
3065                         set { is_base = value; }
3066                 }
3067
3068                 /// <summary>
3069                 ///   Whether this is an instance member.
3070                 /// </summary>
3071                 public abstract bool IsInstance {
3072                         get;
3073                 }
3074
3075                 /// <summary>
3076                 ///   Whether this is a static member.
3077                 /// </summary>
3078                 public abstract bool IsStatic {
3079                         get;
3080                 }
3081
3082                 /// <summary>
3083                 ///   The type which declares this member.
3084                 /// </summary>
3085                 public abstract Type DeclaringType {
3086                         get;
3087                 }
3088
3089                 /// <summary>
3090                 ///   The instance expression associated with this member, if it's a
3091                 ///   non-static member.
3092                 /// </summary>
3093                 public Expression InstanceExpression;
3094
3095                 public static void error176 (Location loc, string name)
3096                 {
3097                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3098                                       "with an instance reference, qualify it with a type name instead", name);
3099                 }
3100
3101                 public static void Error_BaseAccessInExpressionTree (Location loc)
3102                 {
3103                         Report.Error (831, loc, "An expression tree may not contain a base access");
3104                 }
3105
3106                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3107                 {
3108                         if (InstanceExpression != null)
3109                                 InstanceExpression.MutateHoistedGenericType (storey);
3110                 }
3111
3112                 // TODO: possible optimalization
3113                 // Cache resolved constant result in FieldBuilder <-> expression map
3114                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3115                                                                SimpleName original)
3116                 {
3117                         //
3118                         // Precondition:
3119                         //   original == null || original.Resolve (...) ==> left
3120                         //
3121
3122                         if (left is TypeExpr) {
3123                                 left = left.ResolveAsBaseTerminal (ec, false);
3124                                 if (left == null)
3125                                         return null;
3126
3127                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3128                                 // always do all necessary checks
3129                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3130                                 if (oa != null && !ec.IsInObsoleteScope) {
3131                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc);
3132                                 }
3133
3134                                 GenericTypeExpr ct = left as GenericTypeExpr;
3135                                 if (ct != null && !ct.CheckConstraints (ec))
3136                                         return null;
3137                                 //
3138
3139                                 if (!IsStatic) {
3140                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3141                                         return null;
3142                                 }
3143
3144                                 return this;
3145                         }
3146
3147                         if (!IsInstance) {
3148                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3149                                         return this;
3150
3151                                 return ResolveExtensionMemberAccess (left);
3152                         }
3153
3154                         InstanceExpression = left;
3155                         return this;
3156                 }
3157
3158                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3159                 {
3160                         error176 (loc, GetSignatureForError ());
3161                         return this;
3162                 }
3163
3164                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3165                 {
3166                         if (IsStatic)
3167                                 return;
3168
3169                         if (InstanceExpression == EmptyExpression.Null) {
3170                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3171                                 return;
3172                         }
3173
3174                         if (InstanceExpression.Type.IsValueType) {
3175                                 if (InstanceExpression is IMemoryLocation) {
3176                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3177                                 } else {
3178                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3179                                         InstanceExpression.Emit (ec);
3180                                         t.Store (ec);
3181                                         t.AddressOf (ec, AddressOp.Store);
3182                                 }
3183                         } else
3184                                 InstanceExpression.Emit (ec);
3185
3186                         if (prepare_for_load)
3187                                 ec.ig.Emit (OpCodes.Dup);
3188                 }
3189
3190                 public virtual void SetTypeArguments (TypeArguments ta)
3191                 {
3192                         // TODO: need to get correct member type
3193                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3194                                 GetSignatureForError ());
3195                 }
3196         }
3197
3198         ///
3199         /// Represents group of extension methods
3200         ///
3201         public class ExtensionMethodGroupExpr : MethodGroupExpr
3202         {
3203                 readonly NamespaceEntry namespace_entry;
3204                 public Expression ExtensionExpression;
3205                 Argument extension_argument;
3206
3207                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3208                         : base (list, extensionType, l)
3209                 {
3210                         this.namespace_entry = n;
3211                 }
3212
3213                 public override bool IsStatic {
3214                         get { return true; }
3215                 }
3216
3217                 public bool IsTopLevel {
3218                         get { return namespace_entry == null; }
3219                 }
3220
3221                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3222                 {
3223                         if (arguments == null)
3224                                 arguments = new ArrayList (1);
3225                         arguments.Insert (0, extension_argument);
3226                         base.EmitArguments (ec, arguments);
3227                 }
3228
3229                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3230                 {
3231                         if (arguments == null)
3232                                 arguments = new ArrayList (1);
3233                         arguments.Insert (0, extension_argument);
3234                         base.EmitCall (ec, arguments);
3235                 }
3236
3237                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3238                 {
3239                         extension_argument.Expr.MutateHoistedGenericType (storey);
3240                         base.MutateHoistedGenericType (storey);
3241                 }
3242
3243                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3244                 {
3245                         if (arguments == null)
3246                                 arguments = new ArrayList (1);
3247
3248                         arguments.Insert (0, new Argument (ExtensionExpression));
3249                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3250
3251                         // Store resolved argument and restore original arguments
3252                         if (mg != null)
3253                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3254                         arguments.RemoveAt (0);
3255
3256                         return mg;
3257                 }
3258
3259                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3260                 {
3261                         // Use normal resolve rules
3262                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3263                         if (mg != null)
3264                                 return mg;
3265
3266                         if (ns == null)
3267                                 return null;
3268
3269                         // Search continues
3270                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3271                         if (e == null)
3272                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3273
3274                         e.ExtensionExpression = ExtensionExpression;
3275                         e.SetTypeArguments (type_arguments);
3276                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3277                 }
3278         }
3279
3280         /// <summary>
3281         ///   MethodGroupExpr represents a group of method candidates which
3282         ///   can be resolved to the best method overload
3283         /// </summary>
3284         public class MethodGroupExpr : MemberExpr
3285         {
3286                 public interface IErrorHandler
3287                 {
3288                         bool NoExactMatch (EmitContext ec, MethodBase method);
3289                 }
3290
3291                 public IErrorHandler CustomErrorHandler;
3292                 public MethodBase [] Methods;
3293                 MethodBase best_candidate;
3294                 // TODO: make private
3295                 public TypeArguments type_arguments;
3296                 bool identical_type_name;
3297                 bool has_inaccessible_candidates_only;
3298                 Type delegate_type;
3299
3300                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3301                         : this (type, l)
3302                 {
3303                         Methods = new MethodBase [mi.Length];
3304                         mi.CopyTo (Methods, 0);
3305                 }
3306
3307                 public MethodGroupExpr (MemberInfo[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3308                         : this (mi, type, l)
3309                 {
3310                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3311                 }
3312
3313                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3314                         : this (type, l)
3315                 {
3316                         try {
3317                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3318                         } catch {
3319                                 foreach (MemberInfo m in list){
3320                                         if (!(m is MethodBase)){
3321                                                 Console.WriteLine ("Name " + m.Name);
3322                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3323                                         }
3324                                 }
3325                                 throw;
3326                         }
3327
3328
3329                 }
3330
3331                 protected MethodGroupExpr (Type type, Location loc)
3332                 {
3333                         this.loc = loc;
3334                         eclass = ExprClass.MethodGroup;
3335                         this.type = type;
3336                 }
3337
3338                 public override Type DeclaringType {
3339                         get {
3340                                 //
3341                                 // We assume that the top-level type is in the end
3342                                 //
3343                                 return Methods [Methods.Length - 1].DeclaringType;
3344                                 //return Methods [0].DeclaringType;
3345                         }
3346                 }
3347
3348                 public Type DelegateType {
3349                         set {
3350                                 delegate_type = value;
3351                         }
3352                 }
3353
3354                 public bool IdenticalTypeName {
3355                         get {
3356                                 return identical_type_name;
3357                         }
3358                 }
3359
3360                 public override string GetSignatureForError ()
3361                 {
3362                         if (best_candidate != null)
3363                                 return TypeManager.CSharpSignature (best_candidate);
3364
3365                         return TypeManager.CSharpSignature (Methods [0]);
3366                 }
3367
3368                 public override string Name {
3369                         get {
3370                                 return Methods [0].Name;
3371                         }
3372                 }
3373
3374                 public override bool IsInstance {
3375                         get {
3376                                 if (best_candidate != null)
3377                                         return !best_candidate.IsStatic;
3378
3379                                 foreach (MethodBase mb in Methods)
3380                                         if (!mb.IsStatic)
3381                                                 return true;
3382
3383                                 return false;
3384                         }
3385                 }
3386
3387                 public override bool IsStatic {
3388                         get {
3389                                 if (best_candidate != null)
3390                                         return best_candidate.IsStatic;
3391
3392                                 foreach (MethodBase mb in Methods)
3393                                         if (mb.IsStatic)
3394                                                 return true;
3395
3396                                 return false;
3397                         }
3398                 }
3399
3400                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3401                 {
3402                         return (ConstructorInfo)mg.best_candidate;
3403                 }
3404
3405                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3406                 {
3407                         return (MethodInfo)mg.best_candidate;
3408                 }
3409
3410                 //
3411                 //  7.4.3.3  Better conversion from expression
3412                 //  Returns :   1    if a->p is better,
3413                 //              2    if a->q is better,
3414                 //              0 if neither is better
3415                 //
3416                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3417                 {
3418                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3419                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3420                                 //
3421                                 // Uwrap delegate from Expression<T>
3422                                 //
3423                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3424                                         p = TypeManager.GetTypeArguments (p) [0];
3425                                 }
3426                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3427                                         q = TypeManager.GetTypeArguments (q) [0];
3428                                 }
3429
3430                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3431                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3432                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3433                                         return 2;
3434                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3435                                         return 1;
3436                         } else {
3437                                 if (argument_type == p)
3438                                         return 1;
3439
3440                                 if (argument_type == q)
3441                                         return 2;
3442                         }
3443
3444                         return BetterTypeConversion (ec, p, q);
3445                 }
3446
3447                 //
3448                 // 7.4.3.4  Better conversion from type
3449                 //
3450                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3451                 {
3452                         if (p == null || q == null)
3453                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3454
3455                         if (p == TypeManager.int32_type) {
3456                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3457                                         return 1;
3458                         } else if (p == TypeManager.int64_type) {
3459                                 if (q == TypeManager.uint64_type)
3460                                         return 1;
3461                         } else if (p == TypeManager.sbyte_type) {
3462                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3463                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3464                                         return 1;
3465                         } else if (p == TypeManager.short_type) {
3466                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3467                                         q == TypeManager.uint64_type)
3468                                         return 1;
3469                         }
3470
3471                         if (q == TypeManager.int32_type) {
3472                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3473                                         return 2;
3474                         } if (q == TypeManager.int64_type) {
3475                                 if (p == TypeManager.uint64_type)
3476                                         return 2;
3477                         } else if (q == TypeManager.sbyte_type) {
3478                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3479                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3480                                         return 2;
3481                         } if (q == TypeManager.short_type) {
3482                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3483                                         p == TypeManager.uint64_type)
3484                                         return 2;
3485                         }
3486
3487                         // TODO: this is expensive
3488                         Expression p_tmp = new EmptyExpression (p);
3489                         Expression q_tmp = new EmptyExpression (q);
3490
3491                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3492                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3493
3494                         if (p_to_q && !q_to_p)
3495                                 return 1;
3496
3497                         if (q_to_p && !p_to_q)
3498                                 return 2;
3499
3500                         return 0;
3501                 }
3502
3503                 /// <summary>
3504                 ///   Determines "Better function" between candidate
3505                 ///   and the current best match
3506                 /// </summary>
3507                 /// <remarks>
3508                 ///    Returns a boolean indicating :
3509                 ///     false if candidate ain't better
3510                 ///     true  if candidate is better than the current best match
3511                 /// </remarks>
3512                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3513                         MethodBase candidate, bool candidate_params,
3514                         MethodBase best, bool best_params)
3515                 {
3516                         AParametersCollection candidate_pd = TypeManager.GetParameterData (candidate);
3517                         AParametersCollection best_pd = TypeManager.GetParameterData (best);
3518
3519                         bool better_at_least_one = false;
3520                         bool same = true;
3521                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3522                         {
3523                                 Argument a = (Argument) args [j];
3524
3525                                 Type ct = candidate_pd.Types [c_idx];
3526                                 Type bt = best_pd.Types [b_idx];
3527
3528                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3529                                 {
3530                                         ct = TypeManager.GetElementType (ct);
3531                                         --c_idx;
3532                                 }
3533
3534                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3535                                 {
3536                                         bt = TypeManager.GetElementType (bt);
3537                                         --b_idx;
3538                                 }
3539
3540                                 if (ct.Equals (bt))
3541                                         continue;
3542
3543                                 same = false;
3544                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3545
3546                                 // for each argument, the conversion to 'ct' should be no worse than
3547                                 // the conversion to 'bt'.
3548                                 if (result == 2)
3549                                         return false;
3550
3551                                 // for at least one argument, the conversion to 'ct' should be better than
3552                                 // the conversion to 'bt'.
3553                                 if (result != 0)
3554                                         better_at_least_one = true;
3555                         }
3556
3557                         if (better_at_least_one)
3558                                 return true;
3559
3560                         //
3561                         // This handles the case
3562                         //
3563                         //   Add (float f1, float f2, float f3);
3564                         //   Add (params decimal [] foo);
3565                         //
3566                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3567                         // first candidate would've chosen as better.
3568                         //
3569                         if (!same)
3570                                 return false;
3571
3572                         //
3573                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3574                         //
3575                         if (TypeManager.IsGenericMethod (best)) {
3576                                 if (!TypeManager.IsGenericMethod (candidate))
3577                                         return true;
3578                         } else if (TypeManager.IsGenericMethod (candidate)) {
3579                                 return false;
3580                         }
3581
3582                         //
3583                         // This handles the following cases:
3584                         //
3585                         //   Trim () is better than Trim (params char[] chars)
3586                         //   Concat (string s1, string s2, string s3) is better than
3587                         //     Concat (string s1, params string [] srest)
3588                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3589                         //
3590                         if (!candidate_params && best_params)
3591                                 return true;
3592                         if (candidate_params && !best_params)
3593                                 return false;
3594
3595                         int candidate_param_count = candidate_pd.Count;
3596                         int best_param_count = best_pd.Count;
3597
3598                         if (candidate_param_count != best_param_count)
3599                                 // can only happen if (candidate_params && best_params)
3600                                 return candidate_param_count > best_param_count;
3601
3602                         //
3603                         // now, both methods have the same number of parameters, and the parameters have the same types
3604                         // Pick the "more specific" signature
3605                         //
3606
3607                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3608                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3609
3610                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3611                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3612
3613                         bool specific_at_least_once = false;
3614                         for (int j = 0; j < candidate_param_count; ++j)
3615                         {
3616                                 Type ct = orig_candidate_pd.Types [j];
3617                                 Type bt = orig_best_pd.Types [j];
3618                                 if (ct.Equals (bt))
3619                                         continue;
3620                                 Type specific = MoreSpecific (ct, bt);
3621                                 if (specific == bt)
3622                                         return false;
3623                                 if (specific == ct)
3624                                         specific_at_least_once = true;
3625                         }
3626
3627                         if (specific_at_least_once)
3628                                 return true;
3629
3630                         // FIXME: handle lifted operators
3631                         // ...
3632
3633                         return false;
3634                 }
3635
3636                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3637                 {
3638                         if (!IsStatic)
3639                                 return base.ResolveExtensionMemberAccess (left);
3640
3641                         //
3642                         // When left side is an expression and at least one candidate method is
3643                         // static, it can be extension method
3644                         //
3645                         InstanceExpression = left;
3646                         return this;
3647                 }
3648
3649                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3650                                                                 SimpleName original)
3651                 {
3652                         if (!(left is TypeExpr) &&
3653                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3654                                 identical_type_name = true;
3655
3656                         return base.ResolveMemberAccess (ec, left, loc, original);
3657                 }
3658
3659                 public override Expression CreateExpressionTree (EmitContext ec)
3660                 {
3661                         if (best_candidate == null) {
3662                                 Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3663                                 return null;
3664                         }
3665
3666                         if (best_candidate.IsConstructor)
3667                                 return new TypeOfConstructorInfo (best_candidate, loc);
3668
3669                         IMethodData md = TypeManager.GetMethod (best_candidate);
3670                         if (md != null && md.IsExcluded ())
3671                                 Report.Error (765, loc,
3672                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3673
3674                         return new TypeOfMethodInfo (best_candidate, loc);
3675                 }
3676
3677                 override public Expression DoResolve (EmitContext ec)
3678                 {
3679                         if (InstanceExpression != null) {
3680                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3681                                 if (InstanceExpression == null)
3682                                         return null;
3683                         }
3684
3685                         return this;
3686                 }
3687
3688                 public void ReportUsageError ()
3689                 {
3690                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3691                                       Name + "()' is referenced without parentheses");
3692                 }
3693
3694                 override public void Emit (EmitContext ec)
3695                 {
3696                         ReportUsageError ();
3697                 }
3698
3699                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3700                 {
3701                         Invocation.EmitArguments (ec, arguments, false, null);
3702                 }
3703
3704                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3705                 {
3706                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3707                 }
3708
3709                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3710                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3711                 {
3712                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3713
3714                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3715                                 Report.SymbolRelatedToPreviousError (method);
3716                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3717                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3718                                                 TypeManager.CSharpSignature (method));
3719                                         return;
3720                                 }
3721                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3722                                           TypeManager.CSharpSignature (method));
3723                         } else if (delegate_type == null) {
3724                                 Report.SymbolRelatedToPreviousError (method);
3725                                 if (emg != null) {
3726                                         Report.Error (1928, loc,
3727                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3728                                                 emg.ExtensionExpression.GetSignatureForError (),
3729                                                 emg.Name, TypeManager.CSharpSignature (method));
3730                                 } else {
3731                                         Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3732                                                 TypeManager.CSharpSignature (method));
3733                                 }
3734                         } else
3735                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3736                                         TypeManager.CSharpName (delegate_type));
3737
3738                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3739
3740                         string index = (idx + 1).ToString ();
3741                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3742                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3743                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3744                                         Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3745                                                 index, Parameter.GetModifierSignature (a.Modifier));
3746                                 else
3747                                         Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3748                                                 index, Parameter.GetModifierSignature (mod));
3749                         } else {
3750                                 string p1 = a.GetSignatureForError ();
3751                                 string p2 = TypeManager.CSharpName (paramType);
3752
3753                                 if (p1 == p2) {
3754                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3755                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3756                                         Report.SymbolRelatedToPreviousError (paramType);
3757                                 }
3758
3759                                 if (idx == 0 && emg != null) {
3760                                         Report.Error (1929, loc,
3761                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3762                                 } else {
3763                                         Report.Error (1503, loc,
3764                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3765                                 }
3766                         }
3767                 }
3768
3769                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3770                 {
3771                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3772                                 Name, TypeManager.CSharpName (target));
3773                 }
3774
3775                 protected virtual int GetApplicableParametersCount (MethodBase method, AParametersCollection parameters)
3776                 {
3777                         return parameters.Count;
3778                 }
3779
3780                 public static bool IsAncestralType (Type first_type, Type second_type)
3781                 {
3782                         return first_type != second_type &&
3783                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3784                                 TypeManager.ImplementsInterface (second_type, first_type));
3785                 }
3786
3787                 ///
3788                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3789                 /// to the given set of arguments
3790                 /// A return value rates candidate method compatibility,
3791                 /// 0 = the best, int.MaxValue = the worst
3792                 ///
3793                 public int IsApplicable (EmitContext ec,
3794                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3795                 {
3796                         MethodBase candidate = method;
3797
3798                         AParametersCollection pd = TypeManager.GetParameterData (candidate);
3799                         int param_count = GetApplicableParametersCount (candidate, pd);
3800
3801                         if (arg_count != param_count) {
3802                                 if (!pd.HasParams)
3803                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3804                                 if (arg_count < param_count - 1)
3805                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3806
3807                                 // Initialize expanded form of a method with 1 params parameter
3808                                 params_expanded_form = param_count == 1 && pd.HasParams;
3809                         }
3810
3811 #if GMCS_SOURCE
3812                         //
3813                         // 1. Handle generic method using type arguments when specified or type inference
3814                         //
3815                         if (TypeManager.IsGenericMethod (candidate)) {
3816                                 if (type_arguments != null) {
3817                                         Type [] g_args = candidate.GetGenericArguments ();
3818                                         if (g_args.Length != type_arguments.Count)
3819                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3820
3821                                         // TODO: Don't create new method, create Parameters only
3822                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3823                                         candidate = method;
3824                                         pd = TypeManager.GetParameterData (candidate);
3825                                 } else {
3826                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3827                                         if (score != 0)
3828                                                 return score - 20000;
3829
3830                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3831                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3832                                                         TypeManager.CSharpSignature (candidate));
3833
3834                                         pd = TypeManager.GetParameterData (candidate);
3835                                 }
3836                         } else {
3837                                 if (type_arguments != null)
3838                                         return int.MaxValue - 15000;
3839                         }
3840 #endif
3841
3842                         //
3843                         // 2. Each argument has to be implicitly convertible to method parameter
3844                         //
3845                         method = candidate;
3846                         Parameter.Modifier p_mod = 0;
3847                         Type pt = null;
3848                         for (int i = 0; i < arg_count; i++) {
3849                                 Argument a = (Argument) arguments [i];
3850                                 Parameter.Modifier a_mod = a.Modifier &
3851                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3852
3853                                 if (p_mod != Parameter.Modifier.PARAMS) {
3854                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3855
3856                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3857                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3858                                                         continue;
3859
3860                                                 p_mod = 0;
3861                                         }
3862
3863                                         pt = pd.Types [i];
3864                                 } else {
3865                                         params_expanded_form = true;
3866                                 }
3867
3868                                 int score = 1;
3869                                 if (!params_expanded_form)
3870                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3871
3872                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
3873                                         // It can be applicable in expanded form
3874                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3875                                         if (score == 0)
3876                                                 params_expanded_form = true;
3877                                 }
3878
3879                                 if (score != 0) {
3880                                         if (params_expanded_form)
3881                                                 ++score;
3882                                         return (arg_count - i) * 2 + score;
3883                                 }
3884                         }
3885
3886                         if (arg_count != param_count)
3887                                 params_expanded_form = true;
3888
3889                         return 0;
3890                 }
3891
3892                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3893                 {
3894                         //
3895                         // Types have to be identical when ref or out modifer is used
3896                         //
3897                         if (arg_mod != 0 || param_mod != 0) {
3898                                 if (TypeManager.HasElementType (parameter))
3899                                         parameter = parameter.GetElementType ();
3900
3901                                 Type a_type = argument.Type;
3902                                 if (TypeManager.HasElementType (a_type))
3903                                         a_type = a_type.GetElementType ();
3904
3905                                 if (a_type != parameter)
3906                                         return 2;
3907                         } else {
3908                                 if (delegate_type != null ?
3909                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3910                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3911                                         return 2;
3912                         }
3913
3914                         if (arg_mod != param_mod)
3915                                 return 1;
3916
3917                         return 0;
3918                 }
3919
3920                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3921                 {
3922                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3923                                 return false;
3924
3925                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
3926                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
3927
3928                         if (cand_pd.Count != base_pd.Count)
3929                                 return false;
3930
3931                         for (int j = 0; j < cand_pd.Count; ++j)
3932                         {
3933                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
3934                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
3935                                 Type ct = cand_pd.Types [j];
3936                                 Type bt = base_pd.Types [j];
3937
3938                                 if (cm != bm || ct != bt)
3939                                         return false;
3940                         }
3941
3942                         return true;
3943                 }
3944
3945                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
3946                 {
3947                         if (mg1 == null) {
3948                                 if (mg2 == null)
3949                                         return null;
3950                                 return mg2;
3951                         }
3952
3953                         if (mg2 == null)
3954                                 return mg1;
3955
3956                         ArrayList all = new ArrayList (mg1.Methods);
3957                         foreach (MethodBase m in mg2.Methods){
3958                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods, m, false))
3959                                         all.Add (m);
3960                         }
3961
3962                         return new MethodGroupExpr (all, null, loc);
3963                 }
3964
3965                 static Type MoreSpecific (Type p, Type q)
3966                 {
3967                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3968                                 return q;
3969                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3970                                 return p;
3971
3972                         if (TypeManager.HasElementType (p))
3973                         {
3974                                 Type pe = TypeManager.GetElementType (p);
3975                                 Type qe = TypeManager.GetElementType (q);
3976                                 Type specific = MoreSpecific (pe, qe);
3977                                 if (specific == pe)
3978                                         return p;
3979                                 if (specific == qe)
3980                                         return q;
3981                         }
3982                         else if (TypeManager.IsGenericType (p))
3983                         {
3984                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3985                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3986
3987                                 bool p_specific_at_least_once = false;
3988                                 bool q_specific_at_least_once = false;
3989
3990                                 for (int i = 0; i < pargs.Length; i++)
3991                                 {
3992                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3993                                         if (specific == pargs [i])
3994                                                 p_specific_at_least_once = true;
3995                                         if (specific == qargs [i])
3996                                                 q_specific_at_least_once = true;
3997                                 }
3998
3999                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4000                                         return p;
4001                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4002                                         return q;
4003                         }
4004
4005                         return null;
4006                 }
4007
4008                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4009                 {
4010                         base.MutateHoistedGenericType (storey);
4011
4012                         MethodInfo mi = best_candidate as MethodInfo;
4013                         if (mi != null) {
4014                                 best_candidate = storey.MutateGenericMethod (mi);
4015                                 return;
4016                         }
4017
4018                         best_candidate = storey.MutateConstructor ((ConstructorInfo) this);
4019                 }
4020
4021                 /// <summary>
4022                 ///   Find the Applicable Function Members (7.4.2.1)
4023                 ///
4024                 ///   me: Method Group expression with the members to select.
4025                 ///       it might contain constructors or methods (or anything
4026                 ///       that maps to a method).
4027                 ///
4028                 ///   Arguments: ArrayList containing resolved Argument objects.
4029                 ///
4030                 ///   loc: The location if we want an error to be reported, or a Null
4031                 ///        location for "probing" purposes.
4032                 ///
4033                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4034                 ///            that is the best match of me on Arguments.
4035                 ///
4036                 /// </summary>
4037                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4038                         bool may_fail, Location loc)
4039                 {
4040                         bool method_params = false;
4041                         Type applicable_type = null;
4042                         int arg_count = 0;
4043                         ArrayList candidates = new ArrayList (2);
4044                         ArrayList candidate_overrides = null;
4045
4046                         //
4047                         // Used to keep a map between the candidate
4048                         // and whether it is being considered in its
4049                         // normal or expanded form
4050                         //
4051                         // false is normal form, true is expanded form
4052                         //
4053                         Hashtable candidate_to_form = null;
4054
4055                         if (Arguments != null)
4056                                 arg_count = Arguments.Count;
4057
4058                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4059                                 if (!may_fail)
4060                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4061                                 return null;
4062                         }
4063
4064                         int nmethods = Methods.Length;
4065
4066                         if (!IsBase) {
4067                                 //
4068                                 // Methods marked 'override' don't take part in 'applicable_type'
4069                                 // computation, nor in the actual overload resolution.
4070                                 // However, they still need to be emitted instead of a base virtual method.
4071                                 // So, we salt them away into the 'candidate_overrides' array.
4072                                 //
4073                                 // In case of reflected methods, we replace each overriding method with
4074                                 // its corresponding base virtual method.  This is to improve compatibility
4075                                 // with non-C# libraries which change the visibility of overrides (#75636)
4076                                 //
4077                                 int j = 0;
4078                                 for (int i = 0; i < Methods.Length; ++i) {
4079                                         MethodBase m = Methods [i];
4080                                         if (TypeManager.IsOverride (m)) {
4081                                                 if (candidate_overrides == null)
4082                                                         candidate_overrides = new ArrayList ();
4083                                                 candidate_overrides.Add (m);
4084                                                 m = TypeManager.TryGetBaseDefinition (m);
4085                                         }
4086                                         if (m != null)
4087                                                 Methods [j++] = m;
4088                                 }
4089                                 nmethods = j;
4090                         }
4091
4092                         //
4093                         // Enable message recording, it's used mainly by lambda expressions
4094                         //
4095                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4096                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4097
4098                         //
4099                         // First we construct the set of applicable methods
4100                         //
4101                         bool is_sorted = true;
4102                         int best_candidate_rate = int.MaxValue;
4103                         for (int i = 0; i < nmethods; i++) {
4104                                 Type decl_type = Methods [i].DeclaringType;
4105
4106                                 //
4107                                 // If we have already found an applicable method
4108                                 // we eliminate all base types (Section 14.5.5.1)
4109                                 //
4110                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4111                                         continue;
4112
4113                                 //
4114                                 // Check if candidate is applicable (section 14.4.2.1)
4115                                 //
4116                                 bool params_expanded_form = false;
4117                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4118
4119                                 if (candidate_rate < best_candidate_rate) {
4120                                         best_candidate_rate = candidate_rate;
4121                                         best_candidate = Methods [i];
4122                                 }
4123
4124                                 if (params_expanded_form) {
4125                                         if (candidate_to_form == null)
4126                                                 candidate_to_form = new PtrHashtable ();
4127                                         MethodBase candidate = Methods [i];
4128                                         candidate_to_form [candidate] = candidate;
4129                                 }
4130
4131                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4132                                         if (msg_recorder != null)
4133                                                 msg_recorder.EndSession ();
4134                                         continue;
4135                                 }
4136
4137                                 msg_recorder = null;
4138                                 candidates.Add (Methods [i]);
4139
4140                                 if (applicable_type == null)
4141                                         applicable_type = decl_type;
4142                                 else if (applicable_type != decl_type) {
4143                                         is_sorted = false;
4144                                         if (IsAncestralType (applicable_type, decl_type))
4145                                                 applicable_type = decl_type;
4146                                 }
4147                         }
4148
4149                         Report.SetMessageRecorder (prev_recorder);
4150                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4151                                 if (!may_fail)
4152                                         msg_recorder.PrintMessages ();
4153
4154                                 return null;
4155                         }
4156
4157                         int candidate_top = candidates.Count;
4158
4159                         if (applicable_type == null) {
4160                                 //
4161                                 // When we found a top level method which does not match and it's
4162                                 // not an extension method. We start extension methods lookup from here
4163                                 //
4164                                 if (InstanceExpression != null) {
4165                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4166                                         if (ex_method_lookup != null) {
4167                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4168                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4169                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4170                                         }
4171                                 }
4172
4173                                 if (may_fail)
4174                                         return null;
4175
4176                                 //
4177                                 // Okay so we have failed to find exact match so we
4178                                 // return error info about the closest match
4179                                 //
4180                                 if (best_candidate != null) {
4181                                         if (CustomErrorHandler != null) {
4182                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4183                                                         return null;
4184                                         }
4185
4186                                         AParametersCollection pd = TypeManager.GetParameterData (best_candidate);
4187                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4188                                         if (arg_count == pd.Count || pd.HasParams) {
4189                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4190                                                         if (type_arguments == null) {
4191                                                                 Report.Error (411, loc,
4192                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4193                                                                         "the usage. Try specifying the type arguments explicitly",
4194                                                                         TypeManager.CSharpSignature (best_candidate));
4195                                                                 return null;
4196                                                         }
4197
4198                                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate);
4199                                                         if (type_arguments.Count != g_args.Length) {
4200                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4201                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4202                                                                         TypeManager.CSharpSignature (best_candidate),
4203                                                                         g_args.Length.ToString ());
4204                                                                 return null;
4205                                                         }
4206                                                 } else {
4207                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4208                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4209                                                                 return null;
4210                                                         }
4211                                                 }
4212
4213                                                 if (has_inaccessible_candidates_only) {
4214                                                         if (InstanceExpression != null && type != ec.ContainerType && TypeManager.IsNestedFamilyAccessible (ec.ContainerType, best_candidate.DeclaringType)) {
4215                                                                 // Although a derived class can access protected members of
4216                                                                 // its base class it cannot do so through an instance of the
4217                                                                 // base class (CS1540).  If the qualifier_type is a base of the
4218                                                                 // ec.ContainerType and the lookup succeeds with the latter one,
4219                                                                 // then we are in this situation.
4220                                                                 Error_CannotAccessProtected (loc, best_candidate, type, ec.ContainerType);
4221                                                         } else {
4222                                                                 ErrorIsInaccesible (loc, GetSignatureForError ());
4223                                                         }
4224                                                 }
4225
4226                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4227                                                         return null;
4228
4229                                                 if (has_inaccessible_candidates_only)
4230                                                         return null;
4231                                         }
4232                                 }
4233
4234                                 //
4235                                 // We failed to find any method with correct argument count
4236                                 //
4237                                 if (Name == ConstructorInfo.ConstructorName) {
4238                                         Report.SymbolRelatedToPreviousError (type);
4239                                         Report.Error (1729, loc,
4240                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4241                                                 TypeManager.CSharpName (type), arg_count);
4242                                 } else {
4243                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4244                                                 Name, arg_count.ToString ());
4245                                 }
4246
4247                                 return null;
4248                         }
4249
4250                         if (!is_sorted) {
4251                                 //
4252                                 // At this point, applicable_type is _one_ of the most derived types
4253                                 // in the set of types containing the methods in this MethodGroup.
4254                                 // Filter the candidates so that they only contain methods from the
4255                                 // most derived types.
4256                                 //
4257
4258                                 int finalized = 0; // Number of finalized candidates
4259
4260                                 do {
4261                                         // Invariant: applicable_type is a most derived type
4262
4263                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4264                                         // eliminating all it's base types.  At the same time, we'll also move
4265                                         // every unrelated type to the end of the array, and pick the next
4266                                         // 'applicable_type'.
4267
4268                                         Type next_applicable_type = null;
4269                                         int j = finalized; // where to put the next finalized candidate
4270                                         int k = finalized; // where to put the next undiscarded candidate
4271                                         for (int i = finalized; i < candidate_top; ++i) {
4272                                                 MethodBase candidate = (MethodBase) candidates [i];
4273                                                 Type decl_type = candidate.DeclaringType;
4274
4275                                                 if (decl_type == applicable_type) {
4276                                                         candidates [k++] = candidates [j];
4277                                                         candidates [j++] = candidates [i];
4278                                                         continue;
4279                                                 }
4280
4281                                                 if (IsAncestralType (decl_type, applicable_type))
4282                                                         continue;
4283
4284                                                 if (next_applicable_type != null &&
4285                                                         IsAncestralType (decl_type, next_applicable_type))
4286                                                         continue;
4287
4288                                                 candidates [k++] = candidates [i];
4289
4290                                                 if (next_applicable_type == null ||
4291                                                         IsAncestralType (next_applicable_type, decl_type))
4292                                                         next_applicable_type = decl_type;
4293                                         }
4294
4295                                         applicable_type = next_applicable_type;
4296                                         finalized = j;
4297                                         candidate_top = k;
4298                                 } while (applicable_type != null);
4299                         }
4300
4301                         //
4302                         // Now we actually find the best method
4303                         //
4304
4305                         best_candidate = (MethodBase) candidates [0];
4306                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4307
4308                         for (int ix = 1; ix < candidate_top; ix++) {
4309                                 MethodBase candidate = (MethodBase) candidates [ix];
4310
4311                                 if (candidate == best_candidate)
4312                                         continue;
4313
4314                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4315
4316                                 if (BetterFunction (ec, Arguments, arg_count,
4317                                         candidate, cand_params,
4318                                         best_candidate, method_params)) {
4319                                         best_candidate = candidate;
4320                                         method_params = cand_params;
4321                                 }
4322                         }
4323                         //
4324                         // Now check that there are no ambiguities i.e the selected method
4325                         // should be better than all the others
4326                         //
4327                         MethodBase ambiguous = null;
4328                         for (int ix = 1; ix < candidate_top; ix++) {
4329                                 MethodBase candidate = (MethodBase) candidates [ix];
4330
4331                                 if (candidate == best_candidate)
4332                                         continue;
4333
4334                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4335                                 if (!BetterFunction (ec, Arguments, arg_count,
4336                                         best_candidate, method_params,
4337                                         candidate, cand_params))
4338                                 {
4339                                         if (!may_fail)
4340                                                 Report.SymbolRelatedToPreviousError (candidate);
4341                                         ambiguous = candidate;
4342                                 }
4343                         }
4344
4345                         if (ambiguous != null) {
4346                                 Report.SymbolRelatedToPreviousError (best_candidate);
4347                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4348                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4349                                 return this;
4350                         }
4351
4352                         //
4353                         // If the method is a virtual function, pick an override closer to the LHS type.
4354                         //
4355                         if (!IsBase && best_candidate.IsVirtual) {
4356                                 if (TypeManager.IsOverride (best_candidate))
4357                                         throw new InternalErrorException (
4358                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4359
4360                                 if (candidate_overrides != null) {
4361                                         Type[] gen_args = null;
4362                                         bool gen_override = false;
4363                                         if (TypeManager.IsGenericMethod (best_candidate))
4364                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4365
4366                                         foreach (MethodBase candidate in candidate_overrides) {
4367                                                 if (TypeManager.IsGenericMethod (candidate)) {
4368                                                         if (gen_args == null)
4369                                                                 continue;
4370
4371                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4372                                                                 continue;
4373                                                 } else {
4374                                                         if (gen_args != null)
4375                                                                 continue;
4376                                                 }
4377
4378                                                 if (IsOverride (candidate, best_candidate)) {
4379                                                         gen_override = true;
4380                                                         best_candidate = candidate;
4381                                                 }
4382                                         }
4383
4384                                         if (gen_override && gen_args != null) {
4385 #if GMCS_SOURCE
4386                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4387 #endif
4388                                         }
4389                                 }
4390                         }
4391
4392                         //
4393                         // And now check if the arguments are all
4394                         // compatible, perform conversions if
4395                         // necessary etc. and return if everything is
4396                         // all right
4397                         //
4398                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4399                                 method_params, may_fail, loc))
4400                                 return null;
4401
4402                         if (best_candidate == null)
4403                                 return null;
4404
4405                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4406 #if GMCS_SOURCE
4407                         if (the_method.IsGenericMethodDefinition &&
4408                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4409                                 return null;
4410 #endif
4411
4412                         //
4413                         // Check ObsoleteAttribute on the best method
4414                         //
4415                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4416                         if (oa != null && !ec.IsInObsoleteScope)
4417                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
4418
4419                         IMethodData data = TypeManager.GetMethod (the_method);
4420                         if (data != null)
4421                                 data.SetMemberIsUsed ();
4422
4423                         return this;
4424                 }
4425
4426                 public override void SetTypeArguments (TypeArguments ta)
4427                 {
4428                         type_arguments = ta;
4429                 }
4430
4431                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4432                                                           int arg_count, MethodBase method,
4433                                                           bool chose_params_expanded,
4434                                                           bool may_fail, Location loc)
4435                 {
4436                         AParametersCollection pd = TypeManager.GetParameterData (method);
4437
4438                         int errors = Report.Errors;
4439                         Parameter.Modifier p_mod = 0;
4440                         Type pt = null;
4441                         int a_idx = 0, a_pos = 0;
4442                         Argument a = null;
4443                         ArrayList params_initializers = null;
4444                         bool has_unsafe_arg = false;
4445
4446                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4447                                 a = (Argument) arguments [a_idx];
4448                                 if (p_mod != Parameter.Modifier.PARAMS) {
4449                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4450                                         pt = pd.Types [a_idx];
4451                                         has_unsafe_arg |= pt.IsPointer;
4452
4453                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4454                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4455                                                         break;
4456                                                 continue;
4457                                         }
4458
4459                                         if (p_mod == Parameter.Modifier.PARAMS) {
4460                                                 if (chose_params_expanded) {
4461                                                         params_initializers = new ArrayList (arg_count - a_idx);
4462                                                         pt = TypeManager.GetElementType (pt);
4463                                                 }
4464                                         }
4465                                 }
4466
4467                                 //
4468                                 // Types have to be identical when ref or out modifer is used
4469                                 //
4470                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4471                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4472                                                 break;
4473
4474                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4475                                                 break;
4476
4477                                         continue;
4478                                 }
4479
4480                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4481                                 if (conv == null)
4482                                         break;
4483
4484                                 //
4485                                 // Convert params arguments to an array initializer
4486                                 //
4487                                 if (params_initializers != null) {
4488                                         // we choose to use 'a.Expr' rather than 'conv' so that
4489                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4490                                         params_initializers.Add (a.Expr);
4491                                         arguments.RemoveAt (a_idx--);
4492                                         --arg_count;
4493                                         continue;
4494                                 }
4495
4496                                 // Update the argument with the implicit conversion
4497                                 a.Expr = conv;
4498                         }
4499
4500                         //
4501                         // Fill not provided arguments required by params modifier
4502                         //
4503                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4504                                 if (arguments == null)
4505                                         arguments = new ArrayList (1);
4506
4507                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4508                                 pt = TypeManager.GetElementType (pt);
4509                                 has_unsafe_arg |= pt.IsPointer;
4510                                 params_initializers = new ArrayList (0);
4511                         }
4512
4513                         if (a_idx == arg_count) {
4514                                 //
4515                                 // Append an array argument with all params arguments
4516                                 //
4517                                 if (params_initializers != null) {
4518                                         arguments.Add (new Argument (
4519                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4520                                                 params_initializers, loc).Resolve (ec)));
4521                                 }
4522
4523                                 if (has_unsafe_arg && !ec.InUnsafe) {
4524                                         if (!may_fail)
4525                                                 UnsafeError (loc);
4526                                         return false;
4527                                 }
4528
4529                                 return true;
4530                         }
4531
4532                         if (!may_fail && Report.Errors == errors) {
4533                                 if (CustomErrorHandler != null)
4534                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4535                                 else
4536                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4537                         }
4538                         return false;
4539                 }
4540         }
4541
4542         public class ConstantExpr : MemberExpr
4543         {
4544                 FieldInfo constant;
4545
4546                 public ConstantExpr (FieldInfo constant, Location loc)
4547                 {
4548                         this.constant = constant;
4549                         this.loc = loc;
4550                 }
4551
4552                 public override string Name {
4553                         get { throw new NotImplementedException (); }
4554                 }
4555
4556                 public override bool IsInstance {
4557                         get { return !IsStatic; }
4558                 }
4559
4560                 public override bool IsStatic {
4561                         get { return constant.IsStatic; }
4562                 }
4563
4564                 public override Type DeclaringType {
4565                         get { return constant.DeclaringType; }
4566                 }
4567
4568                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4569                 {
4570                         constant = TypeManager.GetGenericFieldDefinition (constant);
4571
4572                         IConstant ic = TypeManager.GetConstant (constant);
4573                         if (ic == null) {
4574                                 if (constant.IsLiteral) {
4575                                         ic = new ExternalConstant (constant);
4576                                 } else {
4577                                         ic = ExternalConstant.CreateDecimal (constant);
4578                                         // HACK: decimal field was not resolved as constant
4579                                         if (ic == null)
4580                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4581                                 }
4582                                 TypeManager.RegisterConstant (constant, ic);
4583                         }
4584
4585                         return base.ResolveMemberAccess (ec, left, loc, original);
4586                 }
4587
4588                 public override Expression CreateExpressionTree (EmitContext ec)
4589                 {
4590                         throw new NotSupportedException ("ET");
4591                 }
4592
4593                 public override Expression DoResolve (EmitContext ec)
4594                 {
4595                         IConstant ic = TypeManager.GetConstant (constant);
4596                         if (ic.ResolveValue ()) {
4597                                 if (!ec.IsInObsoleteScope)
4598                                         ic.CheckObsoleteness (loc);
4599                         }
4600
4601                         return ic.CreateConstantReference (loc);
4602                 }
4603
4604                 public override void Emit (EmitContext ec)
4605                 {
4606                         throw new NotSupportedException ();
4607                 }
4608
4609                 public override string GetSignatureForError ()
4610                 {
4611                         return TypeManager.GetFullNameSignature (constant);
4612                 }
4613         }
4614
4615         /// <summary>
4616         ///   Fully resolved expression that evaluates to a Field
4617         /// </summary>
4618         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariableReference {
4619                 public FieldInfo FieldInfo;
4620                 readonly Type constructed_generic_type;
4621                 VariableInfo variable_info;
4622
4623                 LocalTemporary temp;
4624                 bool prepared;
4625
4626                 protected FieldExpr (Location l)
4627                 {
4628                         loc = l;
4629                 }
4630
4631                 public FieldExpr (FieldInfo fi, Location l)
4632                 {
4633                         FieldInfo = fi;
4634                         type = TypeManager.TypeToCoreType (fi.FieldType);
4635                         loc = l;
4636                 }
4637
4638                 public FieldExpr (FieldInfo fi, Type genericType, Location l)
4639                         : this (fi, l)
4640                 {
4641                         if (TypeManager.IsGenericTypeDefinition (genericType))
4642                                 return;
4643                         this.constructed_generic_type = genericType;
4644                 }
4645
4646                 public override string Name {
4647                         get {
4648                                 return FieldInfo.Name;
4649                         }
4650                 }
4651
4652                 public override bool IsInstance {
4653                         get {
4654                                 return !FieldInfo.IsStatic;
4655                         }
4656                 }
4657
4658                 public override bool IsStatic {
4659                         get {
4660                                 return FieldInfo.IsStatic;
4661                         }
4662                 }
4663
4664                 public override Type DeclaringType {
4665                         get {
4666                                 return FieldInfo.DeclaringType;
4667                         }
4668                 }
4669
4670                 public override string GetSignatureForError ()
4671                 {
4672                         return TypeManager.GetFullNameSignature (FieldInfo);
4673                 }
4674
4675                 public VariableInfo VariableInfo {
4676                         get {
4677                                 return variable_info;
4678                         }
4679                 }
4680
4681                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4682                                                                 SimpleName original)
4683                 {
4684                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4685                         Type t = fi.FieldType;
4686
4687                         if (t.IsPointer && !ec.InUnsafe) {
4688                                 UnsafeError (loc);
4689                         }
4690
4691                         return base.ResolveMemberAccess (ec, left, loc, original);
4692                 }
4693
4694                 public void SetHasAddressTaken ()
4695                 {
4696                         IVariableReference vr = InstanceExpression as IVariableReference;
4697                         if (vr != null)
4698                                 vr.SetHasAddressTaken ();
4699                 }
4700
4701                 public override Expression CreateExpressionTree (EmitContext ec)
4702                 {
4703                         Expression instance;
4704                         if (InstanceExpression == null) {
4705                                 instance = new NullLiteral (loc);
4706                         } else {
4707                                 instance = InstanceExpression.CreateExpressionTree (ec);
4708                         }
4709
4710                         ArrayList args = new ArrayList (2);
4711                         args.Add (new Argument (instance));
4712                         args.Add (new Argument (CreateTypeOfExpression ()));
4713                         return CreateExpressionFactoryCall ("Field", args);
4714                 }
4715
4716                 public Expression CreateTypeOfExpression ()
4717                 {
4718                         return new TypeOfField (GetConstructedFieldInfo (), loc);
4719                 }
4720
4721                 override public Expression DoResolve (EmitContext ec)
4722                 {
4723                         return DoResolve (ec, false, false);
4724                 }
4725
4726                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4727                 {
4728                         if (!FieldInfo.IsStatic){
4729                                 if (InstanceExpression == null){
4730                                         //
4731                                         // This can happen when referencing an instance field using
4732                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4733                                         //
4734                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4735                                         return null;
4736                                 }
4737
4738                                 // Resolve the field's instance expression while flow analysis is turned
4739                                 // off: when accessing a field "a.b", we must check whether the field
4740                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4741
4742                                 if (lvalue_instance) {
4743                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4744                                                 Expression right_side =
4745                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4746                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4747                                         }
4748                                 } else {
4749                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4750                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4751                                 }
4752
4753                                 if (InstanceExpression == null)
4754                                         return null;
4755
4756                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4757                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4758                                 }
4759                         }
4760
4761                         // TODO: the code above uses some non-standard multi-resolve rules
4762                         if (eclass != ExprClass.Invalid)
4763                                 return this;
4764
4765                         if (!ec.IsInObsoleteScope) {
4766                                 FieldBase f = TypeManager.GetField (FieldInfo);
4767                                 if (f != null) {
4768                                         f.CheckObsoleteness (loc);
4769                                 } else {
4770                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4771                                         if (oa != null)
4772                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4773                                 }
4774                         }
4775
4776                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4777                         IVariableReference var = InstanceExpression as IVariableReference;
4778
4779                         if (fb != null) {
4780                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4781                                 if (!ec.InFixedInitializer && (fe == null || !fe.IsFixed)) {
4782                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4783                                 }
4784
4785                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4786                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4787                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4788                                                 TypeManager.GetFullNameSignature (FieldInfo));
4789                                 } else if (var != null && var.IsHoisted) {
4790                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (var, loc);
4791                                 }
4792
4793                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4794                         }
4795
4796                         eclass = ExprClass.Variable;
4797
4798                         // If the instance expression is a local variable or parameter.
4799                         if (var == null || var.VariableInfo == null)
4800                                 return this;
4801
4802                         VariableInfo vi = var.VariableInfo;
4803                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4804                                 return null;
4805
4806                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4807                         eclass = ExprClass.Variable;
4808                         return this;
4809                 }
4810
4811                 static readonly int [] codes = {
4812                         191,    // instance, write access
4813                         192,    // instance, out access
4814                         198,    // static, write access
4815                         199,    // static, out access
4816                         1648,   // member of value instance, write access
4817                         1649,   // member of value instance, out access
4818                         1650,   // member of value static, write access
4819                         1651    // member of value static, out access
4820                 };
4821
4822                 static readonly string [] msgs = {
4823                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4824                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4825                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4826                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4827                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4828                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4829                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4830                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4831                 };
4832
4833                 // The return value is always null.  Returning a value simplifies calling code.
4834                 Expression Report_AssignToReadonly (Expression right_side)
4835                 {
4836                         int i = 0;
4837                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4838                                 i += 1;
4839                         if (IsStatic)
4840                                 i += 2;
4841                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4842                                 i += 4;
4843                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4844
4845                         return null;
4846                 }
4847
4848                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4849                 {
4850                         IVariableReference var = InstanceExpression as IVariableReference;
4851                         if (var != null && var.VariableInfo != null)
4852                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4853
4854                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4855                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4856
4857                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4858
4859                         if (e == null)
4860                                 return null;
4861
4862                         FieldBase fb = TypeManager.GetField (FieldInfo);
4863                         if (fb != null)
4864                                 fb.SetAssigned ();
4865
4866                         if (FieldInfo.IsInitOnly) {
4867                                 // InitOnly fields can only be assigned in constructors or initializers
4868                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4869                                         return Report_AssignToReadonly (right_side);
4870
4871                                 if (ec.IsConstructor) {
4872                                         Type ctype = ec.TypeContainer.CurrentType;
4873                                         if (ctype == null)
4874                                                 ctype = ec.ContainerType;
4875
4876                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4877                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4878                                                 return Report_AssignToReadonly (right_side);
4879                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4880                                         if (IsStatic && !ec.IsStatic)
4881                                                 return Report_AssignToReadonly (right_side);
4882                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4883                                         if (!IsStatic && !(InstanceExpression is This))
4884                                                 return Report_AssignToReadonly (right_side);
4885                                 }
4886                         }
4887
4888                         if (right_side == EmptyExpression.OutAccess &&
4889                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4890                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4891                                 Report.Warning (197, 1, loc,
4892                                                 "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",
4893                                                 GetSignatureForError ());
4894                         }
4895
4896                         eclass = ExprClass.Variable;
4897                         return this;
4898                 }
4899
4900                 bool is_marshal_by_ref ()
4901                 {
4902                         return !IsStatic && Type.IsValueType && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
4903                 }
4904
4905                 public override void CheckMarshalByRefAccess (EmitContext ec)
4906                 {
4907                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
4908                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4909                                 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",
4910                                                 GetSignatureForError ());
4911                         }
4912                 }
4913
4914                 public override int GetHashCode ()
4915                 {
4916                         return FieldInfo.GetHashCode ();
4917                 }
4918
4919                 public bool IsFixed {
4920                         get {
4921                                 //
4922                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type
4923                                 //
4924                                 IVariableReference variable = InstanceExpression as IVariableReference;
4925                                 return variable != null && InstanceExpression.Type.IsValueType && variable.IsFixed;
4926                         }
4927                 }
4928
4929                 public bool IsHoisted {
4930                         get {
4931                                 IVariableReference hv = InstanceExpression as IVariableReference;
4932                                 return hv != null && hv.IsHoisted;
4933                         }
4934                 }
4935
4936                 public override bool Equals (object obj)
4937                 {
4938                         FieldExpr fe = obj as FieldExpr;
4939                         if (fe == null)
4940                                 return false;
4941
4942                         if (FieldInfo != fe.FieldInfo)
4943                                 return false;
4944
4945                         if (InstanceExpression == null || fe.InstanceExpression == null)
4946                                 return true;
4947
4948                         return InstanceExpression.Equals (fe.InstanceExpression);
4949                 }
4950
4951                 public void Emit (EmitContext ec, bool leave_copy)
4952                 {
4953                         ILGenerator ig = ec.ig;
4954                         bool is_volatile = false;
4955
4956                         FieldBase f = TypeManager.GetField (FieldInfo);
4957                         if (f != null){
4958                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4959                                         is_volatile = true;
4960
4961                                 f.SetMemberIsUsed ();
4962                         }
4963
4964                         if (FieldInfo.IsStatic){
4965                                 if (is_volatile)
4966                                         ig.Emit (OpCodes.Volatile);
4967
4968                                 ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
4969                         } else {
4970                                 if (!prepared)
4971                                         EmitInstance (ec, false);
4972
4973                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4974                                 if (ff != null) {
4975                                         ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
4976                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4977                                 } else {
4978                                         if (is_volatile)
4979                                                 ig.Emit (OpCodes.Volatile);
4980
4981                                         ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
4982                                 }
4983                         }
4984
4985                         if (leave_copy) {
4986                                 ec.ig.Emit (OpCodes.Dup);
4987                                 if (!FieldInfo.IsStatic) {
4988                                         temp = new LocalTemporary (this.Type);
4989                                         temp.Store (ec);
4990                                 }
4991                         }
4992                 }
4993
4994                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4995                 {
4996                         FieldAttributes fa = FieldInfo.Attributes;
4997                         bool is_static = (fa & FieldAttributes.Static) != 0;
4998                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4999                         ILGenerator ig = ec.ig;
5000
5001                         if (is_readonly && !ec.IsConstructor){
5002                                 Report_AssignToReadonly (source);
5003                                 return;
5004                         }
5005
5006                         prepared = prepare_for_load;
5007                         EmitInstance (ec, prepared);
5008
5009                         source.Emit (ec);
5010                         if (leave_copy) {
5011                                 ec.ig.Emit (OpCodes.Dup);
5012                                 if (!FieldInfo.IsStatic) {
5013                                         temp = new LocalTemporary (this.Type);
5014                                         temp.Store (ec);
5015                                 }
5016                         }
5017
5018                         FieldBase f = TypeManager.GetField (FieldInfo);
5019                         if (f != null){
5020                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5021                                         ig.Emit (OpCodes.Volatile);
5022
5023                                 f.SetAssigned ();
5024                         }
5025
5026                         if (is_static)
5027                                 ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
5028                         else
5029                                 ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
5030
5031                         if (temp != null) {
5032                                 temp.Emit (ec);
5033                                 temp.Release (ec);
5034                                 temp = null;
5035                         }
5036                 }
5037
5038                 public override void Emit (EmitContext ec)
5039                 {
5040                         Emit (ec, false);
5041                 }
5042
5043                 public override void EmitSideEffect (EmitContext ec)
5044                 {
5045                         FieldBase f = TypeManager.GetField (FieldInfo);
5046                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
5047
5048                         if (is_volatile || is_marshal_by_ref ())
5049                                 base.EmitSideEffect (ec);
5050                 }
5051
5052                 public override void Error_VariableIsUsedBeforeItIsDeclared (string name)
5053                 {
5054                         Report.Error (844, loc,
5055                                 "A local variable `{0}' cannot be used before it is declared. Consider renaming the local variable when it hides the field `{1}'",
5056                                 name, GetSignatureForError ());
5057                 }
5058
5059                 public void AddressOf (EmitContext ec, AddressOp mode)
5060                 {
5061                         ILGenerator ig = ec.ig;
5062
5063                         FieldBase f = TypeManager.GetField (FieldInfo);
5064                         if (f != null){
5065                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
5066                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
5067                                                         f.GetSignatureForError ());
5068                                 }
5069
5070                                 if ((mode & AddressOp.Store) != 0)
5071                                         f.SetAssigned ();
5072                                 if ((mode & AddressOp.Load) != 0)
5073                                         f.SetMemberIsUsed ();
5074                         }
5075
5076                         //
5077                         // Handle initonly fields specially: make a copy and then
5078                         // get the address of the copy.
5079                         //
5080                         bool need_copy;
5081                         if (FieldInfo.IsInitOnly){
5082                                 need_copy = true;
5083                                 if (ec.IsConstructor){
5084                                         if (FieldInfo.IsStatic){
5085                                                 if (ec.IsStatic)
5086                                                         need_copy = false;
5087                                         } else
5088                                                 need_copy = false;
5089                                 }
5090                         } else
5091                                 need_copy = false;
5092
5093                         if (need_copy){
5094                                 LocalBuilder local;
5095                                 Emit (ec);
5096                                 local = ig.DeclareLocal (type);
5097                                 ig.Emit (OpCodes.Stloc, local);
5098                                 ig.Emit (OpCodes.Ldloca, local);
5099                                 return;
5100                         }
5101
5102
5103                         if (FieldInfo.IsStatic){
5104                                 ig.Emit (OpCodes.Ldsflda, GetConstructedFieldInfo ());
5105                         } else {
5106                                 if (!prepared)
5107                                         EmitInstance (ec, false);
5108                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5109                         }
5110                 }
5111
5112                 FieldInfo GetConstructedFieldInfo ()
5113                 {
5114                         if (constructed_generic_type == null)
5115                                 return FieldInfo;
5116 #if GMCS_SOURCE
5117                         return TypeBuilder.GetField (constructed_generic_type, FieldInfo);
5118 #else
5119                         throw new NotSupportedException ();
5120 #endif
5121                 }
5122
5123                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5124                 {
5125                         FieldInfo = storey.MutateField (FieldInfo);
5126                         base.MutateHoistedGenericType (storey);
5127                 }
5128         }
5129
5130
5131         /// <summary>
5132         ///   Expression that evaluates to a Property.  The Assign class
5133         ///   might set the `Value' expression if we are in an assignment.
5134         ///
5135         ///   This is not an LValue because we need to re-write the expression, we
5136         ///   can not take data from the stack and store it.
5137         /// </summary>
5138         public class PropertyExpr : MemberExpr, IAssignMethod {
5139                 public readonly PropertyInfo PropertyInfo;
5140                 MethodInfo getter, setter;
5141                 bool is_static;
5142
5143                 bool resolved;
5144
5145                 LocalTemporary temp;
5146                 bool prepared;
5147
5148                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5149                 {
5150                         PropertyInfo = pi;
5151                         eclass = ExprClass.PropertyAccess;
5152                         is_static = false;
5153                         loc = l;
5154
5155                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5156
5157                         ResolveAccessors (container_type);
5158                 }
5159
5160                 public override string Name {
5161                         get {
5162                                 return PropertyInfo.Name;
5163                         }
5164                 }
5165
5166                 public override bool IsInstance {
5167                         get {
5168                                 return !is_static;
5169                         }
5170                 }
5171
5172                 public override bool IsStatic {
5173                         get {
5174                                 return is_static;
5175                         }
5176                 }
5177
5178                 public override Expression CreateExpressionTree (EmitContext ec)
5179                 {
5180                         ArrayList args;
5181                         if (IsSingleDimensionalArrayLength ()) {
5182                                 args = new ArrayList (1);
5183                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5184                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5185                         }
5186
5187                         if (is_base) {
5188                                 Error_BaseAccessInExpressionTree (loc);
5189                                 return null;
5190                         }
5191
5192                         args = new ArrayList (2);
5193                         if (InstanceExpression == null)
5194                                 args.Add (new Argument (new NullLiteral (loc)));
5195                         else
5196                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5197                         args.Add (new Argument (new TypeOfMethodInfo (getter, loc)));
5198                         return CreateExpressionFactoryCall ("Property", args);
5199                 }
5200
5201                 public Expression CreateSetterTypeOfExpression ()
5202                 {
5203                         return new TypeOfMethodInfo (setter, loc);
5204                 }
5205
5206                 public override Type DeclaringType {
5207                         get {
5208                                 return PropertyInfo.DeclaringType;
5209                         }
5210                 }
5211
5212                 public override string GetSignatureForError ()
5213                 {
5214                         return TypeManager.GetFullNameSignature (PropertyInfo);
5215                 }
5216
5217                 void FindAccessors (Type invocation_type)
5218                 {
5219                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5220                                 BindingFlags.Static | BindingFlags.Instance |
5221                                 BindingFlags.DeclaredOnly;
5222
5223                         Type current = PropertyInfo.DeclaringType;
5224                         for (; current != null; current = current.BaseType) {
5225                                 MemberInfo[] group = TypeManager.MemberLookup (
5226                                         invocation_type, invocation_type, current,
5227                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5228
5229                                 if (group == null)
5230                                         continue;
5231
5232                                 if (group.Length != 1)
5233                                         // Oooops, can this ever happen ?
5234                                         return;
5235
5236                                 PropertyInfo pi = (PropertyInfo) group [0];
5237
5238                                 if (getter == null)
5239                                         getter = pi.GetGetMethod (true);
5240
5241                                 if (setter == null)
5242                                         setter = pi.GetSetMethod (true);
5243
5244                                 MethodInfo accessor = getter != null ? getter : setter;
5245
5246                                 if (!accessor.IsVirtual)
5247                                         return;
5248                         }
5249                 }
5250
5251                 //
5252                 // We also perform the permission checking here, as the PropertyInfo does not
5253                 // hold the information for the accessibility of its setter/getter
5254                 //
5255                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5256                 void ResolveAccessors (Type container_type)
5257                 {
5258                         FindAccessors (container_type);
5259
5260                         if (getter != null) {
5261                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5262                                 IMethodData md = TypeManager.GetMethod (the_getter);
5263                                 if (md != null)
5264                                         md.SetMemberIsUsed ();
5265
5266                                 is_static = getter.IsStatic;
5267                         }
5268
5269                         if (setter != null) {
5270                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5271                                 IMethodData md = TypeManager.GetMethod (the_setter);
5272                                 if (md != null)
5273                                         md.SetMemberIsUsed ();
5274
5275                                 is_static = setter.IsStatic;
5276                         }
5277                 }
5278
5279                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5280                 {
5281                         if (InstanceExpression != null)
5282                                 InstanceExpression.MutateHoistedGenericType (storey);
5283
5284                         type = storey.MutateType (type);
5285                         if (getter != null)
5286                                 getter = storey.MutateGenericMethod (getter);
5287                         if (setter != null)
5288                                 setter = storey.MutateGenericMethod (setter);
5289                 }
5290
5291                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5292                 {
5293                         if (is_static) {
5294                                 InstanceExpression = null;
5295                                 return true;
5296                         }
5297
5298                         if (InstanceExpression == null) {
5299                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5300                                 return false;
5301                         }
5302
5303                         InstanceExpression = InstanceExpression.DoResolve (ec);
5304                         if (lvalue_instance && InstanceExpression != null)
5305                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5306
5307                         if (InstanceExpression == null)
5308                                 return false;
5309
5310                         InstanceExpression.CheckMarshalByRefAccess (ec);
5311
5312                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5313                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5314                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5315                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5316                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5317                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5318                                 return false;
5319                         }
5320
5321                         return true;
5322                 }
5323
5324                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5325                 {
5326                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5327                         if (mi is MethodBuilder) {
5328                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5329                                 return;
5330                         }
5331
5332                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5333                         sig.Append ('.');
5334                         AParametersCollection iparams = TypeManager.GetParameterData (mi);
5335                         sig.Append (getter ? "get_" : "set_");
5336                         sig.Append (Name);
5337                         sig.Append (iparams.GetSignatureForError ());
5338
5339                         Report.SymbolRelatedToPreviousError (mi);
5340                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5341                                 Name, sig.ToString ());
5342                 }
5343
5344                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5345                 {
5346                         bool dummy;
5347                         MethodInfo accessor = lvalue ? setter : getter;
5348                         if (accessor == null && lvalue)
5349                                 accessor = getter;
5350                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5351                 }
5352
5353                 bool IsSingleDimensionalArrayLength ()
5354                 {
5355                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5356                                 return false;
5357
5358                         string t_name = InstanceExpression.Type.Name;
5359                         int t_name_len = t_name.Length;
5360                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5361                 }
5362
5363                 override public Expression DoResolve (EmitContext ec)
5364                 {
5365                         if (resolved)
5366                                 return this;
5367
5368                         if (getter != null){
5369                                 if (TypeManager.GetParameterData (getter).Count != 0){
5370                                         Error_PropertyNotFound (getter, true);
5371                                         return null;
5372                                 }
5373                         }
5374
5375                         if (getter == null){
5376                                 //
5377                                 // The following condition happens if the PropertyExpr was
5378                                 // created, but is invalid (ie, the property is inaccessible),
5379                                 // and we did not want to embed the knowledge about this in
5380                                 // the caller routine.  This only avoids double error reporting.
5381                                 //
5382                                 if (setter == null)
5383                                         return null;
5384
5385                                 if (InstanceExpression != EmptyExpression.Null) {
5386                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5387                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5388                                         return null;
5389                                 }
5390                         }
5391
5392                         bool must_do_cs1540_check = false;
5393                         if (getter != null &&
5394                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5395                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5396                                 if (pm != null && pm.HasCustomAccessModifier) {
5397                                         Report.SymbolRelatedToPreviousError (pm);
5398                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5399                                                 TypeManager.CSharpSignature (getter));
5400                                 }
5401                                 else {
5402                                         Report.SymbolRelatedToPreviousError (getter);
5403                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5404                                 }
5405                                 return null;
5406                         }
5407
5408                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5409                                 return null;
5410
5411                         //
5412                         // Only base will allow this invocation to happen.
5413                         //
5414                         if (IsBase && getter.IsAbstract) {
5415                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5416                         }
5417
5418                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5419                                 UnsafeError (loc);
5420                         }
5421
5422                         if (!ec.IsInObsoleteScope) {
5423                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5424                                 if (pb != null) {
5425                                         pb.CheckObsoleteness (loc);
5426                                 } else {
5427                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5428                                         if (oa != null)
5429                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5430                                 }
5431                         }
5432
5433                         resolved = true;
5434
5435                         return this;
5436                 }
5437
5438                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5439                 {
5440                         if (right_side == EmptyExpression.OutAccess) {
5441                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5442                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5443                                             PropertyInfo.Name);
5444                                 } else {
5445                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5446                                               GetSignatureForError ());
5447                                 }
5448                                 return null;
5449                         }
5450
5451                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5452                                 Error_CannotModifyIntermediateExpressionValue (ec);
5453                         }
5454
5455                         if (setter == null){
5456                                 //
5457                                 // The following condition happens if the PropertyExpr was
5458                                 // created, but is invalid (ie, the property is inaccessible),
5459                                 // and we did not want to embed the knowledge about this in
5460                                 // the caller routine.  This only avoids double error reporting.
5461                                 //
5462                                 if (getter == null)
5463                                         return null;
5464
5465                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5466                                         Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5467                                                 PropertyInfo.Name);
5468                                 } else {
5469                                         Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5470                                                 GetSignatureForError ());
5471                                 }
5472                                 return null;
5473                         }
5474
5475                         if (TypeManager.GetParameterData (setter).Count != 1){
5476                                 Error_PropertyNotFound (setter, false);
5477                                 return null;
5478                         }
5479
5480                         bool must_do_cs1540_check;
5481                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5482                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5483                                 if (pm != null && pm.HasCustomAccessModifier) {
5484                                         Report.SymbolRelatedToPreviousError (pm);
5485                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5486                                                 TypeManager.CSharpSignature (setter));
5487                                 }
5488                                 else {
5489                                         Report.SymbolRelatedToPreviousError (setter);
5490                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5491                                 }
5492                                 return null;
5493                         }
5494
5495                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5496                                 return null;
5497
5498                         //
5499                         // Only base will allow this invocation to happen.
5500                         //
5501                         if (IsBase && setter.IsAbstract){
5502                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5503                         }
5504
5505                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe) {
5506                                 UnsafeError (loc);
5507                         }
5508
5509                         if (!ec.IsInObsoleteScope) {
5510                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5511                                 if (pb != null) {
5512                                         pb.CheckObsoleteness (loc);
5513                                 } else {
5514                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5515                                         if (oa != null)
5516                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5517                                 }
5518                         }
5519
5520                         return this;
5521                 }
5522
5523                 public override void Emit (EmitContext ec)
5524                 {
5525                         Emit (ec, false);
5526                 }
5527
5528                 public void Emit (EmitContext ec, bool leave_copy)
5529                 {
5530                         //
5531                         // Special case: length of single dimension array property is turned into ldlen
5532                         //
5533                         if (IsSingleDimensionalArrayLength ()) {
5534                                 if (!prepared)
5535                                         EmitInstance (ec, false);
5536                                 ec.ig.Emit (OpCodes.Ldlen);
5537                                 ec.ig.Emit (OpCodes.Conv_I4);
5538                                 return;
5539                         }
5540
5541                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5542
5543                         if (leave_copy) {
5544                                 ec.ig.Emit (OpCodes.Dup);
5545                                 if (!is_static) {
5546                                         temp = new LocalTemporary (this.Type);
5547                                         temp.Store (ec);
5548                                 }
5549                         }
5550                 }
5551
5552                 //
5553                 // Implements the IAssignMethod interface for assignments
5554                 //
5555                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5556                 {
5557                         Expression my_source = source;
5558
5559                         if (prepare_for_load) {
5560                                 prepared = true;
5561                                 source.Emit (ec);
5562
5563                                 if (leave_copy) {
5564                                         ec.ig.Emit (OpCodes.Dup);
5565                                         if (!is_static) {
5566                                                 temp = new LocalTemporary (this.Type);
5567                                                 temp.Store (ec);
5568                                         }
5569                                 }
5570                         } else if (leave_copy) {
5571                                 source.Emit (ec);
5572                                 temp = new LocalTemporary (this.Type);
5573                                 temp.Store (ec);
5574                                 my_source = temp;
5575                         }
5576
5577                         ArrayList args = new ArrayList (1);
5578                         args.Add (new Argument (my_source, Argument.AType.Expression));
5579
5580                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5581
5582                         if (temp != null) {
5583                                 temp.Emit (ec);
5584                                 temp.Release (ec);
5585                         }
5586                 }
5587         }
5588
5589         /// <summary>
5590         ///   Fully resolved expression that evaluates to an Event
5591         /// </summary>
5592         public class EventExpr : MemberExpr {
5593                 public readonly EventInfo EventInfo;
5594
5595                 bool is_static;
5596                 MethodInfo add_accessor, remove_accessor;
5597
5598                 public EventExpr (EventInfo ei, Location loc)
5599                 {
5600                         EventInfo = ei;
5601                         this.loc = loc;
5602                         eclass = ExprClass.EventAccess;
5603
5604                         add_accessor = TypeManager.GetAddMethod (ei);
5605                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5606                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5607                                 is_static = true;
5608
5609                         if (EventInfo is MyEventBuilder){
5610                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5611                                 type = eb.EventType;
5612                                 eb.SetUsed ();
5613                         } else
5614                                 type = EventInfo.EventHandlerType;
5615                 }
5616
5617                 public override string Name {
5618                         get {
5619                                 return EventInfo.Name;
5620                         }
5621                 }
5622
5623                 public override bool IsInstance {
5624                         get {
5625                                 return !is_static;
5626                         }
5627                 }
5628
5629                 public override bool IsStatic {
5630                         get {
5631                                 return is_static;
5632                         }
5633                 }
5634
5635                 public override Type DeclaringType {
5636                         get {
5637                                 return EventInfo.DeclaringType;
5638                         }
5639                 }
5640
5641                 void Error_AssignmentEventOnly ()
5642                 {
5643                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5644                                 GetSignatureForError ());
5645                 }
5646
5647                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5648                                                                 SimpleName original)
5649                 {
5650                         //
5651                         // If the event is local to this class, we transform ourselves into a FieldExpr
5652                         //
5653
5654                         if (EventInfo.DeclaringType == ec.ContainerType ||
5655                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5656                                 EventField mi = TypeManager.GetEventField (EventInfo);
5657
5658                                 if (mi != null) {
5659                                         if (!ec.IsInObsoleteScope)
5660                                                 mi.CheckObsoleteness (loc);
5661
5662                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5663                                                 Error_AssignmentEventOnly ();
5664
5665                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5666
5667                                         InstanceExpression = null;
5668
5669                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5670                                 }
5671                         }
5672
5673                         if (left is This && !ec.IsInCompoundAssignment)
5674                                 Error_AssignmentEventOnly ();
5675
5676                         return base.ResolveMemberAccess (ec, left, loc, original);
5677                 }
5678
5679                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5680                 {
5681                         if (is_static) {
5682                                 InstanceExpression = null;
5683                                 return true;
5684                         }
5685
5686                         if (InstanceExpression == null) {
5687                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5688                                 return false;
5689                         }
5690
5691                         InstanceExpression = InstanceExpression.DoResolve (ec);
5692                         if (InstanceExpression == null)
5693                                 return false;
5694
5695                         if (IsBase && add_accessor.IsAbstract) {
5696                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5697                                 return false;
5698                         }
5699
5700                         //
5701                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5702                         // However, in the Event case, we reported a CS0122 instead.
5703                         //
5704                         // TODO: Exact copy from PropertyExpr
5705                         //
5706                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5707                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5708                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5709                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5710                                 Report.SymbolRelatedToPreviousError (EventInfo);
5711                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5712                                 return false;
5713                         }
5714
5715                         return true;
5716                 }
5717
5718                 public bool IsAccessibleFrom (Type invocation_type)
5719                 {
5720                         bool dummy;
5721                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5722                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5723                 }
5724
5725                 public override Expression CreateExpressionTree (EmitContext ec)
5726                 {
5727                         throw new NotSupportedException ("ET");
5728                 }
5729
5730                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5731                 {
5732                         // contexts where an LValue is valid have already devolved to FieldExprs
5733                         Error_CannotAssign ();
5734                         return null;
5735                 }
5736
5737                 public override Expression DoResolve (EmitContext ec)
5738                 {
5739                         bool must_do_cs1540_check;
5740                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5741                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5742                                 Report.SymbolRelatedToPreviousError (EventInfo);
5743                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5744                                 return null;
5745                         }
5746
5747                         if (!InstanceResolve (ec, must_do_cs1540_check))
5748                                 return null;
5749
5750                         if (!ec.IsInCompoundAssignment) {
5751                                 Error_CannotAssign ();
5752                                 return null;
5753                         }
5754
5755                         if (!ec.IsInObsoleteScope) {
5756                                 EventField ev = TypeManager.GetEventField (EventInfo);
5757                                 if (ev != null) {
5758                                         ev.CheckObsoleteness (loc);
5759                                 } else {
5760                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (EventInfo);
5761                                         if (oa != null)
5762                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5763                                 }
5764                         }
5765
5766                         return this;
5767                 }
5768
5769                 public override void Emit (EmitContext ec)
5770                 {
5771                         Error_CannotAssign ();
5772                 }
5773
5774                 public void Error_CannotAssign ()
5775                 {
5776                         Report.Error (70, loc,
5777                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
5778                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
5779                 }
5780
5781                 public override string GetSignatureForError ()
5782                 {
5783                         return TypeManager.CSharpSignature (EventInfo);
5784                 }
5785
5786                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
5787                 {
5788                         ArrayList args = new ArrayList (1);
5789                         args.Add (new Argument (source, Argument.AType.Expression));
5790                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
5791                 }
5792         }
5793
5794         public class TemporaryVariable : VariableReference
5795         {
5796                 LocalInfo li;
5797
5798                 public TemporaryVariable (Type type, Location loc)
5799                 {
5800                         this.type = type;
5801                         this.loc = loc;
5802                         eclass = ExprClass.Variable;
5803                 }
5804
5805                 public override Expression CreateExpressionTree (EmitContext ec)
5806                 {
5807                         throw new NotSupportedException ("ET");
5808                 }
5809
5810                 public override Expression DoResolve (EmitContext ec)
5811                 {
5812                         if (li != null)
5813                                 return this;
5814
5815                         TypeExpr te = new TypeExpression (type, loc);
5816                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5817                         if (!li.Resolve (ec))
5818                                 return null;
5819
5820                         //
5821                         // Don't capture temporary variables except when using
5822                         // iterator redirection
5823                         //
5824                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
5825                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
5826                                 storey.CaptureLocalVariable (ec, li);
5827                         }
5828
5829                         return this;
5830                 }
5831
5832                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5833                 {
5834                         return DoResolve (ec);
5835                 }
5836
5837                 public override void Emit (EmitContext ec)
5838                 {
5839                         Emit (ec, false);
5840                 }
5841
5842                 public void EmitAssign (EmitContext ec, Expression source)
5843                 {
5844                         EmitAssign (ec, source, false, false);
5845                 }
5846
5847                 public override HoistedVariable HoistedVariable {
5848                         get { return li.HoistedVariableReference; }
5849                 }
5850
5851                 public override bool IsFixed {
5852                         get { return true; }
5853                 }
5854
5855                 public override bool IsRef {
5856                         get { return false; }
5857                 }
5858
5859                 public override string Name {
5860                         get { throw new NotImplementedException (); }
5861                 }
5862
5863                 public override void SetHasAddressTaken ()
5864                 {
5865                         throw new NotImplementedException ();
5866                 }
5867
5868                 protected override ILocalVariable Variable {
5869                         get { return li; }
5870                 }
5871
5872                 public override VariableInfo VariableInfo {
5873                         get { throw new NotImplementedException (); }
5874                 }
5875         }
5876
5877         ///
5878         /// Handles `var' contextual keyword; var becomes a keyword only
5879         /// if no type called var exists in a variable scope
5880         ///
5881         public class VarExpr : SimpleName
5882         {
5883                 // Used for error reporting only
5884                 ArrayList initializer;
5885
5886                 public VarExpr (Location loc)
5887                         : base ("var", loc)
5888                 {
5889                 }
5890
5891                 public ArrayList VariableInitializer {
5892                         set {
5893                                 this.initializer = value;
5894                         }
5895                 }
5896
5897                 public bool InferType (EmitContext ec, Expression right_side)
5898                 {
5899                         if (type != null)
5900                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5901
5902                         type = right_side.Type;
5903                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5904                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5905                                               right_side.GetSignatureForError ());
5906                                 return false;
5907                         }
5908
5909                         eclass = ExprClass.Variable;
5910                         return true;
5911                 }
5912
5913                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5914                 {
5915                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5916                 }
5917
5918                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5919                 {
5920                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5921                         if (te != null)
5922                                 return te;
5923
5924                         if (initializer == null)
5925                                 return null;
5926
5927                         if (initializer.Count > 1) {
5928                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5929                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5930                                 initializer = null;
5931                                 return null;
5932                         }
5933
5934                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5935                         if (variable_initializer == null) {
5936                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5937                                 return null;
5938                         }
5939
5940                         return null;
5941                 }
5942         }
5943 }