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 (child_generic_parameter != null)
2134                                 ec.ig.Emit (OpCodes.Box, child_generic_parameter);
2135
2136 #if GMCS_SOURCE
2137                         if (type.IsGenericParameter)
2138                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2139                         else
2140 #endif
2141                                 ec.ig.Emit (OpCodes.Castclass, type);
2142                 }
2143
2144                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2145                 {
2146                         type = storey.MutateType (type);
2147                         if (child_generic_parameter != null)
2148                                 child_generic_parameter = storey.MutateGenericArgument (child_generic_parameter);
2149
2150                         base.MutateHoistedGenericType (storey);
2151                 }
2152         }
2153
2154         //
2155         // Created during resolving pahse when an expression is wrapped or constantified
2156         // and original expression can be used later (e.g. for expression trees)
2157         //
2158         public class ReducedExpression : Expression
2159         {
2160                 sealed class ReducedConstantExpression : EmptyConstantCast
2161                 {
2162                         readonly Expression orig_expr;
2163
2164                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2165                                 : base (expr, expr.Type)
2166                         {
2167                                 this.orig_expr = orig_expr;
2168                         }
2169
2170                         public override Constant ConvertImplicitly (Type target_type)
2171                         {
2172                                 Constant c = base.ConvertImplicitly (target_type);
2173                                 if (c != null)
2174                                         c = new ReducedConstantExpression (c, orig_expr);
2175                                 return c;
2176                         }
2177
2178                         public override Expression CreateExpressionTree (EmitContext ec)
2179                         {
2180                                 return orig_expr.CreateExpressionTree (ec);
2181                         }
2182
2183                         public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
2184                         {
2185                                 //
2186                                 // Even if resolved result is a constant original expression was not
2187                                 // and attribute accepts constants only
2188                                 //
2189                                 Attribute.Error_AttributeArgumentNotValid (orig_expr.Location);
2190                                 value = null;
2191                                 return false;
2192                         }
2193
2194                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2195                         {
2196                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2197                                 if (c != null)
2198                                         c = new ReducedConstantExpression (c, orig_expr);
2199                                 return c;
2200                         }
2201                 }
2202
2203                 sealed class ReducedExpressionStatement : ExpressionStatement
2204                 {
2205                         readonly Expression orig_expr;
2206                         readonly ExpressionStatement stm;
2207
2208                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2209                         {
2210                                 this.orig_expr = orig;
2211                                 this.stm = stm;
2212                                 this.loc = orig.Location;
2213                         }
2214
2215                         public override Expression CreateExpressionTree (EmitContext ec)
2216                         {
2217                                 return orig_expr.CreateExpressionTree (ec);
2218                         }
2219
2220                         public override Expression DoResolve (EmitContext ec)
2221                         {
2222                                 eclass = stm.eclass;
2223                                 type = stm.Type;
2224                                 return this;
2225                         }
2226
2227                         public override void Emit (EmitContext ec)
2228                         {
2229                                 stm.Emit (ec);
2230                         }
2231
2232                         public override void EmitStatement (EmitContext ec)
2233                         {
2234                                 stm.EmitStatement (ec);
2235                         }
2236
2237                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2238                         {
2239                                 stm.MutateHoistedGenericType (storey);
2240                         }
2241                 }
2242
2243                 readonly Expression expr, orig_expr;
2244
2245                 private ReducedExpression (Expression expr, Expression orig_expr)
2246                 {
2247                         this.expr = expr;
2248                         this.orig_expr = orig_expr;
2249                         this.loc = orig_expr.Location;
2250                 }
2251
2252                 public static Constant Create (Constant expr, Expression original_expr)
2253                 {
2254                         return new ReducedConstantExpression (expr, original_expr);
2255                 }
2256
2257                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2258                 {
2259                         return new ReducedExpressionStatement (s, orig);
2260                 }
2261
2262                 public static Expression Create (Expression expr, Expression original_expr)
2263                 {
2264                         Constant c = expr as Constant;
2265                         if (c != null)
2266                                 return Create (c, original_expr);
2267
2268                         ExpressionStatement s = expr as ExpressionStatement;
2269                         if (s != null)
2270                                 return Create (s, original_expr);
2271
2272                         return new ReducedExpression (expr, original_expr);
2273                 }
2274
2275                 public override Expression CreateExpressionTree (EmitContext ec)
2276                 {
2277                         return orig_expr.CreateExpressionTree (ec);
2278                 }
2279
2280                 public override Expression DoResolve (EmitContext ec)
2281                 {
2282                         eclass = expr.eclass;
2283                         type = expr.Type;
2284                         return this;
2285                 }
2286
2287                 public override void Emit (EmitContext ec)
2288                 {
2289                         expr.Emit (ec);
2290                 }
2291
2292                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2293                 {
2294                         expr.EmitBranchable (ec, target, on_true);
2295                 }
2296
2297                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2298                 {
2299                         expr.MutateHoistedGenericType (storey);
2300                 }
2301         }
2302
2303         //
2304         // Unresolved type name expressions
2305         //
2306         public abstract class ATypeNameExpression : FullNamedExpression
2307         {
2308                 public readonly string Name;
2309                 protected TypeArguments targs;
2310
2311                 protected ATypeNameExpression (string name, Location l)
2312                 {
2313                         Name = name;
2314                         loc = l;
2315                 }
2316
2317                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2318                 {
2319                         Name = name;
2320                         this.targs = targs;
2321                         loc = l;
2322                 }
2323
2324                 public bool HasTypeArguments {
2325                         get {
2326                                 return targs != null;
2327                         }
2328                 }
2329
2330                 public override string GetSignatureForError ()
2331                 {
2332                         if (targs != null) {
2333                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2334                                         targs.GetSignatureForError () + ">";
2335                         }
2336
2337                         return Name;
2338                 }
2339         }
2340
2341         /// <summary>
2342         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2343         ///   of a dotted-name.
2344         /// </summary>
2345         public class SimpleName : ATypeNameExpression {
2346                 bool in_transit;
2347
2348                 public SimpleName (string name, Location l)
2349                         : base (name, l)
2350                 {
2351                 }
2352
2353                 public SimpleName (string name, TypeArguments args, Location l)
2354                         : base (name, args, l)
2355                 {
2356                 }
2357
2358                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2359                         : base (name, l)
2360                 {
2361                         targs = new TypeArguments (l);
2362                         foreach (TypeParameter type_param in type_params)
2363                                 targs.Add (new TypeParameterExpr (type_param, l));
2364                 }
2365
2366                 public static string RemoveGenericArity (string name)
2367                 {
2368                         int start = 0;
2369                         StringBuilder sb = null;
2370                         do {
2371                                 int pos = name.IndexOf ('`', start);
2372                                 if (pos < 0) {
2373                                         if (start == 0)
2374                                                 return name;
2375
2376                                         sb.Append (name.Substring (start));
2377                                         break;
2378                                 }
2379
2380                                 if (sb == null)
2381                                         sb = new StringBuilder ();
2382                                 sb.Append (name.Substring (start, pos-start));
2383
2384                                 pos++;
2385                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2386                                         pos++;
2387
2388                                 start = pos;
2389                         } while (start < name.Length);
2390
2391                         return sb.ToString ();
2392                 }
2393
2394                 public SimpleName GetMethodGroup ()
2395                 {
2396                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2397                 }
2398
2399                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2400                 {
2401                         if (ec.IsInFieldInitializer)
2402                                 Report.Error (236, l,
2403                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2404                                         name);
2405                         else
2406                                 Report.Error (120, l,
2407                                         "An object reference is required to access non-static member `{0}'",
2408                                         name);
2409                 }
2410
2411                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2412                 {
2413                         return resolved_to != null && resolved_to.Type != null &&
2414                                 resolved_to.Type.Name == Name &&
2415                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2416                 }
2417
2418                 public override Expression DoResolve (EmitContext ec)
2419                 {
2420                         return SimpleNameResolve (ec, null, false);
2421                 }
2422
2423                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2424                 {
2425                         return SimpleNameResolve (ec, right_side, false);
2426                 }
2427
2428
2429                 public Expression DoResolve (EmitContext ec, bool intermediate)
2430                 {
2431                         return SimpleNameResolve (ec, null, intermediate);
2432                 }
2433
2434                 static bool IsNestedChild (Type t, Type parent)
2435                 {
2436                         while (parent != null) {
2437                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2438                                         return true;
2439
2440                                 parent = parent.BaseType;
2441                         }
2442
2443                         return false;
2444                 }
2445
2446                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2447                 {
2448                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2449                                 return null;
2450
2451                         DeclSpace ds = ec.DeclContainer;
2452                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2453                                 ds = ds.Parent;
2454
2455                         if (ds == null)
2456                                 return null;
2457
2458                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2459
2460                         int arg_count = targs != null ? targs.Count : 0;
2461
2462                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2463                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2464                                         TypeArguments new_args = new TypeArguments (loc);
2465                                         foreach (TypeParameter param in ds.TypeParameters)
2466                                                 new_args.Add (new TypeParameterExpr (param, loc));
2467
2468                                         if (targs != null)
2469                                                 new_args.Add (targs);
2470
2471                                         return new GenericTypeExpr (t, new_args, loc);
2472                                 }
2473                         }
2474
2475                         return null;
2476                 }
2477
2478                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2479                 {
2480                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2481                         if (fne != null)
2482                                 return fne.ResolveAsTypeStep (ec, silent);
2483
2484                         int errors = Report.Errors;
2485                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2486
2487                         if (fne != null) {
2488                                 if (fne.Type == null)
2489                                         return fne;
2490
2491                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2492                                 if (nested != null)
2493                                         return nested.ResolveAsTypeStep (ec, false);
2494
2495                                 if (targs != null) {
2496                                         GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2497                                         return ct.ResolveAsTypeStep (ec, false);
2498                                 }
2499
2500                                 return fne;
2501                         }
2502
2503                         if (silent || errors != Report.Errors)
2504                                 return null;
2505
2506                         Error_TypeOrNamespaceNotFound (ec);
2507                         return null;
2508                 }
2509
2510                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2511                 {
2512                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2513                         if (mc != null) {
2514                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2515                                 return;
2516                         }
2517
2518                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2519                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2520                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2521                                 Type type = a.GetType (fullname);
2522                                 if (type != null) {
2523                                         Report.SymbolRelatedToPreviousError (type);
2524                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2525                                         return;
2526                                 }
2527                         }
2528
2529                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2530                         if (t != null) {
2531                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2532                                 return;
2533                         }
2534
2535                         if (targs != null) {
2536                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2537                                 if (retval != null) {
2538                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval, loc);
2539                                         return;
2540                                 }
2541                         }
2542
2543                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2544                 }
2545
2546                 // TODO: I am still not convinced about this. If someone else will need it
2547                 // implement this as virtual property in MemberCore hierarchy
2548                 public static string GetMemberType (MemberCore mc)
2549                 {
2550                         if (mc is Property)
2551                                 return "property";
2552                         if (mc is Indexer)
2553                                 return "indexer";
2554                         if (mc is FieldBase)
2555                                 return "field";
2556                         if (mc is MethodCore)
2557                                 return "method";
2558                         if (mc is EnumMember)
2559                                 return "enum";
2560                         if (mc is Event)
2561                                 return "event";
2562
2563                         return "type";
2564                 }
2565
2566                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2567                 {
2568                         if (in_transit)
2569                                 return null;
2570
2571                         in_transit = true;
2572                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2573                         in_transit = false;
2574
2575                         if (e == null)
2576                                 return null;
2577
2578                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2579                                 return e;
2580
2581                         return null;
2582                 }
2583
2584                 /// <remarks>
2585                 ///   7.5.2: Simple Names.
2586                 ///
2587                 ///   Local Variables and Parameters are handled at
2588                 ///   parse time, so they never occur as SimpleNames.
2589                 ///
2590                 ///   The `intermediate' flag is used by MemberAccess only
2591                 ///   and it is used to inform us that it is ok for us to
2592                 ///   avoid the static check, because MemberAccess might end
2593                 ///   up resolving the Name as a Type name and the access as
2594                 ///   a static type access.
2595                 ///
2596                 ///   ie: Type Type; .... { Type.GetType (""); }
2597                 ///
2598                 ///   Type is both an instance variable and a Type;  Type.GetType
2599                 ///   is the static method not an instance method of type.
2600                 /// </remarks>
2601                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2602                 {
2603                         Expression e = null;
2604
2605                         //
2606                         // Stage 1: Performed by the parser (binding to locals or parameters).
2607                         //
2608                         Block current_block = ec.CurrentBlock;
2609                         if (current_block != null){
2610                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2611                                 if (vi != null){
2612                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2613                                         if (right_side != null) {
2614                                                 return var.ResolveLValue (ec, right_side, loc);
2615                                         } else {
2616                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2617                                                 if (intermediate)
2618                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2619                                                 return var.Resolve (ec, rf);
2620                                         }
2621                                 }
2622
2623                                 Expression expr = current_block.Toplevel.GetParameterReference (Name, loc);
2624                                 if (expr == null)
2625                                         expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2626
2627                                 if (expr != null) {
2628                                         if (right_side != null)
2629                                                 return expr.ResolveLValue (ec, right_side, loc);
2630
2631                                         return expr.Resolve (ec);
2632                                 }
2633                         }
2634
2635                         //
2636                         // Stage 2: Lookup members
2637                         //
2638
2639                         Type almost_matched_type = null;
2640                         ArrayList almost_matched = null;
2641                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2642                                 // either RootDeclSpace or GenericMethod
2643                                 if (lookup_ds.TypeBuilder == null)
2644                                         continue;
2645
2646                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2647                                 if (e != null) {
2648                                         PropertyExpr pe = e as PropertyExpr;
2649                                         if (pe != null) {
2650                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2651
2652                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2653                                                 // it doesn't know which accessor to check permissions against
2654                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.ContainerType, right_side != null))
2655                                                         break;
2656                                         } else if (e is EventExpr) {
2657                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2658                                                         break;
2659                                         } else {
2660                                                 break;
2661                                         }
2662                                         e = null;
2663                                 }
2664
2665                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2666                                         almost_matched_type = lookup_ds.TypeBuilder;
2667                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2668                                 }
2669                         }
2670
2671                         if (e == null) {
2672                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2673                                         almost_matched_type = ec.ContainerType;
2674                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2675                                 }
2676                                 e = ResolveAsTypeStep (ec, true);
2677                         }
2678
2679                         if (e == null) {
2680                                 if (current_block != null) {
2681                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2682                                         if (ikv != null) {
2683                                                 LocalInfo li = ikv as LocalInfo;
2684                                                 // Supress CS0219 warning
2685                                                 if (li != null)
2686                                                         li.Used = true;
2687
2688                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2689                                                 return null;
2690                                         }
2691                                 }
2692
2693                                 if (RootContext.EvalMode){
2694                                         FieldInfo fi = Evaluator.LookupField (Name);
2695                                         if (fi != null)
2696                                                 return new FieldExpr (fi, loc).Resolve (ec);
2697                                 }
2698
2699                                 if (almost_matched != null)
2700                                         almost_matched_members = almost_matched;
2701                                 if (almost_matched_type == null)
2702                                         almost_matched_type = ec.ContainerType;
2703                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2704                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2705                                 return null;
2706                         }
2707
2708                         if (e is TypeExpr) {
2709                                 if (targs == null)
2710                                         return e;
2711
2712                                 GenericTypeExpr ct = new GenericTypeExpr (
2713                                         e.Type, targs, loc);
2714                                 return ct.ResolveAsTypeStep (ec, false);
2715                         }
2716
2717                         if (e is MemberExpr) {
2718                                 MemberExpr me = (MemberExpr) e;
2719
2720                                 Expression left;
2721                                 if (me.IsInstance) {
2722                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2723                                                 //
2724                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2725                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2726                                                 // and each predicate is true if the MethodGroupExpr contains
2727                                                 // at least one of that kind of method.
2728                                                 //
2729
2730                                                 if (!me.IsStatic &&
2731                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2732                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2733                                                         return null;
2734                                                 }
2735
2736                                                 //
2737                                                 // Pass the buck to MemberAccess and Invocation.
2738                                                 //
2739                                                 left = EmptyExpression.Null;
2740                                         } else {
2741                                                 left = ec.GetThis (loc);
2742                                         }
2743                                 } else {
2744                                         left = new TypeExpression (ec.ContainerType, loc);
2745                                 }
2746
2747                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2748                                 if (me == null)
2749                                         return null;
2750
2751                                 if (targs != null) {
2752                                         targs.Resolve (ec);
2753                                         me.SetTypeArguments (targs);
2754                                 }
2755
2756                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2757                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2758                                     me.InstanceExpression.Type != me.DeclaringType &&
2759                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2760                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2761                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2762                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2763                                         return null;
2764                                 }
2765
2766                                 return (right_side != null)
2767                                         ? me.DoResolveLValue (ec, right_side)
2768                                         : me.DoResolve (ec);
2769                         }
2770
2771                         return e;
2772                 }
2773         }
2774
2775         /// <summary>
2776         ///   Represents a namespace or a type.  The name of the class was inspired by
2777         ///   section 10.8.1 (Fully Qualified Names).
2778         /// </summary>
2779         public abstract class FullNamedExpression : Expression
2780         {
2781                 protected override void CloneTo (CloneContext clonectx, Expression target)
2782                 {
2783                         // Do nothing, most unresolved type expressions cannot be
2784                         // resolved to different type
2785                 }
2786
2787                 public override Expression CreateExpressionTree (EmitContext ec)
2788                 {
2789                         throw new NotSupportedException ("ET");
2790                 }
2791
2792                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2793                 {
2794                         throw new NotSupportedException ();
2795                 }
2796
2797                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2798                 {
2799                         return this;
2800                 }
2801
2802                 public override void Emit (EmitContext ec)
2803                 {
2804                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2805                                 GetSignatureForError ());
2806                 }
2807         }
2808
2809         /// <summary>
2810         ///   Expression that evaluates to a type
2811         /// </summary>
2812         public abstract class TypeExpr : FullNamedExpression {
2813                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2814                 {
2815                         TypeExpr t = DoResolveAsTypeStep (ec);
2816                         if (t == null)
2817                                 return null;
2818
2819                         eclass = ExprClass.Type;
2820                         return t;
2821                 }
2822
2823                 override public Expression DoResolve (EmitContext ec)
2824                 {
2825                         return ResolveAsTypeTerminal (ec, false);
2826                 }
2827
2828                 public virtual bool CheckAccessLevel (DeclSpace ds)
2829                 {
2830                         return ds.CheckAccessLevel (Type);
2831                 }
2832
2833                 public virtual bool AsAccessible (DeclSpace ds)
2834                 {
2835                         return ds.IsAccessibleAs (Type);
2836                 }
2837
2838                 public virtual bool IsClass {
2839                         get { return Type.IsClass; }
2840                 }
2841
2842                 public virtual bool IsValueType {
2843                         get { return Type.IsValueType; }
2844                 }
2845
2846                 public virtual bool IsInterface {
2847                         get { return Type.IsInterface; }
2848                 }
2849
2850                 public virtual bool IsSealed {
2851                         get { return Type.IsSealed; }
2852                 }
2853
2854                 public virtual bool CanInheritFrom ()
2855                 {
2856                         if (Type == TypeManager.enum_type ||
2857                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2858                             Type == TypeManager.multicast_delegate_type ||
2859                             Type == TypeManager.delegate_type ||
2860                             Type == TypeManager.array_type)
2861                                 return false;
2862
2863                         return true;
2864                 }
2865
2866                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2867
2868                 public override bool Equals (object obj)
2869                 {
2870                         TypeExpr tobj = obj as TypeExpr;
2871                         if (tobj == null)
2872                                 return false;
2873
2874                         return Type == tobj.Type;
2875                 }
2876
2877                 public override int GetHashCode ()
2878                 {
2879                         return Type.GetHashCode ();
2880                 }
2881
2882                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2883                 {
2884                         type = storey.MutateType (type);
2885                 }
2886         }
2887
2888         /// <summary>
2889         ///   Fully resolved Expression that already evaluated to a type
2890         /// </summary>
2891         public class TypeExpression : TypeExpr {
2892                 public TypeExpression (Type t, Location l)
2893                 {
2894                         Type = t;
2895                         eclass = ExprClass.Type;
2896                         loc = l;
2897                 }
2898
2899                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2900                 {
2901                         return this;
2902                 }
2903
2904                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2905                 {
2906                         return this;
2907                 }
2908         }
2909
2910         /// <summary>
2911         ///   Used to create types from a fully qualified name.  These are just used
2912         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2913         ///   classified as a type.
2914         /// </summary>
2915         public sealed class TypeLookupExpression : TypeExpr {
2916                 readonly string name;
2917
2918                 public TypeLookupExpression (string name)
2919                 {
2920                         this.name = name;
2921                         eclass = ExprClass.Type;
2922                 }
2923
2924                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2925                 {
2926                         // It's null for corlib compilation only
2927                         if (type == null)
2928                                 return DoResolveAsTypeStep (ec);
2929
2930                         return this;
2931                 }
2932
2933                 private class UnexpectedType
2934                 {
2935                 }
2936
2937                 // This performes recursive type lookup, providing support for generic types.
2938                 // For example, given the type:
2939                 //
2940                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2941                 //
2942                 // The types will be checked in the following order:
2943                 //                                                                             _
2944                 // System                                                                       |
2945                 // System.Collections                                                           |
2946                 // System.Collections.Generic                                                   |
2947                 //                        _                                                     |
2948                 //     System              | recursive call 1                                   |
2949                 //     System.Int32       _|                                                    | main method call
2950                 //                        _                                                     |
2951                 //     System              | recursive call 2                                   |
2952                 //     System.String      _|                                                    |
2953                 //                                                                              |
2954                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2955                 //
2956                 private Type TypeLookup (IResolveContext ec, string name)
2957                 {
2958                         int index = 0;
2959                         int dot = 0;
2960                         bool done = false;
2961                         FullNamedExpression resolved = null;
2962                         Type type = null;
2963                         Type recursive_type = null;
2964                         while (index < name.Length) {
2965                                 if (name[index] == '[') {
2966                                         int open = index;
2967                                         int braces = 1;
2968                                         do {
2969                                                 index++;
2970                                                 if (name[index] == '[')
2971                                                         braces++;
2972                                                 else if (name[index] == ']')
2973                                                         braces--;
2974                                         } while (braces > 0);
2975                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2976                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2977                                                 return recursive_type;
2978                                 }
2979                                 else {
2980                                         if (name[index] == ',')
2981                                                 done = true;
2982                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2983                                                 string substring = name.Substring(dot, index - dot);
2984
2985                                                 if (resolved == null)
2986                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2987                                                 else if (resolved is Namespace)
2988                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2989                                                 else if (type != null)
2990                                                         type = TypeManager.GetNestedType (type, substring);
2991                                                 else
2992                                                         return null;
2993
2994                                                 if (resolved == null)
2995                                                         return null;
2996                                                 else if (type == null && resolved is TypeExpr)
2997                                                         type = resolved.Type;
2998
2999                                                 dot = index + 1;
3000                                         }
3001                                 }
3002                                 index++;
3003                         }
3004                         if (name[0] != '[') {
3005                                 string substring = name.Substring(dot, index - dot);
3006
3007                                 if (type != null)
3008                                         return TypeManager.GetNestedType (type, substring);
3009
3010                                 if (resolved != null) {
3011                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
3012                                         if (resolved is TypeExpr)
3013                                                 return resolved.Type;
3014
3015                                         if (resolved == null)
3016                                                 return null;
3017
3018                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
3019                                         return typeof (UnexpectedType);
3020                                 }
3021                                 else
3022                                         return null;
3023                         }
3024                         else
3025                                 return recursive_type;
3026                         }
3027
3028                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3029                 {
3030                         Type t = TypeLookup (ec, name);
3031                         if (t == null) {
3032                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
3033                                 return null;
3034                         }
3035                         if (t == typeof(UnexpectedType))
3036                                 return null;
3037                         type = t;
3038                         return this;
3039                 }
3040
3041                 public override string GetSignatureForError ()
3042                 {
3043                         if (type == null)
3044                                 return TypeManager.CSharpName (name, null);
3045
3046                         return base.GetSignatureForError ();
3047                 }
3048         }
3049
3050         /// <summary>
3051         ///   This class denotes an expression which evaluates to a member
3052         ///   of a struct or a class.
3053         /// </summary>
3054         public abstract class MemberExpr : Expression
3055         {
3056                 protected bool is_base;
3057
3058                 /// <summary>
3059                 ///   The name of this member.
3060                 /// </summary>
3061                 public abstract string Name {
3062                         get;
3063                 }
3064
3065                 //
3066                 // When base.member is used
3067                 //
3068                 public bool IsBase {
3069                         get { return is_base; }
3070                         set { is_base = value; }
3071                 }
3072
3073                 /// <summary>
3074                 ///   Whether this is an instance member.
3075                 /// </summary>
3076                 public abstract bool IsInstance {
3077                         get;
3078                 }
3079
3080                 /// <summary>
3081                 ///   Whether this is a static member.
3082                 /// </summary>
3083                 public abstract bool IsStatic {
3084                         get;
3085                 }
3086
3087                 /// <summary>
3088                 ///   The type which declares this member.
3089                 /// </summary>
3090                 public abstract Type DeclaringType {
3091                         get;
3092                 }
3093
3094                 /// <summary>
3095                 ///   The instance expression associated with this member, if it's a
3096                 ///   non-static member.
3097                 /// </summary>
3098                 public Expression InstanceExpression;
3099
3100                 public static void error176 (Location loc, string name)
3101                 {
3102                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3103                                       "with an instance reference, qualify it with a type name instead", name);
3104                 }
3105
3106                 public static void Error_BaseAccessInExpressionTree (Location loc)
3107                 {
3108                         Report.Error (831, loc, "An expression tree may not contain a base access");
3109                 }
3110
3111                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3112                 {
3113                         if (InstanceExpression != null)
3114                                 InstanceExpression.MutateHoistedGenericType (storey);
3115                 }
3116
3117                 // TODO: possible optimalization
3118                 // Cache resolved constant result in FieldBuilder <-> expression map
3119                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3120                                                                SimpleName original)
3121                 {
3122                         //
3123                         // Precondition:
3124                         //   original == null || original.Resolve (...) ==> left
3125                         //
3126
3127                         if (left is TypeExpr) {
3128                                 left = left.ResolveAsBaseTerminal (ec, false);
3129                                 if (left == null)
3130                                         return null;
3131
3132                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3133                                 // always do all necessary checks
3134                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3135                                 if (oa != null && !ec.IsInObsoleteScope) {
3136                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc);
3137                                 }
3138
3139                                 GenericTypeExpr ct = left as GenericTypeExpr;
3140                                 if (ct != null && !ct.CheckConstraints (ec))
3141                                         return null;
3142                                 //
3143
3144                                 if (!IsStatic) {
3145                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3146                                         return null;
3147                                 }
3148
3149                                 return this;
3150                         }
3151
3152                         if (!IsInstance) {
3153                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3154                                         return this;
3155
3156                                 return ResolveExtensionMemberAccess (left);
3157                         }
3158
3159                         InstanceExpression = left;
3160                         return this;
3161                 }
3162
3163                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3164                 {
3165                         error176 (loc, GetSignatureForError ());
3166                         return this;
3167                 }
3168
3169                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3170                 {
3171                         if (IsStatic)
3172                                 return;
3173
3174                         if (InstanceExpression == EmptyExpression.Null) {
3175                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3176                                 return;
3177                         }
3178
3179                         if (InstanceExpression.Type.IsValueType) {
3180                                 if (InstanceExpression is IMemoryLocation) {
3181                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3182                                 } else {
3183                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3184                                         InstanceExpression.Emit (ec);
3185                                         t.Store (ec);
3186                                         t.AddressOf (ec, AddressOp.Store);
3187                                 }
3188                         } else
3189                                 InstanceExpression.Emit (ec);
3190
3191                         if (prepare_for_load)
3192                                 ec.ig.Emit (OpCodes.Dup);
3193                 }
3194
3195                 public virtual void SetTypeArguments (TypeArguments ta)
3196                 {
3197                         // TODO: need to get correct member type
3198                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3199                                 GetSignatureForError ());
3200                 }
3201         }
3202
3203         ///
3204         /// Represents group of extension methods
3205         ///
3206         public class ExtensionMethodGroupExpr : MethodGroupExpr
3207         {
3208                 readonly NamespaceEntry namespace_entry;
3209                 public Expression ExtensionExpression;
3210                 Argument extension_argument;
3211
3212                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3213                         : base (list, extensionType, l)
3214                 {
3215                         this.namespace_entry = n;
3216                 }
3217
3218                 public override bool IsStatic {
3219                         get { return true; }
3220                 }
3221
3222                 public bool IsTopLevel {
3223                         get { return namespace_entry == null; }
3224                 }
3225
3226                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3227                 {
3228                         if (arguments == null)
3229                                 arguments = new ArrayList (1);
3230                         arguments.Insert (0, extension_argument);
3231                         base.EmitArguments (ec, arguments);
3232                 }
3233
3234                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3235                 {
3236                         if (arguments == null)
3237                                 arguments = new ArrayList (1);
3238                         arguments.Insert (0, extension_argument);
3239                         base.EmitCall (ec, arguments);
3240                 }
3241
3242                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3243                 {
3244                         extension_argument.Expr.MutateHoistedGenericType (storey);
3245                         base.MutateHoistedGenericType (storey);
3246                 }
3247
3248                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3249                 {
3250                         if (arguments == null)
3251                                 arguments = new ArrayList (1);
3252
3253                         arguments.Insert (0, new Argument (ExtensionExpression));
3254                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3255
3256                         // Store resolved argument and restore original arguments
3257                         if (mg != null)
3258                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3259                         arguments.RemoveAt (0);
3260
3261                         return mg;
3262                 }
3263
3264                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3265                 {
3266                         // Use normal resolve rules
3267                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3268                         if (mg != null)
3269                                 return mg;
3270
3271                         if (ns == null)
3272                                 return null;
3273
3274                         // Search continues
3275                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3276                         if (e == null)
3277                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3278
3279                         e.ExtensionExpression = ExtensionExpression;
3280                         e.SetTypeArguments (type_arguments);
3281                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3282                 }
3283         }
3284
3285         /// <summary>
3286         ///   MethodGroupExpr represents a group of method candidates which
3287         ///   can be resolved to the best method overload
3288         /// </summary>
3289         public class MethodGroupExpr : MemberExpr
3290         {
3291                 public interface IErrorHandler
3292                 {
3293                         bool NoExactMatch (EmitContext ec, MethodBase method);
3294                 }
3295
3296                 public IErrorHandler CustomErrorHandler;
3297                 public MethodBase [] Methods;
3298                 MethodBase best_candidate;
3299                 // TODO: make private
3300                 public TypeArguments type_arguments;
3301                 bool identical_type_name;
3302                 bool has_inaccessible_candidates_only;
3303                 Type delegate_type;
3304
3305                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3306                         : this (type, l)
3307                 {
3308                         Methods = new MethodBase [mi.Length];
3309                         mi.CopyTo (Methods, 0);
3310                 }
3311
3312                 public MethodGroupExpr (MemberInfo[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3313                         : this (mi, type, l)
3314                 {
3315                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3316                 }
3317
3318                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3319                         : this (type, l)
3320                 {
3321                         try {
3322                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3323                         } catch {
3324                                 foreach (MemberInfo m in list){
3325                                         if (!(m is MethodBase)){
3326                                                 Console.WriteLine ("Name " + m.Name);
3327                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3328                                         }
3329                                 }
3330                                 throw;
3331                         }
3332
3333
3334                 }
3335
3336                 protected MethodGroupExpr (Type type, Location loc)
3337                 {
3338                         this.loc = loc;
3339                         eclass = ExprClass.MethodGroup;
3340                         this.type = type;
3341                 }
3342
3343                 public override Type DeclaringType {
3344                         get {
3345                                 //
3346                                 // We assume that the top-level type is in the end
3347                                 //
3348                                 return Methods [Methods.Length - 1].DeclaringType;
3349                                 //return Methods [0].DeclaringType;
3350                         }
3351                 }
3352
3353                 public Type DelegateType {
3354                         set {
3355                                 delegate_type = value;
3356                         }
3357                 }
3358
3359                 public bool IdenticalTypeName {
3360                         get {
3361                                 return identical_type_name;
3362                         }
3363                 }
3364
3365                 public override string GetSignatureForError ()
3366                 {
3367                         if (best_candidate != null)
3368                                 return TypeManager.CSharpSignature (best_candidate);
3369
3370                         return TypeManager.CSharpSignature (Methods [0]);
3371                 }
3372
3373                 public override string Name {
3374                         get {
3375                                 return Methods [0].Name;
3376                         }
3377                 }
3378
3379                 public override bool IsInstance {
3380                         get {
3381                                 if (best_candidate != null)
3382                                         return !best_candidate.IsStatic;
3383
3384                                 foreach (MethodBase mb in Methods)
3385                                         if (!mb.IsStatic)
3386                                                 return true;
3387
3388                                 return false;
3389                         }
3390                 }
3391
3392                 public override bool IsStatic {
3393                         get {
3394                                 if (best_candidate != null)
3395                                         return best_candidate.IsStatic;
3396
3397                                 foreach (MethodBase mb in Methods)
3398                                         if (mb.IsStatic)
3399                                                 return true;
3400
3401                                 return false;
3402                         }
3403                 }
3404
3405                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3406                 {
3407                         return (ConstructorInfo)mg.best_candidate;
3408                 }
3409
3410                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3411                 {
3412                         return (MethodInfo)mg.best_candidate;
3413                 }
3414
3415                 //
3416                 //  7.4.3.3  Better conversion from expression
3417                 //  Returns :   1    if a->p is better,
3418                 //              2    if a->q is better,
3419                 //              0 if neither is better
3420                 //
3421                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3422                 {
3423                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3424                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3425                                 //
3426                                 // Uwrap delegate from Expression<T>
3427                                 //
3428                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3429                                         p = TypeManager.GetTypeArguments (p) [0];
3430                                 }
3431                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3432                                         q = TypeManager.GetTypeArguments (q) [0];
3433                                 }
3434
3435                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3436                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3437                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3438                                         return 2;
3439                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3440                                         return 1;
3441                         } else {
3442                                 if (argument_type == p)
3443                                         return 1;
3444
3445                                 if (argument_type == q)
3446                                         return 2;
3447                         }
3448
3449                         return BetterTypeConversion (ec, p, q);
3450                 }
3451
3452                 //
3453                 // 7.4.3.4  Better conversion from type
3454                 //
3455                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3456                 {
3457                         if (p == null || q == null)
3458                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3459
3460                         if (p == TypeManager.int32_type) {
3461                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3462                                         return 1;
3463                         } else if (p == TypeManager.int64_type) {
3464                                 if (q == TypeManager.uint64_type)
3465                                         return 1;
3466                         } else if (p == TypeManager.sbyte_type) {
3467                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3468                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3469                                         return 1;
3470                         } else if (p == TypeManager.short_type) {
3471                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3472                                         q == TypeManager.uint64_type)
3473                                         return 1;
3474                         }
3475
3476                         if (q == TypeManager.int32_type) {
3477                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3478                                         return 2;
3479                         } if (q == TypeManager.int64_type) {
3480                                 if (p == TypeManager.uint64_type)
3481                                         return 2;
3482                         } else if (q == TypeManager.sbyte_type) {
3483                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3484                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3485                                         return 2;
3486                         } if (q == TypeManager.short_type) {
3487                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3488                                         p == TypeManager.uint64_type)
3489                                         return 2;
3490                         }
3491
3492                         // TODO: this is expensive
3493                         Expression p_tmp = new EmptyExpression (p);
3494                         Expression q_tmp = new EmptyExpression (q);
3495
3496                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3497                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3498
3499                         if (p_to_q && !q_to_p)
3500                                 return 1;
3501
3502                         if (q_to_p && !p_to_q)
3503                                 return 2;
3504
3505                         return 0;
3506                 }
3507
3508                 /// <summary>
3509                 ///   Determines "Better function" between candidate
3510                 ///   and the current best match
3511                 /// </summary>
3512                 /// <remarks>
3513                 ///    Returns a boolean indicating :
3514                 ///     false if candidate ain't better
3515                 ///     true  if candidate is better than the current best match
3516                 /// </remarks>
3517                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3518                         MethodBase candidate, bool candidate_params,
3519                         MethodBase best, bool best_params)
3520                 {
3521                         AParametersCollection candidate_pd = TypeManager.GetParameterData (candidate);
3522                         AParametersCollection best_pd = TypeManager.GetParameterData (best);
3523
3524                         bool better_at_least_one = false;
3525                         bool same = true;
3526                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3527                         {
3528                                 Argument a = (Argument) args [j];
3529
3530                                 Type ct = candidate_pd.Types [c_idx];
3531                                 Type bt = best_pd.Types [b_idx];
3532
3533                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3534                                 {
3535                                         ct = TypeManager.GetElementType (ct);
3536                                         --c_idx;
3537                                 }
3538
3539                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3540                                 {
3541                                         bt = TypeManager.GetElementType (bt);
3542                                         --b_idx;
3543                                 }
3544
3545                                 if (ct.Equals (bt))
3546                                         continue;
3547
3548                                 same = false;
3549                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3550
3551                                 // for each argument, the conversion to 'ct' should be no worse than
3552                                 // the conversion to 'bt'.
3553                                 if (result == 2)
3554                                         return false;
3555
3556                                 // for at least one argument, the conversion to 'ct' should be better than
3557                                 // the conversion to 'bt'.
3558                                 if (result != 0)
3559                                         better_at_least_one = true;
3560                         }
3561
3562                         if (better_at_least_one)
3563                                 return true;
3564
3565                         //
3566                         // This handles the case
3567                         //
3568                         //   Add (float f1, float f2, float f3);
3569                         //   Add (params decimal [] foo);
3570                         //
3571                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3572                         // first candidate would've chosen as better.
3573                         //
3574                         if (!same)
3575                                 return false;
3576
3577                         //
3578                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3579                         //
3580                         if (TypeManager.IsGenericMethod (best)) {
3581                                 if (!TypeManager.IsGenericMethod (candidate))
3582                                         return true;
3583                         } else if (TypeManager.IsGenericMethod (candidate)) {
3584                                 return false;
3585                         }
3586
3587                         //
3588                         // This handles the following cases:
3589                         //
3590                         //   Trim () is better than Trim (params char[] chars)
3591                         //   Concat (string s1, string s2, string s3) is better than
3592                         //     Concat (string s1, params string [] srest)
3593                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3594                         //
3595                         if (!candidate_params && best_params)
3596                                 return true;
3597                         if (candidate_params && !best_params)
3598                                 return false;
3599
3600                         int candidate_param_count = candidate_pd.Count;
3601                         int best_param_count = best_pd.Count;
3602
3603                         if (candidate_param_count != best_param_count)
3604                                 // can only happen if (candidate_params && best_params)
3605                                 return candidate_param_count > best_param_count;
3606
3607                         //
3608                         // now, both methods have the same number of parameters, and the parameters have the same types
3609                         // Pick the "more specific" signature
3610                         //
3611
3612                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3613                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3614
3615                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3616                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3617
3618                         bool specific_at_least_once = false;
3619                         for (int j = 0; j < candidate_param_count; ++j)
3620                         {
3621                                 Type ct = orig_candidate_pd.Types [j];
3622                                 Type bt = orig_best_pd.Types [j];
3623                                 if (ct.Equals (bt))
3624                                         continue;
3625                                 Type specific = MoreSpecific (ct, bt);
3626                                 if (specific == bt)
3627                                         return false;
3628                                 if (specific == ct)
3629                                         specific_at_least_once = true;
3630                         }
3631
3632                         if (specific_at_least_once)
3633                                 return true;
3634
3635                         // FIXME: handle lifted operators
3636                         // ...
3637
3638                         return false;
3639                 }
3640
3641                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3642                 {
3643                         if (!IsStatic)
3644                                 return base.ResolveExtensionMemberAccess (left);
3645
3646                         //
3647                         // When left side is an expression and at least one candidate method is
3648                         // static, it can be extension method
3649                         //
3650                         InstanceExpression = left;
3651                         return this;
3652                 }
3653
3654                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3655                                                                 SimpleName original)
3656                 {
3657                         if (!(left is TypeExpr) &&
3658                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3659                                 identical_type_name = true;
3660
3661                         return base.ResolveMemberAccess (ec, left, loc, original);
3662                 }
3663
3664                 public override Expression CreateExpressionTree (EmitContext ec)
3665                 {
3666                         if (best_candidate == null) {
3667                                 Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3668                                 return null;
3669                         }
3670
3671                         if (best_candidate.IsConstructor)
3672                                 return new TypeOfConstructorInfo (best_candidate, loc);
3673
3674                         IMethodData md = TypeManager.GetMethod (best_candidate);
3675                         if (md != null && md.IsExcluded ())
3676                                 Report.Error (765, loc,
3677                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3678
3679                         return new TypeOfMethodInfo (best_candidate, loc);
3680                 }
3681
3682                 override public Expression DoResolve (EmitContext ec)
3683                 {
3684                         if (InstanceExpression != null) {
3685                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3686                                 if (InstanceExpression == null)
3687                                         return null;
3688                         }
3689
3690                         return this;
3691                 }
3692
3693                 public void ReportUsageError ()
3694                 {
3695                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3696                                       Name + "()' is referenced without parentheses");
3697                 }
3698
3699                 override public void Emit (EmitContext ec)
3700                 {
3701                         ReportUsageError ();
3702                 }
3703
3704                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3705                 {
3706                         Invocation.EmitArguments (ec, arguments, false, null);
3707                 }
3708
3709                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3710                 {
3711                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3712                 }
3713
3714                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3715                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3716                 {
3717                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3718
3719                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3720                                 Report.SymbolRelatedToPreviousError (method);
3721                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3722                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3723                                                 TypeManager.CSharpSignature (method));
3724                                         return;
3725                                 }
3726                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3727                                           TypeManager.CSharpSignature (method));
3728                         } else if (delegate_type == null) {
3729                                 Report.SymbolRelatedToPreviousError (method);
3730                                 if (emg != null) {
3731                                         Report.Error (1928, loc,
3732                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3733                                                 emg.ExtensionExpression.GetSignatureForError (),
3734                                                 emg.Name, TypeManager.CSharpSignature (method));
3735                                 } else {
3736                                         Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3737                                                 TypeManager.CSharpSignature (method));
3738                                 }
3739                         } else
3740                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3741                                         TypeManager.CSharpName (delegate_type));
3742
3743                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3744
3745                         string index = (idx + 1).ToString ();
3746                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3747                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3748                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3749                                         Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3750                                                 index, Parameter.GetModifierSignature (a.Modifier));
3751                                 else
3752                                         Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3753                                                 index, Parameter.GetModifierSignature (mod));
3754                         } else {
3755                                 string p1 = a.GetSignatureForError ();
3756                                 string p2 = TypeManager.CSharpName (paramType);
3757
3758                                 if (p1 == p2) {
3759                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3760                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3761                                         Report.SymbolRelatedToPreviousError (paramType);
3762                                 }
3763
3764                                 if (idx == 0 && emg != null) {
3765                                         Report.Error (1929, loc,
3766                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3767                                 } else {
3768                                         Report.Error (1503, loc,
3769                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3770                                 }
3771                         }
3772                 }
3773
3774                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3775                 {
3776                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3777                                 Name, TypeManager.CSharpName (target));
3778                 }
3779
3780                 protected virtual int GetApplicableParametersCount (MethodBase method, AParametersCollection parameters)
3781                 {
3782                         return parameters.Count;
3783                 }
3784
3785                 public static bool IsAncestralType (Type first_type, Type second_type)
3786                 {
3787                         return first_type != second_type &&
3788                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3789                                 TypeManager.ImplementsInterface (second_type, first_type));
3790                 }
3791
3792                 ///
3793                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3794                 /// to the given set of arguments
3795                 /// A return value rates candidate method compatibility,
3796                 /// 0 = the best, int.MaxValue = the worst
3797                 ///
3798                 public int IsApplicable (EmitContext ec,
3799                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3800                 {
3801                         MethodBase candidate = method;
3802
3803                         AParametersCollection pd = TypeManager.GetParameterData (candidate);
3804                         int param_count = GetApplicableParametersCount (candidate, pd);
3805
3806                         if (arg_count != param_count) {
3807                                 if (!pd.HasParams)
3808                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3809                                 if (arg_count < param_count - 1)
3810                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3811
3812                                 // Initialize expanded form of a method with 1 params parameter
3813                                 params_expanded_form = param_count == 1 && pd.HasParams;
3814                         }
3815
3816 #if GMCS_SOURCE
3817                         //
3818                         // 1. Handle generic method using type arguments when specified or type inference
3819                         //
3820                         if (TypeManager.IsGenericMethod (candidate)) {
3821                                 if (type_arguments != null) {
3822                                         Type [] g_args = candidate.GetGenericArguments ();
3823                                         if (g_args.Length != type_arguments.Count)
3824                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3825
3826                                         // TODO: Don't create new method, create Parameters only
3827                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3828                                         candidate = method;
3829                                         pd = TypeManager.GetParameterData (candidate);
3830                                 } else {
3831                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3832                                         if (score != 0)
3833                                                 return score - 20000;
3834
3835                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3836                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3837                                                         TypeManager.CSharpSignature (candidate));
3838
3839                                         pd = TypeManager.GetParameterData (candidate);
3840                                 }
3841                         } else {
3842                                 if (type_arguments != null)
3843                                         return int.MaxValue - 15000;
3844                         }
3845 #endif
3846
3847                         //
3848                         // 2. Each argument has to be implicitly convertible to method parameter
3849                         //
3850                         method = candidate;
3851                         Parameter.Modifier p_mod = 0;
3852                         Type pt = null;
3853                         for (int i = 0; i < arg_count; i++) {
3854                                 Argument a = (Argument) arguments [i];
3855                                 Parameter.Modifier a_mod = a.Modifier &
3856                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3857
3858                                 if (p_mod != Parameter.Modifier.PARAMS) {
3859                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3860
3861                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3862                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3863                                                         continue;
3864
3865                                                 p_mod = 0;
3866                                         }
3867
3868                                         pt = pd.Types [i];
3869                                 } else {
3870                                         params_expanded_form = true;
3871                                 }
3872
3873                                 int score = 1;
3874                                 if (!params_expanded_form)
3875                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3876
3877                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
3878                                         // It can be applicable in expanded form
3879                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3880                                         if (score == 0)
3881                                                 params_expanded_form = true;
3882                                 }
3883
3884                                 if (score != 0) {
3885                                         if (params_expanded_form)
3886                                                 ++score;
3887                                         return (arg_count - i) * 2 + score;
3888                                 }
3889                         }
3890
3891                         if (arg_count != param_count)
3892                                 params_expanded_form = true;
3893
3894                         return 0;
3895                 }
3896
3897                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3898                 {
3899                         //
3900                         // Types have to be identical when ref or out modifer is used
3901                         //
3902                         if (arg_mod != 0 || param_mod != 0) {
3903                                 if (TypeManager.HasElementType (parameter))
3904                                         parameter = parameter.GetElementType ();
3905
3906                                 Type a_type = argument.Type;
3907                                 if (TypeManager.HasElementType (a_type))
3908                                         a_type = a_type.GetElementType ();
3909
3910                                 if (a_type != parameter)
3911                                         return 2;
3912                         } else {
3913                                 if (delegate_type != null ?
3914                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3915                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3916                                         return 2;
3917                         }
3918
3919                         if (arg_mod != param_mod)
3920                                 return 1;
3921
3922                         return 0;
3923                 }
3924
3925                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3926                 {
3927                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3928                                 return false;
3929
3930                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
3931                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
3932
3933                         if (cand_pd.Count != base_pd.Count)
3934                                 return false;
3935
3936                         for (int j = 0; j < cand_pd.Count; ++j)
3937                         {
3938                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
3939                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
3940                                 Type ct = cand_pd.Types [j];
3941                                 Type bt = base_pd.Types [j];
3942
3943                                 if (cm != bm || ct != bt)
3944                                         return false;
3945                         }
3946
3947                         return true;
3948                 }
3949
3950                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
3951                 {
3952                         if (mg1 == null) {
3953                                 if (mg2 == null)
3954                                         return null;
3955                                 return mg2;
3956                         }
3957
3958                         if (mg2 == null)
3959                                 return mg1;
3960
3961                         ArrayList all = new ArrayList (mg1.Methods);
3962                         foreach (MethodBase m in mg2.Methods){
3963                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods, m, false))
3964                                         all.Add (m);
3965                         }
3966
3967                         return new MethodGroupExpr (all, null, loc);
3968                 }
3969
3970                 static Type MoreSpecific (Type p, Type q)
3971                 {
3972                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3973                                 return q;
3974                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3975                                 return p;
3976
3977                         if (TypeManager.HasElementType (p))
3978                         {
3979                                 Type pe = TypeManager.GetElementType (p);
3980                                 Type qe = TypeManager.GetElementType (q);
3981                                 Type specific = MoreSpecific (pe, qe);
3982                                 if (specific == pe)
3983                                         return p;
3984                                 if (specific == qe)
3985                                         return q;
3986                         }
3987                         else if (TypeManager.IsGenericType (p))
3988                         {
3989                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3990                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3991
3992                                 bool p_specific_at_least_once = false;
3993                                 bool q_specific_at_least_once = false;
3994
3995                                 for (int i = 0; i < pargs.Length; i++)
3996                                 {
3997                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3998                                         if (specific == pargs [i])
3999                                                 p_specific_at_least_once = true;
4000                                         if (specific == qargs [i])
4001                                                 q_specific_at_least_once = true;
4002                                 }
4003
4004                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4005                                         return p;
4006                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4007                                         return q;
4008                         }
4009
4010                         return null;
4011                 }
4012
4013                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4014                 {
4015                         base.MutateHoistedGenericType (storey);
4016
4017                         MethodInfo mi = best_candidate as MethodInfo;
4018                         if (mi != null) {
4019                                 best_candidate = storey.MutateGenericMethod (mi);
4020                                 return;
4021                         }
4022
4023                         best_candidate = storey.MutateConstructor ((ConstructorInfo) this);
4024                 }
4025
4026                 /// <summary>
4027                 ///   Find the Applicable Function Members (7.4.2.1)
4028                 ///
4029                 ///   me: Method Group expression with the members to select.
4030                 ///       it might contain constructors or methods (or anything
4031                 ///       that maps to a method).
4032                 ///
4033                 ///   Arguments: ArrayList containing resolved Argument objects.
4034                 ///
4035                 ///   loc: The location if we want an error to be reported, or a Null
4036                 ///        location for "probing" purposes.
4037                 ///
4038                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4039                 ///            that is the best match of me on Arguments.
4040                 ///
4041                 /// </summary>
4042                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4043                         bool may_fail, Location loc)
4044                 {
4045                         bool method_params = false;
4046                         Type applicable_type = null;
4047                         int arg_count = 0;
4048                         ArrayList candidates = new ArrayList (2);
4049                         ArrayList candidate_overrides = null;
4050
4051                         //
4052                         // Used to keep a map between the candidate
4053                         // and whether it is being considered in its
4054                         // normal or expanded form
4055                         //
4056                         // false is normal form, true is expanded form
4057                         //
4058                         Hashtable candidate_to_form = null;
4059
4060                         if (Arguments != null)
4061                                 arg_count = Arguments.Count;
4062
4063                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4064                                 if (!may_fail)
4065                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4066                                 return null;
4067                         }
4068
4069                         int nmethods = Methods.Length;
4070
4071                         if (!IsBase) {
4072                                 //
4073                                 // Methods marked 'override' don't take part in 'applicable_type'
4074                                 // computation, nor in the actual overload resolution.
4075                                 // However, they still need to be emitted instead of a base virtual method.
4076                                 // So, we salt them away into the 'candidate_overrides' array.
4077                                 //
4078                                 // In case of reflected methods, we replace each overriding method with
4079                                 // its corresponding base virtual method.  This is to improve compatibility
4080                                 // with non-C# libraries which change the visibility of overrides (#75636)
4081                                 //
4082                                 int j = 0;
4083                                 for (int i = 0; i < Methods.Length; ++i) {
4084                                         MethodBase m = Methods [i];
4085                                         if (TypeManager.IsOverride (m)) {
4086                                                 if (candidate_overrides == null)
4087                                                         candidate_overrides = new ArrayList ();
4088                                                 candidate_overrides.Add (m);
4089                                                 m = TypeManager.TryGetBaseDefinition (m);
4090                                         }
4091                                         if (m != null)
4092                                                 Methods [j++] = m;
4093                                 }
4094                                 nmethods = j;
4095                         }
4096
4097                         //
4098                         // Enable message recording, it's used mainly by lambda expressions
4099                         //
4100                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4101                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4102
4103                         //
4104                         // First we construct the set of applicable methods
4105                         //
4106                         bool is_sorted = true;
4107                         int best_candidate_rate = int.MaxValue;
4108                         for (int i = 0; i < nmethods; i++) {
4109                                 Type decl_type = Methods [i].DeclaringType;
4110
4111                                 //
4112                                 // If we have already found an applicable method
4113                                 // we eliminate all base types (Section 14.5.5.1)
4114                                 //
4115                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4116                                         continue;
4117
4118                                 //
4119                                 // Check if candidate is applicable (section 14.4.2.1)
4120                                 //
4121                                 bool params_expanded_form = false;
4122                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4123
4124                                 if (candidate_rate < best_candidate_rate) {
4125                                         best_candidate_rate = candidate_rate;
4126                                         best_candidate = Methods [i];
4127                                 }
4128
4129                                 if (params_expanded_form) {
4130                                         if (candidate_to_form == null)
4131                                                 candidate_to_form = new PtrHashtable ();
4132                                         MethodBase candidate = Methods [i];
4133                                         candidate_to_form [candidate] = candidate;
4134                                 }
4135
4136                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4137                                         if (msg_recorder != null)
4138                                                 msg_recorder.EndSession ();
4139                                         continue;
4140                                 }
4141
4142                                 msg_recorder = null;
4143                                 candidates.Add (Methods [i]);
4144
4145                                 if (applicable_type == null)
4146                                         applicable_type = decl_type;
4147                                 else if (applicable_type != decl_type) {
4148                                         is_sorted = false;
4149                                         if (IsAncestralType (applicable_type, decl_type))
4150                                                 applicable_type = decl_type;
4151                                 }
4152                         }
4153
4154                         Report.SetMessageRecorder (prev_recorder);
4155                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4156                                 if (!may_fail)
4157                                         msg_recorder.PrintMessages ();
4158
4159                                 return null;
4160                         }
4161
4162                         int candidate_top = candidates.Count;
4163
4164                         if (applicable_type == null) {
4165                                 //
4166                                 // When we found a top level method which does not match and it's
4167                                 // not an extension method. We start extension methods lookup from here
4168                                 //
4169                                 if (InstanceExpression != null) {
4170                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4171                                         if (ex_method_lookup != null) {
4172                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4173                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4174                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4175                                         }
4176                                 }
4177
4178                                 if (may_fail)
4179                                         return null;
4180
4181                                 //
4182                                 // Okay so we have failed to find exact match so we
4183                                 // return error info about the closest match
4184                                 //
4185                                 if (best_candidate != null) {
4186                                         if (CustomErrorHandler != null) {
4187                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4188                                                         return null;
4189                                         }
4190
4191                                         AParametersCollection pd = TypeManager.GetParameterData (best_candidate);
4192                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4193                                         if (arg_count == pd.Count || pd.HasParams) {
4194                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4195                                                         if (type_arguments == null) {
4196                                                                 Report.Error (411, loc,
4197                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4198                                                                         "the usage. Try specifying the type arguments explicitly",
4199                                                                         TypeManager.CSharpSignature (best_candidate));
4200                                                                 return null;
4201                                                         }
4202
4203                                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate);
4204                                                         if (type_arguments.Count != g_args.Length) {
4205                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4206                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4207                                                                         TypeManager.CSharpSignature (best_candidate),
4208                                                                         g_args.Length.ToString ());
4209                                                                 return null;
4210                                                         }
4211                                                 } else {
4212                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4213                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4214                                                                 return null;
4215                                                         }
4216                                                 }
4217
4218                                                 if (has_inaccessible_candidates_only) {
4219                                                         if (InstanceExpression != null && type != ec.ContainerType && TypeManager.IsNestedFamilyAccessible (ec.ContainerType, best_candidate.DeclaringType)) {
4220                                                                 // Although a derived class can access protected members of
4221                                                                 // its base class it cannot do so through an instance of the
4222                                                                 // base class (CS1540).  If the qualifier_type is a base of the
4223                                                                 // ec.ContainerType and the lookup succeeds with the latter one,
4224                                                                 // then we are in this situation.
4225                                                                 Error_CannotAccessProtected (loc, best_candidate, type, ec.ContainerType);
4226                                                         } else {
4227                                                                 ErrorIsInaccesible (loc, GetSignatureForError ());
4228                                                         }
4229                                                 }
4230
4231                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4232                                                         return null;
4233
4234                                                 if (has_inaccessible_candidates_only)
4235                                                         return null;
4236                                         }
4237                                 }
4238
4239                                 //
4240                                 // We failed to find any method with correct argument count
4241                                 //
4242                                 if (Name == ConstructorInfo.ConstructorName) {
4243                                         Report.SymbolRelatedToPreviousError (type);
4244                                         Report.Error (1729, loc,
4245                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4246                                                 TypeManager.CSharpName (type), arg_count);
4247                                 } else {
4248                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4249                                                 Name, arg_count.ToString ());
4250                                 }
4251
4252                                 return null;
4253                         }
4254
4255                         if (!is_sorted) {
4256                                 //
4257                                 // At this point, applicable_type is _one_ of the most derived types
4258                                 // in the set of types containing the methods in this MethodGroup.
4259                                 // Filter the candidates so that they only contain methods from the
4260                                 // most derived types.
4261                                 //
4262
4263                                 int finalized = 0; // Number of finalized candidates
4264
4265                                 do {
4266                                         // Invariant: applicable_type is a most derived type
4267
4268                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4269                                         // eliminating all it's base types.  At the same time, we'll also move
4270                                         // every unrelated type to the end of the array, and pick the next
4271                                         // 'applicable_type'.
4272
4273                                         Type next_applicable_type = null;
4274                                         int j = finalized; // where to put the next finalized candidate
4275                                         int k = finalized; // where to put the next undiscarded candidate
4276                                         for (int i = finalized; i < candidate_top; ++i) {
4277                                                 MethodBase candidate = (MethodBase) candidates [i];
4278                                                 Type decl_type = candidate.DeclaringType;
4279
4280                                                 if (decl_type == applicable_type) {
4281                                                         candidates [k++] = candidates [j];
4282                                                         candidates [j++] = candidates [i];
4283                                                         continue;
4284                                                 }
4285
4286                                                 if (IsAncestralType (decl_type, applicable_type))
4287                                                         continue;
4288
4289                                                 if (next_applicable_type != null &&
4290                                                         IsAncestralType (decl_type, next_applicable_type))
4291                                                         continue;
4292
4293                                                 candidates [k++] = candidates [i];
4294
4295                                                 if (next_applicable_type == null ||
4296                                                         IsAncestralType (next_applicable_type, decl_type))
4297                                                         next_applicable_type = decl_type;
4298                                         }
4299
4300                                         applicable_type = next_applicable_type;
4301                                         finalized = j;
4302                                         candidate_top = k;
4303                                 } while (applicable_type != null);
4304                         }
4305
4306                         //
4307                         // Now we actually find the best method
4308                         //
4309
4310                         best_candidate = (MethodBase) candidates [0];
4311                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4312
4313                         for (int ix = 1; ix < candidate_top; ix++) {
4314                                 MethodBase candidate = (MethodBase) candidates [ix];
4315
4316                                 if (candidate == best_candidate)
4317                                         continue;
4318
4319                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4320
4321                                 if (BetterFunction (ec, Arguments, arg_count,
4322                                         candidate, cand_params,
4323                                         best_candidate, method_params)) {
4324                                         best_candidate = candidate;
4325                                         method_params = cand_params;
4326                                 }
4327                         }
4328                         //
4329                         // Now check that there are no ambiguities i.e the selected method
4330                         // should be better than all the others
4331                         //
4332                         MethodBase ambiguous = null;
4333                         for (int ix = 1; ix < candidate_top; ix++) {
4334                                 MethodBase candidate = (MethodBase) candidates [ix];
4335
4336                                 if (candidate == best_candidate)
4337                                         continue;
4338
4339                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4340                                 if (!BetterFunction (ec, Arguments, arg_count,
4341                                         best_candidate, method_params,
4342                                         candidate, cand_params))
4343                                 {
4344                                         if (!may_fail)
4345                                                 Report.SymbolRelatedToPreviousError (candidate);
4346                                         ambiguous = candidate;
4347                                 }
4348                         }
4349
4350                         if (ambiguous != null) {
4351                                 Report.SymbolRelatedToPreviousError (best_candidate);
4352                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4353                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4354                                 return this;
4355                         }
4356
4357                         //
4358                         // If the method is a virtual function, pick an override closer to the LHS type.
4359                         //
4360                         if (!IsBase && best_candidate.IsVirtual) {
4361                                 if (TypeManager.IsOverride (best_candidate))
4362                                         throw new InternalErrorException (
4363                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4364
4365                                 if (candidate_overrides != null) {
4366                                         Type[] gen_args = null;
4367                                         bool gen_override = false;
4368                                         if (TypeManager.IsGenericMethod (best_candidate))
4369                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4370
4371                                         foreach (MethodBase candidate in candidate_overrides) {
4372                                                 if (TypeManager.IsGenericMethod (candidate)) {
4373                                                         if (gen_args == null)
4374                                                                 continue;
4375
4376                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4377                                                                 continue;
4378                                                 } else {
4379                                                         if (gen_args != null)
4380                                                                 continue;
4381                                                 }
4382
4383                                                 if (IsOverride (candidate, best_candidate)) {
4384                                                         gen_override = true;
4385                                                         best_candidate = candidate;
4386                                                 }
4387                                         }
4388
4389                                         if (gen_override && gen_args != null) {
4390 #if GMCS_SOURCE
4391                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4392 #endif
4393                                         }
4394                                 }
4395                         }
4396
4397                         //
4398                         // And now check if the arguments are all
4399                         // compatible, perform conversions if
4400                         // necessary etc. and return if everything is
4401                         // all right
4402                         //
4403                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4404                                 method_params, may_fail, loc))
4405                                 return null;
4406
4407                         if (best_candidate == null)
4408                                 return null;
4409
4410                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4411 #if GMCS_SOURCE
4412                         if (the_method.IsGenericMethodDefinition &&
4413                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4414                                 return null;
4415 #endif
4416
4417                         //
4418                         // Check ObsoleteAttribute on the best method
4419                         //
4420                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4421                         if (oa != null && !ec.IsInObsoleteScope)
4422                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
4423
4424                         IMethodData data = TypeManager.GetMethod (the_method);
4425                         if (data != null)
4426                                 data.SetMemberIsUsed ();
4427
4428                         return this;
4429                 }
4430
4431                 public override void SetTypeArguments (TypeArguments ta)
4432                 {
4433                         type_arguments = ta;
4434                 }
4435
4436                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4437                                                           int arg_count, MethodBase method,
4438                                                           bool chose_params_expanded,
4439                                                           bool may_fail, Location loc)
4440                 {
4441                         AParametersCollection pd = TypeManager.GetParameterData (method);
4442
4443                         int errors = Report.Errors;
4444                         Parameter.Modifier p_mod = 0;
4445                         Type pt = null;
4446                         int a_idx = 0, a_pos = 0;
4447                         Argument a = null;
4448                         ArrayList params_initializers = null;
4449                         bool has_unsafe_arg = false;
4450
4451                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4452                                 a = (Argument) arguments [a_idx];
4453                                 if (p_mod != Parameter.Modifier.PARAMS) {
4454                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4455                                         pt = pd.Types [a_idx];
4456                                         has_unsafe_arg |= pt.IsPointer;
4457
4458                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4459                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4460                                                         break;
4461                                                 continue;
4462                                         }
4463
4464                                         if (p_mod == Parameter.Modifier.PARAMS) {
4465                                                 if (chose_params_expanded) {
4466                                                         params_initializers = new ArrayList (arg_count - a_idx);
4467                                                         pt = TypeManager.GetElementType (pt);
4468                                                 }
4469                                         }
4470                                 }
4471
4472                                 //
4473                                 // Types have to be identical when ref or out modifer is used
4474                                 //
4475                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4476                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4477                                                 break;
4478
4479                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4480                                                 break;
4481
4482                                         continue;
4483                                 }
4484
4485                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4486                                 if (conv == null)
4487                                         break;
4488
4489                                 //
4490                                 // Convert params arguments to an array initializer
4491                                 //
4492                                 if (params_initializers != null) {
4493                                         // we choose to use 'a.Expr' rather than 'conv' so that
4494                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4495                                         params_initializers.Add (a.Expr);
4496                                         arguments.RemoveAt (a_idx--);
4497                                         --arg_count;
4498                                         continue;
4499                                 }
4500
4501                                 // Update the argument with the implicit conversion
4502                                 a.Expr = conv;
4503                         }
4504
4505                         //
4506                         // Fill not provided arguments required by params modifier
4507                         //
4508                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4509                                 if (arguments == null)
4510                                         arguments = new ArrayList (1);
4511
4512                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4513                                 pt = TypeManager.GetElementType (pt);
4514                                 has_unsafe_arg |= pt.IsPointer;
4515                                 params_initializers = new ArrayList (0);
4516                         }
4517
4518                         if (a_idx == arg_count) {
4519                                 //
4520                                 // Append an array argument with all params arguments
4521                                 //
4522                                 if (params_initializers != null) {
4523                                         arguments.Add (new Argument (
4524                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4525                                                 params_initializers, loc).Resolve (ec)));
4526                                 }
4527
4528                                 if (has_unsafe_arg && !ec.InUnsafe) {
4529                                         if (!may_fail)
4530                                                 UnsafeError (loc);
4531                                         return false;
4532                                 }
4533
4534                                 return true;
4535                         }
4536
4537                         if (!may_fail && Report.Errors == errors) {
4538                                 if (CustomErrorHandler != null)
4539                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4540                                 else
4541                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4542                         }
4543                         return false;
4544                 }
4545         }
4546
4547         public class ConstantExpr : MemberExpr
4548         {
4549                 FieldInfo constant;
4550
4551                 public ConstantExpr (FieldInfo constant, Location loc)
4552                 {
4553                         this.constant = constant;
4554                         this.loc = loc;
4555                 }
4556
4557                 public override string Name {
4558                         get { throw new NotImplementedException (); }
4559                 }
4560
4561                 public override bool IsInstance {
4562                         get { return !IsStatic; }
4563                 }
4564
4565                 public override bool IsStatic {
4566                         get { return constant.IsStatic; }
4567                 }
4568
4569                 public override Type DeclaringType {
4570                         get { return constant.DeclaringType; }
4571                 }
4572
4573                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4574                 {
4575                         constant = TypeManager.GetGenericFieldDefinition (constant);
4576
4577                         IConstant ic = TypeManager.GetConstant (constant);
4578                         if (ic == null) {
4579                                 if (constant.IsLiteral) {
4580                                         ic = new ExternalConstant (constant);
4581                                 } else {
4582                                         ic = ExternalConstant.CreateDecimal (constant);
4583                                         // HACK: decimal field was not resolved as constant
4584                                         if (ic == null)
4585                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4586                                 }
4587                                 TypeManager.RegisterConstant (constant, ic);
4588                         }
4589
4590                         return base.ResolveMemberAccess (ec, left, loc, original);
4591                 }
4592
4593                 public override Expression CreateExpressionTree (EmitContext ec)
4594                 {
4595                         throw new NotSupportedException ("ET");
4596                 }
4597
4598                 public override Expression DoResolve (EmitContext ec)
4599                 {
4600                         IConstant ic = TypeManager.GetConstant (constant);
4601                         if (ic.ResolveValue ()) {
4602                                 if (!ec.IsInObsoleteScope)
4603                                         ic.CheckObsoleteness (loc);
4604                         }
4605
4606                         return ic.CreateConstantReference (loc);
4607                 }
4608
4609                 public override void Emit (EmitContext ec)
4610                 {
4611                         throw new NotSupportedException ();
4612                 }
4613
4614                 public override string GetSignatureForError ()
4615                 {
4616                         return TypeManager.GetFullNameSignature (constant);
4617                 }
4618         }
4619
4620         /// <summary>
4621         ///   Fully resolved expression that evaluates to a Field
4622         /// </summary>
4623         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariableReference {
4624                 public FieldInfo FieldInfo;
4625                 readonly Type constructed_generic_type;
4626                 VariableInfo variable_info;
4627
4628                 LocalTemporary temp;
4629                 bool prepared;
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 }