mcs/mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 //
  12
  13 namespace Mono.CSharp {
  14         using System;
  15         using System.Collections;
  16         using System.Diagnostics;
  17         using System.Reflection;
  18         using System.Reflection.Emit;
  19         using System.Text;
  20
  21         /// <remarks>
  22         ///   The ExprClass class contains the is used to pass the
  23         ///   classification of an expression (value, variable, namespace,
  24         ///   type, method group, property access, event access, indexer access,
  25         ///   nothing).
  26         /// </remarks>
  27         public enum ExprClass : byte {
  28                 Invalid,
  29
  30                 Value,
  31                 Variable,
  32                 Namespace,
  33                 Type,
  34                 MethodGroup,
  35                 PropertyAccess,
  36                 EventAccess,
  37                 IndexerAccess,
  38                 Nothing,
  39         }
  40
  41         /// <remarks>
  42         ///   This is used to tell Resolve in which types of expressions we're
  43         ///   interested.
  44         /// </remarks>
  45         [Flags]
  46         public enum ResolveFlags {
  47                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  48                 VariableOrValue         = 1,
  49
  50                 // Returns a type expression.
  51                 Type                    = 2,
  52
  53                 // Returns a method group.
  54                 MethodGroup             = 4,
  55
  56                 // Mask of all the expression class flags.
  57                 MaskExprClass           = 7,
  58
  59                 // Disable control flow analysis while resolving the expression.
  60                 // This is used when resolving the instance expression of a field expression.
  61                 DisableFlowAnalysis     = 8,
  62
  63                 // Set if this is resolving the first part of a MemberAccess.
  64                 Intermediate            = 16,
  65
  66                 // Disable control flow analysis _of struct_ while resolving the expression.
  67                 // This is used when resolving the instance expression of a field expression.
  68                 DisableStructFlowAnalysis       = 32,
  69
  70         }
  71
  72         //
  73         // This is just as a hint to AddressOf of what will be done with the
  74         // address.
  75         [Flags]
  76         public enum AddressOp {
  77                 Store = 1,
  78                 Load  = 2,
  79                 LoadStore = 3
  80         };
  81
  82         /// <summary>
  83         ///   This interface is implemented by variables
  84         /// </summary>
  85         public interface IMemoryLocation {
  86                 /// <summary>
  87                 ///   The AddressOf method should generate code that loads
  88                 ///   the address of the object and leaves it on the stack.
  89                 ///
  90                 ///   The `mode' argument is used to notify the expression
  91                 ///   of whether this will be used to read from the address or
  92                 ///   write to the address.
  93                 ///
  94                 ///   This is just a hint that can be used to provide good error
  95                 ///   reporting, and should have no other side effects.
  96                 /// </summary>
  97                 void AddressOf (EmitContext ec, AddressOp mode);
  98         }
  99
 100         /// <summary>
 101         ///   This interface is implemented by variables
 102         /// </summary>
 103         public interface IVariable {
 104                 VariableInfo VariableInfo {
 105                         get;
 106                 }
 107
 108                 bool VerifyFixed ();
 109         }
 110
 111         /// <remarks>
 112         ///   Base class for expressions
 113         /// </remarks>
 114         public abstract class Expression {
 115                 public ExprClass eclass;
 116                 protected Type type;
 117                 protected Location loc;
 118
 119                 public Type Type {
 120                         get { return type; }
 121                         set { type = value; }
 122                 }
 123
 124                 public virtual Location Location {
 125                         get { return loc; }
 126                 }
 127
 128                 /// <summary>
 129                 ///   Utility wrapper routine for Error, just to beautify the code
 130                 /// </summary>
 131                 public void Error (int error, string s)
 132                 {
 133                         Report.Error (error, loc, s);
 134                 }
 135
 136                 // Not nice but we have broken hierarchy.
 137                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 138                 {
 139                 }
 140
 141                 public virtual bool GetAttributableValue (Type value_type, out object value)
 142                 {
 143                         Attribute.Error_AttributeArgumentNotValid (loc);
 144                         value = null;
 145                         return false;
 146                 }
 147
 148                 public virtual string GetSignatureForError ()
 149                 {
 150                         return TypeManager.CSharpName (type);
 151                 }
 152
 153                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 154                 {
 155                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 156
 157                         must_do_cs1540_check = false; // by default we do not check for this
 158
 159                         if (ma == MethodAttributes.Public)
 160                                 return true;
 161
 162                         //
 163                         // If only accessible to the current class or children
 164                         //
 165                         if (ma == MethodAttributes.Private)
 166                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 167                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 168
 169                         if (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 170                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 171                                         return true;
 172                         } else {
 173                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 174                                         return false;
 175                         }
 176
 177                         // Family and FamANDAssem require that we derive.
 178                         // FamORAssem requires that we derive if in different assemblies.
 179                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 180                                 return false;
 181
 182                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 183                                 must_do_cs1540_check = true;
 184
 185                         return true;
 186                 }
 187
 188                 public virtual bool IsNull {
 189                         get {
 190                                 return false;
 191                         }
 192                 }
 193
 194                 /// <summary>
 195                 ///   Performs semantic analysis on the Expression
 196                 /// </summary>
 197                 ///
 198                 /// <remarks>
 199                 ///   The Resolve method is invoked to perform the semantic analysis
 200                 ///   on the node.
 201                 ///
 202                 ///   The return value is an expression (it can be the
 203                 ///   same expression in some cases) or a new
 204                 ///   expression that better represents this node.
 205                 ///
 206                 ///   For example, optimizations of Unary (LiteralInt)
 207                 ///   would return a new LiteralInt with a negated
 208                 ///   value.
 209                 ///
 210                 ///   If there is an error during semantic analysis,
 211                 ///   then an error should be reported (using Report)
 212                 ///   and a null value should be returned.
 213                 ///
 214                 ///   There are two side effects expected from calling
 215                 ///   Resolve(): the the field variable "eclass" should
 216                 ///   be set to any value of the enumeration
 217                 ///   `ExprClass' and the type variable should be set
 218                 ///   to a valid type (this is the type of the
 219                 ///   expression).
 220                 /// </remarks>
 221                 public abstract Expression DoResolve (EmitContext ec);
 222
 223                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 224                 {
 225                         return null;
 226                 }
 227
 228                 //
 229                 // This is used if the expression should be resolved as a type or namespace name.
 230                 // the default implementation fails.
 231                 //
 232                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 233                 {
 234                         if (!silent) {
 235                                 Expression e = this;
 236                                 EmitContext ec = rc as EmitContext;
 237                                 if (ec != null)
 238                                         e = e.Resolve (ec);
 239                                 if (e != null)
 240                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 241                         }
 242                         return null;
 243                 }
 244
 245                 //
 246                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 247                 // same name exists or as a keyword when no type was found
 248                 //
 249                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 250                 {
 251                         return ResolveAsTypeTerminal (rc, silent);
 252                 }
 253
 254                 //
 255                 // This is used to resolve the expression as a type, a null
 256                 // value will be returned if the expression is not a type
 257                 // reference
 258                 //
 259                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 260                 {
 261                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 262                         if (te == null)
 263                                 return null;
 264
 265                         if (!silent) { // && !(te is TypeParameterExpr)) {
 266                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 267                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 268                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 269                                 }
 270                         }
 271
 272                         // Constrains don't need to be checked for overrides
 273                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 274                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 275                                 te.loc = loc;
 276                                 return te;
 277                         }
 278
 279                         ConstructedType ct = te as ConstructedType;
 280                         if ((ct != null) && !ct.CheckConstraints (ec))
 281                                 return null;
 282
 283                         return te;
 284                 }
 285
 286                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 287                 {
 288                         int errors = Report.Errors;
 289
 290                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 291
 292                         if (fne == null)
 293                                 return null;
 294
 295                         if (fne.eclass != ExprClass.Type) {
 296                                 if (!silent && errors == Report.Errors)
 297                                         fne.Error_UnexpectedKind (null, "type", loc);
 298                                 return null;
 299                         }
 300
 301                         TypeExpr te = fne as TypeExpr;
 302
 303                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 304                                 Report.SymbolRelatedToPreviousError (te.Type);
 305                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 306                                 return null;
 307                         }
 308
 309                         te.loc = loc;
 310                         return te;
 311                 }
 312
 313                 public static void ErrorIsInaccesible (Location loc, string name)
 314                 {
 315                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 316                 }
 317
 318                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 319                 {
 320                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 321                                 + " The qualifier must be of type `{2}' or derived from it",
 322                                 TypeManager.GetFullNameSignature (m),
 323                                 TypeManager.CSharpName (qualifier),
 324                                 TypeManager.CSharpName (container));
 325
 326                 }
 327
 328                 public static void Error_InvalidExpressionStatement (Location loc)
 329                 {
 330                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 331                                        "expressions can be used as a statement");
 332                 }
 333
 334                 public void Error_InvalidExpressionStatement ()
 335                 {
 336                         Error_InvalidExpressionStatement (loc);
 337                 }
 338
 339                 protected void Error_CannotAssign (string to, string roContext)
 340                 {
 341                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 342                                 to, roContext);
 343                 }
 344
 345                 public static void Error_VoidInvalidInTheContext (Location loc)
 346                 {
 347                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 348                 }
 349
 350                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 351                 {
 352                         // The error was already reported as CS1660
 353                         if (type == TypeManager.anonymous_method_type)
 354                                 return;
 355
 356                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 357 #if GMCS_SOURCE
 358                                 string sig1 = type.DeclaringMethod == null ?
 359                                         TypeManager.CSharpName (type.DeclaringType) :
 360                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 361                                 string sig2 = target.DeclaringMethod == null ?
 362                                         TypeManager.CSharpName (target.DeclaringType) :
 363                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 364                                 Report.ExtraInformation (loc,
 365                                         String.Format (
 366                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 367                                                 Type.Name, sig1, sig2));
 368 #endif
 369                         } else if (Type.FullName == target.FullName){
 370                                 Report.ExtraInformation (loc,
 371                                         String.Format (
 372                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 373                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 374                         }
 375
 376                         if (expl) {
 377                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 378                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 379                                 return;
 380                         }
 381
 382                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 383                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 384
 385                         if (b ||
 386                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 387                             Convert.ExplicitUnsafe (e, target) != null ||
 388                             (ec != null && Convert.ExplicitUserConversion (ec, this, target, Location.Null) != null))
 389                         {
 390                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 391                                               "An explicit conversion exists (are you missing a cast?)",
 392                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 393                                 return;
 394                         }
 395
 396                         if (Type != TypeManager.string_type && this is Constant && !(this is EmptyConstantCast)) {
 397                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 398                                         ((Constant)(this)).GetValue ().ToString (), TypeManager.CSharpName (target));
 399                                 return;
 400                         }
 401
 402                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 403                                 TypeManager.CSharpName (type),
 404                                 TypeManager.CSharpName (target));
 405                 }
 406
 407                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 408                 {
 409                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 410                                 name);
 411                 }
 412
 413                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 414                 {
 415                         Error_TypeDoesNotContainDefinition (loc, type, name);
 416                 }
 417
 418                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 419                 {
 420                         Report.SymbolRelatedToPreviousError (type);
 421                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 422                                 TypeManager.CSharpName (type), name);
 423                 }
 424
 425                 protected static void Error_ValueAssignment (Location loc)
 426                 {
 427                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 428                 }
 429
 430                 ResolveFlags ExprClassToResolveFlags
 431                 {
 432                         get {
 433                                 switch (eclass) {
 434                                         case ExprClass.Type:
 435                                         case ExprClass.Namespace:
 436                                                 return ResolveFlags.Type;
 437
 438                                         case ExprClass.MethodGroup:
 439                                                 return ResolveFlags.MethodGroup;
 440
 441                                         case ExprClass.Value:
 442                                         case ExprClass.Variable:
 443                                         case ExprClass.PropertyAccess:
 444                                         case ExprClass.EventAccess:
 445                                         case ExprClass.IndexerAccess:
 446                                                 return ResolveFlags.VariableOrValue;
 447
 448                                         default:
 449                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 450                                 }
 451                         }
 452                 }
 453
 454                 /// <summary>
 455                 ///   Resolves an expression and performs semantic analysis on it.
 456                 /// </summary>
 457                 ///
 458                 /// <remarks>
 459                 ///   Currently Resolve wraps DoResolve to perform sanity
 460                 ///   checking and assertion checking on what we expect from Resolve.
 461                 /// </remarks>
 462                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 463                 {
 464                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 465                                 return ResolveAsTypeStep (ec, false);
 466
 467                         bool do_flow_analysis = ec.DoFlowAnalysis;
 468                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 469                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 470                                 do_flow_analysis = false;
 471                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 472                                 omit_struct_analysis = true;
 473
 474                         Expression e;
 475                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 476                                 if (this is SimpleName) {
 477                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 478                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 479                                 } else {
 480                                         e = DoResolve (ec);
 481                                 }
 482                         }
 483
 484                         if (e == null)
 485                                 return null;
 486
 487                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 488                                 e.Error_UnexpectedKind (flags, loc);
 489                                 return null;
 490                         }
 491
 492                         if (e.type == null && !(e is Namespace)) {
 493                                 throw new Exception (
 494                                         "Expression " + e.GetType () +
 495                                         " did not set its type after Resolve\n" +
 496                                         "called from: " + this.GetType ());
 497                         }
 498
 499                         return e;
 500                 }
 501
 502                 /// <summary>
 503                 ///   Resolves an expression and performs semantic analysis on it.
 504                 /// </summary>
 505                 public Expression Resolve (EmitContext ec)
 506                 {
 507                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 508
 509                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 510                                 ((MethodGroupExpr) e).ReportUsageError ();
 511                                 return null;
 512                         }
 513                         return e;
 514                 }
 515
 516                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 517                 {
 518                         Expression e = Resolve (ec);
 519                         if (e == null)
 520                                 return null;
 521
 522                         Constant c = e as Constant;
 523                         if (c != null)
 524                                 return c;
 525
 526                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 527                         return null;
 528                 }
 529
 530                 /// <summary>
 531                 ///   Resolves an expression for LValue assignment
 532                 /// </summary>
 533                 ///
 534                 /// <remarks>
 535                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 536                 ///   checking and assertion checking on what we expect from Resolve
 537                 /// </remarks>
 538                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 539                 {
 540                         int errors = Report.Errors;
 541                         bool out_access = right_side == EmptyExpression.OutAccess;
 542
 543                         Expression e = DoResolveLValue (ec, right_side);
 544
 545                         if (e != null && out_access && !(e is IMemoryLocation)) {
 546                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 547                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 548
 549                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 550                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 551                                 e = null;
 552                         }
 553
 554                         if (e == null) {
 555                                 if (errors == Report.Errors) {
 556                                         if (out_access)
 557                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 558                                         else
 559                                                 Error_ValueAssignment (loc);
 560                                 }
 561                                 return null;
 562                         }
 563
 564                         if (e.eclass == ExprClass.Invalid)
 565                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 566
 567                         if (e.eclass == ExprClass.MethodGroup) {
 568                                 ((MethodGroupExpr) e).ReportUsageError ();
 569                                 return null;
 570                         }
 571
 572                         if ((e.type == null) && !(e is ConstructedType))
 573                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 574
 575                         return e;
 576                 }
 577
 578                 /// <summary>
 579                 ///   Emits the code for the expression
 580                 /// </summary>
 581                 ///
 582                 /// <remarks>
 583                 ///   The Emit method is invoked to generate the code
 584                 ///   for the expression.
 585                 /// </remarks>
 586                 public abstract void Emit (EmitContext ec);
 587
 588                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 589                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 590                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 591                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 592                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 593                 {
 594                         Emit (ec);
 595                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 596                 }
 597
 598                 // Emit this expression for its side effects, not for its value.
 599                 // The default implementation is to emit the value, and then throw it away.
 600                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 601                 public virtual void EmitSideEffect (EmitContext ec)
 602                 {
 603                         Emit (ec);
 604                         ec.ig.Emit (OpCodes.Pop);
 605                 }
 606
 607                 /// <summary>
 608                 ///   Protected constructor.  Only derivate types should
 609                 ///   be able to be created
 610                 /// </summary>
 611
 612                 protected Expression ()
 613                 {
 614                         eclass = ExprClass.Invalid;
 615                         type = null;
 616                 }
 617
 618                 /// <summary>
 619                 ///   Returns a fully formed expression after a MemberLookup
 620                 /// </summary>
 621                 ///
 622                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 623                 {
 624                         if (mi is EventInfo)
 625                                 return new EventExpr ((EventInfo) mi, loc);
 626                         else if (mi is FieldInfo) {
 627                                 FieldInfo fi = (FieldInfo) mi;
 628                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 629                                         return new ConstantExpr (fi, loc);
 630                                 return new FieldExpr (fi, loc);
 631                         } else if (mi is PropertyInfo)
 632                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 633                         else if (mi is Type) {
 634                                 return new TypeExpression ((System.Type) mi, loc);
 635                         }
 636
 637                         return null;
 638                 }
 639
 640                 protected static ArrayList almost_matched_members = new ArrayList (4);
 641
 642                 //
 643                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 644                 //
 645                 // This code could use some optimizations, but we need to do some
 646                 // measurements.  For example, we could use a delegate to `flag' when
 647                 // something can not any longer be a method-group (because it is something
 648                 // else).
 649                 //
 650                 // Return values:
 651                 //     If the return value is an Array, then it is an array of
 652                 //     MethodBases
 653                 //
 654                 //     If the return value is an MemberInfo, it is anything, but a Method
 655                 //
 656                 //     null on error.
 657                 //
 658                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 659                 // the arguments here and have MemberLookup return only the methods that
 660                 // match the argument count/type, unlike we are doing now (we delay this
 661                 // decision).
 662                 //
 663                 // This is so we can catch correctly attempts to invoke instance methods
 664                 // from a static body (scan for error 120 in ResolveSimpleName).
 665                 //
 666                 //
 667                 // FIXME: Potential optimization, have a static ArrayList
 668                 //
 669
 670                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 671                                                        MemberTypes mt, BindingFlags bf, Location loc)
 672                 {
 673                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 674                 }
 675
 676                 //
 677                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 678                 // `qualifier_type' or null to lookup members in the current class.
 679                 //
 680
 681                 public static Expression MemberLookup (Type container_type,
 682                                                        Type qualifier_type, Type queried_type,
 683                                                        string name, MemberTypes mt,
 684                                                        BindingFlags bf, Location loc)
 685                 {
 686                         almost_matched_members.Clear ();
 687
 688                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 689                                                                      queried_type, mt, bf, name, almost_matched_members);
 690
 691                         if (mi == null)
 692                                 return null;
 693
 694                         if (mi.Length > 1) {
 695                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 696                                 ArrayList methods = new ArrayList (2);
 697                                 ArrayList non_methods = null;
 698
 699                                 foreach (MemberInfo m in mi) {
 700                                         if (m is MethodBase) {
 701                                                 methods.Add (m);
 702                                                 continue;
 703                                         }
 704
 705                                         if (non_methods == null) {
 706                                                 non_methods = new ArrayList (2);
 707                                                 non_methods.Add (m);
 708                                                 continue;
 709                                         }
 710
 711                                         foreach (MemberInfo n_m in non_methods) {
 712                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 713                                                         continue;
 714
 715                                                 Report.SymbolRelatedToPreviousError (m);
 716                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 717                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 718                                                 return null;
 719                                         }
 720                                 }
 721
 722                                 if (methods.Count == 0)
 723                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 724
 725                                 if (non_methods != null) {
 726                                         MethodBase method = (MethodBase) methods [0];
 727                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 728                                         if (method.DeclaringType == non_method.DeclaringType) {
 729                                                 // Cannot happen with C# code, but is valid in IL
 730                                                 Report.SymbolRelatedToPreviousError (method);
 731                                                 Report.SymbolRelatedToPreviousError (non_method);
 732                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 733                                                               TypeManager.GetFullNameSignature (non_method),
 734                                                               TypeManager.CSharpSignature (method));
 735                                                 return null;
 736                                         }
 737
 738                                         if (is_interface) {
 739                                                 Report.SymbolRelatedToPreviousError (method);
 740                                                 Report.SymbolRelatedToPreviousError (non_method);
 741                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 742                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 743                                         }
 744                                 }
 745
 746                                 return new MethodGroupExpr (methods, queried_type, loc);
 747                         }
 748
 749                         if (mi [0] is MethodBase)
 750                                 return new MethodGroupExpr (mi, queried_type, loc);
 751
 752                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 753                 }
 754
 755                 public const MemberTypes AllMemberTypes =
 756                         MemberTypes.Constructor |
 757                         MemberTypes.Event       |
 758                         MemberTypes.Field       |
 759                         MemberTypes.Method      |
 760                         MemberTypes.NestedType  |
 761                         MemberTypes.Property;
 762
 763                 public const BindingFlags AllBindingFlags =
 764                         BindingFlags.Public |
 765                         BindingFlags.Static |
 766                         BindingFlags.Instance;
 767
 768                 public static Expression MemberLookup (Type container_type, Type queried_type,
 769                                                        string name, Location loc)
 770                 {
 771                         return MemberLookup (container_type, null, queried_type, name,
 772                                              AllMemberTypes, AllBindingFlags, loc);
 773                 }
 774
 775                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 776                                                        Type queried_type, string name, Location loc)
 777                 {
 778                         return MemberLookup (container_type, qualifier_type, queried_type,
 779                                              name, AllMemberTypes, AllBindingFlags, loc);
 780                 }
 781
 782                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 783                                                        string name, Location loc)
 784                 {
 785                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 786                                              MemberTypes.Method, AllBindingFlags, loc);
 787                 }
 788
 789                 /// <summary>
 790                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 791                 ///   to find a final definition.  If the final definition is not found, we
 792                 ///   look for private members and display a useful debugging message if we
 793                 ///   find it.
 794                 /// </summary>
 795                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 796                                                             Type queried_type, string name,
 797                                                             MemberTypes mt, BindingFlags bf,
 798                                                             Location loc)
 799                 {
 800                         Expression e;
 801
 802                         int errors = Report.Errors;
 803
 804                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 805
 806                         if (e != null || errors != Report.Errors)
 807                                 return e;
 808
 809                         // No errors were reported by MemberLookup, but there was an error.
 810                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 811                                         name, null, mt, bf);
 812                 }
 813
 814                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 815                                                        Type queried_type, string name, string class_name,
 816                                                            MemberTypes mt, BindingFlags bf)
 817                 {
 818                         if (almost_matched_members.Count != 0) {
 819                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 820                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 821                                         for (int j = 0; j < i; ++j) {
 822                                                 if (m == almost_matched_members [j]) {
 823                                                         m = null;
 824                                                         break;
 825                                                 }
 826                                         }
 827                                         if (m == null)
 828                                                 continue;
 829
 830                                         Type declaring_type = m.DeclaringType;
 831
 832                                         Report.SymbolRelatedToPreviousError (m);
 833                                         if (qualifier_type == null) {
 834                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 835                                                               TypeManager.CSharpName (m.DeclaringType),
 836                                                               TypeManager.CSharpName (container_type));
 837
 838                                         } else if (qualifier_type != container_type &&
 839                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 840                                                 // Although a derived class can access protected members of
 841                                                 // its base class it cannot do so through an instance of the
 842                                                 // base class (CS1540).  If the qualifier_type is a base of the
 843                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 844                                                 // then we are in this situation.
 845                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 846                                         } else {
 847                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 848                                         }
 849                                 }
 850                                 almost_matched_members.Clear ();
 851                                 return null;
 852                         }
 853
 854                         MemberInfo[] lookup = null;
 855                         if (queried_type == null) {
 856                                 class_name = "global::";
 857                         } else {
 858                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 859                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 860                                         name, null);
 861
 862                                 if (lookup != null) {
 863                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 864                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 865                                         return Error_MemberLookupFailed (lookup);
 866                                 }
 867
 868                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 869                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 870                                         name, null);
 871                         }
 872
 873                         if (lookup == null) {
 874                                 if (class_name != null) {
 875                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 876                                                 name);
 877                                 } else {
 878                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 879                                 }
 880                                 return null;
 881                         }
 882
 883                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 884                                                       AllMemberTypes, AllBindingFlags |
 885                                                       BindingFlags.NonPublic, name, null) == null) {
 886                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 887                                         Type t = (Type) lookup [0];
 888
 889                                         Report.Error (305, loc,
 890                                                       "Using the generic type `{0}' " +
 891                                                       "requires {1} type arguments",
 892                                                       TypeManager.CSharpName (t),
 893                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 894                                         return null;
 895                                 }
 896                         }
 897
 898                         return Error_MemberLookupFailed (lookup);
 899                 }
 900
 901                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 902                 {
 903                         for (int i = 0; i < members.Length; ++i) {
 904                                 if (!(members [i] is MethodBase))
 905                                         return null;
 906                         }
 907
 908                         // By default propagate the closest candidates upwards
 909                         return new MethodGroupExpr (members, type, loc);
 910                 }
 911
 912                 protected virtual void Error_NegativeArrayIndex (Location loc)
 913                 {
 914                         throw new NotImplementedException ();
 915                 }
 916
 917                 protected void Error_PointerInsideExpressionTree ()
 918                 {
 919                         Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 920                 }
 921
 922                 /// <summary>
 923                 ///   Returns an expression that can be used to invoke operator true
 924                 ///   on the expression if it exists.
 925                 /// </summary>
 926                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 927                 {
 928                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 929                 }
 930
 931                 /// <summary>
 932                 ///   Returns an expression that can be used to invoke operator false
 933                 ///   on the expression if it exists.
 934                 /// </summary>
 935                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 936                 {
 937                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 938                 }
 939
 940                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 941                 {
 942                         MethodGroupExpr operator_group;
 943                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 944                         operator_group = MethodLookup (ec.ContainerType, e.Type, mname, loc) as MethodGroupExpr;
 945                         if (operator_group == null)
 946                                 return null;
 947
 948                         ArrayList arguments = new ArrayList (1);
 949                         arguments.Add (new Argument (e, Argument.AType.Expression));
 950                         operator_group = operator_group.OverloadResolve (
 951                                 ec, ref arguments, false, loc);
 952
 953                         if (operator_group == null)
 954                                 return null;
 955
 956                         return new UserOperatorCall (operator_group, arguments, null, loc);
 957                 }
 958
 959                 /// <summary>
 960                 ///   Resolves the expression `e' into a boolean expression: either through
 961                 ///   an implicit conversion, or through an `operator true' invocation
 962                 /// </summary>
 963                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 964                 {
 965                         e = e.Resolve (ec);
 966                         if (e == null)
 967                                 return null;
 968
 969                         if (e.Type == TypeManager.bool_type)
 970                                 return e;
 971
 972                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 973
 974                         if (converted != null)
 975                                 return converted;
 976
 977                         //
 978                         // If no implicit conversion to bool exists, try using `operator true'
 979                         //
 980                         converted = Expression.GetOperatorTrue (ec, e, loc);
 981                         if (converted == null){
 982                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 983                                 return null;
 984                         }
 985                         return converted;
 986                 }
 987
 988                 public virtual string ExprClassName
 989                 {
 990                         get {
 991                                 switch (eclass){
 992                                         case ExprClass.Invalid:
 993                                                 return "Invalid";
 994                                         case ExprClass.Value:
 995                                                 return "value";
 996                                         case ExprClass.Variable:
 997                                                 return "variable";
 998                                         case ExprClass.Namespace:
 999                                                 return "namespace";
1000                                         case ExprClass.Type:
1001                                                 return "type";
1002                                         case ExprClass.MethodGroup:
1003                                                 return "method group";
1004                                         case ExprClass.PropertyAccess:
1005                                                 return "property access";
1006                                         case ExprClass.EventAccess:
1007                                                 return "event access";
1008                                         case ExprClass.IndexerAccess:
1009                                                 return "indexer access";
1010                                         case ExprClass.Nothing:
1011                                                 return "null";
1012                                 }
1013                                 throw new Exception ("Should not happen");
1014                         }
1015                 }
1016
1017                 /// <summary>
1018                 ///   Reports that we were expecting `expr' to be of class `expected'
1019                 /// </summary>
1020                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1021                 {
1022                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1023                 }
1024
1025                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1026                 {
1027                         string name = GetSignatureForError ();
1028                         if (ds != null)
1029                                 name = ds.GetSignatureForError () + '.' + name;
1030
1031                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1032                               name, was, expected);
1033                 }
1034
1035                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1036                 {
1037                         string [] valid = new string [4];
1038                         int count = 0;
1039
1040                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1041                                 valid [count++] = "variable";
1042                                 valid [count++] = "value";
1043                         }
1044
1045                         if ((flags & ResolveFlags.Type) != 0)
1046                                 valid [count++] = "type";
1047
1048                         if ((flags & ResolveFlags.MethodGroup) != 0)
1049                                 valid [count++] = "method group";
1050
1051                         if (count == 0)
1052                                 valid [count++] = "unknown";
1053
1054                         StringBuilder sb = new StringBuilder (valid [0]);
1055                         for (int i = 1; i < count - 1; i++) {
1056                                 sb.Append ("', `");
1057                                 sb.Append (valid [i]);
1058                         }
1059                         if (count > 1) {
1060                                 sb.Append ("' or `");
1061                                 sb.Append (valid [count - 1]);
1062                         }
1063
1064                         Report.Error (119, loc,
1065                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1066                 }
1067
1068                 public static void UnsafeError (Location loc)
1069                 {
1070                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1071                 }
1072
1073                 //
1074                 // Load the object from the pointer.
1075                 //
1076                 public static void LoadFromPtr (ILGenerator ig, Type t)
1077                 {
1078                         if (t == TypeManager.int32_type)
1079                                 ig.Emit (OpCodes.Ldind_I4);
1080                         else if (t == TypeManager.uint32_type)
1081                                 ig.Emit (OpCodes.Ldind_U4);
1082                         else if (t == TypeManager.short_type)
1083                                 ig.Emit (OpCodes.Ldind_I2);
1084                         else if (t == TypeManager.ushort_type)
1085                                 ig.Emit (OpCodes.Ldind_U2);
1086                         else if (t == TypeManager.char_type)
1087                                 ig.Emit (OpCodes.Ldind_U2);
1088                         else if (t == TypeManager.byte_type)
1089                                 ig.Emit (OpCodes.Ldind_U1);
1090                         else if (t == TypeManager.sbyte_type)
1091                                 ig.Emit (OpCodes.Ldind_I1);
1092                         else if (t == TypeManager.uint64_type)
1093                                 ig.Emit (OpCodes.Ldind_I8);
1094                         else if (t == TypeManager.int64_type)
1095                                 ig.Emit (OpCodes.Ldind_I8);
1096                         else if (t == TypeManager.float_type)
1097                                 ig.Emit (OpCodes.Ldind_R4);
1098                         else if (t == TypeManager.double_type)
1099                                 ig.Emit (OpCodes.Ldind_R8);
1100                         else if (t == TypeManager.bool_type)
1101                                 ig.Emit (OpCodes.Ldind_I1);
1102                         else if (t == TypeManager.intptr_type)
1103                                 ig.Emit (OpCodes.Ldind_I);
1104                         else if (TypeManager.IsEnumType (t)) {
1105                                 if (t == TypeManager.enum_type)
1106                                         ig.Emit (OpCodes.Ldind_Ref);
1107                                 else
1108                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1109                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1110                                 ig.Emit (OpCodes.Ldobj, t);
1111                         else if (t.IsPointer)
1112                                 ig.Emit (OpCodes.Ldind_I);
1113                         else
1114                                 ig.Emit (OpCodes.Ldind_Ref);
1115                 }
1116
1117                 //
1118                 // The stack contains the pointer and the value of type `type'
1119                 //
1120                 public static void StoreFromPtr (ILGenerator ig, Type type)
1121                 {
1122                         if (TypeManager.IsEnumType (type))
1123                                 type = TypeManager.GetEnumUnderlyingType (type);
1124                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1125                                 ig.Emit (OpCodes.Stind_I4);
1126                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1127                                 ig.Emit (OpCodes.Stind_I8);
1128                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1129                                  type == TypeManager.ushort_type)
1130                                 ig.Emit (OpCodes.Stind_I2);
1131                         else if (type == TypeManager.float_type)
1132                                 ig.Emit (OpCodes.Stind_R4);
1133                         else if (type == TypeManager.double_type)
1134                                 ig.Emit (OpCodes.Stind_R8);
1135                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1136                                  type == TypeManager.bool_type)
1137                                 ig.Emit (OpCodes.Stind_I1);
1138                         else if (type == TypeManager.intptr_type)
1139                                 ig.Emit (OpCodes.Stind_I);
1140                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1141                                 ig.Emit (OpCodes.Stobj, type);
1142                         else
1143                                 ig.Emit (OpCodes.Stind_Ref);
1144                 }
1145
1146                 //
1147                 // Returns the size of type `t' if known, otherwise, 0
1148                 //
1149                 public static int GetTypeSize (Type t)
1150                 {
1151                         t = TypeManager.TypeToCoreType (t);
1152                         if (t == TypeManager.int32_type ||
1153                             t == TypeManager.uint32_type ||
1154                             t == TypeManager.float_type)
1155                                 return 4;
1156                         else if (t == TypeManager.int64_type ||
1157                                  t == TypeManager.uint64_type ||
1158                                  t == TypeManager.double_type)
1159                                 return 8;
1160                         else if (t == TypeManager.byte_type ||
1161                                  t == TypeManager.sbyte_type ||
1162                                  t == TypeManager.bool_type)
1163                                 return 1;
1164                         else if (t == TypeManager.short_type ||
1165                                  t == TypeManager.char_type ||
1166                                  t == TypeManager.ushort_type)
1167                                 return 2;
1168                         else if (t == TypeManager.decimal_type)
1169                                 return 16;
1170                         else
1171                                 return 0;
1172                 }
1173
1174                 protected void Error_CannotCallAbstractBase (string name)
1175                 {
1176                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1177                 }
1178
1179                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1180                 {
1181                         Report.SymbolRelatedToPreviousError (type);
1182                         if (ec.CurrentInitializerVariable != null) {
1183                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1184                                         GetSignatureForError ());
1185                         } else {
1186                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1187                                         GetSignatureForError ());
1188                         }
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                 public virtual Expression CreateExpressionTree (EmitContext ec)
1261                 {
1262                         throw new NotImplementedException (
1263                                 "Expression tree conversion not implemented for " + GetType ());
1264                 }
1265
1266                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1267                 {
1268                         return CreateExpressionFactoryCall (name, null, args, loc);
1269                 }
1270
1271                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1272                 {
1273                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1274                 }
1275
1276                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1277                 {
1278                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1279                 }
1280
1281                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1282                 {
1283                         TypeExpr texpr = TypeManager.expression_type_expr;
1284                         if (texpr == null) {
1285                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1286                                 if (t == null)
1287                                         return null;
1288
1289                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1290                         }
1291
1292                         return texpr;
1293                 }
1294         }
1295
1296         /// <summary>
1297         ///   This is just a base class for expressions that can
1298         ///   appear on statements (invocations, object creation,
1299         ///   assignments, post/pre increment and decrement).  The idea
1300         ///   being that they would support an extra Emition interface that
1301         ///   does not leave a result on the stack.
1302         /// </summary>
1303         public abstract class ExpressionStatement : Expression {
1304
1305                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1306                 {
1307                         Expression e = Resolve (ec);
1308                         if (e == null)
1309                                 return null;
1310
1311                         ExpressionStatement es = e as ExpressionStatement;
1312                         if (es == null)
1313                                 Error_InvalidExpressionStatement ();
1314
1315                         return es;
1316                 }
1317
1318                 /// <summary>
1319                 ///   Requests the expression to be emitted in a `statement'
1320                 ///   context.  This means that no new value is left on the
1321                 ///   stack after invoking this method (constrasted with
1322                 ///   Emit that will always leave a value on the stack).
1323                 /// </summary>
1324                 public abstract void EmitStatement (EmitContext ec);
1325
1326                 public override void EmitSideEffect (EmitContext ec)
1327                 {
1328                         EmitStatement (ec);
1329                 }
1330         }
1331
1332         /// <summary>
1333         ///   This kind of cast is used to encapsulate the child
1334         ///   whose type is child.Type into an expression that is
1335         ///   reported to return "return_type".  This is used to encapsulate
1336         ///   expressions which have compatible types, but need to be dealt
1337         ///   at higher levels with.
1338         ///
1339         ///   For example, a "byte" expression could be encapsulated in one
1340         ///   of these as an "unsigned int".  The type for the expression
1341         ///   would be "unsigned int".
1342         ///
1343         /// </summary>
1344         public abstract class TypeCast : Expression
1345         {
1346                 protected Expression child;
1347
1348                 protected TypeCast (Expression child, Type return_type)
1349                 {
1350                         eclass = child.eclass;
1351                         loc = child.Location;
1352                         type = return_type;
1353                         this.child = child;
1354                 }
1355
1356                 public override Expression CreateExpressionTree (EmitContext ec)
1357                 {
1358                         ArrayList args = new ArrayList (2);
1359                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1360                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1361
1362                         if (type.IsPointer || child.Type.IsPointer)
1363                                 Error_PointerInsideExpressionTree ();
1364
1365                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1366                 }
1367
1368                 public override Expression DoResolve (EmitContext ec)
1369                 {
1370                         // This should never be invoked, we are born in fully
1371                         // initialized state.
1372
1373                         return this;
1374                 }
1375
1376                 public override void Emit (EmitContext ec)
1377                 {
1378                         child.Emit (ec);
1379                 }
1380
1381                 public override bool GetAttributableValue (Type value_type, out object value)
1382                 {
1383                         return child.GetAttributableValue (value_type, out value);
1384                 }
1385
1386                 protected override void CloneTo (CloneContext clonectx, Expression t)
1387                 {
1388                         TypeCast target = (TypeCast) t;
1389
1390                         target.child = child.Clone (clonectx);
1391                 }
1392
1393                 public override bool IsNull {
1394                         get     {
1395                                 return child.IsNull;
1396                         }
1397                 }
1398         }
1399
1400         public class EmptyCast : TypeCast {
1401                 EmptyCast (Expression child, Type target_type)
1402                         : base (child, target_type)
1403                 {
1404                 }
1405
1406                 public static Expression Create (Expression child, Type type)
1407                 {
1408                         Constant c = child as Constant;
1409                         if (c != null)
1410                                 return new EmptyConstantCast (c, type);
1411
1412                         return new EmptyCast (child, type);
1413                 }
1414
1415                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1416                 {
1417                         child.EmitBranchable (ec, label, on_true);
1418                 }
1419
1420                 public override void EmitSideEffect (EmitContext ec)
1421                 {
1422                         child.EmitSideEffect (ec);
1423                 }
1424
1425         }
1426
1427         /// <summary>
1428         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1429         /// </summary>
1430         public class OperatorCast : TypeCast {
1431                 MethodInfo conversion_operator;
1432                 bool find_explicit;
1433
1434                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1435
1436                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1437                         : base (child, target_type)
1438                 {
1439                         this.find_explicit = find_explicit;
1440                 }
1441
1442                 // Returns the implicit operator that converts from
1443                 // 'child.Type' to our target type (type)
1444                 MethodInfo GetConversionOperator (bool find_explicit)
1445                 {
1446                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1447
1448                         MemberInfo [] mi;
1449
1450                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1451                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1452
1453                         if (mi == null){
1454                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1455                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1456                         }
1457
1458                         foreach (MethodInfo oper in mi) {
1459                                 ParameterData pd = TypeManager.GetParameterData (oper);
1460
1461                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1462                                         return oper;
1463                         }
1464
1465                         return null;
1466
1467
1468                 }
1469                 public override void Emit (EmitContext ec)
1470                 {
1471                         ILGenerator ig = ec.ig;
1472
1473                         child.Emit (ec);
1474                         conversion_operator = GetConversionOperator (find_explicit);
1475
1476                         if (conversion_operator == null)
1477                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1478
1479                         ig.Emit (OpCodes.Call, conversion_operator);
1480                 }
1481
1482         }
1483
1484         /// <summary>
1485         ///     This is a numeric cast to a Decimal
1486         /// </summary>
1487         public class CastToDecimal : TypeCast {
1488                 MethodInfo conversion_operator;
1489
1490                 public CastToDecimal (Expression child)
1491                         : this (child, false)
1492                 {
1493                 }
1494
1495                 public CastToDecimal (Expression child, bool find_explicit)
1496                         : base (child, TypeManager.decimal_type)
1497                 {
1498                         conversion_operator = GetConversionOperator (find_explicit);
1499
1500                         if (conversion_operator == null)
1501                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1502                 }
1503
1504                 // Returns the implicit operator that converts from
1505                 // 'child.Type' to System.Decimal.
1506                 MethodInfo GetConversionOperator (bool find_explicit)
1507                 {
1508                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1509
1510                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1511                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1512
1513                         foreach (MethodInfo oper in mi) {
1514                                 ParameterData pd = TypeManager.GetParameterData (oper);
1515
1516                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1517                                         return oper;
1518                         }
1519
1520                         return null;
1521                 }
1522                 public override void Emit (EmitContext ec)
1523                 {
1524                         ILGenerator ig = ec.ig;
1525                         child.Emit (ec);
1526
1527                         ig.Emit (OpCodes.Call, conversion_operator);
1528                 }
1529         }
1530
1531         /// <summary>
1532         ///     This is an explicit numeric cast from a Decimal
1533         /// </summary>
1534         public class CastFromDecimal : TypeCast
1535         {
1536                 static IDictionary operators;
1537
1538                 public CastFromDecimal (Expression child, Type return_type)
1539                         : base (child, return_type)
1540                 {
1541                         if (child.Type != TypeManager.decimal_type)
1542                                 throw new InternalErrorException (
1543                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1544                 }
1545
1546                 // Returns the explicit operator that converts from an
1547                 // express of type System.Decimal to 'type'.
1548                 public Expression Resolve ()
1549                 {
1550                         if (operators == null) {
1551                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1552                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1553                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1554
1555                                 operators = new System.Collections.Specialized.HybridDictionary ();
1556                                 foreach (MethodInfo oper in all_oper) {
1557                                         ParameterData pd = TypeManager.GetParameterData (oper);
1558                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1559                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1560                                 }
1561                         }
1562
1563                         return operators.Contains (type) ? this : null;
1564                 }
1565
1566                 public override void Emit (EmitContext ec)
1567                 {
1568                         ILGenerator ig = ec.ig;
1569                         child.Emit (ec);
1570
1571                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1572                 }
1573         }
1574
1575
1576         //
1577         // Constant specialization of EmptyCast.
1578         // We need to special case this since an empty cast of
1579         // a constant is still a constant.
1580         //
1581         public class EmptyConstantCast : Constant
1582         {
1583                 public readonly Constant child;
1584
1585                 public EmptyConstantCast(Constant child, Type type)
1586                         : base (child.Location)
1587                 {
1588                         eclass = child.eclass;
1589                         this.child = child;
1590                         this.type = type;
1591                 }
1592
1593                 public override string AsString ()
1594                 {
1595                         return child.AsString ();
1596                 }
1597
1598                 public override object GetValue ()
1599                 {
1600                         return child.GetValue ();
1601                 }
1602
1603                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1604                 {
1605                         // FIXME: check that 'type' can be converted to 'target_type' first
1606                         return child.ConvertExplicitly (in_checked_context, target_type);
1607                 }
1608
1609                 public override Expression CreateExpressionTree (EmitContext ec)
1610                 {
1611                         ArrayList args = new ArrayList (2);
1612                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1613                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1614                         if (type.IsPointer)
1615                                 Error_PointerInsideExpressionTree ();
1616
1617                         return CreateExpressionFactoryCall ("Convert", args);
1618                 }
1619
1620                 public override Constant Increment ()
1621                 {
1622                         return child.Increment ();
1623                 }
1624
1625                 public override bool IsDefaultValue {
1626                         get { return child.IsDefaultValue; }
1627                 }
1628
1629                 public override bool IsNegative {
1630                         get { return child.IsNegative; }
1631                 }
1632
1633                 public override bool IsNull {
1634                         get { return child.IsNull; }
1635                 }
1636
1637                 public override bool IsZeroInteger {
1638                         get { return child.IsZeroInteger; }
1639                 }
1640
1641                 public override void Emit (EmitContext ec)
1642                 {
1643                         child.Emit (ec);
1644                 }
1645
1646                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1647                 {
1648                         child.EmitBranchable (ec, label, on_true);
1649                 }
1650
1651                 public override void EmitSideEffect (EmitContext ec)
1652                 {
1653                         child.EmitSideEffect (ec);
1654                 }
1655
1656                 public override Constant ConvertImplicitly (Type target_type)
1657                 {
1658                         // FIXME: Do we need to check user conversions?
1659                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1660                                 return null;
1661                         return child.ConvertImplicitly (target_type);
1662                 }
1663         }
1664
1665
1666         /// <summary>
1667         ///  This class is used to wrap literals which belong inside Enums
1668         /// </summary>
1669         public class EnumConstant : Constant {
1670                 public Constant Child;
1671
1672                 public EnumConstant (Constant child, Type enum_type):
1673                         base (child.Location)
1674                 {
1675                         eclass = child.eclass;
1676                         this.Child = child;
1677                         type = enum_type;
1678                 }
1679
1680                 public override Expression DoResolve (EmitContext ec)
1681                 {
1682                         // This should never be invoked, we are born in fully
1683                         // initialized state.
1684
1685                         return this;
1686                 }
1687
1688                 public override void Emit (EmitContext ec)
1689                 {
1690                         Child.Emit (ec);
1691                 }
1692
1693                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1694                 {
1695                         Child.EmitBranchable (ec, label, on_true);
1696                 }
1697
1698                 public override void EmitSideEffect (EmitContext ec)
1699                 {
1700                         Child.EmitSideEffect (ec);
1701                 }
1702
1703                 public override bool GetAttributableValue (Type value_type, out object value)
1704                 {
1705                         value = GetTypedValue ();
1706                         return true;
1707                 }
1708
1709                 public override string GetSignatureForError()
1710                 {
1711                         return TypeManager.CSharpName (Type);
1712                 }
1713
1714                 public override object GetValue ()
1715                 {
1716                         return Child.GetValue ();
1717                 }
1718
1719                 public override object GetTypedValue ()
1720                 {
1721                         // FIXME: runtime is not ready to work with just emited enums
1722                         if (!RootContext.StdLib) {
1723                                 return Child.GetValue ();
1724                         }
1725
1726                         return System.Enum.ToObject (type, Child.GetValue ());
1727                 }
1728
1729                 public override string AsString ()
1730                 {
1731                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1732                 }
1733
1734                 public override Constant Increment()
1735                 {
1736                         return new EnumConstant (Child.Increment (), type);
1737                 }
1738
1739                 public override bool IsDefaultValue {
1740                         get {
1741                                 return Child.IsDefaultValue;
1742                         }
1743                 }
1744
1745                 public override bool IsZeroInteger {
1746                         get { return Child.IsZeroInteger; }
1747                 }
1748
1749                 public override bool IsNegative {
1750                         get {
1751                                 return Child.IsNegative;
1752                         }
1753                 }
1754
1755                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1756                 {
1757                         if (Child.Type == target_type)
1758                                 return Child;
1759
1760                         return Child.ConvertExplicitly (in_checked_context, target_type);
1761                 }
1762
1763                 public override Constant ConvertImplicitly (Type type)
1764                 {
1765                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1766                         type = TypeManager.DropGenericTypeArguments (type);
1767
1768                         if (this_type == type) {
1769                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1770                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1771                                         return this;
1772
1773                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1774                                 if (type.UnderlyingSystemType != child_type)
1775                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1776                                 return this;
1777                         }
1778
1779                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1780                                 return null;
1781                         }
1782
1783                         return Child.ConvertImplicitly(type);
1784                 }
1785
1786         }
1787
1788         /// <summary>
1789         ///   This kind of cast is used to encapsulate Value Types in objects.
1790         ///
1791         ///   The effect of it is to box the value type emitted by the previous
1792         ///   operation.
1793         /// </summary>
1794         public class BoxedCast : TypeCast {
1795
1796                 public BoxedCast (Expression expr, Type target_type)
1797                         : base (expr, target_type)
1798                 {
1799                         eclass = ExprClass.Value;
1800                 }
1801
1802                 public override Expression DoResolve (EmitContext ec)
1803                 {
1804                         // This should never be invoked, we are born in fully
1805                         // initialized state.
1806
1807                         return this;
1808                 }
1809
1810                 public override void Emit (EmitContext ec)
1811                 {
1812                         base.Emit (ec);
1813
1814                         ec.ig.Emit (OpCodes.Box, child.Type);
1815                 }
1816
1817                 public override void EmitSideEffect (EmitContext ec)
1818                 {
1819                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1820                         // so, we need to emit the box+pop instructions in most cases
1821                         if (child.Type.IsValueType &&
1822                             (type == TypeManager.object_type || type == TypeManager.value_type))
1823                                 child.EmitSideEffect (ec);
1824                         else
1825                                 base.EmitSideEffect (ec);
1826                 }
1827         }
1828
1829         public class UnboxCast : TypeCast {
1830                 public UnboxCast (Expression expr, Type return_type)
1831                         : base (expr, return_type)
1832                 {
1833                 }
1834
1835                 public override Expression DoResolve (EmitContext ec)
1836                 {
1837                         // This should never be invoked, we are born in fully
1838                         // initialized state.
1839
1840                         return this;
1841                 }
1842
1843                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1844                 {
1845                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1846                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1847                         return base.DoResolveLValue (ec, right_side);
1848                 }
1849
1850                 public override void Emit (EmitContext ec)
1851                 {
1852                         Type t = type;
1853                         ILGenerator ig = ec.ig;
1854
1855                         base.Emit (ec);
1856 #if GMCS_SOURCE
1857                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1858                                 ig.Emit (OpCodes.Unbox_Any, t);
1859                         else
1860 #endif
1861                         {
1862                                 ig.Emit (OpCodes.Unbox, t);
1863
1864                                 LoadFromPtr (ig, t);
1865                         }
1866                 }
1867         }
1868
1869         /// <summary>
1870         ///   This is used to perform explicit numeric conversions.
1871         ///
1872         ///   Explicit numeric conversions might trigger exceptions in a checked
1873         ///   context, so they should generate the conv.ovf opcodes instead of
1874         ///   conv opcodes.
1875         /// </summary>
1876         public class ConvCast : TypeCast {
1877                 public enum Mode : byte {
1878                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1879                         U1_I1, U1_CH,
1880                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1881                         U2_I1, U2_U1, U2_I2, U2_CH,
1882                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1883                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1884                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1885                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1886                         CH_I1, CH_U1, CH_I2,
1887                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1888                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1889                 }
1890
1891                 Mode mode;
1892
1893                 public ConvCast (Expression child, Type return_type, Mode m)
1894                         : base (child, return_type)
1895                 {
1896                         mode = m;
1897                 }
1898
1899                 public override Expression DoResolve (EmitContext ec)
1900                 {
1901                         // This should never be invoked, we are born in fully
1902                         // initialized state.
1903
1904                         return this;
1905                 }
1906
1907                 public override string ToString ()
1908                 {
1909                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1910                 }
1911
1912                 public override void Emit (EmitContext ec)
1913                 {
1914                         ILGenerator ig = ec.ig;
1915
1916                         base.Emit (ec);
1917
1918                         if (ec.CheckState){
1919                                 switch (mode){
1920                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1921                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1922                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1923                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1924                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1925
1926                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1927                                 case Mode.U1_CH: /* nothing */ break;
1928
1929                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1930                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1931                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1932                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1933                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1934                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1935
1936                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1937                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1938                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1939                                 case Mode.U2_CH: /* nothing */ break;
1940
1941                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1942                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1943                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1944                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1945                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1946                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1947                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1948
1949                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1950                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1951                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1952                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1953                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1954                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1955
1956                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1957                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1958                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1959                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1960                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1961                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1962                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1963                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1964
1965                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1966                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1967                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1968                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1969                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1970                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1971                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1972                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1973
1974                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1975                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1976                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1977
1978                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1979                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1980                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1981                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1982                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1983                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1984                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1985                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1986                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1987
1988                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1989                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1990                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1991                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1992                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1993                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1994                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1995                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1996                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1997                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1998                                 }
1999                         } else {
2000                                 switch (mode){
2001                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
2002                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
2003                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
2004                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
2005                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
2006
2007                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
2008                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
2009
2010                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2011                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2012                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2013                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2014                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2015                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2016
2017                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2018                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2019                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2020                                 case Mode.U2_CH: /* nothing */ break;
2021
2022                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2023                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2024                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2025                                 case Mode.I4_U4: /* nothing */ break;
2026                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2027                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2028                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2029
2030                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2031                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2032                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2033                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2034                                 case Mode.U4_I4: /* nothing */ break;
2035                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2036
2037                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2038                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2039                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2040                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2041                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2042                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2043                                 case Mode.I8_U8: /* nothing */ break;
2044                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2045
2046                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2047                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2048                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2049                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2050                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2051                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2052                                 case Mode.U8_I8: /* nothing */ break;
2053                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2054
2055                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2056                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2057                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2058
2059                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2060                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2061                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2062                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2063                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2064                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2065                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2066                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2067                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2068
2069                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2070                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2071                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2072                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2073                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2074                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2075                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2076                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2077                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2078                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2079                                 }
2080                         }
2081                 }
2082         }
2083
2084         public class OpcodeCast : TypeCast {
2085                 OpCode op, op2;
2086                 bool second_valid;
2087
2088                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2089                         : base (child, return_type)
2090
2091                 {
2092                         this.op = op;
2093                         second_valid = false;
2094                 }
2095
2096                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
2097                         : base (child, return_type)
2098
2099                 {
2100                         this.op = op;
2101                         this.op2 = op2;
2102                         second_valid = true;
2103                 }
2104
2105                 public override Expression DoResolve (EmitContext ec)
2106                 {
2107                         // This should never be invoked, we are born in fully
2108                         // initialized state.
2109
2110                         return this;
2111                 }
2112
2113                 public override void Emit (EmitContext ec)
2114                 {
2115                         base.Emit (ec);
2116                         ec.ig.Emit (op);
2117
2118                         if (second_valid)
2119                                 ec.ig.Emit (op2);
2120                 }
2121
2122                 public Type UnderlyingType {
2123                         get { return child.Type; }
2124                 }
2125         }
2126
2127         /// <summary>
2128         ///   This kind of cast is used to encapsulate a child and cast it
2129         ///   to the class requested
2130         /// </summary>
2131         public class ClassCast : TypeCast {
2132                 public ClassCast (Expression child, Type return_type)
2133                         : base (child, return_type)
2134
2135                 {
2136                 }
2137
2138                 public override Expression DoResolve (EmitContext ec)
2139                 {
2140                         // This should never be invoked, we are born in fully
2141                         // initialized state.
2142
2143                         return this;
2144                 }
2145
2146                 public override void Emit (EmitContext ec)
2147                 {
2148                         base.Emit (ec);
2149
2150                         if (TypeManager.IsGenericParameter (child.Type))
2151                                 ec.ig.Emit (OpCodes.Box, child.Type);
2152
2153 #if GMCS_SOURCE
2154                         if (type.IsGenericParameter)
2155                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2156                         else
2157 #endif
2158                                 ec.ig.Emit (OpCodes.Castclass, type);
2159                 }
2160         }
2161
2162         //
2163         // Used when resolved expression has different representations for
2164         // expression trees and emit phase
2165         //
2166         public class ReducedExpression : Expression
2167         {
2168                 class ReducedConstantExpression : Constant
2169                 {
2170                         readonly Constant expr;
2171                         readonly Expression orig_expr;
2172
2173                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2174                                 : base (expr.Location)
2175                         {
2176                                 this.expr = expr;
2177                                 this.orig_expr = orig_expr;
2178                                 eclass = expr.eclass;
2179                                 type = expr.Type;
2180                         }
2181
2182                         public override string AsString ()
2183                         {
2184                                 return expr.AsString ();
2185                         }
2186
2187                         public override Expression CreateExpressionTree (EmitContext ec)
2188                         {
2189                                 return orig_expr.CreateExpressionTree (ec);
2190                         }
2191
2192                         public override object GetValue ()
2193                         {
2194                                 return expr.GetValue ();
2195                         }
2196
2197                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2198                         {
2199                                 throw new NotImplementedException ();
2200                         }
2201
2202                         public override Expression DoResolve (EmitContext ec)
2203                         {
2204                                 return this;
2205                         }
2206
2207                         public override Constant Increment ()
2208                         {
2209                                 throw new NotImplementedException ();
2210                         }
2211
2212                         public override bool IsDefaultValue {
2213                                 get {
2214                                         return expr.IsDefaultValue;
2215                                 }
2216                         }
2217
2218                         public override bool IsNegative {
2219                                 get {
2220                                         return expr.IsNegative;
2221                                 }
2222                         }
2223
2224                         public override void Emit (EmitContext ec)
2225                         {
2226                                 expr.Emit (ec);
2227                         }
2228                 }
2229
2230                 readonly Expression expr, orig_expr;
2231
2232                 private ReducedExpression (Expression expr, Expression orig_expr)
2233                 {
2234                         this.expr = expr;
2235                         this.orig_expr = orig_expr;
2236                         this.loc = orig_expr.Location;
2237                 }
2238
2239                 public static Expression Create (Constant expr, Expression original_expr)
2240                 {
2241                         return new ReducedConstantExpression (expr, original_expr);
2242                 }
2243
2244                 public static Expression Create (Expression expr, Expression original_expr)
2245                 {
2246                         Constant c = expr as Constant;
2247                         if (c != null)
2248                                 return Create (c, original_expr);
2249
2250                         return new ReducedExpression (expr, original_expr);
2251                 }
2252
2253                 public override Expression CreateExpressionTree (EmitContext ec)
2254                 {
2255                         return orig_expr.CreateExpressionTree (ec);
2256                 }
2257
2258                 public override Expression DoResolve (EmitContext ec)
2259                 {
2260                         eclass = expr.eclass;
2261                         type = expr.Type;
2262                         return this;
2263                 }
2264
2265                 public override void Emit (EmitContext ec)
2266                 {
2267                         expr.Emit (ec);
2268                 }
2269
2270                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2271                 {
2272                         expr.EmitBranchable (ec, target, on_true);
2273                 }
2274         }
2275
2276         //
2277         // Unresolved type name expressions
2278         //
2279         public abstract class ATypeNameExpression : FullNamedExpression
2280         {
2281                 public readonly string Name;
2282                 protected TypeArguments targs;
2283
2284                 protected ATypeNameExpression (string name, Location l)
2285                 {
2286                         Name = name;
2287                         loc = l;
2288                 }
2289
2290                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2291                 {
2292                         Name = name;
2293                         this.targs = targs;
2294                         loc = l;
2295                 }
2296
2297                 public bool HasTypeArguments {
2298                         get {
2299                                 return targs != null;
2300                         }
2301                 }
2302
2303                 public override string GetSignatureForError ()
2304                 {
2305                         if (targs != null) {
2306                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2307                                         targs.GetSignatureForError () + ">";
2308                         }
2309
2310                         return Name;
2311                 }
2312         }
2313
2314         /// <summary>
2315         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2316         ///   of a dotted-name.
2317         /// </summary>
2318         public class SimpleName : ATypeNameExpression {
2319                 bool in_transit;
2320
2321                 public SimpleName (string name, Location l)
2322                         : base (name, l)
2323                 {
2324                 }
2325
2326                 public SimpleName (string name, TypeArguments args, Location l)
2327                         : base (name, args, l)
2328                 {
2329                 }
2330
2331                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2332                         : base (name, l)
2333                 {
2334                         targs = new TypeArguments (l);
2335                         foreach (TypeParameter type_param in type_params)
2336                                 targs.Add (new TypeParameterExpr (type_param, l));
2337                 }
2338
2339                 public static string RemoveGenericArity (string name)
2340                 {
2341                         int start = 0;
2342                         StringBuilder sb = null;
2343                         do {
2344                                 int pos = name.IndexOf ('`', start);
2345                                 if (pos < 0) {
2346                                         if (start == 0)
2347                                                 return name;
2348
2349                                         sb.Append (name.Substring (start));
2350                                         break;
2351                                 }
2352
2353                                 if (sb == null)
2354                                         sb = new StringBuilder ();
2355                                 sb.Append (name.Substring (start, pos-start));
2356
2357                                 pos++;
2358                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2359                                         pos++;
2360
2361                                 start = pos;
2362                         } while (start < name.Length);
2363
2364                         return sb.ToString ();
2365                 }
2366
2367                 public SimpleName GetMethodGroup ()
2368                 {
2369                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2370                 }
2371
2372                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2373                 {
2374                         if (ec.IsInFieldInitializer)
2375                                 Report.Error (236, l,
2376                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2377                                         name);
2378                         else
2379                                 Report.Error (
2380                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2381                                         name);
2382                 }
2383
2384                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2385                 {
2386                         return resolved_to != null && resolved_to.Type != null &&
2387                                 resolved_to.Type.Name == Name &&
2388                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2389                 }
2390
2391                 public override Expression DoResolve (EmitContext ec)
2392                 {
2393                         return SimpleNameResolve (ec, null, false);
2394                 }
2395
2396                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2397                 {
2398                         return SimpleNameResolve (ec, right_side, false);
2399                 }
2400
2401
2402                 public Expression DoResolve (EmitContext ec, bool intermediate)
2403                 {
2404                         return SimpleNameResolve (ec, null, intermediate);
2405                 }
2406
2407                 static bool IsNestedChild (Type t, Type parent)
2408                 {
2409                         while (parent != null) {
2410                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2411                                         return true;
2412
2413                                 parent = parent.BaseType;
2414                         }
2415
2416                         return false;
2417                 }
2418
2419                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2420                 {
2421                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2422                                 return null;
2423
2424                         DeclSpace ds = ec.DeclContainer;
2425                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2426                                 ds = ds.Parent;
2427
2428                         if (ds == null)
2429                                 return null;
2430
2431                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2432
2433                         int arg_count = targs != null ? targs.Count : 0;
2434
2435                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2436                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2437                                         TypeArguments new_args = new TypeArguments (loc);
2438                                         foreach (TypeParameter param in ds.TypeParameters)
2439                                                 new_args.Add (new TypeParameterExpr (param, loc));
2440
2441                                         if (targs != null)
2442                                                 new_args.Add (targs);
2443
2444                                         return new ConstructedType (t, new_args, loc);
2445                                 }
2446                         }
2447
2448                         return null;
2449                 }
2450
2451                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2452                 {
2453                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2454                         if (fne != null)
2455                                 return fne.ResolveAsTypeStep (ec, silent);
2456
2457                         int errors = Report.Errors;
2458                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2459
2460                         if (fne != null) {
2461                                 if (fne.Type == null)
2462                                         return fne;
2463
2464                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2465                                 if (nested != null)
2466                                         return nested.ResolveAsTypeStep (ec, false);
2467
2468                                 if (targs != null) {
2469                                         ConstructedType ct = new ConstructedType (fne, targs, loc);
2470                                         return ct.ResolveAsTypeStep (ec, false);
2471                                 }
2472
2473                                 return fne;
2474                         }
2475
2476                         if (silent || errors != Report.Errors)
2477                                 return null;
2478
2479                         Error_TypeOrNamespaceNotFound (ec);
2480                         return null;
2481                 }
2482
2483                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2484                 {
2485                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2486                         if (mc != null) {
2487                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2488                                 return;
2489                         }
2490
2491                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2492                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2493                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2494                                 Type type = a.GetType (fullname);
2495                                 if (type != null) {
2496                                         Report.SymbolRelatedToPreviousError (type);
2497                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2498                                         return;
2499                                 }
2500                         }
2501
2502                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2503                         if (t != null) {
2504                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2505                                 return;
2506                         }
2507
2508                         if (targs != null) {
2509                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2510                                 if (retval != null) {
2511                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2512                                         return;
2513                                 }
2514                         }
2515
2516                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2517                 }
2518
2519                 // TODO: I am still not convinced about this. If someone else will need it
2520                 // implement this as virtual property in MemberCore hierarchy
2521                 public static string GetMemberType (MemberCore mc)
2522                 {
2523                         if (mc is Property)
2524                                 return "property";
2525                         if (mc is Indexer)
2526                                 return "indexer";
2527                         if (mc is FieldBase)
2528                                 return "field";
2529                         if (mc is MethodCore)
2530                                 return "method";
2531                         if (mc is EnumMember)
2532                                 return "enum";
2533                         if (mc is Event)
2534                                 return "event";
2535
2536                         return "type";
2537                 }
2538
2539                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2540                 {
2541                         if (in_transit)
2542                                 return null;
2543
2544                         in_transit = true;
2545                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2546                         in_transit = false;
2547
2548                         if (e == null)
2549                                 return null;
2550
2551                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2552                                 return e;
2553
2554                         return null;
2555                 }
2556
2557                 /// <remarks>
2558                 ///   7.5.2: Simple Names.
2559                 ///
2560                 ///   Local Variables and Parameters are handled at
2561                 ///   parse time, so they never occur as SimpleNames.
2562                 ///
2563                 ///   The `intermediate' flag is used by MemberAccess only
2564                 ///   and it is used to inform us that it is ok for us to
2565                 ///   avoid the static check, because MemberAccess might end
2566                 ///   up resolving the Name as a Type name and the access as
2567                 ///   a static type access.
2568                 ///
2569                 ///   ie: Type Type; .... { Type.GetType (""); }
2570                 ///
2571                 ///   Type is both an instance variable and a Type;  Type.GetType
2572                 ///   is the static method not an instance method of type.
2573                 /// </remarks>
2574                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2575                 {
2576                         Expression e = null;
2577
2578                         //
2579                         // Stage 1: Performed by the parser (binding to locals or parameters).
2580                         //
2581                         Block current_block = ec.CurrentBlock;
2582                         if (current_block != null){
2583                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2584                                 if (vi != null){
2585                                         if (targs != null) {
2586                                                 Report.Error (307, loc,
2587                                                               "The variable `{0}' cannot be used with type arguments",
2588                                                               Name);
2589                                                 return null;
2590                                         }
2591
2592                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2593                                         if (right_side != null) {
2594                                                 return var.ResolveLValue (ec, right_side, loc);
2595                                         } else {
2596                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2597                                                 if (intermediate)
2598                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2599                                                 return var.Resolve (ec, rf);
2600                                         }
2601                                 }
2602
2603                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2604                                 if (pref != null) {
2605                                         if (targs != null) {
2606                                                 Report.Error (307, loc,
2607                                                               "The variable `{0}' cannot be used with type arguments",
2608                                                               Name);
2609                                                 return null;
2610                                         }
2611
2612                                         if (right_side != null)
2613                                                 return pref.ResolveLValue (ec, right_side, loc);
2614                                         else
2615                                                 return pref.Resolve (ec);
2616                                 }
2617
2618                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2619                                 if (expr != null) {
2620                                         if (right_side != null)
2621                                                 return expr.ResolveLValue (ec, right_side, loc);
2622                                         return expr.Resolve (ec);
2623                                 }
2624                         }
2625
2626                         //
2627                         // Stage 2: Lookup members
2628                         //
2629
2630                         Type almost_matched_type = null;
2631                         ArrayList almost_matched = null;
2632                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2633                                 // either RootDeclSpace or GenericMethod
2634                                 if (lookup_ds.TypeBuilder == null)
2635                                         continue;
2636
2637                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2638                                 if (e != null) {
2639                                         if (e is PropertyExpr) {
2640                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2641                                                 // it doesn't know which accessor to check permissions against
2642                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2643                                                         break;
2644                                         } else if (e is EventExpr) {
2645                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2646                                                         break;
2647                                         } else {
2648                                                 break;
2649                                         }
2650                                         e = null;
2651                                 }
2652
2653                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2654                                         almost_matched_type = lookup_ds.TypeBuilder;
2655                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2656                                 }
2657                         }
2658
2659                         if (e == null) {
2660                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2661                                         almost_matched_type = ec.ContainerType;
2662                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2663                                 }
2664                                 e = ResolveAsTypeStep (ec, true);
2665                         }
2666
2667                         if (e == null) {
2668                                 if (current_block != null) {
2669                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2670                                         if (ikv != null) {
2671                                                 LocalInfo li = ikv as LocalInfo;
2672                                                 // Supress CS0219 warning
2673                                                 if (li != null)
2674                                                         li.Used = true;
2675
2676                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2677                                                 return null;
2678                                         }
2679                                 }
2680
2681                                 if (almost_matched != null)
2682                                         almost_matched_members = almost_matched;
2683                                 if (almost_matched_type == null)
2684                                         almost_matched_type = ec.ContainerType;
2685                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2686                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2687                                 return null;
2688                         }
2689
2690                         if (e is TypeExpr) {
2691                                 if (targs == null)
2692                                         return e;
2693
2694                                 ConstructedType ct = new ConstructedType (
2695                                         e.Type, targs, loc);
2696                                 return ct.ResolveAsTypeStep (ec, false);
2697                         }
2698
2699                         if (e is MemberExpr) {
2700                                 MemberExpr me = (MemberExpr) e;
2701
2702                                 Expression left;
2703                                 if (me.IsInstance) {
2704                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2705                                                 //
2706                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2707                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2708                                                 // and each predicate is true if the MethodGroupExpr contains
2709                                                 // at least one of that kind of method.
2710                                                 //
2711
2712                                                 if (!me.IsStatic &&
2713                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2714                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2715                                                         return null;
2716                                                 }
2717
2718                                                 //
2719                                                 // Pass the buck to MemberAccess and Invocation.
2720                                                 //
2721                                                 left = EmptyExpression.Null;
2722                                         } else {
2723                                                 left = ec.GetThis (loc);
2724                                         }
2725                                 } else {
2726                                         left = new TypeExpression (ec.ContainerType, loc);
2727                                 }
2728
2729                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2730                                 if (me == null)
2731                                         return null;
2732
2733                                 if (targs != null) {
2734                                         targs.Resolve (ec);
2735                                         me.SetTypeArguments (targs);
2736                                 }
2737
2738                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2739                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2740                                     me.InstanceExpression.Type != me.DeclaringType &&
2741                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2742                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2743                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2744                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2745                                         return null;
2746                                 }
2747
2748                                 return (right_side != null)
2749                                         ? me.DoResolveLValue (ec, right_side)
2750                                         : me.DoResolve (ec);
2751                         }
2752
2753                         return e;
2754                 }
2755
2756                 protected override void CloneTo (CloneContext clonectx, Expression target)
2757                 {
2758                         // CloneTo: Nothing, we do not keep any state on this expression
2759                 }
2760         }
2761
2762         /// <summary>
2763         ///   Represents a namespace or a type.  The name of the class was inspired by
2764         ///   section 10.8.1 (Fully Qualified Names).
2765         /// </summary>
2766         public abstract class FullNamedExpression : Expression {
2767
2768                 public override Expression CreateExpressionTree (EmitContext ec)
2769                 {
2770                         throw new NotSupportedException ("ET");
2771                 }
2772
2773                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2774                 {
2775                         return this;
2776                 }
2777
2778                 public override void Emit (EmitContext ec)
2779                 {
2780                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2781                                 GetSignatureForError ());
2782                 }
2783         }
2784
2785         /// <summary>
2786         ///   Expression that evaluates to a type
2787         /// </summary>
2788         public abstract class TypeExpr : FullNamedExpression {
2789                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2790                 {
2791                         TypeExpr t = DoResolveAsTypeStep (ec);
2792                         if (t == null)
2793                                 return null;
2794
2795                         eclass = ExprClass.Type;
2796                         return t;
2797                 }
2798
2799                 override public Expression DoResolve (EmitContext ec)
2800                 {
2801                         return ResolveAsTypeTerminal (ec, false);
2802                 }
2803
2804                 public virtual bool CheckAccessLevel (DeclSpace ds)
2805                 {
2806                         return ds.CheckAccessLevel (Type);
2807                 }
2808
2809                 public virtual bool AsAccessible (DeclSpace ds)
2810                 {
2811                         return ds.IsAccessibleAs (Type);
2812                 }
2813
2814                 public virtual bool IsClass {
2815                         get { return Type.IsClass; }
2816                 }
2817
2818                 public virtual bool IsValueType {
2819                         get { return Type.IsValueType; }
2820                 }
2821
2822                 public virtual bool IsInterface {
2823                         get { return Type.IsInterface; }
2824                 }
2825
2826                 public virtual bool IsSealed {
2827                         get { return Type.IsSealed; }
2828                 }
2829
2830                 public virtual bool CanInheritFrom ()
2831                 {
2832                         if (Type == TypeManager.enum_type ||
2833                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2834                             Type == TypeManager.multicast_delegate_type ||
2835                             Type == TypeManager.delegate_type ||
2836                             Type == TypeManager.array_type)
2837                                 return false;
2838
2839                         return true;
2840                 }
2841
2842                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2843
2844                 public override bool Equals (object obj)
2845                 {
2846                         TypeExpr tobj = obj as TypeExpr;
2847                         if (tobj == null)
2848                                 return false;
2849
2850                         return Type == tobj.Type;
2851                 }
2852
2853                 public override int GetHashCode ()
2854                 {
2855                         return Type.GetHashCode ();
2856                 }
2857         }
2858
2859         /// <summary>
2860         ///   Fully resolved Expression that already evaluated to a type
2861         /// </summary>
2862         public class TypeExpression : TypeExpr {
2863                 public TypeExpression (Type t, Location l)
2864                 {
2865                         Type = t;
2866                         eclass = ExprClass.Type;
2867                         loc = l;
2868                 }
2869
2870                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2871                 {
2872                         return this;
2873                 }
2874
2875                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2876                 {
2877                         return this;
2878                 }
2879         }
2880
2881         /// <summary>
2882         ///   Used to create types from a fully qualified name.  These are just used
2883         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2884         ///   classified as a type.
2885         /// </summary>
2886         public sealed class TypeLookupExpression : TypeExpr {
2887                 readonly string name;
2888
2889                 public TypeLookupExpression (string name)
2890                 {
2891                         this.name = name;
2892                         eclass = ExprClass.Type;
2893                 }
2894
2895                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2896                 {
2897                         // It's null for corlib compilation only
2898                         if (type == null)
2899                                 return DoResolveAsTypeStep (ec);
2900
2901                         return this;
2902                 }
2903
2904                 private class UnexpectedType
2905                 {
2906                 }
2907
2908                 // This performes recursive type lookup, providing support for generic types.
2909                 // For example, given the type:
2910                 //
2911                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2912                 //
2913                 // The types will be checked in the following order:
2914                 //                                                                             _
2915                 // System                                                                       |
2916                 // System.Collections                                                           |
2917                 // System.Collections.Generic                                                   |
2918                 //                        _                                                     |
2919                 //     System              | recursive call 1                                   |
2920                 //     System.Int32       _|                                                    | main method call
2921                 //                        _                                                     |
2922                 //     System              | recursive call 2                                   |
2923                 //     System.String      _|                                                    |
2924                 //                                                                              |
2925                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2926                 //
2927                 private Type TypeLookup (IResolveContext ec, string name)
2928                 {
2929                         int index = 0;
2930                         int dot = 0;
2931                         bool done = false;
2932                         FullNamedExpression resolved = null;
2933                         Type type = null;
2934                         Type recursive_type = null;
2935                         while (index < name.Length) {
2936                                 if (name[index] == '[') {
2937                                         int open = index;
2938                                         int braces = 1;
2939                                         do {
2940                                                 index++;
2941                                                 if (name[index] == '[')
2942                                                         braces++;
2943                                                 else if (name[index] == ']')
2944                                                         braces--;
2945                                         } while (braces > 0);
2946                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2947                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2948                                                 return recursive_type;
2949                                 }
2950                                 else {
2951                                         if (name[index] == ',')
2952                                                 done = true;
2953                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2954                                                 string substring = name.Substring(dot, index - dot);
2955
2956                                                 if (resolved == null)
2957                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2958                                                 else if (resolved is Namespace)
2959                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2960                                                 else if (type != null)
2961                                                         type = TypeManager.GetNestedType (type, substring);
2962                                                 else
2963                                                         return null;
2964
2965                                                 if (resolved == null)
2966                                                         return null;
2967                                                 else if (type == null && resolved is TypeExpr)
2968                                                         type = resolved.Type;
2969
2970                                                 dot = index + 1;
2971                                         }
2972                                 }
2973                                 index++;
2974                         }
2975                         if (name[0] != '[') {
2976                                 string substring = name.Substring(dot, index - dot);
2977
2978                                 if (type != null)
2979                                         return TypeManager.GetNestedType (type, substring);
2980
2981                                 if (resolved != null) {
2982                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2983                                         if (resolved is TypeExpr)
2984                                                 return resolved.Type;
2985
2986                                         if (resolved == null)
2987                                                 return null;
2988
2989                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2990                                         return typeof (UnexpectedType);
2991                                 }
2992                                 else
2993                                         return null;
2994                         }
2995                         else
2996                                 return recursive_type;
2997                         }
2998
2999                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3000                 {
3001                         Type t = TypeLookup (ec, name);
3002                         if (t == null) {
3003                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
3004                                 return null;
3005                         }
3006                         if (t == typeof(UnexpectedType))
3007                                 return null;
3008                         type = t;
3009                         return this;
3010                 }
3011
3012                 protected override void CloneTo (CloneContext clonectx, Expression target)
3013                 {
3014                         // CloneTo: Nothing, we do not keep any state on this expression
3015                 }
3016
3017                 public override string GetSignatureForError ()
3018                 {
3019                         if (type == null)
3020                                 return TypeManager.CSharpName (name);
3021
3022                         return base.GetSignatureForError ();
3023                 }
3024         }
3025
3026         /// <summary>
3027         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
3028         ///   See 14.5.11.
3029         /// </summary>
3030         public class UnboundTypeExpression : TypeExpr
3031         {
3032                 MemberName name;
3033
3034                 public UnboundTypeExpression (MemberName name, Location l)
3035                 {
3036                         this.name = name;
3037                         loc = l;
3038                 }
3039
3040                 protected override void CloneTo (CloneContext clonectx, Expression target)
3041                 {
3042                         // Nothing to clone
3043                 }
3044
3045                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3046                 {
3047                         Expression expr;
3048                         if (name.Left != null) {
3049                                 Expression lexpr = name.Left.GetTypeExpression ();
3050                                 expr = new MemberAccess (lexpr, name.Basename);
3051                         } else {
3052                                 expr = new SimpleName (name.Basename, loc);
3053                         }
3054
3055                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
3056                         if (fne == null)
3057                                 return null;
3058
3059                         type = fne.Type;
3060                         return new TypeExpression (type, loc);
3061                 }
3062         }
3063
3064         /// <summary>
3065         ///   This class denotes an expression which evaluates to a member
3066         ///   of a struct or a class.
3067         /// </summary>
3068         public abstract class MemberExpr : Expression
3069         {
3070                 protected bool is_base;
3071
3072                 /// <summary>
3073                 ///   The name of this member.
3074                 /// </summary>
3075                 public abstract string Name {
3076                         get;
3077                 }
3078
3079                 //
3080                 // When base.member is used
3081                 //
3082                 public bool IsBase {
3083                         get { return is_base; }
3084                         set { is_base = value; }
3085                 }
3086
3087                 /// <summary>
3088                 ///   Whether this is an instance member.
3089                 /// </summary>
3090                 public abstract bool IsInstance {
3091                         get;
3092                 }
3093
3094                 /// <summary>
3095                 ///   Whether this is a static member.
3096                 /// </summary>
3097                 public abstract bool IsStatic {
3098                         get;
3099                 }
3100
3101                 /// <summary>
3102                 ///   The type which declares this member.
3103                 /// </summary>
3104                 public abstract Type DeclaringType {
3105                         get;
3106                 }
3107
3108                 /// <summary>
3109                 ///   The instance expression associated with this member, if it's a
3110                 ///   non-static member.
3111                 /// </summary>
3112                 public Expression InstanceExpression;
3113
3114                 public static void error176 (Location loc, string name)
3115                 {
3116                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3117                                       "with an instance reference, qualify it with a type name instead", name);
3118                 }
3119
3120                 // TODO: possible optimalization
3121                 // Cache resolved constant result in FieldBuilder <-> expression map
3122                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3123                                                                SimpleName original)
3124                 {
3125                         //
3126                         // Precondition:
3127                         //   original == null || original.Resolve (...) ==> left
3128                         //
3129
3130                         if (left is TypeExpr) {
3131                                 left = left.ResolveAsTypeTerminal (ec, true);
3132                                 if (left == null)
3133                                         return null;
3134
3135                                 if (!IsStatic) {
3136                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3137                                         return null;
3138                                 }
3139
3140                                 return this;
3141                         }
3142
3143                         if (!IsInstance) {
3144                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3145                                         return this;
3146
3147                                 return ResolveExtensionMemberAccess (left);
3148                         }
3149
3150                         InstanceExpression = left;
3151                         return this;
3152                 }
3153
3154                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3155                 {
3156                         error176 (loc, GetSignatureForError ());
3157                         return this;
3158                 }
3159
3160                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3161                 {
3162                         if (IsStatic)
3163                                 return;
3164
3165                         if (InstanceExpression == EmptyExpression.Null) {
3166                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3167                                 return;
3168                         }
3169
3170                         if (InstanceExpression.Type.IsValueType) {
3171                                 if (InstanceExpression is IMemoryLocation) {
3172                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3173                                 } else {
3174                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3175                                         InstanceExpression.Emit (ec);
3176                                         t.Store (ec);
3177                                         t.AddressOf (ec, AddressOp.Store);
3178                                 }
3179                         } else
3180                                 InstanceExpression.Emit (ec);
3181
3182                         if (prepare_for_load)
3183                                 ec.ig.Emit (OpCodes.Dup);
3184                 }
3185
3186                 public virtual void SetTypeArguments (TypeArguments ta)
3187                 {
3188                         // TODO: need to get correct member type
3189                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3190                                 GetSignatureForError ());
3191                 }
3192         }
3193
3194         ///
3195         /// Represents group of extension methods
3196         ///
3197         public class ExtensionMethodGroupExpr : MethodGroupExpr
3198         {
3199                 readonly NamespaceEntry namespace_entry;
3200                 public Expression ExtensionExpression;
3201                 Argument extension_argument;
3202
3203                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3204                         : base (list, extensionType, l)
3205                 {
3206                         this.namespace_entry = n;
3207                 }
3208
3209                 public override bool IsStatic {
3210                         get { return true; }
3211                 }
3212
3213                 public bool IsTopLevel {
3214                         get { return namespace_entry == null; }
3215                 }
3216
3217                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3218                 {
3219                         if (arguments == null)
3220                                 arguments = new ArrayList (1);
3221                         arguments.Insert (0, extension_argument);
3222                         base.EmitArguments (ec, arguments);
3223                 }
3224
3225                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3226                 {
3227                         if (arguments == null)
3228                                 arguments = new ArrayList (1);
3229                         arguments.Insert (0, extension_argument);
3230                         base.EmitCall (ec, arguments);
3231                 }
3232
3233                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3234                 {
3235                         if (arguments == null)
3236                                 arguments = new ArrayList (1);
3237
3238                         arguments.Insert (0, new Argument (ExtensionExpression));
3239                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3240
3241                         // Store resolved argument and restore original arguments
3242                         if (mg != null)
3243                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3244                         arguments.RemoveAt (0);
3245
3246                         return mg;
3247                 }
3248
3249                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3250                 {
3251                         // Use normal resolve rules
3252                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3253                         if (mg != null)
3254                                 return mg;
3255
3256                         if (ns == null)
3257                                 return null;
3258
3259                         // Search continues
3260                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3261                         if (e == null)
3262                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3263
3264                         e.ExtensionExpression = ExtensionExpression;
3265                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3266                 }
3267         }
3268
3269         /// <summary>
3270         ///   MethodGroupExpr represents a group of method candidates which
3271         ///   can be resolved to the best method overload
3272         /// </summary>
3273         public class MethodGroupExpr : MemberExpr
3274         {
3275                 public interface IErrorHandler
3276                 {
3277                         bool NoExactMatch (EmitContext ec, MethodBase method);
3278                 }
3279
3280                 public IErrorHandler CustomErrorHandler;
3281                 public MethodBase [] Methods;
3282                 MethodBase best_candidate;
3283                 // TODO: make private
3284                 public TypeArguments type_arguments;
3285                 bool identical_type_name;
3286                 Type delegate_type;
3287
3288                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3289                         : this (type, l)
3290                 {
3291                         Methods = new MethodBase [mi.Length];
3292                         mi.CopyTo (Methods, 0);
3293                 }
3294
3295                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3296                         : this (type, l)
3297                 {
3298                         try {
3299                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3300                         } catch {
3301                                 foreach (MemberInfo m in list){
3302                                         if (!(m is MethodBase)){
3303                                                 Console.WriteLine ("Name " + m.Name);
3304                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3305                                         }
3306                                 }
3307                                 throw;
3308                         }
3309
3310
3311                 }
3312
3313                 protected MethodGroupExpr (Type type, Location loc)
3314                 {
3315                         this.loc = loc;
3316                         eclass = ExprClass.MethodGroup;
3317                         this.type = type;
3318                 }
3319
3320                 public override Type DeclaringType {
3321                         get {
3322                                 //
3323                                 // We assume that the top-level type is in the end
3324                                 //
3325                                 return Methods [Methods.Length - 1].DeclaringType;
3326                                 //return Methods [0].DeclaringType;
3327                         }
3328                 }
3329
3330                 public Type DelegateType {
3331                         set {
3332                                 delegate_type = value;
3333                         }
3334                 }
3335
3336                 public bool IdenticalTypeName {
3337                         get {
3338                                 return identical_type_name;
3339                         }
3340
3341                         set {
3342                                 identical_type_name = value;
3343                         }
3344                 }
3345
3346                 public override string GetSignatureForError ()
3347                 {
3348                         if (best_candidate != null)
3349                                 return TypeManager.CSharpSignature (best_candidate);
3350
3351                         return TypeManager.CSharpSignature (Methods [0]);
3352                 }
3353
3354                 public override string Name {
3355                         get {
3356                                 return Methods [0].Name;
3357                         }
3358                 }
3359
3360                 public override bool IsInstance {
3361                         get {
3362                                 if (best_candidate != null)
3363                                         return !best_candidate.IsStatic;
3364
3365                                 foreach (MethodBase mb in Methods)
3366                                         if (!mb.IsStatic)
3367                                                 return true;
3368
3369                                 return false;
3370                         }
3371                 }
3372
3373                 public override bool IsStatic {
3374                         get {
3375                                 if (best_candidate != null)
3376                                         return best_candidate.IsStatic;
3377
3378                                 foreach (MethodBase mb in Methods)
3379                                         if (mb.IsStatic)
3380                                                 return true;
3381
3382                                 return false;
3383                         }
3384                 }
3385
3386                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3387                 {
3388                         return (ConstructorInfo)mg.best_candidate;
3389                 }
3390
3391                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3392                 {
3393                         return (MethodInfo)mg.best_candidate;
3394                 }
3395
3396                 //
3397                 //  7.4.3.3  Better conversion from expression
3398                 //  Returns :   1    if a->p is better,
3399                 //              2    if a->q is better,
3400                 //              0 if neither is better
3401                 //
3402                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3403                 {
3404                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3405                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3406                                 //
3407                                 // Uwrap delegate from Expression<T>
3408                                 //
3409                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3410                                         p = TypeManager.GetTypeArguments (p) [0];
3411                                         q = TypeManager.GetTypeArguments (q) [0];
3412                                 }
3413                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3414                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3415                         } else {
3416                                 if (argument_type == p)
3417                                         return 1;
3418
3419                                 if (argument_type == q)
3420                                         return 2;
3421                         }
3422
3423                         return BetterTypeConversion (ec, p, q);
3424                 }
3425
3426                 //
3427                 // 7.4.3.4  Better conversion from type
3428                 //
3429                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3430                 {
3431                         if (p == null || q == null)
3432                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3433
3434                         if (p == TypeManager.int32_type) {
3435                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3436                                         return 1;
3437                         } else if (p == TypeManager.int64_type) {
3438                                 if (q == TypeManager.uint64_type)
3439                                         return 1;
3440                         } else if (p == TypeManager.sbyte_type) {
3441                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3442                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3443                                         return 1;
3444                         } else if (p == TypeManager.short_type) {
3445                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3446                                         q == TypeManager.uint64_type)
3447                                         return 1;
3448                         }
3449
3450                         if (q == TypeManager.int32_type) {
3451                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3452                                         return 2;
3453                         } if (q == TypeManager.int64_type) {
3454                                 if (p == TypeManager.uint64_type)
3455                                         return 2;
3456                         } else if (q == TypeManager.sbyte_type) {
3457                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3458                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3459                                         return 2;
3460                         } if (q == TypeManager.short_type) {
3461                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3462                                         p == TypeManager.uint64_type)
3463                                         return 2;
3464                         }
3465
3466                         // TODO: this is expensive
3467                         Expression p_tmp = new EmptyExpression (p);
3468                         Expression q_tmp = new EmptyExpression (q);
3469
3470                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3471                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3472
3473                         if (p_to_q && !q_to_p)
3474                                 return 1;
3475
3476                         if (q_to_p && !p_to_q)
3477                                 return 2;
3478
3479                         return 0;
3480                 }
3481
3482                 /// <summary>
3483                 ///   Determines "Better function" between candidate
3484                 ///   and the current best match
3485                 /// </summary>
3486                 /// <remarks>
3487                 ///    Returns a boolean indicating :
3488                 ///     false if candidate ain't better
3489                 ///     true  if candidate is better than the current best match
3490                 /// </remarks>
3491                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3492                         MethodBase candidate, bool candidate_params,
3493                         MethodBase best, bool best_params)
3494                 {
3495                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3496                         ParameterData best_pd = TypeManager.GetParameterData (best);
3497
3498                         bool better_at_least_one = false;
3499                         bool same = true;
3500                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3501                         {
3502                                 Argument a = (Argument) args [j];
3503
3504                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3505                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3506
3507                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3508                                 {
3509                                         ct = TypeManager.GetElementType (ct);
3510                                         --c_idx;
3511                                 }
3512
3513                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3514                                 {
3515                                         bt = TypeManager.GetElementType (bt);
3516                                         --b_idx;
3517                                 }
3518
3519                                 if (ct.Equals (bt))
3520                                         continue;
3521
3522                                 same = false;
3523                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3524
3525                                 // for each argument, the conversion to 'ct' should be no worse than
3526                                 // the conversion to 'bt'.
3527                                 if (result == 2)
3528                                         return false;
3529
3530                                 // for at least one argument, the conversion to 'ct' should be better than
3531                                 // the conversion to 'bt'.
3532                                 if (result != 0)
3533                                         better_at_least_one = true;
3534                         }
3535
3536                         if (better_at_least_one)
3537                                 return true;
3538
3539                         //
3540                         // This handles the case
3541                         //
3542                         //   Add (float f1, float f2, float f3);
3543                         //   Add (params decimal [] foo);
3544                         //
3545                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3546                         // first candidate would've chosen as better.
3547                         //
3548                         if (!same)
3549                                 return false;
3550
3551                         //
3552                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3553                         //
3554                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3555                                 return true;
3556                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3557                                 return false;
3558
3559                         //
3560                         // This handles the following cases:
3561                         //
3562                         //   Trim () is better than Trim (params char[] chars)
3563                         //   Concat (string s1, string s2, string s3) is better than
3564                         //     Concat (string s1, params string [] srest)
3565                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3566                         //
3567                         if (!candidate_params && best_params)
3568                                 return true;
3569                         if (candidate_params && !best_params)
3570                                 return false;
3571
3572                         int candidate_param_count = candidate_pd.Count;
3573                         int best_param_count = best_pd.Count;
3574
3575                         if (candidate_param_count != best_param_count)
3576                                 // can only happen if (candidate_params && best_params)
3577                                 return candidate_param_count > best_param_count;
3578
3579                         //
3580                         // now, both methods have the same number of parameters, and the parameters have the same types
3581                         // Pick the "more specific" signature
3582                         //
3583
3584                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3585                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3586
3587                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3588                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3589
3590                         bool specific_at_least_once = false;
3591                         for (int j = 0; j < candidate_param_count; ++j)
3592                         {
3593                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3594                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3595                                 if (ct.Equals (bt))
3596                                         continue;
3597                                 Type specific = MoreSpecific (ct, bt);
3598                                 if (specific == bt)
3599                                         return false;
3600                                 if (specific == ct)
3601                                         specific_at_least_once = true;
3602                         }
3603
3604                         if (specific_at_least_once)
3605                                 return true;
3606
3607                         // FIXME: handle lifted operators
3608                         // ...
3609
3610                         return false;
3611                 }
3612
3613                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3614                 {
3615                         if (!IsStatic)
3616                                 return base.ResolveExtensionMemberAccess (left);
3617
3618                         //
3619                         // When left side is an expression and at least one candidate method is
3620                         // static, it can be extension method
3621                         //
3622                         InstanceExpression = left;
3623                         return this;
3624                 }
3625
3626                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3627                                                                 SimpleName original)
3628                 {
3629                         if (!(left is TypeExpr) &&
3630                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3631                                 IdenticalTypeName = true;
3632
3633                         return base.ResolveMemberAccess (ec, left, loc, original);
3634                 }
3635
3636                 public override Expression CreateExpressionTree (EmitContext ec)
3637                 {
3638                         if (best_candidate.IsConstructor)
3639                                 return new TypeOfConstructorInfo (best_candidate, loc);
3640
3641                         return new TypeOfMethodInfo (best_candidate, loc);
3642                 }
3643
3644                 override public Expression DoResolve (EmitContext ec)
3645                 {
3646                         if (InstanceExpression != null) {
3647                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3648                                 if (InstanceExpression == null)
3649                                         return null;
3650                         }
3651
3652                         return this;
3653                 }
3654
3655                 public void ReportUsageError ()
3656                 {
3657                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3658                                       Name + "()' is referenced without parentheses");
3659                 }
3660
3661                 override public void Emit (EmitContext ec)
3662                 {
3663                         ReportUsageError ();
3664                 }
3665
3666                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3667                 {
3668                         Invocation.EmitArguments (ec, arguments, false, null);
3669                 }
3670
3671                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3672                 {
3673                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3674                 }
3675
3676                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3677                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3678                 {
3679                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3680                                 Report.SymbolRelatedToPreviousError (method);
3681                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3682                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3683                                                 TypeManager.CSharpSignature (method));
3684                                         return;
3685                                 }
3686                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3687                                           TypeManager.CSharpSignature (method));
3688                         } else if (delegate_type == null) {
3689                                 Report.SymbolRelatedToPreviousError (method);
3690                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3691                                                   TypeManager.CSharpSignature (method));
3692                         } else
3693                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3694                                         TypeManager.CSharpName (delegate_type));
3695
3696                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3697
3698                         string index = (idx + 1).ToString ();
3699                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3700                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3701                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3702                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3703                                                 index, Parameter.GetModifierSignature (a.Modifier));
3704                                 else
3705                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3706                                                 index, Parameter.GetModifierSignature (mod));
3707                         } else {
3708                                 string p1 = a.GetSignatureForError ();
3709                                 string p2 = TypeManager.CSharpName (paramType);
3710
3711                                 if (p1 == p2) {
3712                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3713                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3714                                         Report.SymbolRelatedToPreviousError (paramType);
3715                                 }
3716                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3717                         }
3718                 }
3719
3720                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3721                 {
3722                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3723                                 Name, TypeManager.CSharpName (target));
3724                 }
3725
3726                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3727                 {
3728                         return parameters.Count;
3729                 }
3730
3731                 public static bool IsAncestralType (Type first_type, Type second_type)
3732                 {
3733                         return first_type != second_type &&
3734                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3735                                 TypeManager.ImplementsInterface (second_type, first_type));
3736                 }
3737
3738                 ///
3739                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3740                 /// to the given set of arguments
3741                 /// A return value rates candidate method compatibility,
3742                 /// 0 = the best, int.MaxValue = the worst
3743                 ///
3744                 public int IsApplicable (EmitContext ec,
3745                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3746                 {
3747                         MethodBase candidate = method;
3748
3749                         ParameterData pd = TypeManager.GetParameterData (candidate);
3750                         int param_count = GetApplicableParametersCount (candidate, pd);
3751
3752                         if (arg_count != param_count) {
3753                                 if (!pd.HasParams)
3754                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3755                                 if (arg_count < param_count - 1)
3756                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3757                         }
3758
3759 #if GMCS_SOURCE
3760                         //
3761                         // 1. Handle generic method using type arguments when specified or type inference
3762                         //
3763                         if (TypeManager.IsGenericMethod (candidate)) {
3764                                 if (type_arguments != null) {
3765                                         Type [] g_args = candidate.GetGenericArguments ();
3766                                         if (g_args.Length != type_arguments.Count)
3767                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3768
3769                                         // TODO: Don't create new method, create Parameters only
3770                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3771                                         candidate = method;
3772                                         pd = TypeManager.GetParameterData (candidate);
3773                                 } else {
3774                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3775                                         if (score != 0)
3776                                                 return score - 20000;
3777
3778                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3779                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3780                                                         TypeManager.CSharpSignature (candidate));
3781
3782                                         pd = TypeManager.GetParameterData (candidate);
3783                                 }
3784                         } else {
3785                                 if (type_arguments != null)
3786                                         return int.MaxValue - 15000;
3787                         }
3788 #endif
3789
3790                         //
3791                         // 2. Each argument has to be implicitly convertible to method parameter
3792                         //
3793                         method = candidate;
3794                         Parameter.Modifier p_mod = 0;
3795                         Type pt = null;
3796                         for (int i = 0; i < arg_count; i++) {
3797                                 Argument a = (Argument) arguments [i];
3798                                 Parameter.Modifier a_mod = a.Modifier &
3799                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3800
3801                                 if (p_mod != Parameter.Modifier.PARAMS) {
3802                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3803
3804                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3805                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3806                                                         continue;
3807
3808                                                 p_mod = 0;
3809                                         }
3810
3811                                         pt = pd.ParameterType (i);
3812                                 } else {
3813                                         params_expanded_form = true;
3814                                 }
3815
3816                                 int score = 1;
3817                                 if (!params_expanded_form)
3818                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3819
3820                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3821                                         // It can be applicable in expanded form
3822                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3823                                         if (score == 0)
3824                                                 params_expanded_form = true;
3825                                 }
3826
3827                                 if (score != 0) {
3828                                         if (params_expanded_form)
3829                                                 ++score;
3830                                         return (arg_count - i) * 2 + score;
3831                                 }
3832                         }
3833
3834                         if (arg_count != param_count)
3835                                 params_expanded_form = true;
3836
3837                         return 0;
3838                 }
3839
3840                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3841                 {
3842                         //
3843                         // Types have to be identical when ref or out modifer is used
3844                         //
3845                         if (arg_mod != 0 || param_mod != 0) {
3846                                 if (TypeManager.HasElementType (parameter))
3847                                         parameter = parameter.GetElementType ();
3848
3849                                 Type a_type = argument.Type;
3850                                 if (TypeManager.HasElementType (a_type))
3851                                         a_type = a_type.GetElementType ();
3852
3853                                 if (a_type != parameter)
3854                                         return 2;
3855
3856                                 return 0;
3857                         }
3858
3859                         // FIXME: Kill this abomination (EmitContext.TempEc)
3860                         EmitContext prevec = EmitContext.TempEc;
3861                         EmitContext.TempEc = ec;
3862                         try {
3863                                 if (delegate_type != null ?
3864                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3865                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3866                                         return 2;
3867
3868                                 if (arg_mod != param_mod)
3869                                         return 1;
3870
3871                         } finally {
3872                                 EmitContext.TempEc = prevec;
3873                         }
3874
3875                         return 0;
3876                 }
3877
3878                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3879                 {
3880                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3881                                 return false;
3882
3883                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3884                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3885
3886                         if (cand_pd.Count != base_pd.Count)
3887                                 return false;
3888
3889                         for (int j = 0; j < cand_pd.Count; ++j)
3890                         {
3891                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3892                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3893                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3894                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3895
3896                                 if (cm != bm || ct != bt)
3897                                         return false;
3898                         }
3899
3900                         return true;
3901                 }
3902
3903                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3904                 {
3905                         MemberInfo [] miset;
3906                         MethodGroupExpr union;
3907
3908                         if (mg1 == null) {
3909                                 if (mg2 == null)
3910                                         return null;
3911                                 return (MethodGroupExpr) mg2;
3912                         } else {
3913                                 if (mg2 == null)
3914                                         return (MethodGroupExpr) mg1;
3915                         }
3916
3917                         MethodGroupExpr left_set = null, right_set = null;
3918                         int length1 = 0, length2 = 0;
3919
3920                         left_set = (MethodGroupExpr) mg1;
3921                         length1 = left_set.Methods.Length;
3922
3923                         right_set = (MethodGroupExpr) mg2;
3924                         length2 = right_set.Methods.Length;
3925
3926                         ArrayList common = new ArrayList ();
3927
3928                         foreach (MethodBase r in right_set.Methods){
3929                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3930                                         common.Add (r);
3931                         }
3932
3933                         miset = new MemberInfo [length1 + length2 - common.Count];
3934                         left_set.Methods.CopyTo (miset, 0);
3935
3936                         int k = length1;
3937
3938                         foreach (MethodBase r in right_set.Methods) {
3939                                 if (!common.Contains (r))
3940                                         miset [k++] = r;
3941                         }
3942
3943                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3944
3945                         return union;
3946                 }
3947
3948                 static Type MoreSpecific (Type p, Type q)
3949                 {
3950                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3951                                 return q;
3952                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3953                                 return p;
3954
3955                         if (TypeManager.HasElementType (p))
3956                         {
3957                                 Type pe = TypeManager.GetElementType (p);
3958                                 Type qe = TypeManager.GetElementType (q);
3959                                 Type specific = MoreSpecific (pe, qe);
3960                                 if (specific == pe)
3961                                         return p;
3962                                 if (specific == qe)
3963                                         return q;
3964                         }
3965                         else if (TypeManager.IsGenericType (p))
3966                         {
3967                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3968                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3969
3970                                 bool p_specific_at_least_once = false;
3971                                 bool q_specific_at_least_once = false;
3972
3973                                 for (int i = 0; i < pargs.Length; i++)
3974                                 {
3975                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3976                                         if (specific == pargs [i])
3977                                                 p_specific_at_least_once = true;
3978                                         if (specific == qargs [i])
3979                                                 q_specific_at_least_once = true;
3980                                 }
3981
3982                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3983                                         return p;
3984                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3985                                         return q;
3986                         }
3987
3988                         return null;
3989                 }
3990
3991                 /// <summary>
3992                 ///   Find the Applicable Function Members (7.4.2.1)
3993                 ///
3994                 ///   me: Method Group expression with the members to select.
3995                 ///       it might contain constructors or methods (or anything
3996                 ///       that maps to a method).
3997                 ///
3998                 ///   Arguments: ArrayList containing resolved Argument objects.
3999                 ///
4000                 ///   loc: The location if we want an error to be reported, or a Null
4001                 ///        location for "probing" purposes.
4002                 ///
4003                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4004                 ///            that is the best match of me on Arguments.
4005                 ///
4006                 /// </summary>
4007                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4008                         bool may_fail, Location loc)
4009                 {
4010                         bool method_params = false;
4011                         Type applicable_type = null;
4012                         int arg_count = 0;
4013                         ArrayList candidates = new ArrayList (2);
4014                         ArrayList candidate_overrides = null;
4015
4016                         //
4017                         // Used to keep a map between the candidate
4018                         // and whether it is being considered in its
4019                         // normal or expanded form
4020                         //
4021                         // false is normal form, true is expanded form
4022                         //
4023                         Hashtable candidate_to_form = null;
4024
4025                         if (Arguments != null)
4026                                 arg_count = Arguments.Count;
4027
4028                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4029                                 if (!may_fail)
4030                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4031                                 return null;
4032                         }
4033
4034                         int nmethods = Methods.Length;
4035
4036                         if (!IsBase) {
4037                                 //
4038                                 // Methods marked 'override' don't take part in 'applicable_type'
4039                                 // computation, nor in the actual overload resolution.
4040                                 // However, they still need to be emitted instead of a base virtual method.
4041                                 // So, we salt them away into the 'candidate_overrides' array.
4042                                 //
4043                                 // In case of reflected methods, we replace each overriding method with
4044                                 // its corresponding base virtual method.  This is to improve compatibility
4045                                 // with non-C# libraries which change the visibility of overrides (#75636)
4046                                 //
4047                                 int j = 0;
4048                                 for (int i = 0; i < Methods.Length; ++i) {
4049                                         MethodBase m = Methods [i];
4050                                         if (TypeManager.IsOverride (m)) {
4051                                                 if (candidate_overrides == null)
4052                                                         candidate_overrides = new ArrayList ();
4053                                                 candidate_overrides.Add (m);
4054                                                 m = TypeManager.TryGetBaseDefinition (m);
4055                                         }
4056                                         if (m != null)
4057                                                 Methods [j++] = m;
4058                                 }
4059                                 nmethods = j;
4060                         }
4061
4062                         //
4063                         // Enable message recording, it's used mainly by lambda expressions
4064                         //
4065                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4066                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4067
4068                         //
4069                         // First we construct the set of applicable methods
4070                         //
4071                         bool is_sorted = true;
4072                         int best_candidate_rate = int.MaxValue;
4073                         for (int i = 0; i < nmethods; i++) {
4074                                 Type decl_type = Methods [i].DeclaringType;
4075
4076                                 //
4077                                 // If we have already found an applicable method
4078                                 // we eliminate all base types (Section 14.5.5.1)
4079                                 //
4080                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4081                                         continue;
4082
4083                                 //
4084                                 // Check if candidate is applicable (section 14.4.2.1)
4085                                 //
4086                                 bool params_expanded_form = false;
4087                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4088
4089                                 if (candidate_rate < best_candidate_rate) {
4090                                         best_candidate_rate = candidate_rate;
4091                                         best_candidate = Methods [i];
4092                                 }
4093
4094                                 if (params_expanded_form) {
4095                                         if (candidate_to_form == null)
4096                                                 candidate_to_form = new PtrHashtable ();
4097                                         MethodBase candidate = Methods [i];
4098                                         candidate_to_form [candidate] = candidate;
4099                                 }
4100
4101                                 if (candidate_rate != 0) {
4102                                         if (msg_recorder != null)
4103                                                 msg_recorder.EndSession ();
4104                                         continue;
4105                                 }
4106
4107                                 msg_recorder = null;
4108                                 candidates.Add (Methods [i]);
4109
4110                                 if (applicable_type == null)
4111                                         applicable_type = decl_type;
4112                                 else if (applicable_type != decl_type) {
4113                                         is_sorted = false;
4114                                         if (IsAncestralType (applicable_type, decl_type))
4115                                                 applicable_type = decl_type;
4116                                 }
4117                         }
4118
4119                         Report.SetMessageRecorder (prev_recorder);
4120                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4121                                 return null;
4122
4123                         int candidate_top = candidates.Count;
4124
4125                         if (applicable_type == null) {
4126                                 //
4127                                 // When we found a top level method which does not match and it's
4128                                 // not an extension method. We start extension methods lookup from here
4129                                 //
4130                                 if (InstanceExpression != null) {
4131                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4132                                         if (ex_method_lookup != null) {
4133                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4134                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4135                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4136                                         }
4137                                 }
4138
4139                                 if (may_fail)
4140                                         return null;
4141
4142                                 //
4143                                 // Okay so we have failed to find exact match so we
4144                                 // return error info about the closest match
4145                                 //
4146                                 if (best_candidate != null) {
4147                                         if (CustomErrorHandler != null) {
4148                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4149                                                         return null;
4150                                         }
4151
4152                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4153                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4154                                         if (arg_count == pd.Count || pd.HasParams) {
4155                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4156                                                         if (type_arguments == null) {
4157                                                                 Report.Error (411, loc,
4158                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4159                                                                         "the usage. Try specifying the type arguments explicitly",
4160                                                                         TypeManager.CSharpSignature (best_candidate));
4161                                                                 return null;
4162                                                         }
4163
4164                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4165                                                         if (type_arguments.Count != g_args.Length) {
4166                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4167                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4168                                                                         TypeManager.CSharpSignature (best_candidate),
4169                                                                         g_args.Length.ToString ());
4170                                                                 return null;
4171                                                         }
4172                                                 } else {
4173                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4174                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4175                                                                 return null;
4176                                                         }
4177                                                 }
4178
4179                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4180                                                         return null;
4181                                         }
4182                                 }
4183
4184                                 if (almost_matched_members.Count != 0) {
4185                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4186                                         null, MemberTypes.Constructor, AllBindingFlags);
4187                                         return null;
4188                                 }
4189
4190                                 //
4191                                 // We failed to find any method with correct argument count
4192                                 //
4193                                 if (Name == ConstructorInfo.ConstructorName) {
4194                                         Report.SymbolRelatedToPreviousError (type);
4195                                         Report.Error (1729, loc,
4196                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4197                                                 TypeManager.CSharpName (type), arg_count);
4198                                 } else {
4199                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4200                                                 Name, arg_count.ToString ());
4201                                 }
4202
4203                                 return null;
4204                         }
4205
4206                         if (!is_sorted) {
4207                                 //
4208                                 // At this point, applicable_type is _one_ of the most derived types
4209                                 // in the set of types containing the methods in this MethodGroup.
4210                                 // Filter the candidates so that they only contain methods from the
4211                                 // most derived types.
4212                                 //
4213
4214                                 int finalized = 0; // Number of finalized candidates
4215
4216                                 do {
4217                                         // Invariant: applicable_type is a most derived type
4218
4219                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4220                                         // eliminating all it's base types.  At the same time, we'll also move
4221                                         // every unrelated type to the end of the array, and pick the next
4222                                         // 'applicable_type'.
4223
4224                                         Type next_applicable_type = null;
4225                                         int j = finalized; // where to put the next finalized candidate
4226                                         int k = finalized; // where to put the next undiscarded candidate
4227                                         for (int i = finalized; i < candidate_top; ++i) {
4228                                                 MethodBase candidate = (MethodBase) candidates [i];
4229                                                 Type decl_type = candidate.DeclaringType;
4230
4231                                                 if (decl_type == applicable_type) {
4232                                                         candidates [k++] = candidates [j];
4233                                                         candidates [j++] = candidates [i];
4234                                                         continue;
4235                                                 }
4236
4237                                                 if (IsAncestralType (decl_type, applicable_type))
4238                                                         continue;
4239
4240                                                 if (next_applicable_type != null &&
4241                                                         IsAncestralType (decl_type, next_applicable_type))
4242                                                         continue;
4243
4244                                                 candidates [k++] = candidates [i];
4245
4246                                                 if (next_applicable_type == null ||
4247                                                         IsAncestralType (next_applicable_type, decl_type))
4248                                                         next_applicable_type = decl_type;
4249                                         }
4250
4251                                         applicable_type = next_applicable_type;
4252                                         finalized = j;
4253                                         candidate_top = k;
4254                                 } while (applicable_type != null);
4255                         }
4256
4257                         //
4258                         // Now we actually find the best method
4259                         //
4260
4261                         best_candidate = (MethodBase) candidates [0];
4262                         if (delegate_type == null)
4263                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4264
4265                         for (int ix = 1; ix < candidate_top; ix++) {
4266                                 MethodBase candidate = (MethodBase) candidates [ix];
4267
4268                                 if (candidate == best_candidate)
4269                                         continue;
4270
4271                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4272
4273                                 if (BetterFunction (ec, Arguments, arg_count,
4274                                         candidate, cand_params,
4275                                         best_candidate, method_params)) {
4276                                         best_candidate = candidate;
4277                                         method_params = cand_params;
4278                                 }
4279                         }
4280                         //
4281                         // Now check that there are no ambiguities i.e the selected method
4282                         // should be better than all the others
4283                         //
4284                         MethodBase ambiguous = null;
4285                         for (int ix = 1; ix < candidate_top; ix++) {
4286                                 MethodBase candidate = (MethodBase) candidates [ix];
4287
4288                                 if (candidate == best_candidate)
4289                                         continue;
4290
4291                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4292                                 if (!BetterFunction (ec, Arguments, arg_count,
4293                                         best_candidate, method_params,
4294                                         candidate, cand_params))
4295                                 {
4296                                         if (!may_fail)
4297                                                 Report.SymbolRelatedToPreviousError (candidate);
4298                                         ambiguous = candidate;
4299                                 }
4300                         }
4301
4302                         if (ambiguous != null) {
4303                                 Report.SymbolRelatedToPreviousError (best_candidate);
4304                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4305                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4306                                 return this;
4307                         }
4308
4309                         //
4310                         // If the method is a virtual function, pick an override closer to the LHS type.
4311                         //
4312                         if (!IsBase && best_candidate.IsVirtual) {
4313                                 if (TypeManager.IsOverride (best_candidate))
4314                                         throw new InternalErrorException (
4315                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4316
4317                                 if (candidate_overrides != null) {
4318                                         Type[] gen_args = null;
4319                                         bool gen_override = false;
4320                                         if (TypeManager.IsGenericMethod (best_candidate))
4321                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4322
4323                                         foreach (MethodBase candidate in candidate_overrides) {
4324                                                 if (TypeManager.IsGenericMethod (candidate)) {
4325                                                         if (gen_args == null)
4326                                                                 continue;
4327
4328                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4329                                                                 continue;
4330                                                 } else {
4331                                                         if (gen_args != null)
4332                                                                 continue;
4333                                                 }
4334
4335                                                 if (IsOverride (candidate, best_candidate)) {
4336                                                         gen_override = true;
4337                                                         best_candidate = candidate;
4338                                                 }
4339                                         }
4340
4341                                         if (gen_override && gen_args != null) {
4342 #if GMCS_SOURCE
4343                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4344 #endif
4345                                         }
4346                                 }
4347                         }
4348
4349                         //
4350                         // And now check if the arguments are all
4351                         // compatible, perform conversions if
4352                         // necessary etc. and return if everything is
4353                         // all right
4354                         //
4355                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4356                                 method_params, may_fail, loc))
4357                                 return null;
4358
4359                         if (best_candidate == null)
4360                                 return null;
4361
4362                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4363 #if GMCS_SOURCE
4364                         if (the_method.IsGenericMethodDefinition &&
4365                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4366                                 return null;
4367 #endif
4368
4369                         IMethodData data = TypeManager.GetMethod (the_method);
4370                         if (data != null)
4371                                 data.SetMemberIsUsed ();
4372
4373                         return this;
4374                 }
4375
4376                 public override void SetTypeArguments (TypeArguments ta)
4377                 {
4378                         type_arguments = ta;
4379                 }
4380
4381                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4382                                                           int arg_count, MethodBase method,
4383                                                           bool chose_params_expanded,
4384                                                           bool may_fail, Location loc)
4385                 {
4386                         ParameterData pd = TypeManager.GetParameterData (method);
4387
4388                         int errors = Report.Errors;
4389                         Parameter.Modifier p_mod = 0;
4390                         Type pt = null;
4391                         int a_idx = 0, a_pos = 0;
4392                         Argument a = null;
4393                         ArrayList params_initializers = null;
4394
4395                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4396                                 a = (Argument) arguments [a_idx];
4397                                 if (p_mod != Parameter.Modifier.PARAMS) {
4398                                         p_mod = pd.ParameterModifier (a_idx);
4399                                         pt = pd.ParameterType (a_idx);
4400
4401                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4402                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4403                                                         break;
4404                                                 continue;
4405                                         }
4406
4407                                         if (pt.IsPointer && !ec.InUnsafe) {
4408                                                 if (may_fail)
4409                                                         return false;
4410
4411                                                 UnsafeError (loc);
4412                                         }
4413
4414                                         if (p_mod == Parameter.Modifier.PARAMS) {
4415                                                 if (chose_params_expanded) {
4416                                                         params_initializers = new ArrayList (arg_count - a_idx);
4417                                                         pt = TypeManager.GetElementType (pt);
4418                                                 }
4419                                         } else if (p_mod != 0) {
4420                                                 pt = TypeManager.GetElementType (pt);
4421                                         }
4422                                 }
4423
4424                                 //
4425                                 // Types have to be identical when ref or out modifer is used
4426                                 //
4427                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4428                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4429                                                 break;
4430
4431                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4432                                                 break;
4433
4434                                         continue;
4435                                 }
4436
4437                                 Expression conv;
4438                                 if (TypeManager.IsEqual (a.Type, pt)) {
4439                                         conv = a.Expr;
4440                                 } else {
4441                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4442                                         if (conv == null)
4443                                                 break;
4444                                 }
4445
4446                                 //
4447                                 // Convert params arguments to an array initializer
4448                                 //
4449                                 if (params_initializers != null) {
4450                                         // we choose to use 'a.Expr' rather than 'conv' so that
4451                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4452                                         params_initializers.Add (a.Expr);
4453                                         arguments.RemoveAt (a_idx--);
4454                                         --arg_count;
4455                                         continue;
4456                                 }
4457
4458                                 // Update the argument with the implicit conversion
4459                                 a.Expr = conv;
4460                         }
4461
4462                         //
4463                         // Fill not provided arguments required by params modifier
4464                         //
4465                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4466                                 if (arguments == null)
4467                                         arguments = new ArrayList (1);
4468
4469                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4470                                 pt = TypeManager.GetElementType (pt);
4471                                 params_initializers = new ArrayList (0);
4472                         }
4473
4474                         if (a_idx == arg_count) {
4475                                 //
4476                                 // Append an array argument with all params arguments
4477                                 //
4478                                 if (params_initializers != null) {
4479                                         arguments.Add (new Argument (
4480                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4481                                                 params_initializers, loc).Resolve (ec)));
4482                                 }
4483                                 return true;
4484                         }
4485
4486                         if (!may_fail && Report.Errors == errors) {
4487                                 if (CustomErrorHandler != null)
4488                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4489                                 else
4490                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4491                         }
4492                         return false;
4493                 }
4494         }
4495
4496         public class ConstantExpr : MemberExpr
4497         {
4498                 FieldInfo constant;
4499
4500                 public ConstantExpr (FieldInfo constant, Location loc)
4501                 {
4502                         this.constant = constant;
4503                         this.loc = loc;
4504                 }
4505
4506                 public override string Name {
4507                         get { throw new NotImplementedException (); }
4508                 }
4509
4510                 public override bool IsInstance {
4511                         get { return !IsStatic; }
4512                 }
4513
4514                 public override bool IsStatic {
4515                         get { return constant.IsStatic; }
4516                 }
4517
4518                 public override Type DeclaringType {
4519                         get { return constant.DeclaringType; }
4520                 }
4521
4522                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4523                 {
4524                         constant = TypeManager.GetGenericFieldDefinition (constant);
4525
4526                         IConstant ic = TypeManager.GetConstant (constant);
4527                         if (ic == null) {
4528                                 if (constant.IsLiteral) {
4529                                         ic = new ExternalConstant (constant);
4530                                 } else {
4531                                         ic = ExternalConstant.CreateDecimal (constant);
4532                                         // HACK: decimal field was not resolved as constant
4533                                         if (ic == null)
4534                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4535                                 }
4536                                 TypeManager.RegisterConstant (constant, ic);
4537                         }
4538
4539                         return base.ResolveMemberAccess (ec, left, loc, original);
4540                 }
4541
4542                 public override Expression CreateExpressionTree (EmitContext ec)
4543                 {
4544                         throw new NotSupportedException ("ET");
4545                 }
4546
4547                 public override Expression DoResolve (EmitContext ec)
4548                 {
4549                         IConstant ic = TypeManager.GetConstant (constant);
4550                         if (ic.ResolveValue ()) {
4551                                 if (!ec.IsInObsoleteScope)
4552                                         ic.CheckObsoleteness (loc);
4553                         }
4554
4555                         return ic.CreateConstantReference (loc);
4556                 }
4557
4558                 public override void Emit (EmitContext ec)
4559                 {
4560                         throw new NotSupportedException ();
4561                 }
4562
4563                 public override string GetSignatureForError ()
4564                 {
4565                         return TypeManager.GetFullNameSignature (constant);
4566                 }
4567         }
4568
4569         /// <summary>
4570         ///   Fully resolved expression that evaluates to a Field
4571         /// </summary>
4572         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4573                 public readonly FieldInfo FieldInfo;
4574                 VariableInfo variable_info;
4575
4576                 LocalTemporary temp;
4577                 bool prepared;
4578                 bool in_initializer;
4579
4580                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4581                         this (fi, l)
4582                 {
4583                         this.in_initializer = in_initializer;
4584                 }
4585
4586                 public FieldExpr (FieldInfo fi, Location l)
4587                 {
4588                         FieldInfo = fi;
4589                         eclass = ExprClass.Variable;
4590                         type = TypeManager.TypeToCoreType (fi.FieldType);
4591                         loc = l;
4592                 }
4593
4594                 public override string Name {
4595                         get {
4596                                 return FieldInfo.Name;
4597                         }
4598                 }
4599
4600                 public override bool IsInstance {
4601                         get {
4602                                 return !FieldInfo.IsStatic;
4603                         }
4604                 }
4605
4606                 public override bool IsStatic {
4607                         get {
4608                                 return FieldInfo.IsStatic;
4609                         }
4610                 }
4611
4612                 public override Type DeclaringType {
4613                         get {
4614                                 return FieldInfo.DeclaringType;
4615                         }
4616                 }
4617
4618                 public override string GetSignatureForError ()
4619                 {
4620                         return TypeManager.GetFullNameSignature (FieldInfo);
4621                 }
4622
4623                 public VariableInfo VariableInfo {
4624                         get {
4625                                 return variable_info;
4626                         }
4627                 }
4628
4629                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4630                                                                 SimpleName original)
4631                 {
4632                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4633                         Type t = fi.FieldType;
4634
4635                         if (t.IsPointer && !ec.InUnsafe) {
4636                                 UnsafeError (loc);
4637                         }
4638
4639                         return base.ResolveMemberAccess (ec, left, loc, original);
4640                 }
4641
4642                 public override Expression CreateExpressionTree (EmitContext ec)
4643                 {
4644                         Expression instance;
4645                         if (InstanceExpression == null) {
4646                                 instance = new NullLiteral (loc);
4647                         } else {
4648                                 instance = InstanceExpression.CreateExpressionTree (ec);
4649                         }
4650
4651                         ArrayList args = new ArrayList (2);
4652                         args.Add (new Argument (instance));
4653                         args.Add (new Argument (CreateTypeOfExpression ()));
4654                         return CreateExpressionFactoryCall ("Field", args);
4655                 }
4656
4657                 public Expression CreateTypeOfExpression ()
4658                 {
4659                         return new TypeOfField (FieldInfo, loc);
4660                 }
4661
4662                 override public Expression DoResolve (EmitContext ec)
4663                 {
4664                         return DoResolve (ec, false, false);
4665                 }
4666
4667                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4668                 {
4669                         if (!FieldInfo.IsStatic){
4670                                 if (InstanceExpression == null){
4671                                         //
4672                                         // This can happen when referencing an instance field using
4673                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4674                                         //
4675                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4676                                         return null;
4677                                 }
4678
4679                                 // Resolve the field's instance expression while flow analysis is turned
4680                                 // off: when accessing a field "a.b", we must check whether the field
4681                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4682
4683                                 if (lvalue_instance) {
4684                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4685                                                 Expression right_side =
4686                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4687                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4688                                         }
4689                                 } else {
4690                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4691                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4692                                 }
4693
4694                                 if (InstanceExpression == null)
4695                                         return null;
4696
4697                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4698                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4699                                 }
4700                         }
4701
4702                         if (!in_initializer && !ec.IsInFieldInitializer) {
4703                                 ObsoleteAttribute oa;
4704                                 FieldBase f = TypeManager.GetField (FieldInfo);
4705                                 if (f != null) {
4706                                         if (!ec.IsInObsoleteScope)
4707                                                 f.CheckObsoleteness (loc);
4708
4709                                         // To be sure that type is external because we do not register generated fields
4710                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4711                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4712                                         if (oa != null)
4713                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4714                                 }
4715                         }
4716
4717                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4718                         if (am != null){
4719                                 if (!FieldInfo.IsStatic){
4720                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4721                                                 Report.Error (1673, loc,
4722                                                 "Anonymous methods inside structs cannot access instance members of `{0}'. Consider copying `{0}' to a local variable outside the anonymous method and using the local instead",
4723                                                         "this");
4724                                                 return null;
4725                                         }
4726                                 }
4727                         }
4728
4729                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4730                         if (fb != null) {
4731                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4732                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4733                                 }
4734
4735                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4736                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4737                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4738                                                 TypeManager.GetFullNameSignature (FieldInfo));
4739                                 }
4740
4741                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4742                         }
4743
4744                         // If the instance expression is a local variable or parameter.
4745                         IVariable var = InstanceExpression as IVariable;
4746                         if ((var == null) || (var.VariableInfo == null))
4747                                 return this;
4748
4749                         VariableInfo vi = var.VariableInfo;
4750                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4751                                 return null;
4752
4753                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4754                         return this;
4755                 }
4756
4757                 static readonly int [] codes = {
4758                         191,    // instance, write access
4759                         192,    // instance, out access
4760                         198,    // static, write access
4761                         199,    // static, out access
4762                         1648,   // member of value instance, write access
4763                         1649,   // member of value instance, out access
4764                         1650,   // member of value static, write access
4765                         1651    // member of value static, out access
4766                 };
4767
4768                 static readonly string [] msgs = {
4769                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4770                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4771                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4772                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4773                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4774                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4775                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4776                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4777                 };
4778
4779                 // The return value is always null.  Returning a value simplifies calling code.
4780                 Expression Report_AssignToReadonly (Expression right_side)
4781                 {
4782                         int i = 0;
4783                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4784                                 i += 1;
4785                         if (IsStatic)
4786                                 i += 2;
4787                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4788                                 i += 4;
4789                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4790
4791                         return null;
4792                 }
4793
4794                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4795                 {
4796                         IVariable var = InstanceExpression as IVariable;
4797                         if ((var != null) && (var.VariableInfo != null))
4798                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4799
4800                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4801                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4802
4803                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4804
4805                         if (e == null)
4806                                 return null;
4807
4808                         FieldBase fb = TypeManager.GetField (FieldInfo);
4809                         if (fb != null)
4810                                 fb.SetAssigned ();
4811
4812                         if (FieldInfo.IsInitOnly) {
4813                                 // InitOnly fields can only be assigned in constructors or initializers
4814                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4815                                         return Report_AssignToReadonly (right_side);
4816
4817                                 if (ec.IsConstructor) {
4818                                         Type ctype = ec.TypeContainer.CurrentType;
4819                                         if (ctype == null)
4820                                                 ctype = ec.ContainerType;
4821
4822                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4823                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4824                                                 return Report_AssignToReadonly (right_side);
4825                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4826                                         if (IsStatic && !ec.IsStatic)
4827                                                 return Report_AssignToReadonly (right_side);
4828                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4829                                         if (!IsStatic && !(InstanceExpression is This))
4830                                                 return Report_AssignToReadonly (right_side);
4831                                 }
4832                         }
4833
4834                         if (right_side == EmptyExpression.OutAccess &&
4835                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4836                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4837                                 Report.Warning (197, 1, loc,
4838                                                 "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",
4839                                                 GetSignatureForError ());
4840                         }
4841
4842                         return this;
4843                 }
4844
4845                 bool is_marshal_by_ref ()
4846                 {
4847                         return !IsStatic && Type.IsValueType && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
4848                 }
4849
4850                 public override void CheckMarshalByRefAccess (EmitContext ec)
4851                 {
4852                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
4853                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4854                                 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",
4855                                                 GetSignatureForError ());
4856                         }
4857                 }
4858
4859                 public bool VerifyFixed ()
4860                 {
4861                         IVariable variable = InstanceExpression as IVariable;
4862                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4863                         // We defer the InstanceExpression check after the variable check to avoid a
4864                         // separate null check on InstanceExpression.
4865                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4866                 }
4867
4868                 public override int GetHashCode ()
4869                 {
4870                         return FieldInfo.GetHashCode ();
4871                 }
4872
4873                 public override bool Equals (object obj)
4874                 {
4875                         FieldExpr fe = obj as FieldExpr;
4876                         if (fe == null)
4877                                 return false;
4878
4879                         if (FieldInfo != fe.FieldInfo)
4880                                 return false;
4881
4882                         if (InstanceExpression == null || fe.InstanceExpression == null)
4883                                 return true;
4884
4885                         return InstanceExpression.Equals (fe.InstanceExpression);
4886                 }
4887
4888                 public void Emit (EmitContext ec, bool leave_copy)
4889                 {
4890                         ILGenerator ig = ec.ig;
4891                         bool is_volatile = false;
4892
4893                         FieldBase f = TypeManager.GetField (FieldInfo);
4894                         if (f != null){
4895                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4896                                         is_volatile = true;
4897
4898                                 f.SetMemberIsUsed ();
4899                         }
4900
4901                         if (FieldInfo.IsStatic){
4902                                 if (is_volatile)
4903                                         ig.Emit (OpCodes.Volatile);
4904
4905                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4906                         } else {
4907                                 if (!prepared)
4908                                         EmitInstance (ec, false);
4909
4910                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4911                                 if (ff != null) {
4912                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4913                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4914                                 } else {
4915                                         if (is_volatile)
4916                                                 ig.Emit (OpCodes.Volatile);
4917
4918                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4919                                 }
4920                         }
4921
4922                         if (leave_copy) {
4923                                 ec.ig.Emit (OpCodes.Dup);
4924                                 if (!FieldInfo.IsStatic) {
4925                                         temp = new LocalTemporary (this.Type);
4926                                         temp.Store (ec);
4927                                 }
4928                         }
4929                 }
4930
4931                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4932                 {
4933                         FieldAttributes fa = FieldInfo.Attributes;
4934                         bool is_static = (fa & FieldAttributes.Static) != 0;
4935                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4936                         ILGenerator ig = ec.ig;
4937
4938                         if (is_readonly && !ec.IsConstructor){
4939                                 Report_AssignToReadonly (source);
4940                                 return;
4941                         }
4942
4943                         prepared = prepare_for_load;
4944                         EmitInstance (ec, prepared);
4945
4946                         source.Emit (ec);
4947                         if (leave_copy) {
4948                                 ec.ig.Emit (OpCodes.Dup);
4949                                 if (!FieldInfo.IsStatic) {
4950                                         temp = new LocalTemporary (this.Type);
4951                                         temp.Store (ec);
4952                                 }
4953                         }
4954
4955                         FieldBase f = TypeManager.GetField (FieldInfo);
4956                         if (f != null){
4957                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4958                                         ig.Emit (OpCodes.Volatile);
4959
4960                                 f.SetAssigned ();
4961                         }
4962
4963                         if (is_static)
4964                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4965                         else
4966                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4967
4968                         if (temp != null) {
4969                                 temp.Emit (ec);
4970                                 temp.Release (ec);
4971                         }
4972                 }
4973
4974                 public override void Emit (EmitContext ec)
4975                 {
4976                         Emit (ec, false);
4977                 }
4978
4979                 public override void EmitSideEffect (EmitContext ec)
4980                 {
4981                         FieldBase f = TypeManager.GetField (FieldInfo);
4982                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
4983
4984                         if (is_volatile || is_marshal_by_ref ())
4985                                 base.EmitSideEffect (ec);
4986                 }
4987
4988                 public void AddressOf (EmitContext ec, AddressOp mode)
4989                 {
4990                         ILGenerator ig = ec.ig;
4991
4992                         FieldBase f = TypeManager.GetField (FieldInfo);
4993                         if (f != null){
4994                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4995                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4996                                                         f.GetSignatureForError ());
4997                                 }
4998
4999                                 if ((mode & AddressOp.Store) != 0)
5000                                         f.SetAssigned ();
5001                                 if ((mode & AddressOp.Load) != 0)
5002                                         f.SetMemberIsUsed ();
5003                         }
5004
5005                         //
5006                         // Handle initonly fields specially: make a copy and then
5007                         // get the address of the copy.
5008                         //
5009                         bool need_copy;
5010                         if (FieldInfo.IsInitOnly){
5011                                 need_copy = true;
5012                                 if (ec.IsConstructor){
5013                                         if (FieldInfo.IsStatic){
5014                                                 if (ec.IsStatic)
5015                                                         need_copy = false;
5016                                         } else
5017                                                 need_copy = false;
5018                                 }
5019                         } else
5020                                 need_copy = false;
5021
5022                         if (need_copy){
5023                                 LocalBuilder local;
5024                                 Emit (ec);
5025                                 local = ig.DeclareLocal (type);
5026                                 ig.Emit (OpCodes.Stloc, local);
5027                                 ig.Emit (OpCodes.Ldloca, local);
5028                                 return;
5029                         }
5030
5031
5032                         if (FieldInfo.IsStatic){
5033                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
5034                         } else {
5035                                 if (!prepared)
5036                                         EmitInstance (ec, false);
5037                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
5038                         }
5039                 }
5040         }
5041
5042
5043         /// <summary>
5044         ///   Expression that evaluates to a Property.  The Assign class
5045         ///   might set the `Value' expression if we are in an assignment.
5046         ///
5047         ///   This is not an LValue because we need to re-write the expression, we
5048         ///   can not take data from the stack and store it.
5049         /// </summary>
5050         public class PropertyExpr : MemberExpr, IAssignMethod {
5051                 public readonly PropertyInfo PropertyInfo;
5052                 MethodInfo getter, setter;
5053                 bool is_static;
5054
5055                 bool resolved;
5056
5057                 LocalTemporary temp;
5058                 bool prepared;
5059
5060                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5061                 {
5062                         PropertyInfo = pi;
5063                         eclass = ExprClass.PropertyAccess;
5064                         is_static = false;
5065                         loc = l;
5066
5067                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5068
5069                         ResolveAccessors (container_type);
5070                 }
5071
5072                 public override string Name {
5073                         get {
5074                                 return PropertyInfo.Name;
5075                         }
5076                 }
5077
5078                 public override bool IsInstance {
5079                         get {
5080                                 return !is_static;
5081                         }
5082                 }
5083
5084                 public override bool IsStatic {
5085                         get {
5086                                 return is_static;
5087                         }
5088                 }
5089
5090                 public override Expression CreateExpressionTree (EmitContext ec)
5091                 {
5092                         if (IsSingleDimensionalArrayLength ()) {
5093                                 ArrayList args = new ArrayList (1);
5094                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5095                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5096                         }
5097
5098                         // TODO: it's waiting for PropertyExpr refactoring
5099                         //ArrayList args = new ArrayList (2);
5100                         //args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5101                         //args.Add (getter expression);
5102                         //return CreateExpressionFactoryCall ("Property", args);
5103                         return base.CreateExpressionTree (ec);
5104                 }
5105
5106                 public Expression CreateSetterTypeOfExpression ()
5107                 {
5108                         return new TypeOfMethodInfo (setter, loc);
5109                 }
5110
5111                 public override Type DeclaringType {
5112                         get {
5113                                 return PropertyInfo.DeclaringType;
5114                         }
5115                 }
5116
5117                 public override string GetSignatureForError ()
5118                 {
5119                         return TypeManager.GetFullNameSignature (PropertyInfo);
5120                 }
5121
5122                 void FindAccessors (Type invocation_type)
5123                 {
5124                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5125                                 BindingFlags.Static | BindingFlags.Instance |
5126                                 BindingFlags.DeclaredOnly;
5127
5128                         Type current = PropertyInfo.DeclaringType;
5129                         for (; current != null; current = current.BaseType) {
5130                                 MemberInfo[] group = TypeManager.MemberLookup (
5131                                         invocation_type, invocation_type, current,
5132                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5133
5134                                 if (group == null)
5135                                         continue;
5136
5137                                 if (group.Length != 1)
5138                                         // Oooops, can this ever happen ?
5139                                         return;
5140
5141                                 PropertyInfo pi = (PropertyInfo) group [0];
5142
5143                                 if (getter == null)
5144                                         getter = pi.GetGetMethod (true);
5145
5146                                 if (setter == null)
5147                                         setter = pi.GetSetMethod (true);
5148
5149                                 MethodInfo accessor = getter != null ? getter : setter;
5150
5151                                 if (!accessor.IsVirtual)
5152                                         return;
5153                         }
5154                 }
5155
5156                 //
5157                 // We also perform the permission checking here, as the PropertyInfo does not
5158                 // hold the information for the accessibility of its setter/getter
5159                 //
5160                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5161                 void ResolveAccessors (Type container_type)
5162                 {
5163                         FindAccessors (container_type);
5164
5165                         if (getter != null) {
5166                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5167                                 IMethodData md = TypeManager.GetMethod (the_getter);
5168                                 if (md != null)
5169                                         md.SetMemberIsUsed ();
5170
5171                                 is_static = getter.IsStatic;
5172                         }
5173
5174                         if (setter != null) {
5175                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5176                                 IMethodData md = TypeManager.GetMethod (the_setter);
5177                                 if (md != null)
5178                                         md.SetMemberIsUsed ();
5179
5180                                 is_static = setter.IsStatic;
5181                         }
5182                 }
5183
5184                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5185                 {
5186                         if (is_static) {
5187                                 InstanceExpression = null;
5188                                 return true;
5189                         }
5190
5191                         if (InstanceExpression == null) {
5192                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5193                                 return false;
5194                         }
5195
5196                         InstanceExpression = InstanceExpression.DoResolve (ec);
5197                         if (lvalue_instance && InstanceExpression != null)
5198                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5199
5200                         if (InstanceExpression == null)
5201                                 return false;
5202
5203                         InstanceExpression.CheckMarshalByRefAccess (ec);
5204
5205                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5206                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5207                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5208                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5209                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5210                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5211                                 return false;
5212                         }
5213
5214                         return true;
5215                 }
5216
5217                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5218                 {
5219                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5220                         if (mi is MethodBuilder) {
5221                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5222                                 return;
5223                         }
5224
5225                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5226                         sig.Append ('.');
5227                         ParameterData iparams = TypeManager.GetParameterData (mi);
5228                         sig.Append (getter ? "get_" : "set_");
5229                         sig.Append (Name);
5230                         sig.Append (iparams.GetSignatureForError ());
5231
5232                         Report.SymbolRelatedToPreviousError (mi);
5233                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5234                                 Name, sig.ToString ());
5235                 }
5236
5237                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5238                 {
5239                         bool dummy;
5240                         MethodInfo accessor = lvalue ? setter : getter;
5241                         if (accessor == null && lvalue)
5242                                 accessor = getter;
5243                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5244                 }
5245
5246                 bool IsSingleDimensionalArrayLength ()
5247                 {
5248                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5249                                 return false;
5250
5251                         string t_name = InstanceExpression.Type.Name;
5252                         int t_name_len = t_name.Length;
5253                         return t_name_len > 2 && t_name [t_name_len - 2] == '[' && t_name [t_name_len - 3] != ']';
5254                 }
5255
5256                 override public Expression DoResolve (EmitContext ec)
5257                 {
5258                         if (resolved)
5259                                 return this;
5260
5261                         if (getter != null){
5262                                 if (TypeManager.GetParameterData (getter).Count != 0){
5263                                         Error_PropertyNotFound (getter, true);
5264                                         return null;
5265                                 }
5266                         }
5267
5268                         if (getter == null){
5269                                 //
5270                                 // The following condition happens if the PropertyExpr was
5271                                 // created, but is invalid (ie, the property is inaccessible),
5272                                 // and we did not want to embed the knowledge about this in
5273                                 // the caller routine.  This only avoids double error reporting.
5274                                 //
5275                                 if (setter == null)
5276                                         return null;
5277
5278                                 if (InstanceExpression != EmptyExpression.Null) {
5279                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5280                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5281                                         return null;
5282                                 }
5283                         }
5284
5285                         bool must_do_cs1540_check = false;
5286                         if (getter != null &&
5287                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5288                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5289                                 if (pm != null && pm.HasCustomAccessModifier) {
5290                                         Report.SymbolRelatedToPreviousError (pm);
5291                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5292                                                 TypeManager.CSharpSignature (getter));
5293                                 }
5294                                 else {
5295                                         Report.SymbolRelatedToPreviousError (getter);
5296                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5297                                 }
5298                                 return null;
5299                         }
5300
5301                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5302                                 return null;
5303
5304                         //
5305                         // Only base will allow this invocation to happen.
5306                         //
5307                         if (IsBase && getter.IsAbstract) {
5308                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5309                                 return null;
5310                         }
5311
5312                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5313                                 UnsafeError (loc);
5314                                 return null;
5315                         }
5316
5317                         resolved = true;
5318
5319                         return this;
5320                 }
5321
5322                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5323                 {
5324                         if (right_side == EmptyExpression.OutAccess) {
5325                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5326                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5327                                             PropertyInfo.Name);
5328                                 } else {
5329                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5330                                               GetSignatureForError ());
5331                                 }
5332                                 return null;
5333                         }
5334
5335                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5336                                 Error_CannotModifyIntermediateExpressionValue (ec);
5337                         }
5338
5339                         if (setter == null){
5340                                 //
5341                                 // The following condition happens if the PropertyExpr was
5342                                 // created, but is invalid (ie, the property is inaccessible),
5343                                 // and we did not want to embed the knowledge about this in
5344                                 // the caller routine.  This only avoids double error reporting.
5345                                 //
5346                                 if (getter == null)
5347                                         return null;
5348                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5349                                               GetSignatureForError ());
5350                                 return null;
5351                         }
5352
5353                         if (TypeManager.GetParameterData (setter).Count != 1){
5354                                 Error_PropertyNotFound (setter, false);
5355                                 return null;
5356                         }
5357
5358                         bool must_do_cs1540_check;
5359                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5360                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5361                                 if (pm != null && pm.HasCustomAccessModifier) {
5362                                         Report.SymbolRelatedToPreviousError (pm);
5363                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5364                                                 TypeManager.CSharpSignature (setter));
5365                                 }
5366                                 else {
5367                                         Report.SymbolRelatedToPreviousError (setter);
5368                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5369                                 }
5370                                 return null;
5371                         }
5372
5373                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5374                                 return null;
5375
5376                         //
5377                         // Only base will allow this invocation to happen.
5378                         //
5379                         if (IsBase && setter.IsAbstract){
5380                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5381                                 return null;
5382                         }
5383
5384                         return this;
5385                 }
5386
5387                 public override void Emit (EmitContext ec)
5388                 {
5389                         Emit (ec, false);
5390                 }
5391
5392                 public void Emit (EmitContext ec, bool leave_copy)
5393                 {
5394                         //
5395                         // Special case: length of single dimension array property is turned into ldlen
5396                         //
5397                         if (IsSingleDimensionalArrayLength ()) {
5398                                 if (!prepared)
5399                                         EmitInstance (ec, false);
5400                                 ec.ig.Emit (OpCodes.Ldlen);
5401                                 ec.ig.Emit (OpCodes.Conv_I4);
5402                                 return;
5403                         }
5404
5405                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5406
5407                         if (leave_copy) {
5408                                 ec.ig.Emit (OpCodes.Dup);
5409                                 if (!is_static) {
5410                                         temp = new LocalTemporary (this.Type);
5411                                         temp.Store (ec);
5412                                 }
5413                         }
5414                 }
5415
5416                 //
5417                 // Implements the IAssignMethod interface for assignments
5418                 //
5419                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5420                 {
5421                         Expression my_source = source;
5422
5423                         if (prepare_for_load) {
5424                                 prepared = true;
5425                                 source.Emit (ec);
5426
5427                                 if (leave_copy) {
5428                                         ec.ig.Emit (OpCodes.Dup);
5429                                         if (!is_static) {
5430                                                 temp = new LocalTemporary (this.Type);
5431                                                 temp.Store (ec);
5432                                         }
5433                                 }
5434                         } else if (leave_copy) {
5435                                 source.Emit (ec);
5436                                 temp = new LocalTemporary (this.Type);
5437                                 temp.Store (ec);
5438                                 my_source = temp;
5439                         }
5440
5441                         ArrayList args = new ArrayList (1);
5442                         args.Add (new Argument (my_source, Argument.AType.Expression));
5443
5444                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5445
5446                         if (temp != null) {
5447                                 temp.Emit (ec);
5448                                 temp.Release (ec);
5449                         }
5450                 }
5451         }
5452
5453         /// <summary>
5454         ///   Fully resolved expression that evaluates to an Event
5455         /// </summary>
5456         public class EventExpr : MemberExpr {
5457                 public readonly EventInfo EventInfo;
5458
5459                 bool is_static;
5460                 MethodInfo add_accessor, remove_accessor;
5461
5462                 public EventExpr (EventInfo ei, Location loc)
5463                 {
5464                         EventInfo = ei;
5465                         this.loc = loc;
5466                         eclass = ExprClass.EventAccess;
5467
5468                         add_accessor = TypeManager.GetAddMethod (ei);
5469                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5470                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5471                                 is_static = true;
5472
5473                         if (EventInfo is MyEventBuilder){
5474                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5475                                 type = eb.EventType;
5476                                 eb.SetUsed ();
5477                         } else
5478                                 type = EventInfo.EventHandlerType;
5479                 }
5480
5481                 public override string Name {
5482                         get {
5483                                 return EventInfo.Name;
5484                         }
5485                 }
5486
5487                 public override bool IsInstance {
5488                         get {
5489                                 return !is_static;
5490                         }
5491                 }
5492
5493                 public override bool IsStatic {
5494                         get {
5495                                 return is_static;
5496                         }
5497                 }
5498
5499                 public override Type DeclaringType {
5500                         get {
5501                                 return EventInfo.DeclaringType;
5502                         }
5503                 }
5504
5505                 void Error_AssignmentEventOnly ()
5506                 {
5507                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5508                                 GetSignatureForError ());
5509                 }
5510
5511                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5512                                                                 SimpleName original)
5513                 {
5514                         //
5515                         // If the event is local to this class, we transform ourselves into a FieldExpr
5516                         //
5517
5518                         if (EventInfo.DeclaringType == ec.ContainerType ||
5519                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5520                                 EventField mi = TypeManager.GetEventField (EventInfo);
5521
5522                                 if (mi != null) {
5523                                         if (!ec.IsInObsoleteScope)
5524                                                 mi.CheckObsoleteness (loc);
5525
5526                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5527                                                 Error_AssignmentEventOnly ();
5528
5529                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5530
5531                                         InstanceExpression = null;
5532
5533                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5534                                 }
5535                         }
5536
5537                         if (left is This && !ec.IsInCompoundAssignment)
5538                                 Error_AssignmentEventOnly ();
5539
5540                         return base.ResolveMemberAccess (ec, left, loc, original);
5541                 }
5542
5543                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5544                 {
5545                         if (is_static) {
5546                                 InstanceExpression = null;
5547                                 return true;
5548                         }
5549
5550                         if (InstanceExpression == null) {
5551                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5552                                 return false;
5553                         }
5554
5555                         InstanceExpression = InstanceExpression.DoResolve (ec);
5556                         if (InstanceExpression == null)
5557                                 return false;
5558
5559                         if (IsBase && add_accessor.IsAbstract) {
5560                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5561                                 return false;
5562                         }
5563
5564                         //
5565                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5566                         // However, in the Event case, we reported a CS0122 instead.
5567                         //
5568                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5569                             InstanceExpression.Type != ec.ContainerType &&
5570                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5571                                 Report.SymbolRelatedToPreviousError (EventInfo);
5572                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5573                                 return false;
5574                         }
5575
5576                         return true;
5577                 }
5578
5579                 public bool IsAccessibleFrom (Type invocation_type)
5580                 {
5581                         bool dummy;
5582                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5583                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5584                 }
5585
5586                 public override Expression CreateExpressionTree (EmitContext ec)
5587                 {
5588                         throw new NotSupportedException ("ET");
5589                 }
5590
5591                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5592                 {
5593                         // contexts where an LValue is valid have already devolved to FieldExprs
5594                         Error_CannotAssign ();
5595                         return null;
5596                 }
5597
5598                 public override Expression DoResolve (EmitContext ec)
5599                 {
5600                         bool must_do_cs1540_check;
5601                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5602                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5603                                 Report.SymbolRelatedToPreviousError (EventInfo);
5604                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5605                                 return null;
5606                         }
5607
5608                         if (!InstanceResolve (ec, must_do_cs1540_check))
5609                                 return null;
5610
5611                         if (!ec.IsInCompoundAssignment) {
5612                                 Error_CannotAssign ();
5613                                 return null;
5614                         }
5615
5616                         return this;
5617                 }
5618
5619                 public override void Emit (EmitContext ec)
5620                 {
5621                         Error_CannotAssign ();
5622                 }
5623
5624                 public void Error_CannotAssign ()
5625                 {
5626                         Report.Error (70, loc,
5627                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
5628                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
5629                 }
5630
5631                 public override string GetSignatureForError ()
5632                 {
5633                         return TypeManager.CSharpSignature (EventInfo);
5634                 }
5635
5636                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
5637                 {
5638                         ArrayList args = new ArrayList (1);
5639                         args.Add (new Argument (source, Argument.AType.Expression));
5640                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
5641                 }
5642         }
5643
5644         public class TemporaryVariable : Expression, IMemoryLocation
5645         {
5646                 LocalInfo li;
5647                 Variable var;
5648
5649                 public TemporaryVariable (Type type, Location loc)
5650                 {
5651                         this.type = type;
5652                         this.loc = loc;
5653                         eclass = ExprClass.Value;
5654                 }
5655
5656                 public override Expression CreateExpressionTree (EmitContext ec)
5657                 {
5658                         throw new NotSupportedException ("ET");
5659                 }
5660
5661                 public override Expression DoResolve (EmitContext ec)
5662                 {
5663                         if (li != null)
5664                                 return this;
5665
5666                         TypeExpr te = new TypeExpression (type, loc);
5667                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5668                         if (!li.Resolve (ec))
5669                                 return null;
5670
5671                         if (ec.MustCaptureVariable (li)) {
5672                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5673                                 var = scope.AddLocal (li);
5674                                 type = var.Type;
5675                         }
5676
5677                         return this;
5678                 }
5679
5680                 public Variable Variable {
5681                         get { return var != null ? var : li.Variable; }
5682                 }
5683
5684                 public override void Emit (EmitContext ec)
5685                 {
5686                         Variable.EmitInstance (ec);
5687                         Variable.Emit (ec);
5688                 }
5689
5690                 public void EmitLoadAddress (EmitContext ec)
5691                 {
5692                         Variable.EmitInstance (ec);
5693                         Variable.EmitAddressOf (ec);
5694                 }
5695
5696                 public void Store (EmitContext ec, Expression right_side)
5697                 {
5698                         Variable.EmitInstance (ec);
5699                         right_side.Emit (ec);
5700                         Variable.EmitAssign (ec);
5701                 }
5702
5703                 public void EmitThis (EmitContext ec)
5704                 {
5705                         Variable.EmitInstance (ec);
5706                 }
5707
5708                 public void EmitStore (EmitContext ec)
5709                 {
5710                         Variable.EmitAssign (ec);
5711                 }
5712
5713                 public void AddressOf (EmitContext ec, AddressOp mode)
5714                 {
5715                         EmitLoadAddress (ec);
5716                 }
5717         }
5718
5719         ///
5720         /// Handles `var' contextual keyword; var becomes a keyword only
5721         /// if no type called var exists in a variable scope
5722         ///
5723         public class VarExpr : SimpleName
5724         {
5725                 // Used for error reporting only
5726                 ArrayList initializer;
5727
5728                 public VarExpr (Location loc)
5729                         : base ("var", loc)
5730                 {
5731                 }
5732
5733                 public ArrayList VariableInitializer {
5734                         set {
5735                                 this.initializer = value;
5736                         }
5737                 }
5738
5739                 public bool InferType (EmitContext ec, Expression right_side)
5740                 {
5741                         if (type != null)
5742                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5743
5744                         type = right_side.Type;
5745                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5746                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5747                                               right_side.GetSignatureForError ());
5748                                 return false;
5749                         }
5750
5751                         eclass = ExprClass.Variable;
5752                         return true;
5753                 }
5754
5755                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5756                 {
5757                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5758                 }
5759
5760                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5761                 {
5762                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5763                         if (te != null)
5764                                 return te;
5765
5766                         if (initializer == null)
5767                                 return null;
5768
5769                         if (initializer.Count > 1) {
5770                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5771                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5772                                 initializer = null;
5773                                 return null;
5774                         }
5775
5776                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5777                         if (variable_initializer == null) {
5778                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5779                                 return null;
5780                         }
5781
5782                         return null;
5783                 }
5784         }
5785 }