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 #if NET_4_0
  22         using SLE = System.Linq.Expressions;
  23 #endif
  24
  25         /// <remarks>
  26         ///   The ExprClass class contains the is used to pass the
  27         ///   classification of an expression (value, variable, namespace,
  28         ///   type, method group, property access, event access, indexer access,
  29         ///   nothing).
  30         /// </remarks>
  31         public enum ExprClass : byte {
  32                 Invalid,
  33
  34                 Value,
  35                 Variable,
  36                 Namespace,
  37                 Type,
  38                 TypeParameter,
  39                 MethodGroup,
  40                 PropertyAccess,
  41                 EventAccess,
  42                 IndexerAccess,
  43                 Nothing,
  44         }
  45
  46         /// <remarks>
  47         ///   This is used to tell Resolve in which types of expressions we're
  48         ///   interested.
  49         /// </remarks>
  50         [Flags]
  51         public enum ResolveFlags {
  52                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  53                 VariableOrValue         = 1,
  54
  55                 // Returns a type expression.
  56                 Type                    = 1 << 1,
  57
  58                 // Returns a method group.
  59                 MethodGroup             = 1 << 2,
  60
  61                 TypeParameter   = 1 << 3,
  62
  63                 // Mask of all the expression class flags.
  64                 MaskExprClass = VariableOrValue | Type | MethodGroup | TypeParameter,
  65
  66                 // Disable control flow analysis while resolving the expression.
  67                 // This is used when resolving the instance expression of a field expression.
  68                 DisableFlowAnalysis     = 1 << 10,
  69
  70                 // Set if this is resolving the first part of a MemberAccess.
  71                 Intermediate            = 1 << 11,
  72
  73                 // Disable control flow analysis _of struct_ while resolving the expression.
  74                 // This is used when resolving the instance expression of a field expression.
  75                 DisableStructFlowAnalysis       = 1 << 12,
  76
  77         }
  78
  79         //
  80         // This is just as a hint to AddressOf of what will be done with the
  81         // address.
  82         [Flags]
  83         public enum AddressOp {
  84                 Store = 1,
  85                 Load  = 2,
  86                 LoadStore = 3
  87         };
  88
  89         /// <summary>
  90         ///   This interface is implemented by variables
  91         /// </summary>
  92         public interface IMemoryLocation {
  93                 /// <summary>
  94                 ///   The AddressOf method should generate code that loads
  95                 ///   the address of the object and leaves it on the stack.
  96                 ///
  97                 ///   The `mode' argument is used to notify the expression
  98                 ///   of whether this will be used to read from the address or
  99                 ///   write to the address.
 100                 ///
 101                 ///   This is just a hint that can be used to provide good error
 102                 ///   reporting, and should have no other side effects.
 103                 /// </summary>
 104                 void AddressOf (EmitContext ec, AddressOp mode);
 105         }
 106
 107         //
 108         // An expressions resolved as a direct variable reference
 109         //
 110         public interface IVariableReference : IFixedExpression
 111         {
 112                 bool IsHoisted { get; }
 113                 string Name { get; }
 114                 VariableInfo VariableInfo { get; }
 115
 116                 void SetHasAddressTaken ();
 117         }
 118
 119         //
 120         // Implemented by an expression which could be or is always
 121         // fixed
 122         //
 123         public interface IFixedExpression
 124         {
 125                 bool IsFixed { get; }
 126         }
 127
 128         /// <remarks>
 129         ///   Base class for expressions
 130         /// </remarks>
 131         public abstract class Expression {
 132                 public ExprClass eclass;
 133                 protected Type type;
 134                 protected Location loc;
 135
 136                 public Type Type {
 137                         get { return type; }
 138                         set { type = value; }
 139                 }
 140
 141                 public virtual Location Location {
 142                         get { return loc; }
 143                 }
 144
 145                 // Not nice but we have broken hierarchy.
 146                 public virtual void CheckMarshalByRefAccess (ResolveContext ec)
 147                 {
 148                 }
 149
 150                 public virtual bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
 151                 {
 152                         Attribute.Error_AttributeArgumentNotValid (ec, loc);
 153                         value = null;
 154                         return false;
 155                 }
 156
 157                 public virtual string GetSignatureForError ()
 158                 {
 159                         return TypeManager.CSharpName (type);
 160                 }
 161
 162                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 163                 {
 164                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 165
 166                         must_do_cs1540_check = false; // by default we do not check for this
 167
 168                         if (ma == MethodAttributes.Public)
 169                                 return true;
 170
 171                         //
 172                         // If only accessible to the current class or children
 173                         //
 174                         if (ma == MethodAttributes.Private)
 175                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 176                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 177
 178                         if (TypeManager.IsThisOrFriendAssembly (invocation_type.Assembly, mi.DeclaringType.Assembly)) {
 179                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 180                                         return true;
 181                         } else {
 182                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 183                                         return false;
 184                         }
 185
 186                         // Family and FamANDAssem require that we derive.
 187                         // FamORAssem requires that we derive if in different assemblies.
 188                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 189                                 return false;
 190
 191                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 192                                 must_do_cs1540_check = true;
 193
 194                         return true;
 195                 }
 196
 197                 public virtual bool IsNull {
 198                         get {
 199                                 return false;
 200                         }
 201                 }
 202
 203                 /// <summary>
 204                 ///   Performs semantic analysis on the Expression
 205                 /// </summary>
 206                 ///
 207                 /// <remarks>
 208                 ///   The Resolve method is invoked to perform the semantic analysis
 209                 ///   on the node.
 210                 ///
 211                 ///   The return value is an expression (it can be the
 212                 ///   same expression in some cases) or a new
 213                 ///   expression that better represents this node.
 214                 ///
 215                 ///   For example, optimizations of Unary (LiteralInt)
 216                 ///   would return a new LiteralInt with a negated
 217                 ///   value.
 218                 ///
 219                 ///   If there is an error during semantic analysis,
 220                 ///   then an error should be reported (using Report)
 221                 ///   and a null value should be returned.
 222                 ///
 223                 ///   There are two side effects expected from calling
 224                 ///   Resolve(): the the field variable "eclass" should
 225                 ///   be set to any value of the enumeration
 226                 ///   `ExprClass' and the type variable should be set
 227                 ///   to a valid type (this is the type of the
 228                 ///   expression).
 229                 /// </remarks>
 230                 public abstract Expression DoResolve (ResolveContext ec);
 231
 232                 public virtual Expression DoResolveLValue (ResolveContext ec, Expression right_side)
 233                 {
 234                         return null;
 235                 }
 236
 237                 //
 238                 // This is used if the expression should be resolved as a type or namespace name.
 239                 // the default implementation fails.
 240                 //
 241                 public virtual FullNamedExpression ResolveAsTypeStep (IMemberContext rc,  bool silent)
 242                 {
 243                         if (!silent) {
 244                                 ResolveContext ec = new ResolveContext (rc);
 245                                 Expression e = Resolve (ec);
 246                                 if (e != null)
 247                                         e.Error_UnexpectedKind (ec, ResolveFlags.Type, loc);
 248                         }
 249
 250                         return null;
 251                 }
 252
 253                 //
 254                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 255                 // same name exists or as a keyword when no type was found
 256                 //
 257                 public virtual TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
 258                 {
 259                         return ResolveAsTypeTerminal (rc, silent);
 260                 }
 261
 262                 //
 263                 // This is used to resolve the expression as a type, a null
 264                 // value will be returned if the expression is not a type
 265                 // reference
 266                 //
 267                 public virtual TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
 268                 {
 269                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 270                         if (te == null)
 271                                 return null;
 272
 273                         if (!silent) { // && !(te is TypeParameterExpr)) {
 274                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 275                                 if (obsolete_attr != null && !ec.IsObsolete) {
 276                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location, ec.Compiler.Report);
 277                                 }
 278                         }
 279
 280                         GenericTypeExpr ct = te as GenericTypeExpr;
 281                         if (ct != null) {
 282                                 //
 283                                 // TODO: Constrained type parameters check for parameters of generic method overrides is broken
 284                                 // There are 2 solutions.
 285                                 // 1, Skip this check completely when we are in override/explicit impl scope
 286                                 // 2, Copy type parameters constraints from base implementation and pass (they have to be emitted anyway)
 287                                 //
 288                                 MemberCore gm = ec as GenericMethod;
 289                                 if (gm == null)
 290                                         gm = ec as Method;
 291                                 if (gm != null && ((gm.ModFlags & Modifiers.OVERRIDE) != 0 || gm.MemberName.Left != null)) {
 292                                         te.loc = loc;
 293                                         return te;
 294                                 }
 295
 296                                 // TODO: silent flag is ignored
 297                                 ct.CheckConstraints (ec);
 298                         }
 299
 300                         return te;
 301                 }
 302
 303                 public TypeExpr ResolveAsBaseTerminal (IMemberContext ec, bool silent)
 304                 {
 305                         int errors = ec.Compiler.Report.Errors;
 306
 307                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 308
 309                         if (fne == null)
 310                                 return null;
 311
 312                         TypeExpr te = fne as TypeExpr;
 313                         if (te == null) {
 314                                 if (!silent && errors == ec.Compiler.Report.Errors)
 315                                         fne.Error_UnexpectedKind (ec.Compiler.Report, null, "type", loc);
 316                                 return null;
 317                         }
 318
 319                         if (!te.CheckAccessLevel (ec)) {
 320                                 ec.Compiler.Report.SymbolRelatedToPreviousError (te.Type);
 321                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type), ec.Compiler.Report);
 322                                 return null;
 323                         }
 324
 325                         te.loc = loc;
 326                         return te;
 327                 }
 328
 329                 public static void ErrorIsInaccesible (Location loc, string name, Report Report)
 330                 {
 331                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 332                 }
 333
 334                 protected static void Error_CannotAccessProtected (ResolveContext ec, Location loc, MemberInfo m, Type qualifier, Type container)
 335                 {
 336                         ec.Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 337                                 + " The qualifier must be of type `{2}' or derived from it",
 338                                 TypeManager.GetFullNameSignature (m),
 339                                 TypeManager.CSharpName (qualifier),
 340                                 TypeManager.CSharpName (container));
 341
 342                 }
 343
 344                 public static void Error_InvalidExpressionStatement (Report Report, Location loc)
 345                 {
 346                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 347                                        "expressions can be used as a statement");
 348                 }
 349
 350                 public void Error_InvalidExpressionStatement (BlockContext ec)
 351                 {
 352                         Error_InvalidExpressionStatement (ec.Report, loc);
 353                 }
 354
 355                 public static void Error_VoidInvalidInTheContext (Location loc, Report Report)
 356                 {
 357                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 358                 }
 359
 360                 public virtual void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
 361                 {
 362                         Error_ValueCannotBeConvertedCore (ec, loc, target, expl);
 363                 }
 364
 365                 protected void Error_ValueCannotBeConvertedCore (ResolveContext ec, Location loc, Type target, bool expl)
 366                 {
 367                         // The error was already reported as CS1660
 368                         if (type == InternalType.AnonymousMethod)
 369                                 return;
 370
 371                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 372                                 string sig1 = type.DeclaringMethod == null ?
 373                                         TypeManager.CSharpName (type.DeclaringType) :
 374                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 375                                 string sig2 = target.DeclaringMethod == null ?
 376                                         TypeManager.CSharpName (target.DeclaringType) :
 377                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 378                                 ec.Report.ExtraInformation (loc,
 379                                         String.Format (
 380                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 381                                                 Type.Name, sig1, sig2));
 382                         } else if (Type.FullName == target.FullName){
 383                                 ec.Report.ExtraInformation (loc,
 384                                         String.Format (
 385                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 386                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 387                         }
 388
 389                         if (expl) {
 390                                 ec.Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 391                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 392                                 return;
 393                         }
 394
 395                         ec.Report.DisableReporting ();
 396                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 397                         ec.Report.EnableReporting ();
 398
 399                         if (expl_exists) {
 400                                 ec.Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 401                                               "An explicit conversion exists (are you missing a cast?)",
 402                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 403                                 return;
 404                         }
 405
 406                         ec.Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 407                                 TypeManager.CSharpName (type),
 408                                 TypeManager.CSharpName (target));
 409                 }
 410
 411                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (Report Report, string name)
 412                 {
 413                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 414                 }
 415
 416                 public void Error_TypeArgumentsCannotBeUsed (Report report, Location loc)
 417                 {
 418                         // Better message for possible generic expressions
 419                         if (eclass == ExprClass.MethodGroup || eclass == ExprClass.Type) {
 420                                 if (this is TypeExpr)
 421                                         report.SymbolRelatedToPreviousError (type);
 422
 423                                 string name = eclass == ExprClass.Type ? ExprClassName : "method";
 424                                 report.Error (308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 425                                         name, GetSignatureForError ());
 426                         } else {
 427                                 report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
 428                                         ExprClassName, GetSignatureForError ());
 429                         }
 430                 }
 431
 432                 protected virtual void Error_TypeDoesNotContainDefinition (ResolveContext ec, Type type, string name)
 433                 {
 434                         Error_TypeDoesNotContainDefinition (ec, loc, type, name);
 435                 }
 436
 437                 public static void Error_TypeDoesNotContainDefinition (ResolveContext ec, Location loc, Type type, string name)
 438                 {
 439                         ec.Report.SymbolRelatedToPreviousError (type);
 440                         ec.Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 441                                 TypeManager.CSharpName (type), name);
 442                 }
 443
 444                 protected static void Error_ValueAssignment (ResolveContext ec, Location loc)
 445                 {
 446                         ec.Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 447                 }
 448
 449                 ResolveFlags ExprClassToResolveFlags
 450                 {
 451                         get {
 452                                 switch (eclass) {
 453                                 case ExprClass.Type:
 454                                 case ExprClass.Namespace:
 455                                         return ResolveFlags.Type;
 456
 457                                 case ExprClass.MethodGroup:
 458                                         return ResolveFlags.MethodGroup;
 459
 460                                 case ExprClass.TypeParameter:
 461                                         return ResolveFlags.TypeParameter;
 462
 463                                 case ExprClass.Value:
 464                                 case ExprClass.Variable:
 465                                 case ExprClass.PropertyAccess:
 466                                 case ExprClass.EventAccess:
 467                                 case ExprClass.IndexerAccess:
 468                                         return ResolveFlags.VariableOrValue;
 469
 470                                 default:
 471                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 472                                 }
 473                         }
 474                 }
 475
 476                 /// <summary>
 477                 ///   Resolves an expression and performs semantic analysis on it.
 478                 /// </summary>
 479                 ///
 480                 /// <remarks>
 481                 ///   Currently Resolve wraps DoResolve to perform sanity
 482                 ///   checking and assertion checking on what we expect from Resolve.
 483                 /// </remarks>
 484                 public Expression Resolve (ResolveContext ec, ResolveFlags flags)
 485                 {
 486                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 487                                 return ResolveAsTypeStep (ec, false);
 488
 489                         bool do_flow_analysis = ec.DoFlowAnalysis;
 490                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 491                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 492                                 do_flow_analysis = false;
 493                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 494                                 omit_struct_analysis = true;
 495
 496                         Expression e;
 497                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 498                                 if (this is SimpleName) {
 499                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 500                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 501                                 } else {
 502                                         e = DoResolve (ec);
 503                                 }
 504                         }
 505
 506                         if (e == null)
 507                                 return null;
 508
 509                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 510                                 e.Error_UnexpectedKind (ec, flags, loc);
 511                                 return null;
 512                         }
 513
 514                         if (e.type == null && !(e is Namespace)) {
 515                                 throw new Exception (
 516                                         "Expression " + e.GetType () +
 517                                         " did not set its type after Resolve\n" +
 518                                         "called from: " + this.GetType ());
 519                         }
 520
 521                         return e;
 522                 }
 523
 524                 /// <summary>
 525                 ///   Resolves an expression and performs semantic analysis on it.
 526                 /// </summary>
 527                 public Expression Resolve (ResolveContext ec)
 528                 {
 529                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 530
 531                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 532                                 ((MethodGroupExpr) e).ReportUsageError (ec);
 533                                 return null;
 534                         }
 535                         return e;
 536                 }
 537
 538                 public Constant ResolveAsConstant (ResolveContext ec, MemberCore mc)
 539                 {
 540                         Expression e = Resolve (ec);
 541                         if (e == null)
 542                                 return null;
 543
 544                         Constant c = e as Constant;
 545                         if (c != null)
 546                                 return c;
 547
 548                         if (type != null && TypeManager.IsReferenceType (type))
 549                                 Const.Error_ConstantCanBeInitializedWithNullOnly (type, loc, mc.GetSignatureForError (), ec.Report);
 550                         else
 551                                 Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError (), ec.Report);
 552
 553                         return null;
 554                 }
 555
 556                 /// <summary>
 557                 ///   Resolves an expression for LValue assignment
 558                 /// </summary>
 559                 ///
 560                 /// <remarks>
 561                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 562                 ///   checking and assertion checking on what we expect from Resolve
 563                 /// </remarks>
 564                 public Expression ResolveLValue (ResolveContext ec, Expression right_side)
 565                 {
 566                         int errors = ec.Report.Errors;
 567                         bool out_access = right_side == EmptyExpression.OutAccess;
 568
 569                         Expression e = DoResolveLValue (ec, right_side);
 570
 571                         if (e != null && out_access && !(e is IMemoryLocation)) {
 572                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 573                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 574
 575                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 576                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 577                                 e = null;
 578                         }
 579
 580                         if (e == null) {
 581                                 if (errors == ec.Report.Errors) {
 582                                         if (out_access)
 583                                                 ec.Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 584                                         else
 585                                                 Error_ValueAssignment (ec, loc);
 586                                 }
 587                                 return null;
 588                         }
 589
 590                         if (e.eclass == ExprClass.Invalid)
 591                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 592
 593                         if ((e.type == null) && !(e is GenericTypeExpr))
 594                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 595
 596                         return e;
 597                 }
 598
 599                 /// <summary>
 600                 ///   Emits the code for the expression
 601                 /// </summary>
 602                 ///
 603                 /// <remarks>
 604                 ///   The Emit method is invoked to generate the code
 605                 ///   for the expression.
 606                 /// </remarks>
 607                 public abstract void Emit (EmitContext ec);
 608
 609                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 610                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 611                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 612                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 613                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 614                 {
 615                         Emit (ec);
 616                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 617                 }
 618
 619                 // Emit this expression for its side effects, not for its value.
 620                 // The default implementation is to emit the value, and then throw it away.
 621                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 622                 public virtual void EmitSideEffect (EmitContext ec)
 623                 {
 624                         Emit (ec);
 625                         ec.ig.Emit (OpCodes.Pop);
 626                 }
 627
 628                 /// <summary>
 629                 ///   Protected constructor.  Only derivate types should
 630                 ///   be able to be created
 631                 /// </summary>
 632
 633                 protected Expression ()
 634                 {
 635                         eclass = ExprClass.Invalid;
 636                         type = null;
 637                 }
 638
 639                 /// <summary>
 640                 ///   Returns a fully formed expression after a MemberLookup
 641                 /// </summary>
 642                 ///
 643                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 644                 {
 645                         if (mi is EventInfo)
 646                                 return new EventExpr ((EventInfo) mi, loc);
 647                         else if (mi is FieldInfo) {
 648                                 FieldInfo fi = (FieldInfo) mi;
 649                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 650                                         return new ConstantExpr (fi, loc);
 651                                 return new FieldExpr (fi, loc);
 652                         } else if (mi is PropertyInfo)
 653                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 654                         else if (mi is Type) {
 655                                 return new TypeExpression ((System.Type) mi, loc);
 656                         }
 657
 658                         return null;
 659                 }
 660
 661                 // TODO: [Obsolete ("Can be removed")]
 662                 protected static ArrayList almost_matched_members = new ArrayList (4);
 663
 664                 //
 665                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 666                 //
 667                 // This code could use some optimizations, but we need to do some
 668                 // measurements.  For example, we could use a delegate to `flag' when
 669                 // something can not any longer be a method-group (because it is something
 670                 // else).
 671                 //
 672                 // Return values:
 673                 //     If the return value is an Array, then it is an array of
 674                 //     MethodBases
 675                 //
 676                 //     If the return value is an MemberInfo, it is anything, but a Method
 677                 //
 678                 //     null on error.
 679                 //
 680                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 681                 // the arguments here and have MemberLookup return only the methods that
 682                 // match the argument count/type, unlike we are doing now (we delay this
 683                 // decision).
 684                 //
 685                 // This is so we can catch correctly attempts to invoke instance methods
 686                 // from a static body (scan for error 120 in ResolveSimpleName).
 687                 //
 688                 //
 689                 // FIXME: Potential optimization, have a static ArrayList
 690                 //
 691
 692                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type, string name,
 693                                                        MemberTypes mt, BindingFlags bf, Location loc)
 694                 {
 695                         return MemberLookup (ctx, container_type, null, queried_type, name, mt, bf, loc);
 696                 }
 697
 698                 //
 699                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 700                 // `qualifier_type' or null to lookup members in the current class.
 701                 //
 702
 703                 public static Expression MemberLookup (CompilerContext ctx, Type container_type,
 704                                                        Type qualifier_type, Type queried_type,
 705                                                        string name, MemberTypes mt,
 706                                                        BindingFlags bf, Location loc)
 707                 {
 708                         almost_matched_members.Clear ();
 709
 710                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 711                                                                      queried_type, mt, bf, name, almost_matched_members);
 712
 713                         if (mi == null)
 714                                 return null;
 715
 716                         if (mi.Length > 1) {
 717                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 718                                 ArrayList methods = new ArrayList (2);
 719                                 ArrayList non_methods = null;
 720
 721                                 foreach (MemberInfo m in mi) {
 722                                         if (m is MethodBase) {
 723                                                 methods.Add (m);
 724                                                 continue;
 725                                         }
 726
 727                                         if (non_methods == null)
 728                                                 non_methods = new ArrayList (2);
 729
 730                                         bool is_candidate = true;
 731                                         for (int i = 0; i < non_methods.Count; ++i) {
 732                                                 MemberInfo n_m = (MemberInfo) non_methods [i];
 733                                                 if (n_m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType)) {
 734                                                         non_methods.Remove (n_m);
 735                                                         --i;
 736                                                 } else if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (n_m.DeclaringType, m.DeclaringType)) {
 737                                                         is_candidate = false;
 738                                                         break;
 739                                                 }
 740                                         }
 741
 742                                         if (is_candidate) {
 743                                                 non_methods.Add (m);
 744                                         }
 745                                 }
 746
 747                                 if (methods.Count == 0 && non_methods != null && non_methods.Count > 1) {
 748                                         ctx.Report.SymbolRelatedToPreviousError ((MemberInfo)non_methods [1]);
 749                                         ctx.Report.SymbolRelatedToPreviousError ((MemberInfo)non_methods [0]);
 750                                         ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 751                                                 TypeManager.GetFullNameSignature ((MemberInfo)non_methods [1]),
 752                                                 TypeManager.GetFullNameSignature ((MemberInfo)non_methods [0]));
 753                                         return null;
 754                                 }
 755
 756                                 if (methods.Count == 0)
 757                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 758
 759                                 if (non_methods != null && non_methods.Count > 0) {
 760                                         MethodBase method = (MethodBase) methods [0];
 761                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 762                                         if (method.DeclaringType == non_method.DeclaringType) {
 763                                                 // Cannot happen with C# code, but is valid in IL
 764                                                 ctx.Report.SymbolRelatedToPreviousError (method);
 765                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 766                                                 ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 767                                                               TypeManager.GetFullNameSignature (non_method),
 768                                                               TypeManager.CSharpSignature (method));
 769                                                 return null;
 770                                         }
 771
 772                                         if (is_interface) {
 773                                                 ctx.Report.SymbolRelatedToPreviousError (method);
 774                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 775                                                 ctx.Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 776                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 777                                         }
 778                                 }
 779
 780                                 return new MethodGroupExpr (methods, queried_type, loc);
 781                         }
 782
 783                         if (mi [0] is MethodBase)
 784                                 return new MethodGroupExpr (mi, queried_type, loc);
 785
 786                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 787                 }
 788
 789                 public const MemberTypes AllMemberTypes =
 790                         MemberTypes.Constructor |
 791                         MemberTypes.Event       |
 792                         MemberTypes.Field       |
 793                         MemberTypes.Method      |
 794                         MemberTypes.NestedType  |
 795                         MemberTypes.Property;
 796
 797                 public const BindingFlags AllBindingFlags =
 798                         BindingFlags.Public |
 799                         BindingFlags.Static |
 800                         BindingFlags.Instance;
 801
 802                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type,
 803                                                        string name, Location loc)
 804                 {
 805                         return MemberLookup (ctx, container_type, null, queried_type, name,
 806                                              AllMemberTypes, AllBindingFlags, loc);
 807                 }
 808
 809                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type qualifier_type,
 810                                                        Type queried_type, string name, Location loc)
 811                 {
 812                         return MemberLookup (ctx, container_type, qualifier_type, queried_type,
 813                                              name, AllMemberTypes, AllBindingFlags, loc);
 814                 }
 815
 816                 public static MethodGroupExpr MethodLookup (CompilerContext ctx, Type container_type, Type queried_type,
 817                                                        string name, Location loc)
 818                 {
 819                         return (MethodGroupExpr)MemberLookup (ctx, container_type, null, queried_type, name,
 820                                              MemberTypes.Method, AllBindingFlags, loc);
 821                 }
 822
 823                 /// <summary>
 824                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 825                 ///   to find a final definition.  If the final definition is not found, we
 826                 ///   look for private members and display a useful debugging message if we
 827                 ///   find it.
 828                 /// </summary>
 829                 protected Expression MemberLookupFinal (ResolveContext ec, Type qualifier_type,
 830                                                             Type queried_type, string name,
 831                                                             MemberTypes mt, BindingFlags bf,
 832                                                             Location loc)
 833                 {
 834                         Expression e;
 835
 836                         int errors = ec.Report.Errors;
 837                         e = MemberLookup (ec.Compiler, ec.CurrentType, qualifier_type, queried_type, name, mt, bf, loc);
 838
 839                         if (e != null || errors != ec.Report.Errors)
 840                                 return e;
 841
 842                         // No errors were reported by MemberLookup, but there was an error.
 843                         return Error_MemberLookupFailed (ec, ec.CurrentType, qualifier_type, queried_type,
 844                                         name, null, mt, bf);
 845                 }
 846
 847                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type container_type, Type qualifier_type,
 848                                                        Type queried_type, string name, string class_name,
 849                                                            MemberTypes mt, BindingFlags bf)
 850                 {
 851                         MemberInfo[] lookup = null;
 852                         if (queried_type == null) {
 853                                 class_name = "global::";
 854                         } else {
 855                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 856                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 857                                         name, null);
 858
 859                                 if (lookup != null) {
 860                                         Expression e = Error_MemberLookupFailed (ec, queried_type, lookup);
 861
 862                                         //
 863                                         // FIXME: This is still very wrong, it should be done inside
 864                                         // OverloadResolve to do correct arguments matching.
 865                                         // Requires MemberLookup accessiblity check removal
 866                                         //
 867                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 868                                                 MemberInfo mi = lookup[0];
 869                                                 ec.Report.SymbolRelatedToPreviousError (mi);
 870                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 871                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 872                                                         // Although a derived class can access protected members of
 873                                                         // its base class it cannot do so through an instance of the
 874                                                         // base class (CS1540).  If the qualifier_type is a base of the
 875                                                         // ec.CurrentType and the lookup succeeds with the latter one,
 876                                                         // then we are in this situation.
 877                                                         Error_CannotAccessProtected (ec, loc, mi, qualifier_type, container_type);
 878                                                 } else {
 879                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi), ec.Report);
 880                                                 }
 881                                         }
 882
 883                                         return e;
 884                                 }
 885
 886                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 887                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 888                                         name, null);
 889                         }
 890
 891                         if (lookup == null) {
 892                                 if (class_name != null) {
 893                                         ec.Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 894                                                 name);
 895                                 } else {
 896                                         Error_TypeDoesNotContainDefinition (ec, queried_type, name);
 897                                 }
 898                                 return null;
 899                         }
 900
 901                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 902                                                       AllMemberTypes, AllBindingFlags |
 903                                                       BindingFlags.NonPublic, name, null) == null) {
 904                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 905                                         Type t = (Type) lookup [0];
 906
 907                                         ec.Report.Error (305, loc,
 908                                                       "Using the generic type `{0}' " +
 909                                                       "requires {1} type arguments",
 910                                                       TypeManager.CSharpName (t),
 911                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 912                                         return null;
 913                                 }
 914                         }
 915
 916                         return Error_MemberLookupFailed (ec, queried_type, lookup);
 917                 }
 918
 919                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type type, MemberInfo[] members)
 920                 {
 921                         for (int i = 0; i < members.Length; ++i) {
 922                                 if (!(members [i] is MethodBase))
 923                                         return null;
 924                         }
 925
 926                         // By default propagate the closest candidates upwards
 927                         return new MethodGroupExpr (members, type, loc, true);
 928                 }
 929
 930                 protected virtual void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
 931                 {
 932                         throw new NotImplementedException ();
 933                 }
 934
 935                 protected void Error_PointerInsideExpressionTree (ResolveContext ec)
 936                 {
 937                         ec.Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 938                 }
 939
 940                 /// <summary>
 941                 ///   Returns an expression that can be used to invoke operator true
 942                 ///   on the expression if it exists.
 943                 /// </summary>
 944                 protected static Expression GetOperatorTrue (ResolveContext ec, Expression e, Location loc)
 945                 {
 946                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 947                 }
 948
 949                 /// <summary>
 950                 ///   Returns an expression that can be used to invoke operator false
 951                 ///   on the expression if it exists.
 952                 /// </summary>
 953                 static public Expression GetOperatorFalse (ResolveContext ec, Expression e, Location loc)
 954                 {
 955                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 956                 }
 957
 958                 static Expression GetOperatorTrueOrFalse (ResolveContext ec, Expression e, bool is_true, Location loc)
 959                 {
 960                         MethodGroupExpr operator_group;
 961                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 962                         operator_group = MethodLookup (ec.Compiler, ec.CurrentType, e.Type, mname, loc) as MethodGroupExpr;
 963                         if (operator_group == null)
 964                                 return null;
 965
 966                         Arguments arguments = new Arguments (1);
 967                         arguments.Add (new Argument (e));
 968                         operator_group = operator_group.OverloadResolve (
 969                                 ec, ref arguments, false, loc);
 970
 971                         if (operator_group == null)
 972                                 return null;
 973
 974                         return new UserOperatorCall (operator_group, arguments, null, loc);
 975                 }
 976
 977                 public virtual string ExprClassName
 978                 {
 979                         get {
 980                                 switch (eclass){
 981                                 case ExprClass.Invalid:
 982                                         return "Invalid";
 983                                 case ExprClass.Value:
 984                                         return "value";
 985                                 case ExprClass.Variable:
 986                                         return "variable";
 987                                 case ExprClass.Namespace:
 988                                         return "namespace";
 989                                 case ExprClass.Type:
 990                                         return "type";
 991                                 case ExprClass.MethodGroup:
 992                                         return "method group";
 993                                 case ExprClass.PropertyAccess:
 994                                         return "property access";
 995                                 case ExprClass.EventAccess:
 996                                         return "event access";
 997                                 case ExprClass.IndexerAccess:
 998                                         return "indexer access";
 999                                 case ExprClass.Nothing:
1000                                         return "null";
1001                                 case ExprClass.TypeParameter:
1002                                         return "type parameter";
1003                                 }
1004                                 throw new Exception ("Should not happen");
1005                         }
1006                 }
1007
1008                 /// <summary>
1009                 ///   Reports that we were expecting `expr' to be of class `expected'
1010                 /// </summary>
1011                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, Location loc)
1012                 {
1013                         Error_UnexpectedKind (r, mc, expected, ExprClassName, loc);
1014                 }
1015
1016                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, string was, Location loc)
1017                 {
1018                         string name;
1019                         if (mc != null)
1020                                 name = mc.GetSignatureForError ();
1021                         else
1022                                 name = GetSignatureForError ();
1023
1024                         r.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1025                               name, was, expected);
1026                 }
1027
1028                 public void Error_UnexpectedKind (ResolveContext ec, ResolveFlags flags, Location loc)
1029                 {
1030                         string [] valid = new string [4];
1031                         int count = 0;
1032
1033                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1034                                 valid [count++] = "variable";
1035                                 valid [count++] = "value";
1036                         }
1037
1038                         if ((flags & ResolveFlags.Type) != 0)
1039                                 valid [count++] = "type";
1040
1041                         if ((flags & ResolveFlags.MethodGroup) != 0)
1042                                 valid [count++] = "method group";
1043
1044                         if (count == 0)
1045                                 valid [count++] = "unknown";
1046
1047                         StringBuilder sb = new StringBuilder (valid [0]);
1048                         for (int i = 1; i < count - 1; i++) {
1049                                 sb.Append ("', `");
1050                                 sb.Append (valid [i]);
1051                         }
1052                         if (count > 1) {
1053                                 sb.Append ("' or `");
1054                                 sb.Append (valid [count - 1]);
1055                         }
1056
1057                         ec.Report.Error (119, loc,
1058                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1059                 }
1060
1061                 public static void UnsafeError (ResolveContext ec, Location loc)
1062                 {
1063                         UnsafeError (ec.Report, loc);
1064                 }
1065
1066                 public static void UnsafeError (Report Report, Location loc)
1067                 {
1068                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1069                 }
1070
1071                 //
1072                 // Load the object from the pointer.
1073                 //
1074                 public static void LoadFromPtr (ILGenerator ig, Type t)
1075                 {
1076                         if (t == TypeManager.int32_type)
1077                                 ig.Emit (OpCodes.Ldind_I4);
1078                         else if (t == TypeManager.uint32_type)
1079                                 ig.Emit (OpCodes.Ldind_U4);
1080                         else if (t == TypeManager.short_type)
1081                                 ig.Emit (OpCodes.Ldind_I2);
1082                         else if (t == TypeManager.ushort_type)
1083                                 ig.Emit (OpCodes.Ldind_U2);
1084                         else if (t == TypeManager.char_type)
1085                                 ig.Emit (OpCodes.Ldind_U2);
1086                         else if (t == TypeManager.byte_type)
1087                                 ig.Emit (OpCodes.Ldind_U1);
1088                         else if (t == TypeManager.sbyte_type)
1089                                 ig.Emit (OpCodes.Ldind_I1);
1090                         else if (t == TypeManager.uint64_type)
1091                                 ig.Emit (OpCodes.Ldind_I8);
1092                         else if (t == TypeManager.int64_type)
1093                                 ig.Emit (OpCodes.Ldind_I8);
1094                         else if (t == TypeManager.float_type)
1095                                 ig.Emit (OpCodes.Ldind_R4);
1096                         else if (t == TypeManager.double_type)
1097                                 ig.Emit (OpCodes.Ldind_R8);
1098                         else if (t == TypeManager.bool_type)
1099                                 ig.Emit (OpCodes.Ldind_I1);
1100                         else if (t == TypeManager.intptr_type)
1101                                 ig.Emit (OpCodes.Ldind_I);
1102                         else if (TypeManager.IsEnumType (t)) {
1103                                 if (t == TypeManager.enum_type)
1104                                         ig.Emit (OpCodes.Ldind_Ref);
1105                                 else
1106                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1107                         } else if (TypeManager.IsStruct (t) || TypeManager.IsGenericParameter (t))
1108                                 ig.Emit (OpCodes.Ldobj, t);
1109                         else if (t.IsPointer)
1110                                 ig.Emit (OpCodes.Ldind_I);
1111                         else
1112                                 ig.Emit (OpCodes.Ldind_Ref);
1113                 }
1114
1115                 //
1116                 // The stack contains the pointer and the value of type `type'
1117                 //
1118                 public static void StoreFromPtr (ILGenerator ig, Type type)
1119                 {
1120                         if (TypeManager.IsEnumType (type))
1121                                 type = TypeManager.GetEnumUnderlyingType (type);
1122                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1123                                 ig.Emit (OpCodes.Stind_I4);
1124                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1125                                 ig.Emit (OpCodes.Stind_I8);
1126                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1127                                  type == TypeManager.ushort_type)
1128                                 ig.Emit (OpCodes.Stind_I2);
1129                         else if (type == TypeManager.float_type)
1130                                 ig.Emit (OpCodes.Stind_R4);
1131                         else if (type == TypeManager.double_type)
1132                                 ig.Emit (OpCodes.Stind_R8);
1133                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1134                                  type == TypeManager.bool_type)
1135                                 ig.Emit (OpCodes.Stind_I1);
1136                         else if (type == TypeManager.intptr_type)
1137                                 ig.Emit (OpCodes.Stind_I);
1138                         else if (TypeManager.IsStruct (type) || TypeManager.IsGenericParameter (type))
1139                                 ig.Emit (OpCodes.Stobj, type);
1140                         else
1141                                 ig.Emit (OpCodes.Stind_Ref);
1142                 }
1143
1144                 //
1145                 // Returns the size of type `t' if known, otherwise, 0
1146                 //
1147                 public static int GetTypeSize (Type t)
1148                 {
1149                         t = TypeManager.TypeToCoreType (t);
1150                         if (t == TypeManager.int32_type ||
1151                             t == TypeManager.uint32_type ||
1152                             t == TypeManager.float_type)
1153                                 return 4;
1154                         else if (t == TypeManager.int64_type ||
1155                                  t == TypeManager.uint64_type ||
1156                                  t == TypeManager.double_type)
1157                                 return 8;
1158                         else if (t == TypeManager.byte_type ||
1159                                  t == TypeManager.sbyte_type ||
1160                                  t == TypeManager.bool_type)
1161                                 return 1;
1162                         else if (t == TypeManager.short_type ||
1163                                  t == TypeManager.char_type ||
1164                                  t == TypeManager.ushort_type)
1165                                 return 2;
1166                         else if (t == TypeManager.decimal_type)
1167                                 return 16;
1168                         else
1169                                 return 0;
1170                 }
1171
1172                 protected void Error_CannotCallAbstractBase (ResolveContext ec, string name)
1173                 {
1174                         ec.Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1175                 }
1176
1177                 protected void Error_CannotModifyIntermediateExpressionValue (ResolveContext ec)
1178                 {
1179                         ec.Report.SymbolRelatedToPreviousError (type);
1180                         if (ec.CurrentInitializerVariable != null) {
1181                                 ec.Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1182                                         TypeManager.CSharpName (type), GetSignatureForError ());
1183                         } else {
1184                                 ec.Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1185                                         GetSignatureForError ());
1186                         }
1187                 }
1188
1189                 //
1190                 // Converts `source' to an int, uint, long or ulong.
1191                 //
1192                 protected Expression ConvertExpressionToArrayIndex (ResolveContext ec, Expression source)
1193                 {
1194                         if (TypeManager.IsDynamicType (source.type)) {
1195                                 Arguments args = new Arguments (1);
1196                                 args.Add (new Argument (source));
1197                                 return new DynamicConversion (TypeManager.int32_type, CSharpBinderFlags.ConvertArrayIndex, args, loc).Resolve (ec);
1198                         }
1199
1200                         Expression converted;
1201
1202                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
1203                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1204                                 if (converted == null)
1205                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1206                                 if (converted == null)
1207                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1208                                 if (converted == null)
1209                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1210
1211                                 if (converted == null) {
1212                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1213                                         return null;
1214                                 }
1215                         }
1216
1217                         //
1218                         // Only positive constants are allowed at compile time
1219                         //
1220                         Constant c = converted as Constant;
1221                         if (c != null && c.IsNegative)
1222                                 Error_NegativeArrayIndex (ec, source.loc);
1223
1224                         // No conversion needed to array index
1225                         if (converted.Type == TypeManager.int32_type)
1226                                 return converted;
1227
1228                         return new ArrayIndexCast (converted).Resolve (ec);
1229                 }
1230
1231                 //
1232                 // Derived classes implement this method by cloning the fields that
1233                 // could become altered during the Resolve stage
1234                 //
1235                 // Only expressions that are created for the parser need to implement
1236                 // this.
1237                 //
1238                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1239                 {
1240                         throw new NotImplementedException (
1241                                 String.Format (
1242                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1243                 }
1244
1245                 //
1246                 // Clones an expression created by the parser.
1247                 //
1248                 // We only support expressions created by the parser so far, not
1249                 // expressions that have been resolved (many more classes would need
1250                 // to implement CloneTo).
1251                 //
1252                 // This infrastructure is here merely for Lambda expressions which
1253                 // compile the same code using different type values for the same
1254                 // arguments to find the correct overload
1255                 //
1256                 public Expression Clone (CloneContext clonectx)
1257                 {
1258                         Expression cloned = (Expression) MemberwiseClone ();
1259                         CloneTo (clonectx, cloned);
1260
1261                         return cloned;
1262                 }
1263
1264                 //
1265                 // Implementation of expression to expression tree conversion
1266                 //
1267                 public abstract Expression CreateExpressionTree (ResolveContext ec);
1268
1269                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, Arguments args)
1270                 {
1271                         return CreateExpressionFactoryCall (ec, name, null, args, loc);
1272                 }
1273
1274                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args)
1275                 {
1276                         return CreateExpressionFactoryCall (ec, name, typeArguments, args, loc);
1277                 }
1278
1279                 public static Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args, Location loc)
1280                 {
1281                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (ec, loc), name, typeArguments, loc), args);
1282                 }
1283
1284                 protected static TypeExpr CreateExpressionTypeExpression (ResolveContext ec, Location loc)
1285                 {
1286                         TypeExpr texpr = TypeManager.expression_type_expr;
1287                         if (texpr == null) {
1288                                 Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Linq.Expressions", "Expression", Kind.Class, true);
1289                                 if (t == null)
1290                                         return null;
1291
1292                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1293                         }
1294
1295                         return texpr;
1296                 }
1297
1298 #if NET_4_0
1299                 //
1300                 // Implemented by all expressions which support conversion from
1301                 // compiler expression to invokable runtime expression. Used by
1302                 // dynamic C# binder.
1303                 //
1304                 public virtual SLE.Expression MakeExpression (BuilderContext ctx)
1305                 {
1306                         throw new NotImplementedException ("MakeExpression for " + GetType ());
1307                 }
1308 #endif
1309
1310                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1311                 {
1312                         // TODO: It should probably be type = storey.MutateType (type);
1313                 }
1314         }
1315
1316         /// <summary>
1317         ///   This is just a base class for expressions that can
1318         ///   appear on statements (invocations, object creation,
1319         ///   assignments, post/pre increment and decrement).  The idea
1320         ///   being that they would support an extra Emition interface that
1321         ///   does not leave a result on the stack.
1322         /// </summary>
1323         public abstract class ExpressionStatement : Expression {
1324
1325                 public virtual ExpressionStatement ResolveStatement (BlockContext ec)
1326                 {
1327                         Expression e = Resolve (ec);
1328                         if (e == null)
1329                                 return null;
1330
1331                         ExpressionStatement es = e as ExpressionStatement;
1332                         if (es == null)
1333                                 Error_InvalidExpressionStatement (ec);
1334
1335                         return es;
1336                 }
1337
1338                 /// <summary>
1339                 ///   Requests the expression to be emitted in a `statement'
1340                 ///   context.  This means that no new value is left on the
1341                 ///   stack after invoking this method (constrasted with
1342                 ///   Emit that will always leave a value on the stack).
1343                 /// </summary>
1344                 public abstract void EmitStatement (EmitContext ec);
1345
1346                 public override void EmitSideEffect (EmitContext ec)
1347                 {
1348                         EmitStatement (ec);
1349                 }
1350         }
1351
1352         /// <summary>
1353         ///   This kind of cast is used to encapsulate the child
1354         ///   whose type is child.Type into an expression that is
1355         ///   reported to return "return_type".  This is used to encapsulate
1356         ///   expressions which have compatible types, but need to be dealt
1357         ///   at higher levels with.
1358         ///
1359         ///   For example, a "byte" expression could be encapsulated in one
1360         ///   of these as an "unsigned int".  The type for the expression
1361         ///   would be "unsigned int".
1362         ///
1363         /// </summary>
1364         public abstract class TypeCast : Expression
1365         {
1366                 protected readonly Expression child;
1367
1368                 protected TypeCast (Expression child, Type return_type)
1369                 {
1370                         eclass = child.eclass;
1371                         loc = child.Location;
1372                         type = return_type;
1373                         this.child = child;
1374                 }
1375
1376                 public override Expression CreateExpressionTree (ResolveContext ec)
1377                 {
1378                         Arguments args = new Arguments (2);
1379                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1380                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1381
1382                         if (type.IsPointer || child.Type.IsPointer)
1383                                 Error_PointerInsideExpressionTree (ec);
1384
1385                         return CreateExpressionFactoryCall (ec, ec.HasSet (ResolveContext.Options.CheckedScope) ? "ConvertChecked" : "Convert", args);
1386                 }
1387
1388                 public override Expression DoResolve (ResolveContext ec)
1389                 {
1390                         // This should never be invoked, we are born in fully
1391                         // initialized state.
1392
1393                         return this;
1394                 }
1395
1396                 public override void Emit (EmitContext ec)
1397                 {
1398                         child.Emit (ec);
1399                 }
1400
1401                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1402                 {
1403                         return child.GetAttributableValue (ec, value_type, out value);
1404                 }
1405
1406 #if NET_4_0
1407                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1408                 {
1409                         return ctx.HasSet (BuilderContext.Options.CheckedScope) ?
1410                                 SLE.Expression.ConvertChecked (child.MakeExpression (ctx), type) :
1411                                 SLE.Expression.Convert (child.MakeExpression (ctx), type);
1412                 }
1413 #endif
1414
1415                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1416                 {
1417                         type = storey.MutateType (type);
1418                         child.MutateHoistedGenericType (storey);
1419                 }
1420
1421                 protected override void CloneTo (CloneContext clonectx, Expression t)
1422                 {
1423                         // Nothing to clone
1424                 }
1425
1426                 public override bool IsNull {
1427                         get { return child.IsNull; }
1428                 }
1429         }
1430
1431         public class EmptyCast : TypeCast {
1432                 EmptyCast (Expression child, Type target_type)
1433                         : base (child, target_type)
1434                 {
1435                 }
1436
1437                 public static Expression Create (Expression child, Type type)
1438                 {
1439                         Constant c = child as Constant;
1440                         if (c != null)
1441                                 return new EmptyConstantCast (c, type);
1442
1443                         EmptyCast e = child as EmptyCast;
1444                         if (e != null)
1445                                 return new EmptyCast (e.child, type);
1446
1447                         return new EmptyCast (child, type);
1448                 }
1449
1450                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1451                 {
1452                         child.EmitBranchable (ec, label, on_true);
1453                 }
1454
1455                 public override void EmitSideEffect (EmitContext ec)
1456                 {
1457                         child.EmitSideEffect (ec);
1458                 }
1459         }
1460
1461         //
1462         // Used for predefined class library user casts (no obsolete check, etc.)
1463         //
1464         public class OperatorCast : TypeCast {
1465                 MethodInfo conversion_operator;
1466
1467                 public OperatorCast (Expression child, Type target_type)
1468                         : this (child, target_type, false)
1469                 {
1470                 }
1471
1472                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1473                         : base (child, target_type)
1474                 {
1475                         conversion_operator = GetConversionOperator (find_explicit);
1476                         if (conversion_operator == null)
1477                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1478                 }
1479
1480                 // Returns the implicit operator that converts from
1481                 // 'child.Type' to our target type (type)
1482                 MethodInfo GetConversionOperator (bool find_explicit)
1483                 {
1484                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1485
1486                         MemberInfo [] mi;
1487
1488                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1489                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1490
1491                         if (mi == null){
1492                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1493                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1494                         }
1495
1496                         foreach (MethodInfo oper in mi) {
1497                                 AParametersCollection pd = TypeManager.GetParameterData (oper);
1498
1499                                 if (pd.Types [0] == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1500                                         return oper;
1501                         }
1502
1503                         return null;
1504                 }
1505
1506                 public override void Emit (EmitContext ec)
1507                 {
1508                         child.Emit (ec);
1509                         ec.ig.Emit (OpCodes.Call, conversion_operator);
1510                 }
1511         }
1512
1513         /// <summary>
1514         ///     This is a numeric cast to a Decimal
1515         /// </summary>
1516         public class CastToDecimal : OperatorCast {
1517                 public CastToDecimal (Expression child)
1518                         : this (child, false)
1519                 {
1520                 }
1521
1522                 public CastToDecimal (Expression child, bool find_explicit)
1523                         : base (child, TypeManager.decimal_type, find_explicit)
1524                 {
1525                 }
1526         }
1527
1528         /// <summary>
1529         ///     This is an explicit numeric cast from a Decimal
1530         /// </summary>
1531         public class CastFromDecimal : TypeCast
1532         {
1533                 static IDictionary operators;
1534
1535                 public CastFromDecimal (Expression child, Type return_type)
1536                         : base (child, return_type)
1537                 {
1538                         if (child.Type != TypeManager.decimal_type)
1539                                 throw new InternalErrorException (
1540                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1541                 }
1542
1543                 // Returns the explicit operator that converts from an
1544                 // express of type System.Decimal to 'type'.
1545                 public Expression Resolve ()
1546                 {
1547                         if (operators == null) {
1548                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1549                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1550                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1551
1552                                 operators = new System.Collections.Specialized.HybridDictionary ();
1553                                 foreach (MethodInfo oper in all_oper) {
1554                                         AParametersCollection pd = TypeManager.GetParameterData (oper);
1555                                         if (pd.Types [0] == TypeManager.decimal_type)
1556                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1557                                 }
1558                         }
1559
1560                         return operators.Contains (type) ? this : null;
1561                 }
1562
1563                 public override void Emit (EmitContext ec)
1564                 {
1565                         ILGenerator ig = ec.ig;
1566                         child.Emit (ec);
1567
1568                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1569                 }
1570         }
1571
1572
1573         //
1574         // Constant specialization of EmptyCast.
1575         // We need to special case this since an empty cast of
1576         // a constant is still a constant.
1577         //
1578         public class EmptyConstantCast : Constant
1579         {
1580                 public readonly Constant child;
1581
1582                 public EmptyConstantCast(Constant child, Type type)
1583                         : base (child.Location)
1584                 {
1585                         eclass = child.eclass;
1586                         this.child = child;
1587                         this.type = type;
1588                 }
1589
1590                 public override string AsString ()
1591                 {
1592                         return child.AsString ();
1593                 }
1594
1595                 public override object GetValue ()
1596                 {
1597                         return child.GetValue ();
1598                 }
1599
1600                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1601                 {
1602                         // FIXME: check that 'type' can be converted to 'target_type' first
1603                         return child.ConvertExplicitly (in_checked_context, target_type);
1604                 }
1605
1606                 public override Expression CreateExpressionTree (ResolveContext ec)
1607                 {
1608                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1609                                 child.CreateExpressionTree (ec),
1610                                 new TypeOf (new TypeExpression (type, loc), loc));
1611
1612                         if (type.IsPointer)
1613                                 Error_PointerInsideExpressionTree (ec);
1614
1615                         return CreateExpressionFactoryCall (ec, "Convert", args);
1616                 }
1617
1618                 public override Constant Increment ()
1619                 {
1620                         return child.Increment ();
1621                 }
1622
1623                 public override bool IsDefaultValue {
1624                         get { return child.IsDefaultValue; }
1625                 }
1626
1627                 public override bool IsNegative {
1628                         get { return child.IsNegative; }
1629                 }
1630
1631                 public override bool IsNull {
1632                         get { return child.IsNull; }
1633                 }
1634
1635                 public override bool IsZeroInteger {
1636                         get { return child.IsZeroInteger; }
1637                 }
1638
1639                 public override void Emit (EmitContext ec)
1640                 {
1641                         child.Emit (ec);
1642                 }
1643
1644                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1645                 {
1646                         child.EmitBranchable (ec, label, on_true);
1647
1648                         // Only to make verifier happy
1649                         if (TypeManager.IsGenericParameter (type) && child.IsNull)
1650                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1651                 }
1652
1653                 public override void EmitSideEffect (EmitContext ec)
1654                 {
1655                         child.EmitSideEffect (ec);
1656                 }
1657
1658                 public override Constant ConvertImplicitly (Type target_type)
1659                 {
1660                         // FIXME: Do we need to check user conversions?
1661                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1662                                 return null;
1663                         return child.ConvertImplicitly (target_type);
1664                 }
1665
1666                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1667                 {
1668                         child.MutateHoistedGenericType (storey);
1669                 }
1670         }
1671
1672
1673         /// <summary>
1674         ///  This class is used to wrap literals which belong inside Enums
1675         /// </summary>
1676         public class EnumConstant : Constant {
1677                 public Constant Child;
1678
1679                 public EnumConstant (Constant child, Type enum_type):
1680                         base (child.Location)
1681                 {
1682                         eclass = child.eclass;
1683                         this.Child = child;
1684                         type = enum_type;
1685                 }
1686
1687                 public override Expression DoResolve (ResolveContext ec)
1688                 {
1689                         // This should never be invoked, we are born in fully
1690                         // initialized state.
1691
1692                         return this;
1693                 }
1694
1695                 public override void Emit (EmitContext ec)
1696                 {
1697                         Child.Emit (ec);
1698                 }
1699
1700                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1701                 {
1702                         Child.EmitBranchable (ec, label, on_true);
1703                 }
1704
1705                 public override void EmitSideEffect (EmitContext ec)
1706                 {
1707                         Child.EmitSideEffect (ec);
1708                 }
1709
1710                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1711                 {
1712                         value = GetTypedValue ();
1713                         return true;
1714                 }
1715
1716                 public override string GetSignatureForError()
1717                 {
1718                         return TypeManager.CSharpName (Type);
1719                 }
1720
1721                 public override object GetValue ()
1722                 {
1723                         return Child.GetValue ();
1724                 }
1725
1726                 public override object GetTypedValue ()
1727                 {
1728                         // FIXME: runtime is not ready to work with just emited enums
1729                         if (!RootContext.StdLib) {
1730                                 return Child.GetValue ();
1731                         }
1732
1733 #if MS_COMPATIBLE
1734                         // Small workaround for big problem
1735                         // System.Enum.ToObject cannot be called on dynamic types
1736                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1737                         // because it does not properly support generics
1738                         //
1739                         // This works only sometimes
1740                         //
1741                         if (type.Module == RootContext.ToplevelTypes.Builder)
1742                                 return Child.GetValue ();
1743 #endif
1744
1745                         return System.Enum.ToObject (type, Child.GetValue ());
1746                 }
1747
1748                 public override string AsString ()
1749                 {
1750                         return Child.AsString ();
1751                 }
1752
1753                 public override Constant Increment()
1754                 {
1755                         return new EnumConstant (Child.Increment (), type);
1756                 }
1757
1758                 public override bool IsDefaultValue {
1759                         get {
1760                                 return Child.IsDefaultValue;
1761                         }
1762                 }
1763
1764                 public override bool IsZeroInteger {
1765                         get { return Child.IsZeroInteger; }
1766                 }
1767
1768                 public override bool IsNegative {
1769                         get {
1770                                 return Child.IsNegative;
1771                         }
1772                 }
1773
1774                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1775                 {
1776                         if (Child.Type == target_type)
1777                                 return Child;
1778
1779                         return Child.ConvertExplicitly (in_checked_context, target_type);
1780                 }
1781
1782                 public override Constant ConvertImplicitly (Type type)
1783                 {
1784                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1785                         type = TypeManager.DropGenericTypeArguments (type);
1786
1787                         if (this_type == type) {
1788                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1789                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1790                                         return this;
1791
1792                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1793                                 if (type.UnderlyingSystemType != child_type)
1794                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1795                                 return this;
1796                         }
1797
1798                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1799                                 return null;
1800                         }
1801
1802                         return Child.ConvertImplicitly(type);
1803                 }
1804
1805         }
1806
1807         /// <summary>
1808         ///   This kind of cast is used to encapsulate Value Types in objects.
1809         ///
1810         ///   The effect of it is to box the value type emitted by the previous
1811         ///   operation.
1812         /// </summary>
1813         public class BoxedCast : TypeCast {
1814
1815                 public BoxedCast (Expression expr, Type target_type)
1816                         : base (expr, target_type)
1817                 {
1818                         eclass = ExprClass.Value;
1819                 }
1820
1821                 public override Expression DoResolve (ResolveContext ec)
1822                 {
1823                         // This should never be invoked, we are born in fully
1824                         // initialized state.
1825
1826                         return this;
1827                 }
1828
1829                 public override void Emit (EmitContext ec)
1830                 {
1831                         base.Emit (ec);
1832
1833                         ec.ig.Emit (OpCodes.Box, child.Type);
1834                 }
1835
1836                 public override void EmitSideEffect (EmitContext ec)
1837                 {
1838                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1839                         // so, we need to emit the box+pop instructions in most cases
1840                         if (TypeManager.IsStruct (child.Type) &&
1841                             (type == TypeManager.object_type || type == TypeManager.value_type))
1842                                 child.EmitSideEffect (ec);
1843                         else
1844                                 base.EmitSideEffect (ec);
1845                 }
1846         }
1847
1848         public class UnboxCast : TypeCast {
1849                 public UnboxCast (Expression expr, Type return_type)
1850                         : base (expr, return_type)
1851                 {
1852                 }
1853
1854                 public override Expression DoResolve (ResolveContext ec)
1855                 {
1856                         // This should never be invoked, we are born in fully
1857                         // initialized state.
1858
1859                         return this;
1860                 }
1861
1862                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1863                 {
1864                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1865                                 ec.Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1866                         return base.DoResolveLValue (ec, right_side);
1867                 }
1868
1869                 public override void Emit (EmitContext ec)
1870                 {
1871                         base.Emit (ec);
1872
1873                         ILGenerator ig = ec.ig;
1874                         ig.Emit (OpCodes.Unbox_Any, type);
1875                 }
1876
1877                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1878                 {
1879                         type = storey.MutateType (type);
1880                         base.MutateHoistedGenericType (storey);
1881                 }
1882         }
1883
1884         /// <summary>
1885         ///   This is used to perform explicit numeric conversions.
1886         ///
1887         ///   Explicit numeric conversions might trigger exceptions in a checked
1888         ///   context, so they should generate the conv.ovf opcodes instead of
1889         ///   conv opcodes.
1890         /// </summary>
1891         public class ConvCast : TypeCast {
1892                 public enum Mode : byte {
1893                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1894                         U1_I1, U1_CH,
1895                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1896                         U2_I1, U2_U1, U2_I2, U2_CH,
1897                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1898                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1899                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH, I8_I,
1900                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH, U8_I,
1901                         CH_I1, CH_U1, CH_I2,
1902                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1903                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4,
1904                         I_I8,
1905                 }
1906
1907                 Mode mode;
1908
1909                 public ConvCast (Expression child, Type return_type, Mode m)
1910                         : base (child, return_type)
1911                 {
1912                         mode = m;
1913                 }
1914
1915                 public override Expression DoResolve (ResolveContext ec)
1916                 {
1917                         // This should never be invoked, we are born in fully
1918                         // initialized state.
1919
1920                         return this;
1921                 }
1922
1923                 public override string ToString ()
1924                 {
1925                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1926                 }
1927
1928                 public override void Emit (EmitContext ec)
1929                 {
1930                         ILGenerator ig = ec.ig;
1931
1932                         base.Emit (ec);
1933
1934                         if (ec.HasSet (EmitContext.Options.CheckedScope)) {
1935                                 switch (mode){
1936                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1937                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1938                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1939                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1940                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1941
1942                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1943                                 case Mode.U1_CH: /* nothing */ break;
1944
1945                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1946                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1947                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1948                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1949                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1950                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1951
1952                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1953                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1954                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1955                                 case Mode.U2_CH: /* nothing */ break;
1956
1957                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1958                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1959                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1960                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1961                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1962                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1963                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1964
1965                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1966                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1967                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1968                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1969                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1970                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1971
1972                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1973                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1974                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1975                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1976                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1977                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1978                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1979                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1980                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_Ovf_U); break;
1981
1982                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1983                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1984                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1985                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1986                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1987                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1988                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1989                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1990                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_Ovf_U_Un); break;
1991
1992                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1993                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1994                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1995
1996                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1997                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1998                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1999                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
2000                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
2001                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
2002                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
2003                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
2004                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
2005
2006                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
2007                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
2008                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
2009                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
2010                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
2011                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
2012                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
2013                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
2014                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
2015                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2016
2017                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
2018                                 }
2019                         } else {
2020                                 switch (mode){
2021                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
2022                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
2023                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
2024                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
2025                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
2026
2027                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
2028                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
2029
2030                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2031                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2032                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2033                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2034                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2035                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2036
2037                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2038                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2039                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2040                                 case Mode.U2_CH: /* nothing */ break;
2041
2042                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2043                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2044                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2045                                 case Mode.I4_U4: /* nothing */ break;
2046                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2047                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2048                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2049
2050                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2051                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2052                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2053                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2054                                 case Mode.U4_I4: /* nothing */ break;
2055                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2056
2057                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2058                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2059                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2060                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2061                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2062                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2063                                 case Mode.I8_U8: /* nothing */ break;
2064                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2065                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_U); break;
2066
2067                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2068                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2069                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2070                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2071                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2072                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2073                                 case Mode.U8_I8: /* nothing */ break;
2074                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2075                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_U); break;
2076
2077                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2078                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2079                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2080
2081                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2082                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2083                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2084                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2085                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2086                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2087                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2088                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2089                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2090
2091                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2092                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2093                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2094                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2095                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2096                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2097                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2098                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2099                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2100                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2101
2102                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_U8); break;
2103                                 }
2104                         }
2105                 }
2106         }
2107
2108         public class OpcodeCast : TypeCast {
2109                 readonly OpCode op;
2110
2111                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2112                         : base (child, return_type)
2113                 {
2114                         this.op = op;
2115                 }
2116
2117                 public override Expression DoResolve (ResolveContext ec)
2118                 {
2119                         // This should never be invoked, we are born in fully
2120                         // initialized state.
2121
2122                         return this;
2123                 }
2124
2125                 public override void Emit (EmitContext ec)
2126                 {
2127                         base.Emit (ec);
2128                         ec.ig.Emit (op);
2129                 }
2130
2131                 public Type UnderlyingType {
2132                         get { return child.Type; }
2133                 }
2134         }
2135
2136         /// <summary>
2137         ///   This kind of cast is used to encapsulate a child and cast it
2138         ///   to the class requested
2139         /// </summary>
2140         public sealed class ClassCast : TypeCast {
2141                 readonly bool forced;
2142
2143                 public ClassCast (Expression child, Type return_type)
2144                         : base (child, return_type)
2145                 {
2146                 }
2147
2148                 public ClassCast (Expression child, Type return_type, bool forced)
2149                         : base (child, return_type)
2150                 {
2151                         this.forced = forced;
2152                 }
2153
2154                 public override void Emit (EmitContext ec)
2155                 {
2156                         base.Emit (ec);
2157
2158                         bool gen = TypeManager.IsGenericParameter (child.Type);
2159                         if (gen)
2160                                 ec.ig.Emit (OpCodes.Box, child.Type);
2161
2162                         if (type.IsGenericParameter) {
2163                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2164                                 return;
2165                         }
2166
2167                         if (gen && !forced)
2168                                 return;
2169
2170                         ec.ig.Emit (OpCodes.Castclass, type);
2171                 }
2172         }
2173
2174         //
2175         // Created during resolving pahse when an expression is wrapped or constantified
2176         // and original expression can be used later (e.g. for expression trees)
2177         //
2178         public class ReducedExpression : Expression
2179         {
2180                 sealed class ReducedConstantExpression : EmptyConstantCast
2181                 {
2182                         readonly Expression orig_expr;
2183
2184                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2185                                 : base (expr, expr.Type)
2186                         {
2187                                 this.orig_expr = orig_expr;
2188                         }
2189
2190                         public override Constant ConvertImplicitly (Type target_type)
2191                         {
2192                                 Constant c = base.ConvertImplicitly (target_type);
2193                                 if (c != null)
2194                                         c = new ReducedConstantExpression (c, orig_expr);
2195                                 return c;
2196                         }
2197
2198                         public override Expression CreateExpressionTree (ResolveContext ec)
2199                         {
2200                                 return orig_expr.CreateExpressionTree (ec);
2201                         }
2202
2203                         public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
2204                         {
2205                                 //
2206                                 // Even if resolved result is a constant original expression was not
2207                                 // and attribute accepts constants only
2208                                 //
2209                                 Attribute.Error_AttributeArgumentNotValid (ec, orig_expr.Location);
2210                                 value = null;
2211                                 return false;
2212                         }
2213
2214                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2215                         {
2216                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2217                                 if (c != null)
2218                                         c = new ReducedConstantExpression (c, orig_expr);
2219                                 return c;
2220                         }
2221                 }
2222
2223                 sealed class ReducedExpressionStatement : ExpressionStatement
2224                 {
2225                         readonly Expression orig_expr;
2226                         readonly ExpressionStatement stm;
2227
2228                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2229                         {
2230                                 this.orig_expr = orig;
2231                                 this.stm = stm;
2232                                 this.loc = orig.Location;
2233                         }
2234
2235                         public override Expression CreateExpressionTree (ResolveContext ec)
2236                         {
2237                                 return orig_expr.CreateExpressionTree (ec);
2238                         }
2239
2240                         public override Expression DoResolve (ResolveContext ec)
2241                         {
2242                                 eclass = stm.eclass;
2243                                 type = stm.Type;
2244                                 return this;
2245                         }
2246
2247                         public override void Emit (EmitContext ec)
2248                         {
2249                                 stm.Emit (ec);
2250                         }
2251
2252                         public override void EmitStatement (EmitContext ec)
2253                         {
2254                                 stm.EmitStatement (ec);
2255                         }
2256
2257                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2258                         {
2259                                 stm.MutateHoistedGenericType (storey);
2260                         }
2261                 }
2262
2263                 readonly Expression expr, orig_expr;
2264
2265                 private ReducedExpression (Expression expr, Expression orig_expr)
2266                 {
2267                         this.expr = expr;
2268                         this.orig_expr = orig_expr;
2269                         this.loc = orig_expr.Location;
2270                 }
2271
2272                 public static Constant Create (Constant expr, Expression original_expr)
2273                 {
2274                         return new ReducedConstantExpression (expr, original_expr);
2275                 }
2276
2277                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2278                 {
2279                         return new ReducedExpressionStatement (s, orig);
2280                 }
2281
2282                 public static Expression Create (Expression expr, Expression original_expr)
2283                 {
2284                         Constant c = expr as Constant;
2285                         if (c != null)
2286                                 return Create (c, original_expr);
2287
2288                         ExpressionStatement s = expr as ExpressionStatement;
2289                         if (s != null)
2290                                 return Create (s, original_expr);
2291
2292                         return new ReducedExpression (expr, original_expr);
2293                 }
2294
2295                 public override Expression CreateExpressionTree (ResolveContext ec)
2296                 {
2297                         return orig_expr.CreateExpressionTree (ec);
2298                 }
2299
2300                 public override Expression DoResolve (ResolveContext ec)
2301                 {
2302                         eclass = expr.eclass;
2303                         type = expr.Type;
2304                         return this;
2305                 }
2306
2307                 public override void Emit (EmitContext ec)
2308                 {
2309                         expr.Emit (ec);
2310                 }
2311
2312                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2313                 {
2314                         expr.EmitBranchable (ec, target, on_true);
2315                 }
2316
2317 #if NET_4_0
2318                 public override SLE.Expression MakeExpression (BuilderContext ctx)
2319                 {
2320                         return orig_expr.MakeExpression (ctx);
2321                 }
2322 #endif
2323
2324                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2325                 {
2326                         expr.MutateHoistedGenericType (storey);
2327                 }
2328         }
2329
2330         //
2331         // Base of expressions used only to narrow resolve flow
2332         //
2333         public abstract class ShimExpression : Expression
2334         {
2335                 protected Expression expr;
2336
2337                 protected ShimExpression (Expression expr)
2338                 {
2339                         this.expr = expr;
2340                 }
2341
2342                 protected override void CloneTo (CloneContext clonectx, Expression t)
2343                 {
2344                         if (expr == null)
2345                                 return;
2346
2347                         ShimExpression target = (ShimExpression) t;
2348                         target.expr = expr.Clone (clonectx);
2349                 }
2350
2351                 public override Expression CreateExpressionTree (ResolveContext ec)
2352                 {
2353                         throw new NotSupportedException ("ET");
2354                 }
2355
2356                 public override void Emit (EmitContext ec)
2357                 {
2358                         throw new InternalErrorException ("Missing Resolve call");
2359                 }
2360
2361                 public Expression Expr {
2362                         get { return expr; }
2363                 }
2364
2365                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2366                 {
2367                         throw new InternalErrorException ("Missing Resolve call");
2368                 }
2369         }
2370
2371         //
2372         // Unresolved type name expressions
2373         //
2374         public abstract class ATypeNameExpression : FullNamedExpression
2375         {
2376                 string name;
2377                 protected TypeArguments targs;
2378
2379                 protected ATypeNameExpression (string name, Location l)
2380                 {
2381                         this.name = name;
2382                         loc = l;
2383                 }
2384
2385                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2386                 {
2387                         this.name = name;
2388                         this.targs = targs;
2389                         loc = l;
2390                 }
2391
2392                 public bool HasTypeArguments {
2393                         get {
2394                                 return targs != null;
2395                         }
2396                 }
2397
2398                 public override bool Equals (object obj)
2399                 {
2400                         ATypeNameExpression atne = obj as ATypeNameExpression;
2401                         return atne != null && atne.Name == Name &&
2402                                 (targs == null || targs.Equals (atne.targs));
2403                 }
2404
2405                 public override int GetHashCode ()
2406                 {
2407                         return Name.GetHashCode ();
2408                 }
2409
2410                 public override string GetSignatureForError ()
2411                 {
2412                         if (targs != null) {
2413                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2414                                         targs.GetSignatureForError () + ">";
2415                         }
2416
2417                         return Name;
2418                 }
2419
2420                 public string Name {
2421                         get {
2422                                 return name;
2423                         }
2424                         set {
2425                                 name = value;
2426                         }
2427                 }
2428
2429                 public TypeArguments TypeArguments {
2430                         get {
2431                                 return targs;
2432                         }
2433                 }
2434         }
2435
2436         /// <summary>
2437         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2438         ///   of a dotted-name.
2439         /// </summary>
2440         public class SimpleName : ATypeNameExpression {
2441                 bool in_transit;
2442
2443                 public SimpleName (string name, Location l)
2444                         : base (name, l)
2445                 {
2446                 }
2447
2448                 public SimpleName (string name, TypeArguments args, Location l)
2449                         : base (name, args, l)
2450                 {
2451                 }
2452
2453                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2454                         : base (name, l)
2455                 {
2456                         targs = new TypeArguments ();
2457                         foreach (TypeParameter type_param in type_params)
2458                                 targs.Add (new TypeParameterExpr (type_param, l));
2459                 }
2460
2461                 public static string RemoveGenericArity (string name)
2462                 {
2463                         int start = 0;
2464                         StringBuilder sb = null;
2465                         do {
2466                                 int pos = name.IndexOf ('`', start);
2467                                 if (pos < 0) {
2468                                         if (start == 0)
2469                                                 return name;
2470
2471                                         sb.Append (name.Substring (start));
2472                                         break;
2473                                 }
2474
2475                                 if (sb == null)
2476                                         sb = new StringBuilder ();
2477                                 sb.Append (name.Substring (start, pos-start));
2478
2479                                 pos++;
2480                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2481                                         pos++;
2482
2483                                 start = pos;
2484                         } while (start < name.Length);
2485
2486                         return sb.ToString ();
2487                 }
2488
2489                 public SimpleName GetMethodGroup ()
2490                 {
2491                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2492                 }
2493
2494                 public static void Error_ObjectRefRequired (ResolveContext ec, Location l, string name)
2495                 {
2496                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
2497                                 ec.Report.Error (236, l,
2498                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2499                                         name);
2500                         else
2501                                 ec.Report.Error (120, l,
2502                                         "An object reference is required to access non-static member `{0}'",
2503                                         name);
2504                 }
2505
2506                 public bool IdenticalNameAndTypeName (IMemberContext mc, Expression resolved_to, Location loc)
2507                 {
2508                         return resolved_to != null && resolved_to.Type != null &&
2509                                 resolved_to.Type.Name == Name &&
2510                                 (mc.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2511                 }
2512
2513                 public override Expression DoResolve (ResolveContext ec)
2514                 {
2515                         return SimpleNameResolve (ec, null, false);
2516                 }
2517
2518                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
2519                 {
2520                         return SimpleNameResolve (ec, right_side, false);
2521                 }
2522
2523
2524                 public Expression DoResolve (ResolveContext ec, bool intermediate)
2525                 {
2526                         return SimpleNameResolve (ec, null, intermediate);
2527                 }
2528
2529                 static bool IsNestedChild (Type t, Type parent)
2530                 {
2531                         while (parent != null) {
2532                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2533                                         return true;
2534
2535                                 parent = parent.BaseType;
2536                         }
2537
2538                         return false;
2539                 }
2540
2541                 FullNamedExpression ResolveNested (Type t)
2542                 {
2543                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2544                                 return null;
2545
2546                         Type ds = t;
2547                         while (ds != null && !IsNestedChild (t, ds))
2548                                 ds = ds.DeclaringType;
2549
2550                         if (ds == null)
2551                                 return null;
2552
2553                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2554
2555                         int arg_count = targs != null ? targs.Count : 0;
2556
2557                         for (; (ds != null) && TypeManager.IsGenericType (ds); ds = ds.DeclaringType) {
2558                                 Type[] gargs = TypeManager.GetTypeArguments (ds);
2559                                 if (arg_count + gargs.Length == gen_params.Length) {
2560                                         TypeArguments new_args = new TypeArguments ();
2561                                         foreach (Type param in gargs)
2562                                                 new_args.Add (new TypeExpression (param, loc));
2563
2564                                         if (targs != null)
2565                                                 new_args.Add (targs);
2566
2567                                         return new GenericTypeExpr (t, new_args, loc);
2568                                 }
2569                         }
2570
2571                         return null;
2572                 }
2573
2574                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2575                 {
2576                         int errors = ec.Compiler.Report.Errors;
2577                         FullNamedExpression fne = ec.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2578
2579                         if (fne != null) {
2580                                 if (fne.Type == null)
2581                                         return fne;
2582
2583                                 FullNamedExpression nested = ResolveNested (fne.Type);
2584                                 if (nested != null)
2585                                         return nested.ResolveAsTypeStep (ec, false);
2586
2587                                 if (targs != null) {
2588                                         if (TypeManager.IsGenericType (fne.Type)) {
2589                                                 GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2590                                                 return ct.ResolveAsTypeStep (ec, false);
2591                                         }
2592
2593                                         fne.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2594                                 }
2595
2596                                 return fne;
2597                         }
2598
2599                         if (!HasTypeArguments && Name == "dynamic" && RootContext.Version > LanguageVersion.V_3)
2600                                 return new DynamicTypeExpr (loc);
2601
2602                         if (silent || errors != ec.Compiler.Report.Errors)
2603                                 return null;
2604
2605                         Error_TypeOrNamespaceNotFound (ec);
2606                         return null;
2607                 }
2608
2609                 protected virtual void Error_TypeOrNamespaceNotFound (IMemberContext ec)
2610                 {
2611                         if (ec.CurrentType != null) {
2612                                 if (ec.CurrentTypeDefinition != null) {
2613                                         MemberCore mc = ec.CurrentTypeDefinition.GetDefinition (Name);
2614                                         if (mc != null) {
2615                                                 Error_UnexpectedKind (ec.Compiler.Report, mc, "type", GetMemberType (mc), loc);
2616                                                 return;
2617                                         }
2618                                 }
2619
2620                                 string ns = ec.CurrentType.Namespace;
2621                                 string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2622                                 foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
2623                                         Type type = a.GetType (fullname);
2624                                         if (type != null) {
2625                                                 ec.Compiler.Report.SymbolRelatedToPreviousError (type);
2626                                                 Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type), ec.Compiler.Report);
2627                                                 return;
2628                                         }
2629                                 }
2630
2631                                 if (ec.CurrentTypeDefinition != null) {
2632                                         Type t = ec.CurrentTypeDefinition.LookupAnyGeneric (Name);
2633                                         if (t != null) {
2634                                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2635                                                 return;
2636                                         }
2637                                 }
2638                         }
2639
2640                         if (targs != null) {
2641                                 FullNamedExpression retval = ec.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2642                                 if (retval != null) {
2643                                         retval.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2644                                         return;
2645                                 }
2646                         }
2647
2648                         NamespaceEntry.Error_NamespaceNotFound (loc, Name, ec.Compiler.Report);
2649                 }
2650
2651                 // TODO: I am still not convinced about this. If someone else will need it
2652                 // implement this as virtual property in MemberCore hierarchy
2653                 public static string GetMemberType (MemberCore mc)
2654                 {
2655                         if (mc is Property)
2656                                 return "property";
2657                         if (mc is Indexer)
2658                                 return "indexer";
2659                         if (mc is FieldBase)
2660                                 return "field";
2661                         if (mc is MethodCore)
2662                                 return "method";
2663                         if (mc is EnumMember)
2664                                 return "enum";
2665                         if (mc is Event)
2666                                 return "event";
2667
2668                         return "type";
2669                 }
2670
2671                 Expression SimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2672                 {
2673                         if (in_transit)
2674                                 return null;
2675
2676                         in_transit = true;
2677                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2678                         in_transit = false;
2679
2680                         if (e == null)
2681                                 return null;
2682
2683                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2684                                 return e;
2685
2686                         return null;
2687                 }
2688
2689                 /// <remarks>
2690                 ///   7.5.2: Simple Names.
2691                 ///
2692                 ///   Local Variables and Parameters are handled at
2693                 ///   parse time, so they never occur as SimpleNames.
2694                 ///
2695                 ///   The `intermediate' flag is used by MemberAccess only
2696                 ///   and it is used to inform us that it is ok for us to
2697                 ///   avoid the static check, because MemberAccess might end
2698                 ///   up resolving the Name as a Type name and the access as
2699                 ///   a static type access.
2700                 ///
2701                 ///   ie: Type Type; .... { Type.GetType (""); }
2702                 ///
2703                 ///   Type is both an instance variable and a Type;  Type.GetType
2704                 ///   is the static method not an instance method of type.
2705                 /// </remarks>
2706                 Expression DoSimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2707                 {
2708                         Expression e = null;
2709
2710                         //
2711                         // Stage 1: Performed by the parser (binding to locals or parameters).
2712                         //
2713                         Block current_block = ec.CurrentBlock;
2714                         if (current_block != null){
2715                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2716                                 if (vi != null){
2717                                         e = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2718
2719                                         if (right_side != null) {
2720                                                 e = e.ResolveLValue (ec, right_side);
2721                                         } else {
2722                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2723                                                 if (intermediate)
2724                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2725
2726                                                 e = e.Resolve (ec, rf);
2727                                         }
2728
2729                                         if (targs != null && e != null)
2730                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2731
2732                                         return e;
2733                                 }
2734
2735                                 e = current_block.Toplevel.GetParameterReference (Name, loc);
2736                                 if (e != null) {
2737                                         if (right_side != null)
2738                                                 e = e.ResolveLValue (ec, right_side);
2739                                         else
2740                                                 e = e.Resolve (ec);
2741
2742                                         if (targs != null && e != null)
2743                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2744
2745                                         return e;
2746                                 }
2747                         }
2748
2749                         //
2750                         // Stage 2: Lookup members
2751                         //
2752
2753                         Type almost_matched_type = null;
2754                         ArrayList almost_matched = null;
2755                         for (Type lookup_ds = ec.CurrentType; lookup_ds != null; lookup_ds = lookup_ds.DeclaringType) {
2756                                 e = MemberLookup (ec.Compiler, ec.CurrentType, lookup_ds, Name, loc);
2757                                 if (e != null) {
2758                                         PropertyExpr pe = e as PropertyExpr;
2759                                         if (pe != null) {
2760                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2761
2762                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2763                                                 // it doesn't know which accessor to check permissions against
2764                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.CurrentType, right_side != null))
2765                                                         break;
2766                                         } else if (e is EventExpr) {
2767                                                 if (((EventExpr) e).IsAccessibleFrom (ec.CurrentType))
2768                                                         break;
2769                                         } else if (targs != null && e is TypeExpression) {
2770                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2771                                                 break;
2772                                         } else {
2773                                                 break;
2774                                         }
2775                                         e = null;
2776                                 }
2777
2778                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2779                                         almost_matched_type = lookup_ds;
2780                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2781                                 }
2782                         }
2783
2784                         if (e == null) {
2785                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2786                                         almost_matched_type = ec.CurrentType;
2787                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2788                                 }
2789                                 e = ResolveAsTypeStep (ec, true);
2790                         }
2791
2792                         if (e == null) {
2793                                 if (current_block != null) {
2794                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2795                                         if (ikv != null) {
2796                                                 LocalInfo li = ikv as LocalInfo;
2797                                                 // Supress CS0219 warning
2798                                                 if (li != null)
2799                                                         li.Used = true;
2800
2801                                                 Error_VariableIsUsedBeforeItIsDeclared (ec.Report, Name);
2802                                                 return null;
2803                                         }
2804                                 }
2805
2806                                 if (RootContext.EvalMode){
2807                                         FieldInfo fi = Evaluator.LookupField (Name);
2808                                         if (fi != null)
2809                                                 return new FieldExpr (fi, loc).Resolve (ec);
2810                                 }
2811
2812                                 if (almost_matched != null)
2813                                         almost_matched_members = almost_matched;
2814                                 if (almost_matched_type == null)
2815                                         almost_matched_type = ec.CurrentType;
2816
2817                                 string type_name = ec.MemberContext.CurrentType == null ? null : ec.MemberContext.CurrentType.Name;
2818                                 return Error_MemberLookupFailed (ec, ec.CurrentType, null, almost_matched_type, Name,
2819                                         type_name, AllMemberTypes, AllBindingFlags);
2820                         }
2821
2822                         if (e is MemberExpr) {
2823                                 MemberExpr me = (MemberExpr) e;
2824
2825                                 Expression left;
2826                                 if (me.IsInstance) {
2827                                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope)) {
2828                                                 //
2829                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2830                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2831                                                 // and each predicate is true if the MethodGroupExpr contains
2832                                                 // at least one of that kind of method.
2833                                                 //
2834
2835                                                 if (!me.IsStatic &&
2836                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2837                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2838                                                         return null;
2839                                                 }
2840
2841                                                 //
2842                                                 // Pass the buck to MemberAccess and Invocation.
2843                                                 //
2844                                                 left = EmptyExpression.Null;
2845                                         } else {
2846                                                 left = ec.GetThis (loc);
2847                                         }
2848                                 } else {
2849                                         left = new TypeExpression (ec.CurrentType, loc);
2850                                 }
2851
2852                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2853                                 if (me == null)
2854                                         return null;
2855
2856                                 if (targs != null) {
2857                                         if (!targs.Resolve (ec))
2858                                                 return null;
2859
2860                                         me.SetTypeArguments (ec, targs);
2861                                 }
2862
2863                                 if (!me.IsStatic && (me.InstanceExpression != null && me.InstanceExpression != EmptyExpression.Null) &&
2864                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2865                                     me.InstanceExpression.Type != me.DeclaringType &&
2866                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2867                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2868                                         ec.Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2869                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2870                                         return null;
2871                                 }
2872
2873                                 return (right_side != null)
2874                                         ? me.DoResolveLValue (ec, right_side)
2875                                         : me.DoResolve (ec);
2876                         }
2877
2878                         return e;
2879                 }
2880         }
2881
2882         /// <summary>
2883         ///   Represents a namespace or a type.  The name of the class was inspired by
2884         ///   section 10.8.1 (Fully Qualified Names).
2885         /// </summary>
2886         public abstract class FullNamedExpression : Expression
2887         {
2888                 protected override void CloneTo (CloneContext clonectx, Expression target)
2889                 {
2890                         // Do nothing, most unresolved type expressions cannot be
2891                         // resolved to different type
2892                 }
2893
2894                 public override Expression CreateExpressionTree (ResolveContext ec)
2895                 {
2896                         throw new NotSupportedException ("ET");
2897                 }
2898
2899                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2900                 {
2901                         throw new NotSupportedException ();
2902                 }
2903
2904                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2905                 {
2906                         return this;
2907                 }
2908
2909                 public override void Emit (EmitContext ec)
2910                 {
2911                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2912                                 GetSignatureForError ());
2913                 }
2914         }
2915
2916         /// <summary>
2917         ///   Expression that evaluates to a type
2918         /// </summary>
2919         public abstract class TypeExpr : FullNamedExpression {
2920                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2921                 {
2922                         TypeExpr t = DoResolveAsTypeStep (ec);
2923                         if (t == null)
2924                                 return null;
2925
2926                         eclass = ExprClass.Type;
2927                         return t;
2928                 }
2929
2930                 override public Expression DoResolve (ResolveContext ec)
2931                 {
2932                         return ResolveAsTypeTerminal (ec, false);
2933                 }
2934
2935                 public virtual bool CheckAccessLevel (IMemberContext mc)
2936                 {
2937                         return mc.CurrentTypeDefinition.CheckAccessLevel (Type);
2938                 }
2939
2940                 public virtual bool IsClass {
2941                         get { return Type.IsClass; }
2942                 }
2943
2944                 public virtual bool IsValueType {
2945                         get { return TypeManager.IsStruct (Type); }
2946                 }
2947
2948                 public virtual bool IsInterface {
2949                         get { return Type.IsInterface; }
2950                 }
2951
2952                 public virtual bool IsSealed {
2953                         get { return Type.IsSealed; }
2954                 }
2955
2956                 public virtual bool CanInheritFrom ()
2957                 {
2958                         if (Type == TypeManager.enum_type ||
2959                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2960                             Type == TypeManager.multicast_delegate_type ||
2961                             Type == TypeManager.delegate_type ||
2962                             Type == TypeManager.array_type)
2963                                 return false;
2964
2965                         return true;
2966                 }
2967
2968                 protected abstract TypeExpr DoResolveAsTypeStep (IMemberContext ec);
2969
2970                 public override bool Equals (object obj)
2971                 {
2972                         TypeExpr tobj = obj as TypeExpr;
2973                         if (tobj == null)
2974                                 return false;
2975
2976                         return Type == tobj.Type;
2977                 }
2978
2979                 public override int GetHashCode ()
2980                 {
2981                         return Type.GetHashCode ();
2982                 }
2983
2984                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2985                 {
2986                         type = storey.MutateType (type);
2987                 }
2988         }
2989
2990         /// <summary>
2991         ///   Fully resolved Expression that already evaluated to a type
2992         /// </summary>
2993         public class TypeExpression : TypeExpr {
2994                 public TypeExpression (Type t, Location l)
2995                 {
2996                         Type = t;
2997                         eclass = ExprClass.Type;
2998                         loc = l;
2999                 }
3000
3001                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3002                 {
3003                         return this;
3004                 }
3005
3006                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3007                 {
3008                         return this;
3009                 }
3010         }
3011
3012         //
3013         // Used to create types from a fully qualified name.  These are just used
3014         // by the parser to setup the core types.
3015         //
3016         public sealed class TypeLookupExpression : TypeExpr {
3017                 readonly string ns_name;
3018                 readonly string name;
3019
3020                 public TypeLookupExpression (string ns, string name)
3021                 {
3022                         this.name = name;
3023                         this.ns_name = ns;
3024                         eclass = ExprClass.Type;
3025                 }
3026
3027                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3028                 {
3029                         //
3030                         // It's null only during mscorlib bootstrap when DefineType
3031                         // nees to resolve base type of same type
3032                         //
3033                         // For instance struct Char : IComparable<char>
3034                         //
3035                         // TODO: it could be removed when Resolve starts to use
3036                         // DeclSpace instead of Type
3037                         //
3038                         if (type == null) {
3039                                 Namespace ns = GlobalRootNamespace.Instance.GetNamespace (ns_name, false);
3040                                 FullNamedExpression fne = ns.Lookup (ec.Compiler, name, loc);
3041                                 if (fne != null)
3042                                         type = fne.Type;
3043                         }
3044
3045                         return this;
3046                 }
3047
3048                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3049                 {
3050                         return this;
3051                 }
3052
3053                 public override string GetSignatureForError ()
3054                 {
3055                         if (type == null)
3056                                 return TypeManager.CSharpName (ns_name + "." + name, null);
3057
3058                         return base.GetSignatureForError ();
3059                 }
3060         }
3061
3062         /// <summary>
3063         ///   This class denotes an expression which evaluates to a member
3064         ///   of a struct or a class.
3065         /// </summary>
3066         public abstract class MemberExpr : Expression
3067         {
3068                 protected bool is_base;
3069
3070                 /// <summary>
3071                 ///   The name of this member.
3072                 /// </summary>
3073                 public abstract string Name {
3074                         get;
3075                 }
3076
3077                 //
3078                 // When base.member is used
3079                 //
3080                 public bool IsBase {
3081                         get { return is_base; }
3082                         set { is_base = value; }
3083                 }
3084
3085                 /// <summary>
3086                 ///   Whether this is an instance member.
3087                 /// </summary>
3088                 public abstract bool IsInstance {
3089                         get;
3090                 }
3091
3092                 /// <summary>
3093                 ///   Whether this is a static member.
3094                 /// </summary>
3095                 public abstract bool IsStatic {
3096                         get;
3097                 }
3098
3099                 /// <summary>
3100                 ///   The type which declares this member.
3101                 /// </summary>
3102                 public abstract Type DeclaringType {
3103                         get;
3104                 }
3105
3106                 /// <summary>
3107                 ///   The instance expression associated with this member, if it's a
3108                 ///   non-static member.
3109                 /// </summary>
3110                 public Expression InstanceExpression;
3111
3112                 public static void error176 (ResolveContext ec, Location loc, string name)
3113                 {
3114                         ec.Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3115                                       "with an instance reference, qualify it with a type name instead", name);
3116                 }
3117
3118                 public static void Error_BaseAccessInExpressionTree (ResolveContext ec, Location loc)
3119                 {
3120                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
3121                 }
3122
3123                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3124                 {
3125                         if (InstanceExpression != null)
3126                                 InstanceExpression.MutateHoistedGenericType (storey);
3127                 }
3128
3129                 // TODO: possible optimalization
3130                 // Cache resolved constant result in FieldBuilder <-> expression map
3131                 public virtual MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3132                                                                SimpleName original)
3133                 {
3134                         //
3135                         // Precondition:
3136                         //   original == null || original.Resolve (...) ==> left
3137                         //
3138
3139                         if (left is TypeExpr) {
3140                                 left = left.ResolveAsBaseTerminal (ec, false);
3141                                 if (left == null)
3142                                         return null;
3143
3144                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3145                                 // always do all necessary checks
3146                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3147                                 if (oa != null && !ec.IsObsolete) {
3148                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc, ec.Report);
3149                                 }
3150
3151                                 GenericTypeExpr ct = left as GenericTypeExpr;
3152                                 if (ct != null && !ct.CheckConstraints (ec))
3153                                         return null;
3154                                 //
3155
3156                                 if (!IsStatic) {
3157                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3158                                         return null;
3159                                 }
3160
3161                                 return this;
3162                         }
3163
3164                         if (!IsInstance) {
3165                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3166                                         return this;
3167
3168                                 return ResolveExtensionMemberAccess (ec, left);
3169                         }
3170
3171                         InstanceExpression = left;
3172                         return this;
3173                 }
3174
3175                 protected virtual MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3176                 {
3177                         error176 (ec, loc, GetSignatureForError ());
3178                         return this;
3179                 }
3180
3181                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3182                 {
3183                         if (IsStatic)
3184                                 return;
3185
3186                         if (InstanceExpression == EmptyExpression.Null) {
3187                                 // FIXME: This should not be here at all
3188                                 SimpleName.Error_ObjectRefRequired (new ResolveContext (ec.MemberContext), loc, GetSignatureForError ());
3189                                 return;
3190                         }
3191
3192                         if (TypeManager.IsValueType (InstanceExpression.Type)) {
3193                                 if (InstanceExpression is IMemoryLocation) {
3194                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3195                                 } else {
3196                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3197                                         InstanceExpression.Emit (ec);
3198                                         t.Store (ec);
3199                                         t.AddressOf (ec, AddressOp.Store);
3200                                 }
3201                         } else
3202                                 InstanceExpression.Emit (ec);
3203
3204                         if (prepare_for_load)
3205                                 ec.ig.Emit (OpCodes.Dup);
3206                 }
3207
3208                 public virtual void SetTypeArguments (ResolveContext ec, TypeArguments ta)
3209                 {
3210                         // TODO: need to get correct member type
3211                         ec.Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3212                                 GetSignatureForError ());
3213                 }
3214         }
3215
3216         ///
3217         /// Represents group of extension methods
3218         ///
3219         public class ExtensionMethodGroupExpr : MethodGroupExpr
3220         {
3221                 readonly NamespaceEntry namespace_entry;
3222                 public Expression ExtensionExpression;
3223                 Argument extension_argument;
3224
3225                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3226                         : base (list, extensionType, l)
3227                 {
3228                         this.namespace_entry = n;
3229                 }
3230
3231                 public override bool IsStatic {
3232                         get { return true; }
3233                 }
3234
3235                 public bool IsTopLevel {
3236                         get { return namespace_entry == null; }
3237                 }
3238
3239                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3240                 {
3241                         extension_argument.Expr.MutateHoistedGenericType (storey);
3242                         base.MutateHoistedGenericType (storey);
3243                 }
3244
3245                 public override MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments arguments, bool may_fail, Location loc)
3246                 {
3247                         if (arguments == null)
3248                                 arguments = new Arguments (1);
3249
3250                         arguments.Insert (0, new Argument (ExtensionExpression));
3251                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, ref arguments, namespace_entry, loc);
3252
3253                         // Store resolved argument and restore original arguments
3254                         if (mg != null)
3255                                 ((ExtensionMethodGroupExpr)mg).extension_argument = arguments [0];
3256                         else
3257                                 arguments.RemoveAt (0); // Clean-up modified arguments for error reporting
3258
3259                         return mg;
3260                 }
3261
3262                 MethodGroupExpr ResolveOverloadExtensions (ResolveContext ec, ref Arguments arguments, NamespaceEntry ns, Location loc)
3263                 {
3264                         // Use normal resolve rules
3265                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3266                         if (mg != null)
3267                                 return mg;
3268
3269                         if (ns == null)
3270                                 return null;
3271
3272                         // Search continues
3273                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, Name, loc);
3274                         if (e == null)
3275                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3276
3277                         e.ExtensionExpression = ExtensionExpression;
3278                         e.SetTypeArguments (ec, type_arguments);
3279                         return e.ResolveOverloadExtensions (ec, ref arguments, e.namespace_entry, loc);
3280                 }
3281         }
3282
3283         /// <summary>
3284         ///   MethodGroupExpr represents a group of method candidates which
3285         ///   can be resolved to the best method overload
3286         /// </summary>
3287         public class MethodGroupExpr : MemberExpr
3288         {
3289                 public interface IErrorHandler
3290                 {
3291                         bool AmbiguousCall (ResolveContext ec, MethodBase ambiguous);
3292                         bool NoExactMatch (ResolveContext ec, MethodBase method);
3293                 }
3294
3295                 public IErrorHandler CustomErrorHandler;
3296                 public MethodBase [] Methods;
3297                 MethodBase best_candidate;
3298                 // TODO: make private
3299                 public TypeArguments type_arguments;
3300                 bool identical_type_name;
3301                 bool has_inaccessible_candidates_only;
3302                 Type delegate_type;
3303                 Type queried_type;
3304
3305                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3306                         : this (type, l)
3307                 {
3308                         Methods = new MethodBase [mi.Length];
3309                         mi.CopyTo (Methods, 0);
3310                 }
3311
3312                 public MethodGroupExpr (MemberInfo[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3313                         : this (mi, type, l)
3314                 {
3315                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3316                 }
3317
3318                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3319                         : this (type, l)
3320                 {
3321                         try {
3322                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3323                         } catch {
3324                                 foreach (MemberInfo m in list){
3325                                         if (!(m is MethodBase)){
3326                                                 Console.WriteLine ("Name " + m.Name);
3327                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3328                                         }
3329                                 }
3330                                 throw;
3331                         }
3332
3333
3334                 }
3335
3336                 protected MethodGroupExpr (Type type, Location loc)
3337                 {
3338                         this.loc = loc;
3339                         eclass = ExprClass.MethodGroup;
3340                         this.type = InternalType.MethodGroup;
3341                         queried_type = type;
3342                 }
3343
3344                 public override Type DeclaringType {
3345                         get {
3346                                 return queried_type;
3347                         }
3348                 }
3349
3350                 public Type DelegateType {
3351                         set {
3352                                 delegate_type = value;
3353                         }
3354                 }
3355
3356                 public bool IdenticalTypeName {
3357                         get {
3358                                 return identical_type_name;
3359                         }
3360                 }
3361
3362                 public override string GetSignatureForError ()
3363                 {
3364                         if (best_candidate != null)
3365                                 return TypeManager.CSharpSignature (best_candidate);
3366
3367                         return TypeManager.CSharpSignature (Methods [0]);
3368                 }
3369
3370                 public override string Name {
3371                         get {
3372                                 return Methods [0].Name;
3373                         }
3374                 }
3375
3376                 public override bool IsInstance {
3377                         get {
3378                                 if (best_candidate != null)
3379                                         return !best_candidate.IsStatic;
3380
3381                                 foreach (MethodBase mb in Methods)
3382                                         if (!mb.IsStatic)
3383                                                 return true;
3384
3385                                 return false;
3386                         }
3387                 }
3388
3389                 public override bool IsStatic {
3390                         get {
3391                                 if (best_candidate != null)
3392                                         return best_candidate.IsStatic;
3393
3394                                 foreach (MethodBase mb in Methods)
3395                                         if (mb.IsStatic)
3396                                                 return true;
3397
3398                                 return false;
3399                         }
3400                 }
3401
3402                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3403                 {
3404                         return (ConstructorInfo)mg.best_candidate;
3405                 }
3406
3407                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3408                 {
3409                         return (MethodInfo)mg.best_candidate;
3410                 }
3411
3412                 //
3413                 //  7.4.3.3  Better conversion from expression
3414                 //  Returns :   1    if a->p is better,
3415                 //              2    if a->q is better,
3416                 //              0 if neither is better
3417                 //
3418                 static int BetterExpressionConversion (ResolveContext ec, Argument a, Type p, Type q)
3419                 {
3420                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3421                         if (argument_type == InternalType.AnonymousMethod && RootContext.Version > LanguageVersion.ISO_2) {
3422                                 //
3423                                 // Uwrap delegate from Expression<T>
3424                                 //
3425                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3426                                         p = TypeManager.GetTypeArguments (p) [0];
3427                                 }
3428                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3429                                         q = TypeManager.GetTypeArguments (q) [0];
3430                                 }
3431
3432                                 p = Delegate.GetInvokeMethod (ec.Compiler, null, p).ReturnType;
3433                                 q = Delegate.GetInvokeMethod (ec.Compiler, null, q).ReturnType;
3434                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3435                                         return 2;
3436                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3437                                         return 1;
3438                         } else {
3439                                 if (argument_type == p)
3440                                         return 1;
3441
3442                                 if (argument_type == q)
3443                                         return 2;
3444                         }
3445
3446                         return BetterTypeConversion (ec, p, q);
3447                 }
3448
3449                 //
3450                 // 7.4.3.4  Better conversion from type
3451                 //
3452                 public static int BetterTypeConversion (ResolveContext ec, Type p, Type q)
3453                 {
3454                         if (p == null || q == null)
3455                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3456
3457                         if (p == TypeManager.int32_type) {
3458                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3459                                         return 1;
3460                         } else if (p == TypeManager.int64_type) {
3461                                 if (q == TypeManager.uint64_type)
3462                                         return 1;
3463                         } else if (p == TypeManager.sbyte_type) {
3464                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3465                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3466                                         return 1;
3467                         } else if (p == TypeManager.short_type) {
3468                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3469                                         q == TypeManager.uint64_type)
3470                                         return 1;
3471                         }
3472
3473                         if (q == TypeManager.int32_type) {
3474                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3475                                         return 2;
3476                         } if (q == TypeManager.int64_type) {
3477                                 if (p == TypeManager.uint64_type)
3478                                         return 2;
3479                         } else if (q == TypeManager.sbyte_type) {
3480                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3481                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3482                                         return 2;
3483                         } if (q == TypeManager.short_type) {
3484                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3485                                         p == TypeManager.uint64_type)
3486                                         return 2;
3487                         }
3488
3489                         // TODO: this is expensive
3490                         Expression p_tmp = new EmptyExpression (p);
3491                         Expression q_tmp = new EmptyExpression (q);
3492
3493                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3494                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3495
3496                         if (p_to_q && !q_to_p)
3497                                 return 1;
3498
3499                         if (q_to_p && !p_to_q)
3500                                 return 2;
3501
3502                         return 0;
3503                 }
3504
3505                 /// <summary>
3506                 ///   Determines "Better function" between candidate
3507                 ///   and the current best match
3508                 /// </summary>
3509                 /// <remarks>
3510                 ///    Returns a boolean indicating :
3511                 ///     false if candidate ain't better
3512                 ///     true  if candidate is better than the current best match
3513                 /// </remarks>
3514                 static bool BetterFunction (ResolveContext ec, Arguments args, int argument_count,
3515                         MethodBase candidate, bool candidate_params,
3516                         MethodBase best, bool best_params)
3517                 {
3518                         AParametersCollection candidate_pd = TypeManager.GetParameterData (candidate);
3519                         AParametersCollection best_pd = TypeManager.GetParameterData (best);
3520
3521                         bool better_at_least_one = false;
3522                         bool same = true;
3523                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3524                         {
3525                                 Argument a = args [j];
3526
3527                                 // Provided default argument value is never better
3528                                 if (a.IsDefaultArgument && candidate_params == best_params)
3529                                         return false;
3530
3531                                 Type ct = candidate_pd.Types [c_idx];
3532                                 Type bt = best_pd.Types [b_idx];
3533
3534                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3535                                 {
3536                                         ct = TypeManager.GetElementType (ct);
3537                                         --c_idx;
3538                                 }
3539
3540                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3541                                 {
3542                                         bt = TypeManager.GetElementType (bt);
3543                                         --b_idx;
3544                                 }
3545
3546                                 if (ct.Equals (bt))
3547                                         continue;
3548
3549                                 same = false;
3550                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3551
3552                                 // for each argument, the conversion to 'ct' should be no worse than
3553                                 // the conversion to 'bt'.
3554                                 if (result == 2)
3555                                         return false;
3556
3557                                 // for at least one argument, the conversion to 'ct' should be better than
3558                                 // the conversion to 'bt'.
3559                                 if (result != 0)
3560                                         better_at_least_one = true;
3561                         }
3562
3563                         if (better_at_least_one)
3564                                 return true;
3565
3566                         //
3567                         // This handles the case
3568                         //
3569                         //   Add (float f1, float f2, float f3);
3570                         //   Add (params decimal [] foo);
3571                         //
3572                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3573                         // first candidate would've chosen as better.
3574                         //
3575                         if (!same)
3576                                 return false;
3577
3578                         //
3579                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3580                         //
3581                         if (TypeManager.IsGenericMethod (best)) {
3582                                 if (!TypeManager.IsGenericMethod (candidate))
3583                                         return true;
3584                         } else if (TypeManager.IsGenericMethod (candidate)) {
3585                                 return false;
3586                         }
3587
3588                         //
3589                         // This handles the following cases:
3590                         //
3591                         //   Trim () is better than Trim (params char[] chars)
3592                         //   Concat (string s1, string s2, string s3) is better than
3593                         //     Concat (string s1, params string [] srest)
3594                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3595                         //
3596                         if (!candidate_params && best_params)
3597                                 return true;
3598                         if (candidate_params && !best_params)
3599                                 return false;
3600
3601                         int candidate_param_count = candidate_pd.Count;
3602                         int best_param_count = best_pd.Count;
3603
3604                         if (candidate_param_count != best_param_count)
3605                                 // can only happen if (candidate_params && best_params)
3606                                 return candidate_param_count > best_param_count && best_pd.HasParams;
3607
3608                         //
3609                         // now, both methods have the same number of parameters, and the parameters have the same types
3610                         // Pick the "more specific" signature
3611                         //
3612
3613                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3614                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3615
3616                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3617                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3618
3619                         bool specific_at_least_once = false;
3620                         for (int j = 0; j < candidate_param_count; ++j)
3621                         {
3622                                 Type ct = orig_candidate_pd.Types [j];
3623                                 Type bt = orig_best_pd.Types [j];
3624                                 if (ct.Equals (bt))
3625                                         continue;
3626                                 Type specific = MoreSpecific (ct, bt);
3627                                 if (specific == bt)
3628                                         return false;
3629                                 if (specific == ct)
3630                                         specific_at_least_once = true;
3631                         }
3632
3633                         if (specific_at_least_once)
3634                                 return true;
3635
3636                         // FIXME: handle lifted operators
3637                         // ...
3638
3639                         return false;
3640                 }
3641
3642                 protected override MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3643                 {
3644                         if (!IsStatic)
3645                                 return base.ResolveExtensionMemberAccess (ec, left);
3646
3647                         //
3648                         // When left side is an expression and at least one candidate method is
3649                         // static, it can be extension method
3650                         //
3651                         InstanceExpression = left;
3652                         return this;
3653                 }
3654
3655                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3656                                                                 SimpleName original)
3657                 {
3658                         if (!(left is TypeExpr) &&
3659                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3660                                 identical_type_name = true;
3661
3662                         return base.ResolveMemberAccess (ec, left, loc, original);
3663                 }
3664
3665                 public override Expression CreateExpressionTree (ResolveContext ec)
3666                 {
3667                         if (best_candidate == null) {
3668                                 ec.Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3669                                 return null;
3670                         }
3671
3672                         IMethodData md = TypeManager.GetMethod (best_candidate);
3673                         if (md != null && md.IsExcluded ())
3674                                 ec.Report.Error (765, loc,
3675                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3676
3677                         return new TypeOfMethod (best_candidate, loc);
3678                 }
3679
3680                 override public Expression DoResolve (ResolveContext ec)
3681                 {
3682                         if (InstanceExpression != null) {
3683                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3684                                 if (InstanceExpression == null)
3685                                         return null;
3686                         }
3687
3688                         return this;
3689                 }
3690
3691                 public void ReportUsageError (ResolveContext ec)
3692                 {
3693                         ec.Report.Error (654, loc, "Method `" + DeclaringType + "." +
3694                                       Name + "()' is referenced without parentheses");
3695                 }
3696
3697                 override public void Emit (EmitContext ec)
3698                 {
3699                         throw new NotSupportedException ();
3700                         // ReportUsageError ();
3701                 }
3702
3703                 public void EmitCall (EmitContext ec, Arguments arguments)
3704                 {
3705                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3706                 }
3707
3708                 void Error_AmbiguousCall (ResolveContext ec, MethodBase ambiguous)
3709                 {
3710                         if (CustomErrorHandler != null && CustomErrorHandler.AmbiguousCall (ec, ambiguous))
3711                                 return;
3712
3713                         ec.Report.SymbolRelatedToPreviousError (best_candidate);
3714                         ec.Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
3715                                 TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
3716                 }
3717
3718                 protected virtual void Error_InvalidArguments (ResolveContext ec, Location loc, int idx, MethodBase method,
3719                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3720                 {
3721                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3722
3723                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3724                                 ec.Report.SymbolRelatedToPreviousError (method);
3725                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3726                                         ec.Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3727                                                 TypeManager.CSharpSignature (method));
3728                                         return;
3729                                 }
3730                                 ec.Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3731                                           TypeManager.CSharpSignature (method));
3732                         } else if (TypeManager.IsDelegateType (method.DeclaringType)) {
3733                                 ec.Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3734                                         TypeManager.CSharpName (method.DeclaringType));
3735                         } else {
3736                                 ec.Report.SymbolRelatedToPreviousError (method);
3737                                 if (emg != null) {
3738                                         ec.Report.Error (1928, loc,
3739                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3740                                                 emg.ExtensionExpression.GetSignatureForError (),
3741                                                 emg.Name, TypeManager.CSharpSignature (method));
3742                                 } else {
3743                                         ec.Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3744                                                 TypeManager.CSharpSignature (method));
3745                                 }
3746                         }
3747
3748                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3749
3750                         string index = (idx + 1).ToString ();
3751                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3752                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3753                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3754                                         ec.Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3755                                                 index, Parameter.GetModifierSignature (a.Modifier));
3756                                 else
3757                                         ec.Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3758                                                 index, Parameter.GetModifierSignature (mod));
3759                         } else {
3760                                 string p1 = a.GetSignatureForError ();
3761                                 string p2 = TypeManager.CSharpName (paramType);
3762
3763                                 if (p1 == p2) {
3764                                         ec.Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3765                                         ec.Report.SymbolRelatedToPreviousError (a.Expr.Type);
3766                                         ec.Report.SymbolRelatedToPreviousError (paramType);
3767                                 }
3768
3769                                 if (idx == 0 && emg != null) {
3770                                         ec.Report.Error (1929, loc,
3771                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3772                                 } else {
3773                                         ec.Report.Error (1503, loc,
3774                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3775                                 }
3776                         }
3777                 }
3778
3779                 public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
3780                 {
3781                         ec.Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3782                                 Name, TypeManager.CSharpName (target));
3783                 }
3784
3785                 void Error_ArgumentCountWrong (ResolveContext ec, int arg_count)
3786                 {
3787                         ec.Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
3788                                       Name, arg_count.ToString ());
3789                 }
3790
3791                 protected virtual int GetApplicableParametersCount (MethodBase method, AParametersCollection parameters)
3792                 {
3793                         return parameters.Count;
3794                 }
3795
3796                 public static bool IsAncestralType (Type first_type, Type second_type)
3797                 {
3798                         return first_type != second_type &&
3799                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3800                                 TypeManager.ImplementsInterface (second_type, first_type));
3801                 }
3802
3803                 ///
3804                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3805                 /// to the given set of arguments
3806                 /// A return value rates candidate method compatibility,
3807                 /// 0 = the best, int.MaxValue = the worst
3808                 ///
3809                 public int IsApplicable (ResolveContext ec,
3810                                                 ref Arguments arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3811                 {
3812                         MethodBase candidate = method;
3813
3814                         AParametersCollection pd = TypeManager.GetParameterData (candidate);
3815                         int param_count = GetApplicableParametersCount (candidate, pd);
3816                         int optional_count = 0;
3817
3818                         if (arg_count != param_count) {
3819                                 for (int i = 0; i < pd.Count; ++i) {
3820                                         if (pd.FixedParameters [i].HasDefaultValue) {
3821                                                 optional_count = pd.Count - i;
3822                                                 break;
3823                                         }
3824                                 }
3825
3826                                 int args_gap = Math.Abs (arg_count - param_count);
3827                                 if (optional_count != 0) {
3828                                         if (args_gap > optional_count)
3829                                                 return int.MaxValue - 10000 + args_gap - optional_count;
3830
3831                                         // Readjust expected number when params used
3832                                         if (pd.HasParams) {
3833                                                 optional_count--;
3834                                                 if (arg_count < param_count)
3835                                                         param_count--;
3836                                         } else if (arg_count > param_count) {
3837                                                 return int.MaxValue - 10000 + args_gap;
3838                                         }
3839                                 } else if (arg_count != param_count) {
3840                                         if (!pd.HasParams)
3841                                                 return int.MaxValue - 10000 + args_gap;
3842                                         if (arg_count < param_count - 1)
3843                                                 return int.MaxValue - 10000 + args_gap;
3844                                 }
3845
3846                                 // Initialize expanded form of a method with 1 params parameter
3847                                 params_expanded_form = param_count == 1 && pd.HasParams;
3848
3849                                 // Resize to fit optional arguments
3850                                 if (optional_count != 0) {
3851                                         Arguments resized;
3852                                         if (arguments == null) {
3853                                                 resized = new Arguments (optional_count);
3854                                         } else {
3855                                                 resized = new Arguments (param_count);
3856                                                 resized.AddRange (arguments);
3857                                         }
3858
3859                                         for (int i = arg_count; i < param_count; ++i)
3860                                                 resized.Add (null);
3861                                         arguments = resized;
3862                                 }
3863                         }
3864
3865                         if (arg_count > 0) {
3866                                 //
3867                                 // Shuffle named arguments to the right positions if there are any
3868                                 //
3869                                 if (arguments [arg_count - 1] is NamedArgument) {
3870                                         arg_count = arguments.Count;
3871
3872                                         for (int i = 0; i < arg_count; ++i) {
3873                                                 bool arg_moved = false;
3874                                                 while (true) {
3875                                                         NamedArgument na = arguments[i] as NamedArgument;
3876                                                         if (na == null)
3877                                                                 break;
3878
3879                                                         int index = pd.GetParameterIndexByName (na.Name.Value);
3880
3881                                                         // Named parameter not found or already reordered
3882                                                         if (index <= i)
3883                                                                 break;
3884
3885                                                         // When using parameters which should not be available to the user
3886                                                         if (index >= param_count)
3887                                                                 break;
3888
3889                                                         if (!arg_moved) {
3890                                                                 arguments.MarkReorderedArgument (na);
3891                                                                 arg_moved = true;
3892                                                         }
3893
3894                                                         Argument temp = arguments[index];
3895                                                         arguments[index] = arguments[i];
3896                                                         arguments[i] = temp;
3897
3898                                                         if (temp == null)
3899                                                                 break;
3900                                                 }
3901                                         }
3902                                 } else {
3903                                         arg_count = arguments.Count;
3904                                 }
3905                         } else if (arguments != null) {
3906                                 arg_count = arguments.Count;
3907                         }
3908
3909                         //
3910                         // 1. Handle generic method using type arguments when specified or type inference
3911                         //
3912                         if (TypeManager.IsGenericMethod (candidate)) {
3913                                 if (type_arguments != null) {
3914                                         Type [] g_args = candidate.GetGenericArguments ();
3915                                         if (g_args.Length != type_arguments.Count)
3916                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3917
3918                                         // TODO: Don't create new method, create Parameters only
3919                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3920                                         candidate = method;
3921                                         pd = TypeManager.GetParameterData (candidate);
3922                                 } else {
3923                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3924                                         if (score != 0)
3925                                                 return score - 20000;
3926
3927                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3928                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3929                                                         TypeManager.CSharpSignature (candidate));
3930
3931                                         pd = TypeManager.GetParameterData (candidate);
3932                                 }
3933                         } else {
3934                                 if (type_arguments != null)
3935                                         return int.MaxValue - 15000;
3936                         }
3937
3938                         //
3939                         // 2. Each argument has to be implicitly convertible to method parameter
3940                         //
3941                         method = candidate;
3942                         Parameter.Modifier p_mod = 0;
3943                         Type pt = null;
3944                         for (int i = 0; i < arg_count; i++) {
3945                                 Argument a = arguments [i];
3946                                 if (a == null) {
3947                                         if (!pd.FixedParameters [i].HasDefaultValue)
3948                                                 throw new InternalErrorException ();
3949
3950                                         Expression e = pd.FixedParameters [i].DefaultValue as Constant;
3951                                         if (e == null)
3952                                                 e = new DefaultValueExpression (new TypeExpression (pd.Types [i], loc), loc).Resolve (ec);
3953
3954                                         arguments [i] = new Argument (e, Argument.AType.Default);
3955                                         continue;
3956                                 }
3957
3958                                 if (p_mod != Parameter.Modifier.PARAMS) {
3959                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3960                                         pt = pd.Types [i];
3961                                 } else {
3962                                         params_expanded_form = true;
3963                                 }
3964
3965                                 Parameter.Modifier a_mod = a.Modifier & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3966                                 int score = 1;
3967                                 if (!params_expanded_form)
3968                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3969
3970                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
3971                                         // It can be applicable in expanded form
3972                                         score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
3973                                         if (score == 0)
3974                                                 params_expanded_form = true;
3975                                 }
3976
3977                                 if (score != 0) {
3978                                         if (params_expanded_form)
3979                                                 ++score;
3980                                         return (arg_count - i) * 2 + score;
3981                                 }
3982                         }
3983
3984                         if (arg_count != param_count)
3985                                 params_expanded_form = true;
3986
3987                         return 0;
3988                 }
3989
3990                 int IsArgumentCompatible (ResolveContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3991                 {
3992                         //
3993                         // Types have to be identical when ref or out modifer is used
3994                         //
3995                         if (arg_mod != 0 || param_mod != 0) {
3996                                 if (TypeManager.HasElementType (parameter))
3997                                         parameter = TypeManager.GetElementType (parameter);
3998
3999                                 Type a_type = argument.Type;
4000                                 if (TypeManager.HasElementType (a_type))
4001                                         a_type = TypeManager.GetElementType (a_type);
4002
4003                                 if (a_type != parameter)
4004                                         return 2;
4005                         } else {
4006                                 if (!Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
4007                                         return 2;
4008                         }
4009
4010                         if (arg_mod != param_mod)
4011                                 return 1;
4012
4013                         return 0;
4014                 }
4015
4016                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
4017                 {
4018                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
4019                                 return false;
4020
4021                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
4022                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
4023
4024                         if (cand_pd.Count != base_pd.Count)
4025                                 return false;
4026
4027                         for (int j = 0; j < cand_pd.Count; ++j)
4028                         {
4029                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
4030                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
4031                                 Type ct = cand_pd.Types [j];
4032                                 Type bt = base_pd.Types [j];
4033
4034                                 if (cm != bm || ct != bt)
4035                                         return false;
4036                         }
4037
4038                         return true;
4039                 }
4040
4041                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
4042                 {
4043                         if (mg1 == null) {
4044                                 if (mg2 == null)
4045                                         return null;
4046                                 return mg2;
4047                         }
4048
4049                         if (mg2 == null)
4050                                 return mg1;
4051
4052                         ArrayList all = new ArrayList (mg1.Methods);
4053                         foreach (MethodBase m in mg2.Methods){
4054                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods, m, false))
4055                                         all.Add (m);
4056                         }
4057
4058                         return new MethodGroupExpr (all, null, loc);
4059                 }
4060
4061                 static Type MoreSpecific (Type p, Type q)
4062                 {
4063                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
4064                                 return q;
4065                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
4066                                 return p;
4067
4068                         if (TypeManager.HasElementType (p))
4069                         {
4070                                 Type pe = TypeManager.GetElementType (p);
4071                                 Type qe = TypeManager.GetElementType (q);
4072                                 Type specific = MoreSpecific (pe, qe);
4073                                 if (specific == pe)
4074                                         return p;
4075                                 if (specific == qe)
4076                                         return q;
4077                         }
4078                         else if (TypeManager.IsGenericType (p))
4079                         {
4080                                 Type[] pargs = TypeManager.GetTypeArguments (p);
4081                                 Type[] qargs = TypeManager.GetTypeArguments (q);
4082
4083                                 bool p_specific_at_least_once = false;
4084                                 bool q_specific_at_least_once = false;
4085
4086                                 for (int i = 0; i < pargs.Length; i++)
4087                                 {
4088                                         Type specific = MoreSpecific (TypeManager.TypeToCoreType (pargs [i]), TypeManager.TypeToCoreType (qargs [i]));
4089                                         if (specific == pargs [i])
4090                                                 p_specific_at_least_once = true;
4091                                         if (specific == qargs [i])
4092                                                 q_specific_at_least_once = true;
4093                                 }
4094
4095                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4096                                         return p;
4097                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4098                                         return q;
4099                         }
4100
4101                         return null;
4102                 }
4103
4104                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4105                 {
4106                         base.MutateHoistedGenericType (storey);
4107
4108                         MethodInfo mi = best_candidate as MethodInfo;
4109                         if (mi != null) {
4110                                 best_candidate = storey.MutateGenericMethod (mi);
4111                                 return;
4112                         }
4113
4114                         best_candidate = storey.MutateConstructor ((ConstructorInfo) this);
4115                 }
4116
4117                 /// <summary>
4118                 ///   Find the Applicable Function Members (7.4.2.1)
4119                 ///
4120                 ///   me: Method Group expression with the members to select.
4121                 ///       it might contain constructors or methods (or anything
4122                 ///       that maps to a method).
4123                 ///
4124                 ///   Arguments: ArrayList containing resolved Argument objects.
4125                 ///
4126                 ///   loc: The location if we want an error to be reported, or a Null
4127                 ///        location for "probing" purposes.
4128                 ///
4129                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4130                 ///            that is the best match of me on Arguments.
4131                 ///
4132                 /// </summary>
4133                 public virtual MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments Arguments,
4134                         bool may_fail, Location loc)
4135                 {
4136                         bool method_params = false;
4137                         Type applicable_type = null;
4138                         ArrayList candidates = new ArrayList (2);
4139                         ArrayList candidate_overrides = null;
4140
4141                         //
4142                         // Used to keep a map between the candidate
4143                         // and whether it is being considered in its
4144                         // normal or expanded form
4145                         //
4146                         // false is normal form, true is expanded form
4147                         //
4148                         Hashtable candidate_to_form = null;
4149                         Hashtable candidates_expanded = null;
4150                         Arguments candidate_args = Arguments;
4151
4152                         int arg_count = Arguments != null ? Arguments.Count : 0;
4153
4154                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4155                                 if (!may_fail)
4156                                         ec.Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4157                                 return null;
4158                         }
4159
4160                         int nmethods = Methods.Length;
4161
4162                         if (!IsBase) {
4163                                 //
4164                                 // Methods marked 'override' don't take part in 'applicable_type'
4165                                 // computation, nor in the actual overload resolution.
4166                                 // However, they still need to be emitted instead of a base virtual method.
4167                                 // So, we salt them away into the 'candidate_overrides' array.
4168                                 //
4169                                 // In case of reflected methods, we replace each overriding method with
4170                                 // its corresponding base virtual method.  This is to improve compatibility
4171                                 // with non-C# libraries which change the visibility of overrides (#75636)
4172                                 //
4173                                 int j = 0;
4174                                 for (int i = 0; i < Methods.Length; ++i) {
4175                                         MethodBase m = Methods [i];
4176                                         if (TypeManager.IsOverride (m)) {
4177                                                 if (candidate_overrides == null)
4178                                                         candidate_overrides = new ArrayList ();
4179                                                 candidate_overrides.Add (m);
4180                                                 m = TypeManager.TryGetBaseDefinition (m);
4181                                         }
4182                                         if (m != null)
4183                                                 Methods [j++] = m;
4184                                 }
4185                                 nmethods = j;
4186                         }
4187
4188                         //
4189                         // Enable message recording, it's used mainly by lambda expressions
4190                         //
4191                         SessionReportPrinter msg_recorder = new SessionReportPrinter ();
4192                         ReportPrinter prev_recorder = ec.Report.SetPrinter (msg_recorder);
4193
4194                         //
4195                         // First we construct the set of applicable methods
4196                         //
4197                         bool is_sorted = true;
4198                         int best_candidate_rate = int.MaxValue;
4199                         for (int i = 0; i < nmethods; i++) {
4200                                 Type decl_type = Methods [i].DeclaringType;
4201
4202                                 //
4203                                 // If we have already found an applicable method
4204                                 // we eliminate all base types (Section 14.5.5.1)
4205                                 //
4206                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4207                                         continue;
4208
4209                                 //
4210                                 // Check if candidate is applicable (section 14.4.2.1)
4211                                 //
4212                                 bool params_expanded_form = false;
4213                                 int candidate_rate = IsApplicable (ec, ref candidate_args, arg_count, ref Methods [i], ref params_expanded_form);
4214
4215                                 if (candidate_rate < best_candidate_rate) {
4216                                         best_candidate_rate = candidate_rate;
4217                                         best_candidate = Methods [i];
4218                                 }
4219
4220                                 if (params_expanded_form) {
4221                                         if (candidate_to_form == null)
4222                                                 candidate_to_form = new PtrHashtable ();
4223                                         MethodBase candidate = Methods [i];
4224                                         candidate_to_form [candidate] = candidate;
4225                                 }
4226
4227                                 if (candidate_args != Arguments) {
4228                                         if (candidates_expanded == null)
4229                                                 candidates_expanded = new Hashtable (2);
4230
4231                                         candidates_expanded.Add (Methods [i], candidate_args);
4232                                         candidate_args = Arguments;
4233                                 }
4234
4235                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4236                                         if (msg_recorder != null)
4237                                                 msg_recorder.EndSession ();
4238                                         continue;
4239                                 }
4240
4241                                 msg_recorder = null;
4242                                 candidates.Add (Methods [i]);
4243
4244                                 if (applicable_type == null)
4245                                         applicable_type = decl_type;
4246                                 else if (applicable_type != decl_type) {
4247                                         is_sorted = false;
4248                                         if (IsAncestralType (applicable_type, decl_type))
4249                                                 applicable_type = decl_type;
4250                                 }
4251                         }
4252
4253                         ec.Report.SetPrinter (prev_recorder);
4254                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4255                                 if (!may_fail)
4256                                         msg_recorder.Merge (prev_recorder);
4257
4258                                 return null;
4259                         }
4260
4261                         int candidate_top = candidates.Count;
4262
4263                         if (applicable_type == null) {
4264                                 //
4265                                 // When we found a top level method which does not match and it's
4266                                 // not an extension method. We start extension methods lookup from here
4267                                 //
4268                                 if (InstanceExpression != null) {
4269                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (type, Name, loc);
4270                                         if (ex_method_lookup != null) {
4271                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4272                                                 ex_method_lookup.SetTypeArguments (ec, type_arguments);
4273                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4274                                         }
4275                                 }
4276
4277                                 if (may_fail)
4278                                         return null;
4279
4280                                 //
4281                                 // Okay so we have failed to find exact match so we
4282                                 // return error info about the closest match
4283                                 //
4284                                 if (best_candidate != null) {
4285                                         if (CustomErrorHandler != null && !has_inaccessible_candidates_only && CustomErrorHandler.NoExactMatch (ec, best_candidate))
4286                                                 return null;
4287
4288                                         AParametersCollection pd = TypeManager.GetParameterData (best_candidate);
4289                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4290                                         if (arg_count == pd.Count || pd.HasParams) {
4291                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4292                                                         if (type_arguments == null) {
4293                                                                 ec.Report.Error (411, loc,
4294                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4295                                                                         "the usage. Try specifying the type arguments explicitly",
4296                                                                         TypeManager.CSharpSignature (best_candidate));
4297                                                                 return null;
4298                                                         }
4299
4300                                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate);
4301                                                         if (type_arguments.Count != g_args.Length) {
4302                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4303                                                                 ec.Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4304                                                                         TypeManager.CSharpSignature (best_candidate),
4305                                                                         g_args.Length.ToString ());
4306                                                                 return null;
4307                                                         }
4308                                                 } else {
4309                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4310                                                                 Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
4311                                                                 return null;
4312                                                         }
4313                                                 }
4314
4315                                                 if (has_inaccessible_candidates_only) {
4316                                                         if (InstanceExpression != null && type != ec.CurrentType && TypeManager.IsNestedFamilyAccessible (ec.CurrentType, best_candidate.DeclaringType)) {
4317                                                                 // Although a derived class can access protected members of
4318                                                                 // its base class it cannot do so through an instance of the
4319                                                                 // base class (CS1540).  If the qualifier_type is a base of the
4320                                                                 // ec.CurrentType and the lookup succeeds with the latter one,
4321                                                                 // then we are in this situation.
4322                                                                 Error_CannotAccessProtected (ec, loc, best_candidate, queried_type, ec.CurrentType);
4323                                                         } else {
4324                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4325                                                                 ErrorIsInaccesible (loc, GetSignatureForError (), ec.Report);
4326                                                         }
4327                                                 }
4328
4329                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4330                                                         return null;
4331
4332                                                 if (has_inaccessible_candidates_only)
4333                                                         return null;
4334
4335                                                 throw new InternalErrorException ("VerifyArgumentsCompat didn't find any problem with rejected candidate " + best_candidate);
4336                                         }
4337                                 }
4338
4339                                 //
4340                                 // We failed to find any method with correct argument count
4341                                 //
4342                                 if (Name == ConstructorInfo.ConstructorName) {
4343                                         ec.Report.SymbolRelatedToPreviousError (queried_type);
4344                                         ec.Report.Error (1729, loc,
4345                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4346                                                 TypeManager.CSharpName (queried_type), arg_count);
4347                                 } else {
4348                                         Error_ArgumentCountWrong (ec, arg_count);
4349                                 }
4350
4351                                 return null;
4352                         }
4353
4354                         if (!is_sorted) {
4355                                 //
4356                                 // At this point, applicable_type is _one_ of the most derived types
4357                                 // in the set of types containing the methods in this MethodGroup.
4358                                 // Filter the candidates so that they only contain methods from the
4359                                 // most derived types.
4360                                 //
4361
4362                                 int finalized = 0; // Number of finalized candidates
4363
4364                                 do {
4365                                         // Invariant: applicable_type is a most derived type
4366
4367                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4368                                         // eliminating all it's base types.  At the same time, we'll also move
4369                                         // every unrelated type to the end of the array, and pick the next
4370                                         // 'applicable_type'.
4371
4372                                         Type next_applicable_type = null;
4373                                         int j = finalized; // where to put the next finalized candidate
4374                                         int k = finalized; // where to put the next undiscarded candidate
4375                                         for (int i = finalized; i < candidate_top; ++i) {
4376                                                 MethodBase candidate = (MethodBase) candidates [i];
4377                                                 Type decl_type = candidate.DeclaringType;
4378
4379                                                 if (decl_type == applicable_type) {
4380                                                         candidates [k++] = candidates [j];
4381                                                         candidates [j++] = candidates [i];
4382                                                         continue;
4383                                                 }
4384
4385                                                 if (IsAncestralType (decl_type, applicable_type))
4386                                                         continue;
4387
4388                                                 if (next_applicable_type != null &&
4389                                                         IsAncestralType (decl_type, next_applicable_type))
4390                                                         continue;
4391
4392                                                 candidates [k++] = candidates [i];
4393
4394                                                 if (next_applicable_type == null ||
4395                                                         IsAncestralType (next_applicable_type, decl_type))
4396                                                         next_applicable_type = decl_type;
4397                                         }
4398
4399                                         applicable_type = next_applicable_type;
4400                                         finalized = j;
4401                                         candidate_top = k;
4402                                 } while (applicable_type != null);
4403                         }
4404
4405                         //
4406                         // Now we actually find the best method
4407                         //
4408
4409                         best_candidate = (MethodBase) candidates [0];
4410                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4411
4412                         //
4413                         // TODO: Broken inverse order of candidates logic does not work with optional
4414                         // parameters used for method overrides and I am not going to fix it for SRE
4415                         //
4416                         if (candidates_expanded != null && candidates_expanded.Contains (best_candidate)) {
4417                                 candidate_args = (Arguments) candidates_expanded [best_candidate];
4418                                 arg_count = candidate_args.Count;
4419                         }
4420
4421                         for (int ix = 1; ix < candidate_top; ix++) {
4422                                 MethodBase candidate = (MethodBase) candidates [ix];
4423
4424                                 if (candidate == best_candidate)
4425                                         continue;
4426
4427                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4428
4429                                 if (BetterFunction (ec, candidate_args, arg_count,
4430                                         candidate, cand_params,
4431                                         best_candidate, method_params)) {
4432                                         best_candidate = candidate;
4433                                         method_params = cand_params;
4434                                 }
4435                         }
4436                         //
4437                         // Now check that there are no ambiguities i.e the selected method
4438                         // should be better than all the others
4439                         //
4440                         MethodBase ambiguous = null;
4441                         for (int ix = 1; ix < candidate_top; ix++) {
4442                                 MethodBase candidate = (MethodBase) candidates [ix];
4443
4444                                 if (candidate == best_candidate)
4445                                         continue;
4446
4447                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4448                                 if (!BetterFunction (ec, candidate_args, arg_count,
4449                                         best_candidate, method_params,
4450                                         candidate, cand_params))
4451                                 {
4452                                         if (!may_fail)
4453                                                 ec.Report.SymbolRelatedToPreviousError (candidate);
4454                                         ambiguous = candidate;
4455                                 }
4456                         }
4457
4458                         if (ambiguous != null) {
4459                                 Error_AmbiguousCall (ec, ambiguous);
4460                                 return this;
4461                         }
4462
4463                         //
4464                         // If the method is a virtual function, pick an override closer to the LHS type.
4465                         //
4466                         if (!IsBase && best_candidate.IsVirtual) {
4467                                 if (TypeManager.IsOverride (best_candidate))
4468                                         throw new InternalErrorException (
4469                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4470
4471                                 if (candidate_overrides != null) {
4472                                         Type[] gen_args = null;
4473                                         bool gen_override = false;
4474                                         if (TypeManager.IsGenericMethod (best_candidate))
4475                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4476
4477                                         foreach (MethodBase candidate in candidate_overrides) {
4478                                                 if (TypeManager.IsGenericMethod (candidate)) {
4479                                                         if (gen_args == null)
4480                                                                 continue;
4481
4482                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4483                                                                 continue;
4484                                                 } else {
4485                                                         if (gen_args != null)
4486                                                                 continue;
4487                                                 }
4488
4489                                                 if (IsOverride (candidate, best_candidate)) {
4490                                                         gen_override = true;
4491                                                         best_candidate = candidate;
4492                                                 }
4493                                         }
4494
4495                                         if (gen_override && gen_args != null) {
4496                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4497                                         }
4498                                 }
4499                         }
4500
4501                         //
4502                         // And now check if the arguments are all
4503                         // compatible, perform conversions if
4504                         // necessary etc. and return if everything is
4505                         // all right
4506                         //
4507                         if (!VerifyArgumentsCompat (ec, ref candidate_args, arg_count, best_candidate,
4508                                 method_params, may_fail, loc))
4509                                 return null;
4510
4511                         if (best_candidate == null)
4512                                 return null;
4513
4514                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4515                         if (TypeManager.IsGenericMethodDefinition (the_method) &&
4516                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4517                                 return null;
4518
4519                         //
4520                         // Check ObsoleteAttribute on the best method
4521                         //
4522                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4523                         if (oa != null && !ec.IsObsolete)
4524                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
4525
4526                         IMethodData data = TypeManager.GetMethod (the_method);
4527                         if (data != null)
4528                                 data.SetMemberIsUsed ();
4529
4530                         Arguments = candidate_args;
4531                         return this;
4532                 }
4533
4534                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
4535                 {
4536                         type_arguments = ta;
4537                 }
4538
4539                 public bool VerifyArgumentsCompat (ResolveContext ec, ref Arguments arguments,
4540                                                           int arg_count, MethodBase method,
4541                                                           bool chose_params_expanded,
4542                                                           bool may_fail, Location loc)
4543                 {
4544                         AParametersCollection pd = TypeManager.GetParameterData (method);
4545                         int param_count = GetApplicableParametersCount (method, pd);
4546
4547                         int errors = ec.Report.Errors;
4548                         Parameter.Modifier p_mod = 0;
4549                         Type pt = null;
4550                         int a_idx = 0, a_pos = 0;
4551                         Argument a = null;
4552                         ArrayList params_initializers = null;
4553                         bool has_unsafe_arg = method is MethodInfo ? ((MethodInfo) method).ReturnType.IsPointer : false;
4554
4555                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4556                                 a = arguments [a_idx];
4557                                 if (p_mod != Parameter.Modifier.PARAMS) {
4558                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4559                                         pt = pd.Types [a_idx];
4560                                         has_unsafe_arg |= pt.IsPointer;
4561
4562                                         if (p_mod == Parameter.Modifier.PARAMS) {
4563                                                 if (chose_params_expanded) {
4564                                                         params_initializers = new ArrayList (arg_count - a_idx);
4565                                                         pt = TypeManager.GetElementType (pt);
4566                                                 }
4567                                         }
4568                                 }
4569
4570                                 //
4571                                 // Types have to be identical when ref or out modifer is used
4572                                 //
4573                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4574                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4575                                                 break;
4576
4577                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4578                                                 break;
4579
4580                                         continue;
4581                                 } else {
4582                                         NamedArgument na = a as NamedArgument;
4583                                         if (na != null) {
4584                                                 int name_index = pd.GetParameterIndexByName (na.Name.Value);
4585                                                 if (name_index < 0 || name_index >= param_count) {
4586                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType)) {
4587                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4588                                                                 ec.Report.Error (1746, na.Name.Location,
4589                                                                         "The delegate `{0}' does not contain a parameter named `{1}'",
4590                                                                         TypeManager.CSharpName (DeclaringType), na.Name.Value);
4591                                                         } else {
4592                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4593                                                                 ec.Report.Error (1739, na.Name.Location,
4594                                                                         "The best overloaded method match for `{0}' does not contain a parameter named `{1}'",
4595                                                                         TypeManager.CSharpSignature (method), na.Name.Value);
4596                                                         }
4597                                                 } else if (arguments[name_index] != a) {
4598                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType))
4599                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4600                                                         else
4601                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4602
4603                                                         ec.Report.Error (1744, na.Name.Location,
4604                                                                 "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
4605                                                                 na.Name.Value);
4606                                                 }
4607                                         }
4608                                 }
4609
4610                                 if (delegate_type != null && !Delegate.IsTypeCovariant (a.Expr, pt))
4611                                         break;
4612
4613                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4614                                 if (conv == null)
4615                                         break;
4616
4617                                 //
4618                                 // Convert params arguments to an array initializer
4619                                 //
4620                                 if (params_initializers != null) {
4621                                         // we choose to use 'a.Expr' rather than 'conv' so that
4622                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4623                                         params_initializers.Add (a.Expr);
4624                                         arguments.RemoveAt (a_idx--);
4625                                         --arg_count;
4626                                         continue;
4627                                 }
4628
4629                                 // Update the argument with the implicit conversion
4630                                 a.Expr = conv;
4631                         }
4632
4633                         if (a_idx != arg_count) {
4634                                 if (!may_fail && ec.Report.Errors == errors) {
4635                                         if (CustomErrorHandler != null)
4636                                                 CustomErrorHandler.NoExactMatch (ec, best_candidate);
4637                                         else
4638                                                 Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4639                                 }
4640                                 return false;
4641                         }
4642
4643                         //
4644                         // Fill not provided arguments required by params modifier
4645                         //
4646                         if (params_initializers == null && pd.HasParams && arg_count + 1 == param_count) {
4647                                 if (arguments == null)
4648                                         arguments = new Arguments (1);
4649
4650                                 pt = pd.Types [param_count - 1];
4651                                 pt = TypeManager.GetElementType (pt);
4652                                 has_unsafe_arg |= pt.IsPointer;
4653                                 params_initializers = new ArrayList (0);
4654                         }
4655
4656                         //
4657                         // Append an array argument with all params arguments
4658                         //
4659                         if (params_initializers != null) {
4660                                 arguments.Add (new Argument (
4661                                                        new ArrayCreation (new TypeExpression (pt, loc), "[]",
4662                                                                           params_initializers, loc).Resolve (ec)));
4663                                 arg_count++;
4664                         }
4665
4666                         if (arg_count < param_count) {
4667                                 if (!may_fail)
4668                                         Error_ArgumentCountWrong (ec, arg_count);
4669                                 return false;
4670                         }
4671
4672                         if (has_unsafe_arg && !ec.IsUnsafe) {
4673                                 if (!may_fail)
4674                                         UnsafeError (ec, loc);
4675                                 return false;
4676                         }
4677
4678                         return true;
4679                 }
4680         }
4681
4682         public class ConstantExpr : MemberExpr
4683         {
4684                 FieldInfo constant;
4685
4686                 public ConstantExpr (FieldInfo constant, Location loc)
4687                 {
4688                         this.constant = constant;
4689                         this.loc = loc;
4690                 }
4691
4692                 public override string Name {
4693                         get { throw new NotImplementedException (); }
4694                 }
4695
4696                 public override bool IsInstance {
4697                         get { return !IsStatic; }
4698                 }
4699
4700                 public override bool IsStatic {
4701                         get { return constant.IsStatic; }
4702                 }
4703
4704                 public override Type DeclaringType {
4705                         get { return constant.DeclaringType; }
4706                 }
4707
4708                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc, SimpleName original)
4709                 {
4710                         constant = TypeManager.GetGenericFieldDefinition (constant);
4711
4712                         IConstant ic = TypeManager.GetConstant (constant);
4713                         if (ic == null) {
4714                                 if (constant.IsLiteral) {
4715                                         ic = new ExternalConstant (constant);
4716                                 } else {
4717                                         ic = ExternalConstant.CreateDecimal (constant);
4718                                         // HACK: decimal field was not resolved as constant
4719                                         if (ic == null)
4720                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4721                                 }
4722                                 TypeManager.RegisterConstant (constant, ic);
4723                         }
4724
4725                         return base.ResolveMemberAccess (ec, left, loc, original);
4726                 }
4727
4728                 public override Expression CreateExpressionTree (ResolveContext ec)
4729                 {
4730                         throw new NotSupportedException ("ET");
4731                 }
4732
4733                 public override Expression DoResolve (ResolveContext ec)
4734                 {
4735                         IConstant ic = TypeManager.GetConstant (constant);
4736                         if (ic.ResolveValue ()) {
4737                                 if (!ec.IsObsolete)
4738                                         ic.CheckObsoleteness (loc);
4739                         }
4740
4741                         return ic.CreateConstantReference (loc);
4742                 }
4743
4744                 public override void Emit (EmitContext ec)
4745                 {
4746                         throw new NotSupportedException ();
4747                 }
4748
4749                 public override string GetSignatureForError ()
4750                 {
4751                         return TypeManager.GetFullNameSignature (constant);
4752                 }
4753         }
4754
4755         /// <summary>
4756         ///   Fully resolved expression that evaluates to a Field
4757         /// </summary>
4758         public class FieldExpr : MemberExpr, IDynamicAssign, IMemoryLocation, IVariableReference {
4759                 public FieldInfo FieldInfo;
4760                 readonly Type constructed_generic_type;
4761                 VariableInfo variable_info;
4762
4763                 LocalTemporary temp;
4764                 bool prepared;
4765
4766                 protected FieldExpr (Location l)
4767                 {
4768                         loc = l;
4769                 }
4770
4771                 public FieldExpr (FieldInfo fi, Location l)
4772                 {
4773                         FieldInfo = fi;
4774                         type = TypeManager.TypeToCoreType (fi.FieldType);
4775                         loc = l;
4776                 }
4777
4778                 public FieldExpr (FieldInfo fi, Type genericType, Location l)
4779                         : this (fi, l)
4780                 {
4781                         if (TypeManager.IsGenericTypeDefinition (genericType))
4782                                 return;
4783                         this.constructed_generic_type = genericType;
4784                 }
4785
4786                 public override string Name {
4787                         get {
4788                                 return FieldInfo.Name;
4789                         }
4790                 }
4791
4792                 public override bool IsInstance {
4793                         get {
4794                                 return !FieldInfo.IsStatic;
4795                         }
4796                 }
4797
4798                 public override bool IsStatic {
4799                         get {
4800                                 return FieldInfo.IsStatic;
4801                         }
4802                 }
4803
4804                 public override Type DeclaringType {
4805                         get {
4806                                 return FieldInfo.DeclaringType;
4807                         }
4808                 }
4809
4810                 public override string GetSignatureForError ()
4811                 {
4812                         return TypeManager.GetFullNameSignature (FieldInfo);
4813                 }
4814
4815                 public VariableInfo VariableInfo {
4816                         get {
4817                                 return variable_info;
4818                         }
4819                 }
4820
4821                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
4822                                                                 SimpleName original)
4823                 {
4824                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4825                         Type t = fi.FieldType;
4826
4827                         if (t.IsPointer && !ec.IsUnsafe) {
4828                                 UnsafeError (ec, loc);
4829                         }
4830
4831                         return base.ResolveMemberAccess (ec, left, loc, original);
4832                 }
4833
4834                 public void SetHasAddressTaken ()
4835                 {
4836                         IVariableReference vr = InstanceExpression as IVariableReference;
4837                         if (vr != null)
4838                                 vr.SetHasAddressTaken ();
4839                 }
4840
4841                 public override Expression CreateExpressionTree (ResolveContext ec)
4842                 {
4843                         Expression instance;
4844                         if (InstanceExpression == null) {
4845                                 instance = new NullLiteral (loc);
4846                         } else {
4847                                 instance = InstanceExpression.CreateExpressionTree (ec);
4848                         }
4849
4850                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
4851                                 instance,
4852                                 CreateTypeOfExpression ());
4853
4854                         return CreateExpressionFactoryCall (ec, "Field", args);
4855                 }
4856
4857                 public Expression CreateTypeOfExpression ()
4858                 {
4859                         return new TypeOfField (GetConstructedFieldInfo (), loc);
4860                 }
4861
4862                 override public Expression DoResolve (ResolveContext ec)
4863                 {
4864                         return DoResolve (ec, false, false);
4865                 }
4866
4867                 Expression DoResolve (ResolveContext ec, bool lvalue_instance, bool out_access)
4868                 {
4869                         if (!FieldInfo.IsStatic){
4870                                 if (InstanceExpression == null){
4871                                         //
4872                                         // This can happen when referencing an instance field using
4873                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4874                                         //
4875                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4876                                         return null;
4877                                 }
4878
4879                                 // Resolve the field's instance expression while flow analysis is turned
4880                                 // off: when accessing a field "a.b", we must check whether the field
4881                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4882
4883                                 if (lvalue_instance) {
4884                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
4885                                                 Expression right_side =
4886                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4887
4888                                                 if (InstanceExpression != EmptyExpression.Null)
4889                                                         InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side);
4890                                         }
4891                                 } else {
4892                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4893
4894                                         if (InstanceExpression != EmptyExpression.Null)
4895                                                 InstanceExpression = InstanceExpression.Resolve (ec, rf);
4896                                 }
4897
4898                                 if (InstanceExpression == null)
4899                                         return null;
4900
4901                                 using (ec.Set (ResolveContext.Options.OmitStructFlowAnalysis)) {
4902                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4903                                 }
4904                         }
4905
4906                         // TODO: the code above uses some non-standard multi-resolve rules
4907                         if (eclass != ExprClass.Invalid)
4908                                 return this;
4909
4910                         if (!ec.IsObsolete) {
4911                                 FieldBase f = TypeManager.GetField (FieldInfo);
4912                                 if (f != null) {
4913                                         f.CheckObsoleteness (loc);
4914                                 } else {
4915                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4916                                         if (oa != null)
4917                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc, ec.Report);
4918                                 }
4919                         }
4920
4921                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4922                         IVariableReference var = InstanceExpression as IVariableReference;
4923
4924                         if (fb != null) {
4925                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4926                                 if (!ec.HasSet (ResolveContext.Options.FixedInitializerScope) && (fe == null || !fe.IsFixed)) {
4927                                         ec.Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4928                                 }
4929
4930                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4931                                         ec.Report.SymbolRelatedToPreviousError (FieldInfo);
4932                                         ec.Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4933                                                 TypeManager.GetFullNameSignature (FieldInfo));
4934                                 } else if (var != null && var.IsHoisted) {
4935                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, var, loc);
4936                                 }
4937
4938                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4939                         }
4940
4941                         eclass = ExprClass.Variable;
4942
4943                         // If the instance expression is a local variable or parameter.
4944                         if (var == null || var.VariableInfo == null)
4945                                 return this;
4946
4947                         VariableInfo vi = var.VariableInfo;
4948                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4949                                 return null;
4950
4951                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4952                         eclass = ExprClass.Variable;
4953                         return this;
4954                 }
4955
4956                 static readonly int [] codes = {
4957                         191,    // instance, write access
4958                         192,    // instance, out access
4959                         198,    // static, write access
4960                         199,    // static, out access
4961                         1648,   // member of value instance, write access
4962                         1649,   // member of value instance, out access
4963                         1650,   // member of value static, write access
4964                         1651    // member of value static, out access
4965                 };
4966
4967                 static readonly string [] msgs = {
4968                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4969                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4970                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4971                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4972                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4973                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4974                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4975                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4976                 };
4977
4978                 // The return value is always null.  Returning a value simplifies calling code.
4979                 Expression Report_AssignToReadonly (ResolveContext ec, Expression right_side)
4980                 {
4981                         int i = 0;
4982                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4983                                 i += 1;
4984                         if (IsStatic)
4985                                 i += 2;
4986                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4987                                 i += 4;
4988                         ec.Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4989
4990                         return null;
4991                 }
4992
4993                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
4994                 {
4995                         IVariableReference var = InstanceExpression as IVariableReference;
4996                         if (var != null && var.VariableInfo != null)
4997                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4998
4999                         bool lvalue_instance = !FieldInfo.IsStatic && TypeManager.IsValueType (FieldInfo.DeclaringType);
5000                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
5001
5002                         Expression e = DoResolve (ec, lvalue_instance, out_access);
5003
5004                         if (e == null)
5005                                 return null;
5006
5007                         FieldBase fb = TypeManager.GetField (FieldInfo);
5008                         if (fb != null) {
5009                                 fb.SetAssigned ();
5010
5011                                 if ((right_side == EmptyExpression.UnaryAddress || right_side == EmptyExpression.OutAccess) &&
5012                                         (fb.ModFlags & Modifiers.VOLATILE) != 0) {
5013                                         ec.Report.Warning (420, 1, loc,
5014                                                 "`{0}': A volatile field references will not be treated as volatile",
5015                                                 fb.GetSignatureForError ());
5016                                 }
5017                         }
5018
5019                         if (FieldInfo.IsInitOnly) {
5020                                 // InitOnly fields can only be assigned in constructors or initializers
5021                                 if (!ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.ConstructorScope))
5022                                         return Report_AssignToReadonly (ec, right_side);
5023
5024                                 if (ec.HasSet (ResolveContext.Options.ConstructorScope)) {
5025                                         Type ctype = ec.CurrentType;
5026
5027                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
5028                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
5029                                                 return Report_AssignToReadonly (ec, right_side);
5030                                         // static InitOnly fields cannot be assigned-to in an instance constructor
5031                                         if (IsStatic && !ec.IsStatic)
5032                                                 return Report_AssignToReadonly (ec, right_side);
5033                                         // instance constructors can't modify InitOnly fields of other instances of the same type
5034                                         if (!IsStatic && !(InstanceExpression is This))
5035                                                 return Report_AssignToReadonly (ec, right_side);
5036                                 }
5037                         }
5038
5039                         if (right_side == EmptyExpression.OutAccess &&
5040                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
5041                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5042                                 ec.Report.Warning (197, 1, loc,
5043                                                 "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",
5044                                                 GetSignatureForError ());
5045                         }
5046
5047                         eclass = ExprClass.Variable;
5048                         return this;
5049                 }
5050
5051                 bool is_marshal_by_ref ()
5052                 {
5053                         return !IsStatic && TypeManager.IsStruct (Type) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
5054                 }
5055
5056                 public override void CheckMarshalByRefAccess (ResolveContext ec)
5057                 {
5058                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
5059                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5060                                 ec.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",
5061                                                 GetSignatureForError ());
5062                         }
5063                 }
5064
5065                 public override int GetHashCode ()
5066                 {
5067                         return FieldInfo.GetHashCode ();
5068                 }
5069
5070                 public bool IsFixed {
5071                         get {
5072                                 //
5073                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type
5074                                 //
5075                                 IVariableReference variable = InstanceExpression as IVariableReference;
5076                                 if (variable != null)
5077                                         return TypeManager.IsStruct (InstanceExpression.Type) && variable.IsFixed;
5078
5079                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
5080                                 return fe != null && fe.IsFixed;
5081                         }
5082                 }
5083
5084                 public bool IsHoisted {
5085                         get {
5086                                 IVariableReference hv = InstanceExpression as IVariableReference;
5087                                 return hv != null && hv.IsHoisted;
5088                         }
5089                 }
5090
5091                 public override bool Equals (object obj)
5092                 {
5093                         FieldExpr fe = obj as FieldExpr;
5094                         if (fe == null)
5095                                 return false;
5096
5097                         if (FieldInfo != fe.FieldInfo)
5098                                 return false;
5099
5100                         if (InstanceExpression == null || fe.InstanceExpression == null)
5101                                 return true;
5102
5103                         return InstanceExpression.Equals (fe.InstanceExpression);
5104                 }
5105
5106                 public void Emit (EmitContext ec, bool leave_copy)
5107                 {
5108                         ILGenerator ig = ec.ig;
5109                         bool is_volatile = false;
5110
5111                         FieldBase f = TypeManager.GetField (FieldInfo);
5112                         if (f != null){
5113                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5114                                         is_volatile = true;
5115
5116                                 f.SetMemberIsUsed ();
5117                         }
5118
5119                         if (FieldInfo.IsStatic){
5120                                 if (is_volatile)
5121                                         ig.Emit (OpCodes.Volatile);
5122
5123                                 ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
5124                         } else {
5125                                 if (!prepared)
5126                                         EmitInstance (ec, false);
5127
5128                                 // Optimization for build-in types
5129                                 if (TypeManager.IsStruct (type) && TypeManager.IsEqual (type, ec.MemberContext.CurrentType)) {
5130                                         LoadFromPtr (ig, type);
5131                                 } else {
5132                                         IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
5133                                         if (ff != null) {
5134                                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5135                                                 ig.Emit (OpCodes.Ldflda, ff.Element);
5136                                         } else {
5137                                                 if (is_volatile)
5138                                                         ig.Emit (OpCodes.Volatile);
5139
5140                                                 ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
5141                                         }
5142                                 }
5143                         }
5144
5145                         if (leave_copy) {
5146                                 ec.ig.Emit (OpCodes.Dup);
5147                                 if (!FieldInfo.IsStatic) {
5148                                         temp = new LocalTemporary (this.Type);
5149                                         temp.Store (ec);
5150                                 }
5151                         }
5152                 }
5153
5154                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5155                 {
5156                         FieldAttributes fa = FieldInfo.Attributes;
5157                         bool is_static = (fa & FieldAttributes.Static) != 0;
5158                         ILGenerator ig = ec.ig;
5159
5160                         prepared = prepare_for_load;
5161                         EmitInstance (ec, prepared);
5162
5163                         source.Emit (ec);
5164                         if (leave_copy) {
5165                                 ec.ig.Emit (OpCodes.Dup);
5166                                 if (!FieldInfo.IsStatic) {
5167                                         temp = new LocalTemporary (this.Type);
5168                                         temp.Store (ec);
5169                                 }
5170                         }
5171
5172                         FieldBase f = TypeManager.GetField (FieldInfo);
5173                         if (f != null){
5174                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5175                                         ig.Emit (OpCodes.Volatile);
5176
5177                                 f.SetAssigned ();
5178                         }
5179
5180                         if (is_static)
5181                                 ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
5182                         else
5183                                 ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
5184
5185                         if (temp != null) {
5186                                 temp.Emit (ec);
5187                                 temp.Release (ec);
5188                                 temp = null;
5189                         }
5190                 }
5191
5192                 public override void Emit (EmitContext ec)
5193                 {
5194                         Emit (ec, false);
5195                 }
5196
5197                 public override void EmitSideEffect (EmitContext ec)
5198                 {
5199                         FieldBase f = TypeManager.GetField (FieldInfo);
5200                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
5201
5202                         if (is_volatile || is_marshal_by_ref ())
5203                                 base.EmitSideEffect (ec);
5204                 }
5205
5206                 public override void Error_VariableIsUsedBeforeItIsDeclared (Report r, string name)
5207                 {
5208                         r.Error (844, loc,
5209                                 "A local variable `{0}' cannot be used before it is declared. Consider renaming the local variable when it hides the field `{1}'",
5210                                 name, GetSignatureForError ());
5211                 }
5212
5213                 public void AddressOf (EmitContext ec, AddressOp mode)
5214                 {
5215                         ILGenerator ig = ec.ig;
5216
5217                         FieldBase f = TypeManager.GetField (FieldInfo);
5218                         if (f != null){
5219                                 if ((mode & AddressOp.Store) != 0)
5220                                         f.SetAssigned ();
5221                                 if ((mode & AddressOp.Load) != 0)
5222                                         f.SetMemberIsUsed ();
5223                         }
5224
5225                         //
5226                         // Handle initonly fields specially: make a copy and then
5227                         // get the address of the copy.
5228                         //
5229                         bool need_copy;
5230                         if (FieldInfo.IsInitOnly){
5231                                 need_copy = true;
5232                                 if (ec.HasSet (EmitContext.Options.ConstructorScope)){
5233                                         if (FieldInfo.IsStatic){
5234                                                 if (ec.IsStatic)
5235                                                         need_copy = false;
5236                                         } else
5237                                                 need_copy = false;
5238                                 }
5239                         } else
5240                                 need_copy = false;
5241
5242                         if (need_copy){
5243                                 LocalBuilder local;
5244                                 Emit (ec);
5245                                 local = ig.DeclareLocal (type);
5246                                 ig.Emit (OpCodes.Stloc, local);
5247                                 ig.Emit (OpCodes.Ldloca, local);
5248                                 return;
5249                         }
5250
5251
5252                         if (FieldInfo.IsStatic){
5253                                 ig.Emit (OpCodes.Ldsflda, GetConstructedFieldInfo ());
5254                         } else {
5255                                 if (!prepared)
5256                                         EmitInstance (ec, false);
5257                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5258                         }
5259                 }
5260
5261                 FieldInfo GetConstructedFieldInfo ()
5262                 {
5263                         if (constructed_generic_type == null)
5264                                 return FieldInfo;
5265
5266                         return TypeBuilder.GetField (constructed_generic_type, FieldInfo);
5267                 }
5268
5269 #if NET_4_0
5270                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5271                 {
5272                         return MakeExpression (ctx);
5273                 }
5274
5275                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5276                 {
5277                         return SLE.Expression.Field (InstanceExpression.MakeExpression (ctx), FieldInfo);
5278                 }
5279 #endif
5280
5281                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5282                 {
5283                         FieldInfo = storey.MutateField (FieldInfo);
5284                         base.MutateHoistedGenericType (storey);
5285                 }
5286         }
5287
5288
5289         /// <summary>
5290         ///   Expression that evaluates to a Property.  The Assign class
5291         ///   might set the `Value' expression if we are in an assignment.
5292         ///
5293         ///   This is not an LValue because we need to re-write the expression, we
5294         ///   can not take data from the stack and store it.
5295         /// </summary>
5296         public class PropertyExpr : MemberExpr, IDynamicAssign
5297         {
5298                 public readonly PropertyInfo PropertyInfo;
5299                 MethodInfo getter, setter;
5300                 bool is_static;
5301
5302                 bool resolved;
5303                 TypeArguments targs;
5304
5305                 LocalTemporary temp;
5306                 bool prepared;
5307
5308                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5309                 {
5310                         PropertyInfo = pi;
5311                         eclass = ExprClass.PropertyAccess;
5312                         is_static = false;
5313                         loc = l;
5314
5315                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5316
5317                         ResolveAccessors (container_type);
5318                 }
5319
5320                 public override string Name {
5321                         get {
5322                                 return PropertyInfo.Name;
5323                         }
5324                 }
5325
5326                 public override bool IsInstance {
5327                         get {
5328                                 return !is_static;
5329                         }
5330                 }
5331
5332                 public override bool IsStatic {
5333                         get {
5334                                 return is_static;
5335                         }
5336                 }
5337
5338                 public override Expression CreateExpressionTree (ResolveContext ec)
5339                 {
5340                         Arguments args;
5341                         if (IsSingleDimensionalArrayLength ()) {
5342                                 args = new Arguments (1);
5343                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5344                                 return CreateExpressionFactoryCall (ec, "ArrayLength", args);
5345                         }
5346
5347                         if (is_base) {
5348                                 Error_BaseAccessInExpressionTree (ec, loc);
5349                                 return null;
5350                         }
5351
5352                         args = new Arguments (2);
5353                         if (InstanceExpression == null)
5354                                 args.Add (new Argument (new NullLiteral (loc)));
5355                         else
5356                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5357                         args.Add (new Argument (new TypeOfMethod (getter, loc)));
5358                         return CreateExpressionFactoryCall (ec, "Property", args);
5359                 }
5360
5361                 public Expression CreateSetterTypeOfExpression ()
5362                 {
5363                         return new TypeOfMethod (setter, loc);
5364                 }
5365
5366                 public override Type DeclaringType {
5367                         get {
5368                                 return PropertyInfo.DeclaringType;
5369                         }
5370                 }
5371
5372                 public override string GetSignatureForError ()
5373                 {
5374                         return TypeManager.GetFullNameSignature (PropertyInfo);
5375                 }
5376
5377                 void FindAccessors (Type invocation_type)
5378                 {
5379                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5380                                 BindingFlags.Static | BindingFlags.Instance |
5381                                 BindingFlags.DeclaredOnly;
5382
5383                         Type current = PropertyInfo.DeclaringType;
5384                         for (; current != null; current = current.BaseType) {
5385                                 MemberInfo[] group = TypeManager.MemberLookup (
5386                                         invocation_type, invocation_type, current,
5387                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5388
5389                                 if (group == null)
5390                                         continue;
5391
5392                                 if (group.Length != 1)
5393                                         // Oooops, can this ever happen ?
5394                                         return;
5395
5396                                 PropertyInfo pi = (PropertyInfo) group [0];
5397
5398                                 if (getter == null)
5399                                         getter = pi.GetGetMethod (true);
5400
5401                                 if (setter == null)
5402                                         setter = pi.GetSetMethod (true);
5403
5404                                 MethodInfo accessor = getter != null ? getter : setter;
5405
5406                                 if (!accessor.IsVirtual)
5407                                         return;
5408                         }
5409                 }
5410
5411                 //
5412                 // We also perform the permission checking here, as the PropertyInfo does not
5413                 // hold the information for the accessibility of its setter/getter
5414                 //
5415                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5416                 void ResolveAccessors (Type container_type)
5417                 {
5418                         FindAccessors (container_type);
5419
5420                         if (getter != null) {
5421                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5422                                 IMethodData md = TypeManager.GetMethod (the_getter);
5423                                 if (md != null)
5424                                         md.SetMemberIsUsed ();
5425
5426                                 is_static = getter.IsStatic;
5427                         }
5428
5429                         if (setter != null) {
5430                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5431                                 IMethodData md = TypeManager.GetMethod (the_setter);
5432                                 if (md != null)
5433                                         md.SetMemberIsUsed ();
5434
5435                                 is_static = setter.IsStatic;
5436                         }
5437                 }
5438
5439 #if NET_4_0
5440                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5441                 {
5442                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), setter);
5443                 }
5444
5445                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5446                 {
5447                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), getter);
5448                 }
5449 #endif
5450
5451                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5452                 {
5453                         if (InstanceExpression != null)
5454                                 InstanceExpression.MutateHoistedGenericType (storey);
5455
5456                         type = storey.MutateType (type);
5457                         if (getter != null)
5458                                 getter = storey.MutateGenericMethod (getter);
5459                         if (setter != null)
5460                                 setter = storey.MutateGenericMethod (setter);
5461                 }
5462
5463                 bool InstanceResolve (ResolveContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5464                 {
5465                         if (is_static) {
5466                                 InstanceExpression = null;
5467                                 return true;
5468                         }
5469
5470                         if (InstanceExpression == null) {
5471                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5472                                 return false;
5473                         }
5474
5475                         InstanceExpression = InstanceExpression.DoResolve (ec);
5476                         if (lvalue_instance && InstanceExpression != null)
5477                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess);
5478
5479                         if (InstanceExpression == null)
5480                                 return false;
5481
5482                         InstanceExpression.CheckMarshalByRefAccess (ec);
5483
5484                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5485                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5486                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5487                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5488                                 ec.Report.SymbolRelatedToPreviousError (PropertyInfo);
5489                                 Error_CannotAccessProtected (ec, loc, PropertyInfo, InstanceExpression.Type, ec.CurrentType);
5490                                 return false;
5491                         }
5492
5493                         return true;
5494                 }
5495
5496                 void Error_PropertyNotFound (ResolveContext ec, MethodInfo mi, bool getter)
5497                 {
5498                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5499                         if (mi is MethodBuilder) {
5500                                 Error_TypeDoesNotContainDefinition (ec, loc, PropertyInfo.DeclaringType, Name);
5501                                 return;
5502                         }
5503
5504                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5505                         sig.Append ('.');
5506                         AParametersCollection iparams = TypeManager.GetParameterData (mi);
5507                         sig.Append (getter ? "get_" : "set_");
5508                         sig.Append (Name);
5509                         sig.Append (iparams.GetSignatureForError ());
5510
5511                         ec.Report.SymbolRelatedToPreviousError (mi);
5512                         ec.Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5513                                 Name, sig.ToString ());
5514                 }
5515
5516                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5517                 {
5518                         bool dummy;
5519                         MethodInfo accessor = lvalue ? setter : getter;
5520                         if (accessor == null && lvalue)
5521                                 accessor = getter;
5522                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5523                 }
5524
5525                 bool IsSingleDimensionalArrayLength ()
5526                 {
5527                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5528                                 return false;
5529
5530                         string t_name = InstanceExpression.Type.Name;
5531                         int t_name_len = t_name.Length;
5532                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5533                 }
5534
5535                 public override Expression DoResolve (ResolveContext ec)
5536                 {
5537                         if (resolved)
5538                                 return this;
5539
5540                         bool must_do_cs1540_check = false;
5541                         ec.Report.DisableReporting ();
5542                         bool res = ResolveGetter (ec, ref must_do_cs1540_check);
5543                         ec.Report.EnableReporting ();
5544
5545                         if (!res) {
5546                                 if (InstanceExpression != null) {
5547                                         Type expr_type = InstanceExpression.Type;
5548                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (expr_type, Name, loc);
5549                                         if (ex_method_lookup != null) {
5550                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
5551                                                 ex_method_lookup.SetTypeArguments (ec, targs);
5552                                                 return ex_method_lookup.DoResolve (ec);
5553                                         }
5554                                 }
5555
5556                                 ResolveGetter (ec, ref must_do_cs1540_check);
5557                                 return null;
5558                         }
5559
5560                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5561                                 return null;
5562
5563                         //
5564                         // Only base will allow this invocation to happen.
5565                         //
5566                         if (IsBase && getter.IsAbstract) {
5567                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (PropertyInfo));
5568                         }
5569
5570                         if (PropertyInfo.PropertyType.IsPointer && !ec.IsUnsafe){
5571                                 UnsafeError (ec, loc);
5572                         }
5573
5574                         if (!ec.IsObsolete) {
5575                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5576                                 if (pb != null) {
5577                                         pb.CheckObsoleteness (loc);
5578                                 } else {
5579                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5580                                         if (oa != null)
5581                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5582                                 }
5583                         }
5584
5585                         resolved = true;
5586
5587                         return this;
5588                 }
5589
5590                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5591                 {
5592                         if (right_side == EmptyExpression.OutAccess) {
5593                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5594                                         ec.Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5595                                             PropertyInfo.Name);
5596                                 } else {
5597                                         ec.Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5598                                               GetSignatureForError ());
5599                                 }
5600                                 return null;
5601                         }
5602
5603                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5604                                 Error_CannotModifyIntermediateExpressionValue (ec);
5605                         }
5606
5607                         if (setter == null){
5608                                 //
5609                                 // The following condition happens if the PropertyExpr was
5610                                 // created, but is invalid (ie, the property is inaccessible),
5611                                 // and we did not want to embed the knowledge about this in
5612                                 // the caller routine.  This only avoids double error reporting.
5613                                 //
5614                                 if (getter == null)
5615                                         return null;
5616
5617                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5618                                         ec.Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5619                                                 PropertyInfo.Name);
5620                                 } else {
5621                                         ec.Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5622                                                 GetSignatureForError ());
5623                                 }
5624                                 return null;
5625                         }
5626
5627                         if (targs != null) {
5628                                 base.SetTypeArguments (ec, targs);
5629                                 return null;
5630                         }
5631
5632                         if (TypeManager.GetParameterData (setter).Count != 1){
5633                                 Error_PropertyNotFound (ec, setter, false);
5634                                 return null;
5635                         }
5636
5637                         bool must_do_cs1540_check;
5638                         if (!IsAccessorAccessible (ec.CurrentType, setter, out must_do_cs1540_check)) {
5639                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5640                                 if (pm != null && pm.HasCustomAccessModifier) {
5641                                         ec.Report.SymbolRelatedToPreviousError (pm);
5642                                         ec.Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5643                                                 TypeManager.CSharpSignature (setter));
5644                                 }
5645                                 else {
5646                                         ec.Report.SymbolRelatedToPreviousError (setter);
5647                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter), ec.Report);
5648                                 }
5649                                 return null;
5650                         }
5651
5652                         if (!InstanceResolve (ec, TypeManager.IsStruct (PropertyInfo.DeclaringType), must_do_cs1540_check))
5653                                 return null;
5654
5655                         //
5656                         // Only base will allow this invocation to happen.
5657                         //
5658                         if (IsBase && setter.IsAbstract){
5659                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (PropertyInfo));
5660                         }
5661
5662                         if (PropertyInfo.PropertyType.IsPointer && !ec.IsUnsafe) {
5663                                 UnsafeError (ec, loc);
5664                         }
5665
5666                         if (!ec.IsObsolete) {
5667                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5668                                 if (pb != null) {
5669                                         pb.CheckObsoleteness (loc);
5670                                 } else {
5671                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5672                                         if (oa != null)
5673                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5674                                 }
5675                         }
5676
5677                         return this;
5678                 }
5679
5680                 public override void Emit (EmitContext ec)
5681                 {
5682                         Emit (ec, false);
5683                 }
5684
5685                 public void Emit (EmitContext ec, bool leave_copy)
5686                 {
5687                         //
5688                         // Special case: length of single dimension array property is turned into ldlen
5689                         //
5690                         if (IsSingleDimensionalArrayLength ()) {
5691                                 if (!prepared)
5692                                         EmitInstance (ec, false);
5693                                 ec.ig.Emit (OpCodes.Ldlen);
5694                                 ec.ig.Emit (OpCodes.Conv_I4);
5695                                 return;
5696                         }
5697
5698                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5699
5700                         if (leave_copy) {
5701                                 ec.ig.Emit (OpCodes.Dup);
5702                                 if (!is_static) {
5703                                         temp = new LocalTemporary (this.Type);
5704                                         temp.Store (ec);
5705                                 }
5706                         }
5707                 }
5708
5709                 //
5710                 // Implements the IAssignMethod interface for assignments
5711                 //
5712                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5713                 {
5714                         Expression my_source = source;
5715
5716                         if (prepare_for_load) {
5717                                 prepared = true;
5718                                 source.Emit (ec);
5719
5720                                 if (leave_copy) {
5721                                         ec.ig.Emit (OpCodes.Dup);
5722                                         if (!is_static) {
5723                                                 temp = new LocalTemporary (this.Type);
5724                                                 temp.Store (ec);
5725                                         }
5726                                 }
5727                         } else if (leave_copy) {
5728                                 source.Emit (ec);
5729                                 temp = new LocalTemporary (this.Type);
5730                                 temp.Store (ec);
5731                                 my_source = temp;
5732                         }
5733
5734                         Arguments args = new Arguments (1);
5735                         args.Add (new Argument (my_source));
5736
5737                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5738
5739                         if (temp != null) {
5740                                 temp.Emit (ec);
5741                                 temp.Release (ec);
5742                         }
5743                 }
5744
5745                 bool ResolveGetter (ResolveContext ec, ref bool must_do_cs1540_check)
5746                 {
5747                         if (targs != null) {
5748                                 base.SetTypeArguments (ec, targs);
5749                                 return false;
5750                         }
5751
5752                         if (getter != null) {
5753                                 if (TypeManager.GetParameterData (getter).Count != 0) {
5754                                         Error_PropertyNotFound (ec, getter, true);
5755                                         return false;
5756                                 }
5757                         }
5758
5759                         if (getter == null) {
5760                                 //
5761                                 // The following condition happens if the PropertyExpr was
5762                                 // created, but is invalid (ie, the property is inaccessible),
5763                                 // and we did not want to embed the knowledge about this in
5764                                 // the caller routine.  This only avoids double error reporting.
5765                                 //
5766                                 if (setter == null)
5767                                         return false;
5768
5769                                 if (InstanceExpression != EmptyExpression.Null) {
5770                                         ec.Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5771                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5772                                         return false;
5773                                 }
5774                         }
5775
5776                         if (getter != null &&
5777                                 !IsAccessorAccessible (ec.CurrentType, getter, out must_do_cs1540_check)) {
5778                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5779                                 if (pm != null && pm.HasCustomAccessModifier) {
5780                                         ec.Report.SymbolRelatedToPreviousError (pm);
5781                                         ec.Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5782                                                 TypeManager.CSharpSignature (getter));
5783                                 } else {
5784                                         ec.Report.SymbolRelatedToPreviousError (getter);
5785                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter), ec.Report);
5786                                 }
5787
5788                                 return false;
5789                         }
5790
5791                         return true;
5792                 }
5793
5794                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
5795                 {
5796                         targs = ta;
5797                 }
5798         }
5799
5800         /// <summary>
5801         ///   Fully resolved expression that evaluates to an Event
5802         /// </summary>
5803         public class EventExpr : MemberExpr {
5804                 public readonly EventInfo EventInfo;
5805
5806                 bool is_static;
5807                 MethodInfo add_accessor, remove_accessor;
5808
5809                 public EventExpr (EventInfo ei, Location loc)
5810                 {
5811                         EventInfo = ei;
5812                         this.loc = loc;
5813                         eclass = ExprClass.EventAccess;
5814
5815                         add_accessor = TypeManager.GetAddMethod (ei);
5816                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5817                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5818                                 is_static = true;
5819
5820                         if (EventInfo is MyEventBuilder){
5821                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5822                                 type = eb.EventType;
5823                                 eb.SetUsed ();
5824                         } else
5825                                 type = EventInfo.EventHandlerType;
5826                 }
5827
5828                 public override string Name {
5829                         get {
5830                                 return EventInfo.Name;
5831                         }
5832                 }
5833
5834                 public override bool IsInstance {
5835                         get {
5836                                 return !is_static;
5837                         }
5838                 }
5839
5840                 public override bool IsStatic {
5841                         get {
5842                                 return is_static;
5843                         }
5844                 }
5845
5846                 public override Type DeclaringType {
5847                         get {
5848                                 return EventInfo.DeclaringType;
5849                         }
5850                 }
5851
5852                 public void Error_AssignmentEventOnly (ResolveContext ec)
5853                 {
5854                         ec.Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5855                                 GetSignatureForError ());
5856                 }
5857
5858                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
5859                                                                 SimpleName original)
5860                 {
5861                         //
5862                         // If the event is local to this class, we transform ourselves into a FieldExpr
5863                         //
5864
5865                         if (EventInfo.DeclaringType == ec.CurrentType ||
5866                             TypeManager.IsNestedChildOf(ec.CurrentType, EventInfo.DeclaringType)) {
5867                                 EventField mi = TypeManager.GetEventField (EventInfo);
5868
5869                                 if (mi != null) {
5870                                         if (!ec.IsObsolete)
5871                                                 mi.CheckObsoleteness (loc);
5872
5873                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5874                                                 Error_AssignmentEventOnly (ec);
5875
5876                                         FieldExpr ml = new FieldExpr (mi.BackingField.FieldBuilder, loc);
5877
5878                                         InstanceExpression = null;
5879
5880                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5881                                 }
5882                         }
5883
5884                         if (left is This && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5885                                 Error_AssignmentEventOnly (ec);
5886
5887                         return base.ResolveMemberAccess (ec, left, loc, original);
5888                 }
5889
5890                 bool InstanceResolve (ResolveContext ec, bool must_do_cs1540_check)
5891                 {
5892                         if (is_static) {
5893                                 InstanceExpression = null;
5894                                 return true;
5895                         }
5896
5897                         if (InstanceExpression == null) {
5898                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5899                                 return false;
5900                         }
5901
5902                         InstanceExpression = InstanceExpression.DoResolve (ec);
5903                         if (InstanceExpression == null)
5904                                 return false;
5905
5906                         if (IsBase && add_accessor.IsAbstract) {
5907                                 Error_CannotCallAbstractBase (ec, TypeManager.CSharpSignature(add_accessor));
5908                                 return false;
5909                         }
5910
5911                         //
5912                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5913                         // However, in the Event case, we reported a CS0122 instead.
5914                         //
5915                         // TODO: Exact copy from PropertyExpr
5916                         //
5917                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5918                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5919                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5920                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5921                                 ec.Report.SymbolRelatedToPreviousError (EventInfo);
5922                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo), ec.Report);
5923                                 return false;
5924                         }
5925
5926                         return true;
5927                 }
5928
5929                 public bool IsAccessibleFrom (Type invocation_type)
5930                 {
5931                         bool dummy;
5932                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5933                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5934                 }
5935
5936                 public override Expression CreateExpressionTree (ResolveContext ec)
5937                 {
5938                         throw new NotSupportedException ("ET");
5939                 }
5940
5941                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5942                 {
5943                         // contexts where an LValue is valid have already devolved to FieldExprs
5944                         Error_CannotAssign (ec);
5945                         return null;
5946                 }
5947
5948                 public override Expression DoResolve (ResolveContext ec)
5949                 {
5950                         bool must_do_cs1540_check;
5951                         if (!(IsAccessorAccessible (ec.CurrentType, add_accessor, out must_do_cs1540_check) &&
5952                               IsAccessorAccessible (ec.CurrentType, remove_accessor, out must_do_cs1540_check))) {
5953                                 ec.Report.SymbolRelatedToPreviousError (EventInfo);
5954                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo), ec.Report);
5955                                 return null;
5956                         }
5957
5958                         if (!InstanceResolve (ec, must_do_cs1540_check))
5959                                 return null;
5960
5961                         if (!ec.HasSet (ResolveContext.Options.CompoundAssignmentScope)) {
5962                                 Error_CannotAssign (ec);
5963                                 return null;
5964                         }
5965
5966                         if (!ec.IsObsolete) {
5967                                 EventField ev = TypeManager.GetEventField (EventInfo);
5968                                 if (ev != null) {
5969                                         ev.CheckObsoleteness (loc);
5970                                 } else {
5971                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (EventInfo);
5972                                         if (oa != null)
5973                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5974                                 }
5975                         }
5976
5977                         return this;
5978                 }
5979
5980                 public override void Emit (EmitContext ec)
5981                 {
5982                         throw new NotSupportedException ();
5983                         //Error_CannotAssign ();
5984                 }
5985
5986                 public void Error_CannotAssign (ResolveContext ec)
5987                 {
5988                         ec.Report.Error (70, loc,
5989                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
5990                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
5991                 }
5992
5993                 public override string GetSignatureForError ()
5994                 {
5995                         return TypeManager.CSharpSignature (EventInfo);
5996                 }
5997
5998                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
5999                 {
6000                         Arguments args = new Arguments (1);
6001                         args.Add (new Argument (source));
6002                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
6003                 }
6004         }
6005
6006         public class TemporaryVariable : VariableReference
6007         {
6008                 LocalInfo li;
6009
6010                 public TemporaryVariable (Type type, Location loc)
6011                 {
6012                         this.type = type;
6013                         this.loc = loc;
6014                         eclass = ExprClass.Variable;
6015                 }
6016
6017                 public override Expression CreateExpressionTree (ResolveContext ec)
6018                 {
6019                         throw new NotSupportedException ("ET");
6020                 }
6021
6022                 public override Expression DoResolve (ResolveContext ec)
6023                 {
6024                         if (li != null)
6025                                 return this;
6026
6027                         TypeExpr te = new TypeExpression (type, loc);
6028                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
6029                         if (!li.Resolve (ec))
6030                                 return null;
6031
6032                         //
6033                         // Don't capture temporary variables except when using
6034                         // iterator redirection
6035                         //
6036                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
6037                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
6038                                 storey.CaptureLocalVariable (ec, li);
6039                         }
6040
6041                         return this;
6042                 }
6043
6044                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6045                 {
6046                         return DoResolve (ec);
6047                 }
6048
6049                 public override void Emit (EmitContext ec)
6050                 {
6051                         Emit (ec, false);
6052                 }
6053
6054                 public void EmitAssign (EmitContext ec, Expression source)
6055                 {
6056                         EmitAssign (ec, source, false, false);
6057                 }
6058
6059                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6060                 {
6061                         return li.HoistedVariableReference;
6062                 }
6063
6064                 public override bool IsFixed {
6065                         get { return true; }
6066                 }
6067
6068                 public override bool IsRef {
6069                         get { return false; }
6070                 }
6071
6072                 public override string Name {
6073                         get { throw new NotImplementedException (); }
6074                 }
6075
6076                 public override void SetHasAddressTaken ()
6077                 {
6078                         throw new NotImplementedException ();
6079                 }
6080
6081                 protected override ILocalVariable Variable {
6082                         get { return li; }
6083                 }
6084
6085                 public override VariableInfo VariableInfo {
6086                         get { throw new NotImplementedException (); }
6087                 }
6088         }
6089
6090         ///
6091         /// Handles `var' contextual keyword; var becomes a keyword only
6092         /// if no type called var exists in a variable scope
6093         ///
6094         class VarExpr : SimpleName
6095         {
6096                 // Used for error reporting only
6097                 ArrayList initializer;
6098
6099                 public VarExpr (Location loc)
6100                         : base ("var", loc)
6101                 {
6102                 }
6103
6104                 public ArrayList VariableInitializer {
6105                         set {
6106                                 this.initializer = value;
6107                         }
6108                 }
6109
6110                 public bool InferType (ResolveContext ec, Expression right_side)
6111                 {
6112                         if (type != null)
6113                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
6114
6115                         type = right_side.Type;
6116                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == InternalType.AnonymousMethod || type == InternalType.MethodGroup) {
6117                                 ec.Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
6118                                               right_side.GetSignatureForError ());
6119                                 return false;
6120                         }
6121
6122                         eclass = ExprClass.Variable;
6123                         return true;
6124                 }
6125
6126                 protected override void Error_TypeOrNamespaceNotFound (IMemberContext ec)
6127                 {
6128                         if (RootContext.Version < LanguageVersion.V_3)
6129                                 base.Error_TypeOrNamespaceNotFound (ec);
6130                         else
6131                                 ec.Compiler.Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
6132                 }
6133
6134                 public override TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
6135                 {
6136                         TypeExpr te = base.ResolveAsContextualType (rc, true);
6137                         if (te != null)
6138                                 return te;
6139
6140                         if (RootContext.Version < LanguageVersion.V_3)
6141                                 rc.Compiler.Report.FeatureIsNotAvailable (loc, "implicitly typed local variable");
6142
6143                         if (initializer == null)
6144                                 return null;
6145
6146                         if (initializer.Count > 1) {
6147                                 Location loc_init = ((CSharpParser.VariableDeclaration) initializer[1]).Location;
6148                                 rc.Compiler.Report.Error (819, loc_init, "An implicitly typed local variable declaration cannot include multiple declarators");
6149                                 initializer = null;
6150                                 return null;
6151                         }
6152
6153                         Expression variable_initializer = ((CSharpParser.VariableDeclaration) initializer[0]).expression_or_array_initializer;
6154                         if (variable_initializer == null) {
6155                                 rc.Compiler.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
6156                                 return null;
6157                         }
6158
6159                         return null;
6160                 }
6161         }
6162 }