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 using System;
  14 using System.Collections.Generic;
  15 using System.Diagnostics;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19 using SLE = System.Linq.Expressions;
  20 using System.Linq;
  21
  22 namespace Mono.CSharp {
  23
  24         /// <remarks>
  25         ///   The ExprClass class contains the is used to pass the
  26         ///   classification of an expression (value, variable, namespace,
  27         ///   type, method group, property access, event access, indexer access,
  28         ///   nothing).
  29         /// </remarks>
  30         public enum ExprClass : byte {
  31                 Unresolved      = 0,
  32
  33                 Value,
  34                 Variable,
  35                 Namespace,
  36                 Type,
  37                 TypeParameter,
  38                 MethodGroup,
  39                 PropertyAccess,
  40                 EventAccess,
  41                 IndexerAccess,
  42                 Nothing,
  43         }
  44
  45         /// <remarks>
  46         ///   This is used to tell Resolve in which types of expressions we're
  47         ///   interested.
  48         /// </remarks>
  49         [Flags]
  50         public enum ResolveFlags {
  51                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  52                 VariableOrValue         = 1,
  53
  54                 // Returns a type expression.
  55                 Type                    = 1 << 1,
  56
  57                 // Returns a method group.
  58                 MethodGroup             = 1 << 2,
  59
  60                 TypeParameter   = 1 << 3,
  61
  62                 // Mask of all the expression class flags.
  63                 MaskExprClass = VariableOrValue | Type | MethodGroup | TypeParameter,
  64
  65                 // Set if this is resolving the first part of a MemberAccess.
  66                 Intermediate            = 1 << 11,
  67         }
  68
  69         //
  70         // This is just as a hint to AddressOf of what will be done with the
  71         // address.
  72         [Flags]
  73         public enum AddressOp {
  74                 Store = 1,
  75                 Load  = 2,
  76                 LoadStore = 3
  77         };
  78
  79         /// <summary>
  80         ///   This interface is implemented by variables
  81         /// </summary>
  82         public interface IMemoryLocation {
  83                 /// <summary>
  84                 ///   The AddressOf method should generate code that loads
  85                 ///   the address of the object and leaves it on the stack.
  86                 ///
  87                 ///   The `mode' argument is used to notify the expression
  88                 ///   of whether this will be used to read from the address or
  89                 ///   write to the address.
  90                 ///
  91                 ///   This is just a hint that can be used to provide good error
  92                 ///   reporting, and should have no other side effects.
  93                 /// </summary>
  94                 void AddressOf (EmitContext ec, AddressOp mode);
  95         }
  96
  97         //
  98         // An expressions resolved as a direct variable reference
  99         //
 100         public interface IVariableReference : IFixedExpression
 101         {
 102                 bool IsHoisted { get; }
 103                 string Name { get; }
 104                 VariableInfo VariableInfo { get; }
 105
 106                 void SetHasAddressTaken ();
 107         }
 108
 109         //
 110         // Implemented by an expression which could be or is always
 111         // fixed
 112         //
 113         public interface IFixedExpression
 114         {
 115                 bool IsFixed { get; }
 116         }
 117
 118         /// <remarks>
 119         ///   Base class for expressions
 120         /// </remarks>
 121         public abstract class Expression {
 122                 public ExprClass eclass;
 123                 protected Type type;
 124                 protected Location loc;
 125
 126                 public Type Type {
 127                         get { return type; }
 128                         set { type = value; }
 129                 }
 130
 131                 public virtual Location Location {
 132                         get { return loc; }
 133                 }
 134
 135                 // Not nice but we have broken hierarchy.
 136                 public virtual void CheckMarshalByRefAccess (ResolveContext ec)
 137                 {
 138                 }
 139
 140                 public virtual string GetSignatureForError ()
 141                 {
 142                         return TypeManager.CSharpName (type);
 143                 }
 144
 145                 public static bool IsAccessorAccessible (Type invocation_type, MethodSpec mi, out bool must_do_cs1540_check)
 146                 {
 147                         var ma = mi.Modifiers & Modifiers.AccessibilityMask;
 148
 149                         must_do_cs1540_check = false; // by default we do not check for this
 150
 151                         if (ma == Modifiers.PUBLIC)
 152                                 return true;
 153
 154                         //
 155                         // If only accessible to the current class or children
 156                         //
 157                         if (ma == Modifiers.PRIVATE)
 158                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 159                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 160
 161                         if ((ma & Modifiers.INTERNAL) != 0) {
 162                                 var b = TypeManager.IsThisOrFriendAssembly (invocation_type.Assembly, mi.DeclaringType.Assembly);
 163                                 if (b || ma == Modifiers.INTERNAL)
 164                                         return b;
 165                         }
 166
 167                         // Family and FamANDAssem require that we derive.
 168                         // FamORAssem requires that we derive if in different assemblies.
 169                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 170                                 return false;
 171
 172                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 173                                 must_do_cs1540_check = true;
 174
 175                         return true;
 176                 }
 177
 178                 public virtual bool IsNull {
 179                         get {
 180                                 return false;
 181                         }
 182                 }
 183
 184                 /// <summary>
 185                 ///   Performs semantic analysis on the Expression
 186                 /// </summary>
 187                 ///
 188                 /// <remarks>
 189                 ///   The Resolve method is invoked to perform the semantic analysis
 190                 ///   on the node.
 191                 ///
 192                 ///   The return value is an expression (it can be the
 193                 ///   same expression in some cases) or a new
 194                 ///   expression that better represents this node.
 195                 ///
 196                 ///   For example, optimizations of Unary (LiteralInt)
 197                 ///   would return a new LiteralInt with a negated
 198                 ///   value.
 199                 ///
 200                 ///   If there is an error during semantic analysis,
 201                 ///   then an error should be reported (using Report)
 202                 ///   and a null value should be returned.
 203                 ///
 204                 ///   There are two side effects expected from calling
 205                 ///   Resolve(): the the field variable "eclass" should
 206                 ///   be set to any value of the enumeration
 207                 ///   `ExprClass' and the type variable should be set
 208                 ///   to a valid type (this is the type of the
 209                 ///   expression).
 210                 /// </remarks>
 211                 protected abstract Expression DoResolve (ResolveContext rc);
 212
 213                 public virtual Expression DoResolveLValue (ResolveContext rc, Expression right_side)
 214                 {
 215                         return null;
 216                 }
 217
 218                 //
 219                 // This is used if the expression should be resolved as a type or namespace name.
 220                 // the default implementation fails.
 221                 //
 222                 public virtual FullNamedExpression ResolveAsTypeStep (IMemberContext rc,  bool silent)
 223                 {
 224                         if (!silent) {
 225                                 ResolveContext ec = new ResolveContext (rc);
 226                                 Expression e = Resolve (ec);
 227                                 if (e != null)
 228                                         e.Error_UnexpectedKind (ec, ResolveFlags.Type, loc);
 229                         }
 230
 231                         return null;
 232                 }
 233
 234                 //
 235                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 236                 // same name exists or as a keyword when no type was found
 237                 //
 238                 public virtual TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
 239                 {
 240                         return ResolveAsTypeTerminal (rc, silent);
 241                 }
 242
 243                 //
 244                 // This is used to resolve the expression as a type, a null
 245                 // value will be returned if the expression is not a type
 246                 // reference
 247                 //
 248                 public virtual TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
 249                 {
 250                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 251                         if (te == null)
 252                                 return null;
 253
 254                         if (!silent) { // && !(te is TypeParameterExpr)) {
 255                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 256                                 if (obsolete_attr != null && !ec.IsObsolete) {
 257                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location, ec.Compiler.Report);
 258                                 }
 259                         }
 260
 261                         GenericTypeExpr ct = te as GenericTypeExpr;
 262                         if (ct != null) {
 263                                 //
 264                                 // TODO: Constrained type parameters check for parameters of generic method overrides is broken
 265                                 // There are 2 solutions.
 266                                 // 1, Skip this check completely when we are in override/explicit impl scope
 267                                 // 2, Copy type parameters constraints from base implementation and pass (they have to be emitted anyway)
 268                                 //
 269                                 MemberCore gm = ec as GenericMethod;
 270                                 if (gm == null)
 271                                         gm = ec as Method;
 272                                 if (gm != null && ((gm.ModFlags & Modifiers.OVERRIDE) != 0 || gm.MemberName.Left != null)) {
 273                                         te.loc = loc;
 274                                         return te;
 275                                 }
 276
 277                                 // TODO: silent flag is ignored
 278                                 ct.CheckConstraints (ec);
 279                         }
 280
 281                         return te;
 282                 }
 283
 284                 public TypeExpr ResolveAsBaseTerminal (IMemberContext ec, bool silent)
 285                 {
 286                         int errors = ec.Compiler.Report.Errors;
 287
 288                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 289
 290                         if (fne == null)
 291                                 return null;
 292
 293                         TypeExpr te = fne as TypeExpr;
 294                         if (te == null) {
 295                                 if (!silent && errors == ec.Compiler.Report.Errors)
 296                                         fne.Error_UnexpectedKind (ec.Compiler.Report, null, "type", loc);
 297                                 return null;
 298                         }
 299
 300                         if (!te.CheckAccessLevel (ec)) {
 301                                 ec.Compiler.Report.SymbolRelatedToPreviousError (te.Type);
 302                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type), ec.Compiler.Report);
 303                                 return null;
 304                         }
 305
 306                         te.loc = loc;
 307                         return te;
 308                 }
 309
 310                 public static void ErrorIsInaccesible (Location loc, string name, Report Report)
 311                 {
 312                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 313                 }
 314
 315                 protected static void Error_CannotAccessProtected (ResolveContext ec, Location loc, MemberInfo m, Type qualifier, Type container)
 316                 {
 317                         ec.Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 318                                 + " The qualifier must be of type `{2}' or derived from it",
 319                                 TypeManager.GetFullNameSignature (m),
 320                                 TypeManager.CSharpName (qualifier),
 321                                 TypeManager.CSharpName (container));
 322
 323                 }
 324
 325                 public void Error_ExpressionMustBeConstant (ResolveContext rc, Location loc, string e_name)
 326                 {
 327                         rc.Report.Error (133, loc, "The expression being assigned to `{0}' must be constant", e_name);
 328                 }
 329
 330                 public void Error_ConstantCanBeInitializedWithNullOnly (ResolveContext rc, Type type, Location loc, string name)
 331                 {
 332                         rc.Report.Error (134, loc, "A constant `{0}' of reference type `{1}' can only be initialized with null",
 333                                 name, TypeManager.CSharpName (type));
 334                 }
 335
 336                 public static void Error_InvalidExpressionStatement (Report Report, Location loc)
 337                 {
 338                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 339                                        "expressions can be used as a statement");
 340                 }
 341
 342                 public void Error_InvalidExpressionStatement (BlockContext ec)
 343                 {
 344                         Error_InvalidExpressionStatement (ec.Report, loc);
 345                 }
 346
 347                 public static void Error_VoidInvalidInTheContext (Location loc, Report Report)
 348                 {
 349                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 350                 }
 351
 352                 public virtual void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
 353                 {
 354                         Error_ValueCannotBeConvertedCore (ec, loc, target, expl);
 355                 }
 356
 357                 protected void Error_ValueCannotBeConvertedCore (ResolveContext ec, Location loc, Type target, bool expl)
 358                 {
 359                         // The error was already reported as CS1660
 360                         if (type == InternalType.AnonymousMethod)
 361                                 return;
 362
 363                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 364                                 string sig1 = type.DeclaringMethod == null ?
 365                                         TypeManager.CSharpName (type.DeclaringType) :
 366                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 367                                 string sig2 = target.DeclaringMethod == null ?
 368                                         TypeManager.CSharpName (target.DeclaringType) :
 369                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 370                                 ec.Report.ExtraInformation (loc,
 371                                         String.Format (
 372                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 373                                                 Type.Name, sig1, sig2));
 374                         } else if (Type.FullName == target.FullName){
 375                                 ec.Report.ExtraInformation (loc,
 376                                         String.Format (
 377                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 378                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 379                         }
 380
 381                         if (expl) {
 382                                 ec.Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 383                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 384                                 return;
 385                         }
 386
 387                         ec.Report.DisableReporting ();
 388                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 389                         ec.Report.EnableReporting ();
 390
 391                         if (expl_exists) {
 392                                 ec.Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 393                                               "An explicit conversion exists (are you missing a cast?)",
 394                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 395                                 return;
 396                         }
 397
 398                         ec.Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 399                                 TypeManager.CSharpName (type),
 400                                 TypeManager.CSharpName (target));
 401                 }
 402
 403                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (Report Report, string name)
 404                 {
 405                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 406                 }
 407
 408                 public void Error_TypeArgumentsCannotBeUsed (Report report, Location loc)
 409                 {
 410                         // Better message for possible generic expressions
 411                         if (eclass == ExprClass.MethodGroup || eclass == ExprClass.Type) {
 412                                 if (this is TypeExpr)
 413                                         report.SymbolRelatedToPreviousError (type);
 414
 415                                 string name = eclass == ExprClass.Type ? ExprClassName : "method";
 416                                 report.Error (308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 417                                         name, GetSignatureForError ());
 418                         } else {
 419                                 report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
 420                                         ExprClassName, GetSignatureForError ());
 421                         }
 422                 }
 423
 424                 protected virtual void Error_TypeDoesNotContainDefinition (ResolveContext ec, Type type, string name)
 425                 {
 426                         Error_TypeDoesNotContainDefinition (ec, loc, type, name);
 427                 }
 428
 429                 public static void Error_TypeDoesNotContainDefinition (ResolveContext ec, Location loc, Type type, string name)
 430                 {
 431                         ec.Report.SymbolRelatedToPreviousError (type);
 432                         ec.Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 433                                 TypeManager.CSharpName (type), name);
 434                 }
 435
 436                 protected static void Error_ValueAssignment (ResolveContext ec, Location loc)
 437                 {
 438                         ec.Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 439                 }
 440
 441                 ResolveFlags ExprClassToResolveFlags {
 442                         get {
 443                                 switch (eclass) {
 444                                 case ExprClass.Type:
 445                                 case ExprClass.Namespace:
 446                                         return ResolveFlags.Type;
 447
 448                                 case ExprClass.MethodGroup:
 449                                         return ResolveFlags.MethodGroup;
 450
 451                                 case ExprClass.TypeParameter:
 452                                         return ResolveFlags.TypeParameter;
 453
 454                                 case ExprClass.Value:
 455                                 case ExprClass.Variable:
 456                                 case ExprClass.PropertyAccess:
 457                                 case ExprClass.EventAccess:
 458                                 case ExprClass.IndexerAccess:
 459                                         return ResolveFlags.VariableOrValue;
 460
 461                                 default:
 462                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 463                                 }
 464                         }
 465                 }
 466
 467                 /// <summary>
 468                 ///   Resolves an expression and performs semantic analysis on it.
 469                 /// </summary>
 470                 ///
 471                 /// <remarks>
 472                 ///   Currently Resolve wraps DoResolve to perform sanity
 473                 ///   checking and assertion checking on what we expect from Resolve.
 474                 /// </remarks>
 475                 public Expression Resolve (ResolveContext ec, ResolveFlags flags)
 476                 {
 477                         if (eclass != ExprClass.Unresolved)
 478                                 return this;
 479
 480                         Expression e;
 481                         if (this is SimpleName) {
 482                                 e = ((SimpleName) this).DoResolve (ec, (flags & ResolveFlags.Intermediate) != 0);
 483                         } else {
 484                                 e = DoResolve (ec);
 485                         }
 486
 487                         if (e == null)
 488                                 return null;
 489
 490                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 491                                 e.Error_UnexpectedKind (ec, flags, loc);
 492                                 return null;
 493                         }
 494
 495                         if (e.type == null)
 496                                 throw new InternalErrorException ("Expression `{0}' didn't set its type in DoResolve", e.GetType ());
 497
 498                         return e;
 499                 }
 500
 501                 /// <summary>
 502                 ///   Resolves an expression and performs semantic analysis on it.
 503                 /// </summary>
 504                 public Expression Resolve (ResolveContext rc)
 505                 {
 506                         return Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 507                 }
 508
 509                 /// <summary>
 510                 ///   Resolves an expression for LValue assignment
 511                 /// </summary>
 512                 ///
 513                 /// <remarks>
 514                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 515                 ///   checking and assertion checking on what we expect from Resolve
 516                 /// </remarks>
 517                 public Expression ResolveLValue (ResolveContext ec, Expression right_side)
 518                 {
 519                         int errors = ec.Report.Errors;
 520                         bool out_access = right_side == EmptyExpression.OutAccess.Instance;
 521
 522                         Expression e = DoResolveLValue (ec, right_side);
 523
 524                         if (e != null && out_access && !(e is IMemoryLocation)) {
 525                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 526                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 527
 528                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 529                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 530                                 e = null;
 531                         }
 532
 533                         if (e == null) {
 534                                 if (errors == ec.Report.Errors) {
 535                                         if (out_access)
 536                                                 ec.Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 537                                         else
 538                                                 Error_ValueAssignment (ec, loc);
 539                                 }
 540                                 return null;
 541                         }
 542
 543                         if (e.eclass == ExprClass.Unresolved)
 544                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 545
 546                         if ((e.type == null) && !(e is GenericTypeExpr))
 547                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 548
 549                         return e;
 550                 }
 551
 552                 public virtual void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, Type targetType)
 553                 {
 554                         Attribute.Error_AttributeArgumentNotValid (rc, loc);
 555                 }
 556
 557                 /// <summary>
 558                 ///   Emits the code for the expression
 559                 /// </summary>
 560                 ///
 561                 /// <remarks>
 562                 ///   The Emit method is invoked to generate the code
 563                 ///   for the expression.
 564                 /// </remarks>
 565                 public abstract void Emit (EmitContext ec);
 566
 567
 568                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 569                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 570                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 571                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 572                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 573                 {
 574                         Emit (ec);
 575                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 576                 }
 577
 578                 // Emit this expression for its side effects, not for its value.
 579                 // The default implementation is to emit the value, and then throw it away.
 580                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 581                 public virtual void EmitSideEffect (EmitContext ec)
 582                 {
 583                         Emit (ec);
 584                         ec.ig.Emit (OpCodes.Pop);
 585                 }
 586
 587                 /// <summary>
 588                 ///   Protected constructor.  Only derivate types should
 589                 ///   be able to be created
 590                 /// </summary>
 591
 592                 protected Expression ()
 593                 {
 594                 }
 595
 596                 /// <summary>
 597                 ///   Returns a fully formed expression after a MemberLookup
 598                 /// </summary>
 599                 ///
 600                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 601                 {
 602                         if (mi is EventInfo)
 603                                 return new EventExpr (Import.CreateEvent ((EventInfo) mi), loc);
 604                         else if (mi is FieldInfo) {
 605                                 FieldInfo fi = (FieldInfo) mi;
 606                                 var spec = Import.CreateField (fi);
 607                                 if (spec is ConstSpec)
 608                                         return new ConstantExpr ((ConstSpec) spec, loc);
 609                                 return new FieldExpr (spec, loc);
 610                         } else if (mi is PropertyInfo)
 611                                 return new PropertyExpr (container_type, Import.CreateProperty ((PropertyInfo) mi), loc);
 612                         else if (mi is Type) {
 613                                 return new TypeExpression ((System.Type) mi, loc);
 614                         }
 615
 616                         return null;
 617                 }
 618
 619                 // TODO: [Obsolete ("Can be removed")]
 620                 protected static IList<MemberInfo> almost_matched_members = new List<MemberInfo> (4);
 621
 622                 //
 623                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 624                 //
 625                 // This code could use some optimizations, but we need to do some
 626                 // measurements.  For example, we could use a delegate to `flag' when
 627                 // something can not any longer be a method-group (because it is something
 628                 // else).
 629                 //
 630                 // Return values:
 631                 //     If the return value is an Array, then it is an array of
 632                 //     MethodBases
 633                 //
 634                 //     If the return value is an MemberInfo, it is anything, but a Method
 635                 //
 636                 //     null on error.
 637                 //
 638                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 639                 // the arguments here and have MemberLookup return only the methods that
 640                 // match the argument count/type, unlike we are doing now (we delay this
 641                 // decision).
 642                 //
 643                 // This is so we can catch correctly attempts to invoke instance methods
 644                 // from a static body (scan for error 120 in ResolveSimpleName).
 645                 //
 646                 //
 647                 // FIXME: Potential optimization, have a static ArrayList
 648                 //
 649
 650                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type, string name,
 651                                                        MemberTypes mt, BindingFlags bf, Location loc)
 652                 {
 653                         return MemberLookup (ctx, container_type, null, queried_type, name, mt, bf, loc);
 654                 }
 655
 656                 //
 657                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 658                 // `qualifier_type' or null to lookup members in the current class.
 659                 //
 660
 661                 public static Expression MemberLookup (CompilerContext ctx, Type container_type,
 662                                                        Type qualifier_type, Type queried_type,
 663                                                        string name, MemberTypes mt,
 664                                                        BindingFlags bf, Location loc)
 665                 {
 666                         almost_matched_members.Clear ();
 667
 668                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 669                                                                      queried_type, mt, bf, name, almost_matched_members);
 670
 671                         if (mi == null)
 672                                 return null;
 673
 674                         if (mi.Length > 1) {
 675                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 676                                 var methods = new List<MethodSpec> (2);
 677                                 List<MemberInfo> non_methods = null;
 678
 679                                 foreach (var m in mi) {
 680                                         if (m is MethodBase) {
 681                                                 methods.Add (Import.CreateMethod ((MethodBase) m));
 682                                                 continue;
 683                                         }
 684
 685                                         if (non_methods == null)
 686                                                 non_methods = new List<MemberInfo> (2);
 687
 688                                         bool is_candidate = true;
 689                                         for (int i = 0; i < non_methods.Count; ++i) {
 690                                                 MemberInfo n_m = non_methods [i];
 691                                                 if (n_m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType)) {
 692                                                         non_methods.Remove (n_m);
 693                                                         --i;
 694                                                 } else if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (n_m.DeclaringType, m.DeclaringType)) {
 695                                                         is_candidate = false;
 696                                                         break;
 697                                                 }
 698                                         }
 699
 700                                         if (is_candidate) {
 701                                                 non_methods.Add (m);
 702                                         }
 703                                 }
 704
 705                                 if (methods.Count == 0 && non_methods != null && non_methods.Count > 1) {
 706                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [1]);
 707                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [0]);
 708                                         ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 709                                                 TypeManager.GetFullNameSignature (non_methods [1]),
 710                                                 TypeManager.GetFullNameSignature (non_methods [0]));
 711                                         return null;
 712                                 }
 713
 714                                 if (methods.Count == 0)
 715                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 716
 717                                 if (non_methods != null && non_methods.Count > 0) {
 718                                         var method = methods [0];
 719                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 720                                         if (method.DeclaringType == non_method.DeclaringType) {
 721                                                 // Cannot happen with C# code, but is valid in IL
 722                                                 ctx.Report.SymbolRelatedToPreviousError (method.MetaInfo);
 723                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 724                                                 ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 725                                                               TypeManager.GetFullNameSignature (non_method),
 726                                                               TypeManager.CSharpSignature (method.MetaInfo));
 727                                                 return null;
 728                                         }
 729
 730                                         if (is_interface) {
 731                                                 ctx.Report.SymbolRelatedToPreviousError (method.MetaInfo);
 732                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 733                                                 ctx.Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 734                                                                 TypeManager.CSharpSignature (method.MetaInfo), TypeManager.GetFullNameSignature (non_method));
 735                                         }
 736                                 }
 737
 738                                 return new MethodGroupExpr (methods, queried_type, loc);
 739                         }
 740
 741                         if (mi [0] is MethodBase)
 742                                 return new MethodGroupExpr (mi.Select (l => Import.CreateMethod ((MethodBase) l)).ToArray (), queried_type, loc);
 743
 744                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 745                 }
 746
 747                 public const MemberTypes AllMemberTypes =
 748                         MemberTypes.Constructor |
 749                         MemberTypes.Event       |
 750                         MemberTypes.Field       |
 751                         MemberTypes.Method      |
 752                         MemberTypes.NestedType  |
 753                         MemberTypes.Property;
 754
 755                 public const BindingFlags AllBindingFlags =
 756                         BindingFlags.Public |
 757                         BindingFlags.Static |
 758                         BindingFlags.Instance;
 759
 760                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type,
 761                                                        string name, Location loc)
 762                 {
 763                         return MemberLookup (ctx, container_type, null, queried_type, name,
 764                                              AllMemberTypes, AllBindingFlags, loc);
 765                 }
 766
 767                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type qualifier_type,
 768                                                        Type queried_type, string name, Location loc)
 769                 {
 770                         return MemberLookup (ctx, container_type, qualifier_type, queried_type,
 771                                              name, AllMemberTypes, AllBindingFlags, loc);
 772                 }
 773
 774                 public static MethodGroupExpr MethodLookup (CompilerContext ctx, Type container_type, Type queried_type,
 775                                                        string name, Location loc)
 776                 {
 777                         return (MethodGroupExpr)MemberLookup (ctx, container_type, null, queried_type, name,
 778                                              MemberTypes.Method, AllBindingFlags, loc);
 779                 }
 780
 781                 /// <summary>
 782                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 783                 ///   to find a final definition.  If the final definition is not found, we
 784                 ///   look for private members and display a useful debugging message if we
 785                 ///   find it.
 786                 /// </summary>
 787                 protected Expression MemberLookupFinal (ResolveContext ec, Type qualifier_type,
 788                                                             Type queried_type, string name,
 789                                                             MemberTypes mt, BindingFlags bf,
 790                                                             Location loc)
 791                 {
 792                         Expression e;
 793
 794                         int errors = ec.Report.Errors;
 795                         e = MemberLookup (ec.Compiler, ec.CurrentType, qualifier_type, queried_type, name, mt, bf, loc);
 796
 797                         if (e != null || errors != ec.Report.Errors)
 798                                 return e;
 799
 800                         // No errors were reported by MemberLookup, but there was an error.
 801                         return Error_MemberLookupFailed (ec, ec.CurrentType, qualifier_type, queried_type,
 802                                         name, null, mt, bf);
 803                 }
 804
 805                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type container_type, Type qualifier_type,
 806                                                        Type queried_type, string name, string class_name,
 807                                                            MemberTypes mt, BindingFlags bf)
 808                 {
 809                         MemberInfo[] lookup = null;
 810                         if (queried_type == null) {
 811                                 class_name = "global::";
 812                         } else {
 813                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 814                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 815                                         name, null);
 816
 817                                 if (lookup != null) {
 818                                         Expression e = Error_MemberLookupFailed (ec, queried_type, lookup);
 819
 820                                         //
 821                                         // FIXME: This is still very wrong, it should be done inside
 822                                         // OverloadResolve to do correct arguments matching.
 823                                         // Requires MemberLookup accessiblity check removal
 824                                         //
 825                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 826                                                 MemberInfo mi = lookup[0];
 827                                                 ec.Report.SymbolRelatedToPreviousError (mi);
 828                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 829                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 830                                                         // Although a derived class can access protected members of
 831                                                         // its base class it cannot do so through an instance of the
 832                                                         // base class (CS1540).  If the qualifier_type is a base of the
 833                                                         // ec.CurrentType and the lookup succeeds with the latter one,
 834                                                         // then we are in this situation.
 835                                                         Error_CannotAccessProtected (ec, loc, mi, qualifier_type, container_type);
 836                                                 } else {
 837                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi), ec.Report);
 838                                                 }
 839                                         }
 840
 841                                         return e;
 842                                 }
 843
 844                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 845                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 846                                         name, null);
 847                         }
 848
 849                         if (lookup == null) {
 850                                 if (class_name != null) {
 851                                         ec.Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 852                                                 name);
 853                                 } else {
 854                                         Error_TypeDoesNotContainDefinition (ec, queried_type, name);
 855                                 }
 856                                 return null;
 857                         }
 858
 859                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 860                                                       AllMemberTypes, AllBindingFlags |
 861                                                       BindingFlags.NonPublic, name, null) == null) {
 862                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 863                                         Type t = (Type) lookup [0];
 864
 865                                         ec.Report.Error (305, loc,
 866                                                       "Using the generic type `{0}' " +
 867                                                       "requires {1} type arguments",
 868                                                       TypeManager.CSharpName (t),
 869                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 870                                         return null;
 871                                 }
 872                         }
 873
 874                         return Error_MemberLookupFailed (ec, queried_type, lookup);
 875                 }
 876
 877                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type type, MemberInfo[] members)
 878                 {
 879                         List<MethodSpec> methods = new List<MethodSpec> ();
 880                         for (int i = 0; i < members.Length; ++i) {
 881                                 if (!(members [i] is MethodBase))
 882                                         return null;
 883
 884                                 methods.Add (Import.CreateMethod (members[i] as MethodBase));
 885                         }
 886
 887                         // By default propagate the closest candidates upwards
 888                         return new MethodGroupExpr (methods.ToArray (), type, loc, true);
 889                 }
 890
 891                 protected virtual void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
 892                 {
 893                         throw new NotImplementedException ();
 894                 }
 895
 896                 protected void Error_PointerInsideExpressionTree (ResolveContext ec)
 897                 {
 898                         ec.Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 899                 }
 900
 901                 /// <summary>
 902                 ///   Returns an expression that can be used to invoke operator true
 903                 ///   on the expression if it exists.
 904                 /// </summary>
 905                 protected static Expression GetOperatorTrue (ResolveContext ec, Expression e, Location loc)
 906                 {
 907                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 908                 }
 909
 910                 /// <summary>
 911                 ///   Returns an expression that can be used to invoke operator false
 912                 ///   on the expression if it exists.
 913                 /// </summary>
 914                 static public Expression GetOperatorFalse (ResolveContext ec, Expression e, Location loc)
 915                 {
 916                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 917                 }
 918
 919                 static Expression GetOperatorTrueOrFalse (ResolveContext ec, Expression e, bool is_true, Location loc)
 920                 {
 921                         MethodGroupExpr operator_group;
 922                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 923                         operator_group = MethodLookup (ec.Compiler, ec.CurrentType, e.Type, mname, loc) as MethodGroupExpr;
 924                         if (operator_group == null)
 925                                 return null;
 926
 927                         Arguments arguments = new Arguments (1);
 928                         arguments.Add (new Argument (e));
 929                         operator_group = operator_group.OverloadResolve (
 930                                 ec, ref arguments, false, loc);
 931
 932                         if (operator_group == null)
 933                                 return null;
 934
 935                         return new UserOperatorCall (operator_group, arguments, null, loc);
 936                 }
 937
 938                 public virtual string ExprClassName
 939                 {
 940                         get {
 941                                 switch (eclass){
 942                                 case ExprClass.Unresolved:
 943                                         return "Unresolved";
 944                                 case ExprClass.Value:
 945                                         return "value";
 946                                 case ExprClass.Variable:
 947                                         return "variable";
 948                                 case ExprClass.Namespace:
 949                                         return "namespace";
 950                                 case ExprClass.Type:
 951                                         return "type";
 952                                 case ExprClass.MethodGroup:
 953                                         return "method group";
 954                                 case ExprClass.PropertyAccess:
 955                                         return "property access";
 956                                 case ExprClass.EventAccess:
 957                                         return "event access";
 958                                 case ExprClass.IndexerAccess:
 959                                         return "indexer access";
 960                                 case ExprClass.Nothing:
 961                                         return "null";
 962                                 case ExprClass.TypeParameter:
 963                                         return "type parameter";
 964                                 }
 965                                 throw new Exception ("Should not happen");
 966                         }
 967                 }
 968
 969                 /// <summary>
 970                 ///   Reports that we were expecting `expr' to be of class `expected'
 971                 /// </summary>
 972                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, Location loc)
 973                 {
 974                         Error_UnexpectedKind (r, mc, expected, ExprClassName, loc);
 975                 }
 976
 977                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, string was, Location loc)
 978                 {
 979                         string name;
 980                         if (mc != null)
 981                                 name = mc.GetSignatureForError ();
 982                         else
 983                                 name = GetSignatureForError ();
 984
 985                         r.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
 986                               name, was, expected);
 987                 }
 988
 989                 public void Error_UnexpectedKind (ResolveContext ec, ResolveFlags flags, Location loc)
 990                 {
 991                         string [] valid = new string [4];
 992                         int count = 0;
 993
 994                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 995                                 valid [count++] = "variable";
 996                                 valid [count++] = "value";
 997                         }
 998
 999                         if ((flags & ResolveFlags.Type) != 0)
1000                                 valid [count++] = "type";
1001
1002                         if ((flags & ResolveFlags.MethodGroup) != 0)
1003                                 valid [count++] = "method group";
1004
1005                         if (count == 0)
1006                                 valid [count++] = "unknown";
1007
1008                         StringBuilder sb = new StringBuilder (valid [0]);
1009                         for (int i = 1; i < count - 1; i++) {
1010                                 sb.Append ("', `");
1011                                 sb.Append (valid [i]);
1012                         }
1013                         if (count > 1) {
1014                                 sb.Append ("' or `");
1015                                 sb.Append (valid [count - 1]);
1016                         }
1017
1018                         ec.Report.Error (119, loc,
1019                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1020                 }
1021
1022                 public static void UnsafeError (ResolveContext ec, Location loc)
1023                 {
1024                         UnsafeError (ec.Report, loc);
1025                 }
1026
1027                 public static void UnsafeError (Report Report, Location loc)
1028                 {
1029                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1030                 }
1031
1032                 //
1033                 // Load the object from the pointer.
1034                 //
1035                 public static void LoadFromPtr (ILGenerator ig, Type t)
1036                 {
1037                         if (t == TypeManager.int32_type)
1038                                 ig.Emit (OpCodes.Ldind_I4);
1039                         else if (t == TypeManager.uint32_type)
1040                                 ig.Emit (OpCodes.Ldind_U4);
1041                         else if (t == TypeManager.short_type)
1042                                 ig.Emit (OpCodes.Ldind_I2);
1043                         else if (t == TypeManager.ushort_type)
1044                                 ig.Emit (OpCodes.Ldind_U2);
1045                         else if (t == TypeManager.char_type)
1046                                 ig.Emit (OpCodes.Ldind_U2);
1047                         else if (t == TypeManager.byte_type)
1048                                 ig.Emit (OpCodes.Ldind_U1);
1049                         else if (t == TypeManager.sbyte_type)
1050                                 ig.Emit (OpCodes.Ldind_I1);
1051                         else if (t == TypeManager.uint64_type)
1052                                 ig.Emit (OpCodes.Ldind_I8);
1053                         else if (t == TypeManager.int64_type)
1054                                 ig.Emit (OpCodes.Ldind_I8);
1055                         else if (t == TypeManager.float_type)
1056                                 ig.Emit (OpCodes.Ldind_R4);
1057                         else if (t == TypeManager.double_type)
1058                                 ig.Emit (OpCodes.Ldind_R8);
1059                         else if (t == TypeManager.bool_type)
1060                                 ig.Emit (OpCodes.Ldind_I1);
1061                         else if (t == TypeManager.intptr_type)
1062                                 ig.Emit (OpCodes.Ldind_I);
1063                         else if (TypeManager.IsEnumType (t)) {
1064                                 if (t == TypeManager.enum_type)
1065                                         ig.Emit (OpCodes.Ldind_Ref);
1066                                 else
1067                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1068                         } else if (TypeManager.IsStruct (t) || TypeManager.IsGenericParameter (t))
1069                                 ig.Emit (OpCodes.Ldobj, t);
1070                         else if (t.IsPointer)
1071                                 ig.Emit (OpCodes.Ldind_I);
1072                         else
1073                                 ig.Emit (OpCodes.Ldind_Ref);
1074                 }
1075
1076                 //
1077                 // The stack contains the pointer and the value of type `type'
1078                 //
1079                 public static void StoreFromPtr (ILGenerator ig, Type type)
1080                 {
1081                         if (TypeManager.IsEnumType (type))
1082                                 type = TypeManager.GetEnumUnderlyingType (type);
1083                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1084                                 ig.Emit (OpCodes.Stind_I4);
1085                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1086                                 ig.Emit (OpCodes.Stind_I8);
1087                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1088                                  type == TypeManager.ushort_type)
1089                                 ig.Emit (OpCodes.Stind_I2);
1090                         else if (type == TypeManager.float_type)
1091                                 ig.Emit (OpCodes.Stind_R4);
1092                         else if (type == TypeManager.double_type)
1093                                 ig.Emit (OpCodes.Stind_R8);
1094                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1095                                  type == TypeManager.bool_type)
1096                                 ig.Emit (OpCodes.Stind_I1);
1097                         else if (type == TypeManager.intptr_type)
1098                                 ig.Emit (OpCodes.Stind_I);
1099                         else if (TypeManager.IsStruct (type) || TypeManager.IsGenericParameter (type))
1100                                 ig.Emit (OpCodes.Stobj, type);
1101                         else
1102                                 ig.Emit (OpCodes.Stind_Ref);
1103                 }
1104
1105                 //
1106                 // Returns the size of type `t' if known, otherwise, 0
1107                 //
1108                 public static int GetTypeSize (Type t)
1109                 {
1110                         t = TypeManager.TypeToCoreType (t);
1111                         if (t == TypeManager.int32_type ||
1112                             t == TypeManager.uint32_type ||
1113                             t == TypeManager.float_type)
1114                                 return 4;
1115                         else if (t == TypeManager.int64_type ||
1116                                  t == TypeManager.uint64_type ||
1117                                  t == TypeManager.double_type)
1118                                 return 8;
1119                         else if (t == TypeManager.byte_type ||
1120                                  t == TypeManager.sbyte_type ||
1121                                  t == TypeManager.bool_type)
1122                                 return 1;
1123                         else if (t == TypeManager.short_type ||
1124                                  t == TypeManager.char_type ||
1125                                  t == TypeManager.ushort_type)
1126                                 return 2;
1127                         else if (t == TypeManager.decimal_type)
1128                                 return 16;
1129                         else
1130                                 return 0;
1131                 }
1132
1133                 protected void Error_CannotCallAbstractBase (ResolveContext ec, string name)
1134                 {
1135                         ec.Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1136                 }
1137
1138                 protected void Error_CannotModifyIntermediateExpressionValue (ResolveContext ec)
1139                 {
1140                         ec.Report.SymbolRelatedToPreviousError (type);
1141                         if (ec.CurrentInitializerVariable != null) {
1142                                 ec.Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1143                                         TypeManager.CSharpName (type), GetSignatureForError ());
1144                         } else {
1145                                 ec.Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1146                                         GetSignatureForError ());
1147                         }
1148                 }
1149
1150                 //
1151                 // Converts `source' to an int, uint, long or ulong.
1152                 //
1153                 protected Expression ConvertExpressionToArrayIndex (ResolveContext ec, Expression source)
1154                 {
1155                         if (TypeManager.IsDynamicType (source.type)) {
1156                                 Arguments args = new Arguments (1);
1157                                 args.Add (new Argument (source));
1158                                 return new DynamicConversion (TypeManager.int32_type, CSharpBinderFlags.ConvertArrayIndex, args, loc).Resolve (ec);
1159                         }
1160
1161                         Expression converted;
1162
1163                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
1164                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1165                                 if (converted == null)
1166                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1167                                 if (converted == null)
1168                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1169                                 if (converted == null)
1170                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1171
1172                                 if (converted == null) {
1173                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1174                                         return null;
1175                                 }
1176                         }
1177
1178                         //
1179                         // Only positive constants are allowed at compile time
1180                         //
1181                         Constant c = converted as Constant;
1182                         if (c != null && c.IsNegative)
1183                                 Error_NegativeArrayIndex (ec, source.loc);
1184
1185                         // No conversion needed to array index
1186                         if (converted.Type == TypeManager.int32_type)
1187                                 return converted;
1188
1189                         return new ArrayIndexCast (converted).Resolve (ec);
1190                 }
1191
1192                 //
1193                 // Derived classes implement this method by cloning the fields that
1194                 // could become altered during the Resolve stage
1195                 //
1196                 // Only expressions that are created for the parser need to implement
1197                 // this.
1198                 //
1199                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1200                 {
1201                         throw new NotImplementedException (
1202                                 String.Format (
1203                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1204                 }
1205
1206                 //
1207                 // Clones an expression created by the parser.
1208                 //
1209                 // We only support expressions created by the parser so far, not
1210                 // expressions that have been resolved (many more classes would need
1211                 // to implement CloneTo).
1212                 //
1213                 // This infrastructure is here merely for Lambda expressions which
1214                 // compile the same code using different type values for the same
1215                 // arguments to find the correct overload
1216                 //
1217                 public Expression Clone (CloneContext clonectx)
1218                 {
1219                         Expression cloned = (Expression) MemberwiseClone ();
1220                         CloneTo (clonectx, cloned);
1221
1222                         return cloned;
1223                 }
1224
1225                 //
1226                 // Implementation of expression to expression tree conversion
1227                 //
1228                 public abstract Expression CreateExpressionTree (ResolveContext ec);
1229
1230                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, Arguments args)
1231                 {
1232                         return CreateExpressionFactoryCall (ec, name, null, args, loc);
1233                 }
1234
1235                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args)
1236                 {
1237                         return CreateExpressionFactoryCall (ec, name, typeArguments, args, loc);
1238                 }
1239
1240                 public static Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args, Location loc)
1241                 {
1242                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (ec, loc), name, typeArguments, loc), args);
1243                 }
1244
1245                 protected static TypeExpr CreateExpressionTypeExpression (ResolveContext ec, Location loc)
1246                 {
1247                         TypeExpr texpr = TypeManager.expression_type_expr;
1248                         if (texpr == null) {
1249                                 Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Linq.Expressions", "Expression", MemberKind.Class, true);
1250                                 if (t == null)
1251                                         return null;
1252
1253                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1254                         }
1255
1256                         return texpr;
1257                 }
1258
1259                 //
1260                 // Implemented by all expressions which support conversion from
1261                 // compiler expression to invokable runtime expression. Used by
1262                 // dynamic C# binder.
1263                 //
1264                 public virtual SLE.Expression MakeExpression (BuilderContext ctx)
1265                 {
1266                         throw new NotImplementedException ("MakeExpression for " + GetType ());
1267                 }
1268
1269                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1270                 {
1271                         // TODO: It should probably be type = storey.MutateType (type);
1272                 }
1273         }
1274
1275         /// <summary>
1276         ///   This is just a base class for expressions that can
1277         ///   appear on statements (invocations, object creation,
1278         ///   assignments, post/pre increment and decrement).  The idea
1279         ///   being that they would support an extra Emition interface that
1280         ///   does not leave a result on the stack.
1281         /// </summary>
1282         public abstract class ExpressionStatement : Expression {
1283
1284                 public virtual ExpressionStatement ResolveStatement (BlockContext ec)
1285                 {
1286                         Expression e = Resolve (ec);
1287                         if (e == null)
1288                                 return null;
1289
1290                         ExpressionStatement es = e as ExpressionStatement;
1291                         if (es == null)
1292                                 Error_InvalidExpressionStatement (ec);
1293
1294                         return es;
1295                 }
1296
1297                 /// <summary>
1298                 ///   Requests the expression to be emitted in a `statement'
1299                 ///   context.  This means that no new value is left on the
1300                 ///   stack after invoking this method (constrasted with
1301                 ///   Emit that will always leave a value on the stack).
1302                 /// </summary>
1303                 public abstract void EmitStatement (EmitContext ec);
1304
1305                 public override void EmitSideEffect (EmitContext ec)
1306                 {
1307                         EmitStatement (ec);
1308                 }
1309         }
1310
1311         /// <summary>
1312         ///   This kind of cast is used to encapsulate the child
1313         ///   whose type is child.Type into an expression that is
1314         ///   reported to return "return_type".  This is used to encapsulate
1315         ///   expressions which have compatible types, but need to be dealt
1316         ///   at higher levels with.
1317         ///
1318         ///   For example, a "byte" expression could be encapsulated in one
1319         ///   of these as an "unsigned int".  The type for the expression
1320         ///   would be "unsigned int".
1321         ///
1322         /// </summary>
1323         public abstract class TypeCast : Expression
1324         {
1325                 protected readonly Expression child;
1326
1327                 protected TypeCast (Expression child, Type return_type)
1328                 {
1329                         eclass = child.eclass;
1330                         loc = child.Location;
1331                         type = return_type;
1332                         this.child = child;
1333                 }
1334
1335                 public Expression Child {
1336                         get {
1337                                 return child;
1338                         }
1339                 }
1340
1341                 public override Expression CreateExpressionTree (ResolveContext ec)
1342                 {
1343                         Arguments args = new Arguments (2);
1344                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1345                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1346
1347                         if (type.IsPointer || child.Type.IsPointer)
1348                                 Error_PointerInsideExpressionTree (ec);
1349
1350                         return CreateExpressionFactoryCall (ec, ec.HasSet (ResolveContext.Options.CheckedScope) ? "ConvertChecked" : "Convert", args);
1351                 }
1352
1353                 protected override Expression DoResolve (ResolveContext ec)
1354                 {
1355                         // This should never be invoked, we are born in fully
1356                         // initialized state.
1357
1358                         return this;
1359                 }
1360
1361                 public override void Emit (EmitContext ec)
1362                 {
1363                         child.Emit (ec);
1364                 }
1365
1366                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1367                 {
1368                         return ctx.HasSet (BuilderContext.Options.CheckedScope) ?
1369                                 SLE.Expression.ConvertChecked (child.MakeExpression (ctx), type) :
1370                                 SLE.Expression.Convert (child.MakeExpression (ctx), type);
1371                 }
1372
1373                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1374                 {
1375                         type = storey.MutateType (type);
1376                         child.MutateHoistedGenericType (storey);
1377                 }
1378
1379                 protected override void CloneTo (CloneContext clonectx, Expression t)
1380                 {
1381                         // Nothing to clone
1382                 }
1383
1384                 public override bool IsNull {
1385                         get { return child.IsNull; }
1386                 }
1387         }
1388
1389         public class EmptyCast : TypeCast {
1390                 EmptyCast (Expression child, Type target_type)
1391                         : base (child, target_type)
1392                 {
1393                 }
1394
1395                 public static Expression Create (Expression child, Type type)
1396                 {
1397                         Constant c = child as Constant;
1398                         if (c != null)
1399                                 return new EmptyConstantCast (c, type);
1400
1401                         EmptyCast e = child as EmptyCast;
1402                         if (e != null)
1403                                 return new EmptyCast (e.child, type);
1404
1405                         return new EmptyCast (child, type);
1406                 }
1407
1408                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1409                 {
1410                         child.EmitBranchable (ec, label, on_true);
1411                 }
1412
1413                 public override void EmitSideEffect (EmitContext ec)
1414                 {
1415                         child.EmitSideEffect (ec);
1416                 }
1417         }
1418
1419         //
1420         // Used for predefined class library user casts (no obsolete check, etc.)
1421         //
1422         public class OperatorCast : TypeCast {
1423                 MethodInfo conversion_operator;
1424
1425                 public OperatorCast (Expression child, Type target_type)
1426                         : this (child, target_type, false)
1427                 {
1428                 }
1429
1430                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1431                         : base (child, target_type)
1432                 {
1433                         conversion_operator = GetConversionOperator (find_explicit);
1434                         if (conversion_operator == null)
1435                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1436                 }
1437
1438                 // Returns the implicit operator that converts from
1439                 // 'child.Type' to our target type (type)
1440                 MethodInfo GetConversionOperator (bool find_explicit)
1441                 {
1442                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1443
1444                         MemberInfo [] mi;
1445
1446                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1447                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1448
1449                         if (mi == null){
1450                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1451                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1452                         }
1453
1454                         foreach (MethodInfo oper in mi) {
1455                                 AParametersCollection pd = TypeManager.GetParameterData (oper);
1456
1457                                 if (pd.Types [0] == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1458                                         return oper;
1459                         }
1460
1461                         return null;
1462                 }
1463
1464                 public override void Emit (EmitContext ec)
1465                 {
1466                         child.Emit (ec);
1467                         ec.ig.Emit (OpCodes.Call, conversion_operator);
1468                 }
1469         }
1470
1471         /// <summary>
1472         ///     This is a numeric cast to a Decimal
1473         /// </summary>
1474         public class CastToDecimal : OperatorCast {
1475                 public CastToDecimal (Expression child)
1476                         : this (child, false)
1477                 {
1478                 }
1479
1480                 public CastToDecimal (Expression child, bool find_explicit)
1481                         : base (child, TypeManager.decimal_type, find_explicit)
1482                 {
1483                 }
1484         }
1485
1486         /// <summary>
1487         ///     This is an explicit numeric cast from a Decimal
1488         /// </summary>
1489         public class CastFromDecimal : TypeCast
1490         {
1491                 static Dictionary<Type, MethodInfo> operators;
1492
1493                 public CastFromDecimal (Expression child, Type return_type)
1494                         : base (child, return_type)
1495                 {
1496                         if (child.Type != TypeManager.decimal_type)
1497                                 throw new InternalErrorException (
1498                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1499                 }
1500
1501                 // Returns the explicit operator that converts from an
1502                 // express of type System.Decimal to 'type'.
1503                 public Expression Resolve ()
1504                 {
1505                         if (operators == null) {
1506                                 MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1507                                    TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1508                                    BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1509
1510                                 operators = new Dictionary<Type, MethodInfo> (ReferenceEquality<Type>.Default);
1511                                 foreach (MethodInfo oper in all_oper) {
1512                                         AParametersCollection pd = TypeManager.GetParameterData (oper);
1513                                         if (pd.Types [0] == TypeManager.decimal_type)
1514                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1515                                 }
1516                         }
1517
1518                         return operators.ContainsKey (type) ? this : null;
1519                 }
1520
1521                 public override void Emit (EmitContext ec)
1522                 {
1523                         ILGenerator ig = ec.ig;
1524                         child.Emit (ec);
1525
1526                         ig.Emit (OpCodes.Call, operators [type]);
1527                 }
1528         }
1529
1530
1531         //
1532         // Constant specialization of EmptyCast.
1533         // We need to special case this since an empty cast of
1534         // a constant is still a constant.
1535         //
1536         public class EmptyConstantCast : Constant
1537         {
1538                 public Constant child;
1539
1540                 public EmptyConstantCast (Constant child, Type type)
1541                         : base (child.Location)
1542                 {
1543                         if (child == null)
1544                                 throw new ArgumentNullException ("child");
1545
1546                         this.child = child;
1547                         this.eclass = child.eclass;
1548                         this.type = type;
1549                 }
1550
1551                 public override string AsString ()
1552                 {
1553                         return child.AsString ();
1554                 }
1555
1556                 public override object GetValue ()
1557                 {
1558                         return child.GetValue ();
1559                 }
1560
1561                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1562                 {
1563                         if (child.Type == target_type)
1564                                 return child;
1565
1566                         // FIXME: check that 'type' can be converted to 'target_type' first
1567                         return child.ConvertExplicitly (in_checked_context, target_type);
1568                 }
1569
1570                 public override Expression CreateExpressionTree (ResolveContext ec)
1571                 {
1572                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1573                                 child.CreateExpressionTree (ec),
1574                                 new TypeOf (new TypeExpression (type, loc), loc));
1575
1576                         if (type.IsPointer)
1577                                 Error_PointerInsideExpressionTree (ec);
1578
1579                         return CreateExpressionFactoryCall (ec, "Convert", args);
1580                 }
1581
1582                 public override bool IsDefaultValue {
1583                         get { return child.IsDefaultValue; }
1584                 }
1585
1586                 public override bool IsNegative {
1587                         get { return child.IsNegative; }
1588                 }
1589
1590                 public override bool IsNull {
1591                         get { return child.IsNull; }
1592                 }
1593
1594                 public override bool IsOneInteger {
1595                         get { return child.IsOneInteger; }
1596                 }
1597
1598                 public override bool IsZeroInteger {
1599                         get { return child.IsZeroInteger; }
1600                 }
1601
1602                 protected override Expression DoResolve (ResolveContext rc)
1603                 {
1604                         return this;
1605                 }
1606
1607                 public override void Emit (EmitContext ec)
1608                 {
1609                         child.Emit (ec);
1610                 }
1611
1612                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1613                 {
1614                         child.EmitBranchable (ec, label, on_true);
1615
1616                         // Only to make verifier happy
1617                         if (TypeManager.IsGenericParameter (type) && child.IsNull)
1618                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1619                 }
1620
1621                 public override void EmitSideEffect (EmitContext ec)
1622                 {
1623                         child.EmitSideEffect (ec);
1624                 }
1625
1626                 public override Constant ConvertImplicitly (ResolveContext rc, Type target_type)
1627                 {
1628                         // FIXME: Do we need to check user conversions?
1629                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1630                                 return null;
1631                         return child.ConvertImplicitly (rc, target_type);
1632                 }
1633
1634                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1635                 {
1636                         child.MutateHoistedGenericType (storey);
1637                 }
1638         }
1639
1640         /// <summary>
1641         ///  This class is used to wrap literals which belong inside Enums
1642         /// </summary>
1643         public class EnumConstant : Constant
1644         {
1645                 public Constant Child;
1646
1647                 public EnumConstant (Constant child, Type enum_type)
1648                         : base (child.Location)
1649                 {
1650                         this.Child = child;
1651                         this.type = enum_type;
1652                 }
1653
1654                 protected EnumConstant (Location loc)
1655                         : base (loc)
1656                 {
1657                 }
1658
1659                 protected override Expression DoResolve (ResolveContext rc)
1660                 {
1661                         Child = Child.Resolve (rc);
1662                         this.eclass = ExprClass.Value;
1663                         return this;
1664                 }
1665
1666                 public override void Emit (EmitContext ec)
1667                 {
1668                         Child.Emit (ec);
1669                 }
1670
1671                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, Type targetType)
1672                 {
1673                         Child.EncodeAttributeValue (rc, enc, Child.Type);
1674                 }
1675
1676                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1677                 {
1678                         Child.EmitBranchable (ec, label, on_true);
1679                 }
1680
1681                 public override void EmitSideEffect (EmitContext ec)
1682                 {
1683                         Child.EmitSideEffect (ec);
1684                 }
1685
1686                 public override string GetSignatureForError()
1687                 {
1688                         return TypeManager.CSharpName (Type);
1689                 }
1690
1691                 public override object GetValue ()
1692                 {
1693                         return Child.GetValue ();
1694                 }
1695
1696                 public override object GetTypedValue ()
1697                 {
1698                         // FIXME: runtime is not ready to work with just emited enums
1699                         if (!RootContext.StdLib) {
1700                                 return Child.GetValue ();
1701                         }
1702
1703 #if MS_COMPATIBLE
1704                         // Small workaround for big problem
1705                         // System.Enum.ToObject cannot be called on dynamic types
1706                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1707                         // because it does not properly support generics
1708                         //
1709                         // This works only sometimes
1710                         //
1711                         if (TypeManager.IsBeingCompiled (type))
1712                                 return Child.GetValue ();
1713 #endif
1714
1715                         return System.Enum.ToObject (type, Child.GetValue ());
1716                 }
1717
1718                 public override string AsString ()
1719                 {
1720                         return Child.AsString ();
1721                 }
1722
1723                 public EnumConstant Increment()
1724                 {
1725                         return new EnumConstant (((IntegralConstant) Child).Increment (), type);
1726                 }
1727
1728                 public override bool IsDefaultValue {
1729                         get {
1730                                 return Child.IsDefaultValue;
1731                         }
1732                 }
1733
1734                 public override bool IsZeroInteger {
1735                         get { return Child.IsZeroInteger; }
1736                 }
1737
1738                 public override bool IsNegative {
1739                         get {
1740                                 return Child.IsNegative;
1741                         }
1742                 }
1743
1744                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1745                 {
1746                         if (Child.Type == target_type)
1747                                 return Child;
1748
1749                         return Child.ConvertExplicitly (in_checked_context, target_type);
1750                 }
1751
1752                 public override Constant ConvertImplicitly (ResolveContext rc, Type type)
1753                 {
1754                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1755                         type = TypeManager.DropGenericTypeArguments (type);
1756
1757                         if (this_type == type) {
1758                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1759                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1760                                         return this;
1761
1762                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1763                                 if (type.UnderlyingSystemType != child_type)
1764                                         Child = Child.ConvertImplicitly (rc, type.UnderlyingSystemType);
1765                                 return this;
1766                         }
1767
1768                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1769                                 return null;
1770                         }
1771
1772                         return Child.ConvertImplicitly (rc, type);
1773                 }
1774         }
1775
1776         /// <summary>
1777         ///   This kind of cast is used to encapsulate Value Types in objects.
1778         ///
1779         ///   The effect of it is to box the value type emitted by the previous
1780         ///   operation.
1781         /// </summary>
1782         public class BoxedCast : TypeCast {
1783
1784                 public BoxedCast (Expression expr, Type target_type)
1785                         : base (expr, target_type)
1786                 {
1787                         eclass = ExprClass.Value;
1788                 }
1789
1790                 protected override Expression DoResolve (ResolveContext ec)
1791                 {
1792                         // This should never be invoked, we are born in fully
1793                         // initialized state.
1794
1795                         return this;
1796                 }
1797
1798                 public override void EncodeAttributeValue (IMemberContext rc, AttributeEncoder enc, Type targetType)
1799                 {
1800                         enc.Encode (child.Type);
1801                         child.EncodeAttributeValue (rc, enc, child.Type);
1802                 }
1803
1804                 public override void Emit (EmitContext ec)
1805                 {
1806                         base.Emit (ec);
1807
1808                         ec.ig.Emit (OpCodes.Box, child.Type);
1809                 }
1810
1811                 public override void EmitSideEffect (EmitContext ec)
1812                 {
1813                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1814                         // so, we need to emit the box+pop instructions in most cases
1815                         if (TypeManager.IsStruct (child.Type) &&
1816                             (type == TypeManager.object_type || type == TypeManager.value_type))
1817                                 child.EmitSideEffect (ec);
1818                         else
1819                                 base.EmitSideEffect (ec);
1820                 }
1821         }
1822
1823         public class UnboxCast : TypeCast {
1824                 public UnboxCast (Expression expr, Type return_type)
1825                         : base (expr, return_type)
1826                 {
1827                 }
1828
1829                 protected override Expression DoResolve (ResolveContext ec)
1830                 {
1831                         // This should never be invoked, we are born in fully
1832                         // initialized state.
1833
1834                         return this;
1835                 }
1836
1837                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1838                 {
1839                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1840                                 ec.Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1841                         return base.DoResolveLValue (ec, right_side);
1842                 }
1843
1844                 public override void Emit (EmitContext ec)
1845                 {
1846                         base.Emit (ec);
1847
1848                         ILGenerator ig = ec.ig;
1849                         ig.Emit (OpCodes.Unbox_Any, type);
1850                 }
1851
1852                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1853                 {
1854                         type = storey.MutateType (type);
1855                         base.MutateHoistedGenericType (storey);
1856                 }
1857         }
1858
1859         /// <summary>
1860         ///   This is used to perform explicit numeric conversions.
1861         ///
1862         ///   Explicit numeric conversions might trigger exceptions in a checked
1863         ///   context, so they should generate the conv.ovf opcodes instead of
1864         ///   conv opcodes.
1865         /// </summary>
1866         public class ConvCast : TypeCast {
1867                 public enum Mode : byte {
1868                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1869                         U1_I1, U1_CH,
1870                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1871                         U2_I1, U2_U1, U2_I2, U2_CH,
1872                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1873                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1874                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH, I8_I,
1875                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH, U8_I,
1876                         CH_I1, CH_U1, CH_I2,
1877                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1878                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4,
1879                         I_I8,
1880                 }
1881
1882                 Mode mode;
1883
1884                 public ConvCast (Expression child, Type return_type, Mode m)
1885                         : base (child, return_type)
1886                 {
1887                         mode = m;
1888                 }
1889
1890                 protected override Expression DoResolve (ResolveContext ec)
1891                 {
1892                         // This should never be invoked, we are born in fully
1893                         // initialized state.
1894
1895                         return this;
1896                 }
1897
1898                 public override string ToString ()
1899                 {
1900                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1901                 }
1902
1903                 public override void Emit (EmitContext ec)
1904                 {
1905                         ILGenerator ig = ec.ig;
1906
1907                         base.Emit (ec);
1908
1909                         if (ec.HasSet (EmitContext.Options.CheckedScope)) {
1910                                 switch (mode){
1911                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1912                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1913                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1914                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1915                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1916
1917                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1918                                 case Mode.U1_CH: /* nothing */ break;
1919
1920                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1921                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1922                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1923                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1924                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1925                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1926
1927                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1928                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1929                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1930                                 case Mode.U2_CH: /* nothing */ break;
1931
1932                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1933                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1934                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1935                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1936                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1937                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1938                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1939
1940                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1941                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1942                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1943                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1944                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1945                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1946
1947                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1948                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1949                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1950                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1951                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1952                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1953                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1954                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1955                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_Ovf_U); break;
1956
1957                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1958                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1959                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1960                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1961                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1962                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1963                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1964                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1965                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_Ovf_U_Un); break;
1966
1967                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1968                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1969                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1970
1971                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1972                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1973                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1974                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1975                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1976                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1977                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1978                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1979                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1980
1981                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1982                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1983                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1984                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1985                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1986                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1987                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1988                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1989                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1990                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1991
1992                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1993                                 }
1994                         } else {
1995                                 switch (mode){
1996                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1997                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1998                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1999                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
2000                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
2001
2002                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
2003                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
2004
2005                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2006                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2007                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2008                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2009                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2010                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2011
2012                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2013                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2014                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2015                                 case Mode.U2_CH: /* nothing */ break;
2016
2017                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2018                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2019                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2020                                 case Mode.I4_U4: /* nothing */ break;
2021                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2022                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2023                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2024
2025                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2026                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2027                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2028                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2029                                 case Mode.U4_I4: /* nothing */ break;
2030                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2031
2032                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2033                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2034                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2035                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2036                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2037                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2038                                 case Mode.I8_U8: /* nothing */ break;
2039                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2040                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_U); break;
2041
2042                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2043                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2044                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2045                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2046                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2047                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2048                                 case Mode.U8_I8: /* nothing */ break;
2049                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2050                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_U); break;
2051
2052                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2053                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2054                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2055
2056                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2057                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2058                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2059                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2060                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2061                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2062                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2063                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2064                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2065
2066                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2067                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2068                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2069                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2070                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2071                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2072                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2073                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2074                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2075                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2076
2077                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_U8); break;
2078                                 }
2079                         }
2080                 }
2081         }
2082
2083         public class OpcodeCast : TypeCast {
2084                 readonly OpCode op;
2085
2086                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2087                         : base (child, return_type)
2088                 {
2089                         this.op = op;
2090                 }
2091
2092                 protected override Expression DoResolve (ResolveContext ec)
2093                 {
2094                         // This should never be invoked, we are born in fully
2095                         // initialized state.
2096
2097                         return this;
2098                 }
2099
2100                 public override void Emit (EmitContext ec)
2101                 {
2102                         base.Emit (ec);
2103                         ec.ig.Emit (op);
2104                 }
2105
2106                 public Type UnderlyingType {
2107                         get { return child.Type; }
2108                 }
2109         }
2110
2111         /// <summary>
2112         ///   This kind of cast is used to encapsulate a child and cast it
2113         ///   to the class requested
2114         /// </summary>
2115         public sealed class ClassCast : TypeCast {
2116                 readonly bool forced;
2117
2118                 public ClassCast (Expression child, Type return_type)
2119                         : base (child, return_type)
2120                 {
2121                 }
2122
2123                 public ClassCast (Expression child, Type return_type, bool forced)
2124                         : base (child, return_type)
2125                 {
2126                         this.forced = forced;
2127                 }
2128
2129                 public override void Emit (EmitContext ec)
2130                 {
2131                         base.Emit (ec);
2132
2133                         bool gen = TypeManager.IsGenericParameter (child.Type);
2134                         if (gen)
2135                                 ec.ig.Emit (OpCodes.Box, child.Type);
2136
2137                         if (type.IsGenericParameter) {
2138                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2139                                 return;
2140                         }
2141
2142                         if (gen && !forced)
2143                                 return;
2144
2145                         ec.ig.Emit (OpCodes.Castclass, type);
2146                 }
2147         }
2148
2149         //
2150         // Created during resolving pahse when an expression is wrapped or constantified
2151         // and original expression can be used later (e.g. for expression trees)
2152         //
2153         public class ReducedExpression : Expression
2154         {
2155                 sealed class ReducedConstantExpression : EmptyConstantCast
2156                 {
2157                         readonly Expression orig_expr;
2158
2159                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2160                                 : base (expr, expr.Type)
2161                         {
2162                                 this.orig_expr = orig_expr;
2163                         }
2164
2165                         public override Constant ConvertImplicitly (ResolveContext rc, Type target_type)
2166                         {
2167                                 Constant c = base.ConvertImplicitly (rc, target_type);
2168                                 if (c != null)
2169                                         c = new ReducedConstantExpression (c, orig_expr);
2170
2171                                 return c;
2172                         }
2173
2174                         public override Expression CreateExpressionTree (ResolveContext ec)
2175                         {
2176                                 return orig_expr.CreateExpressionTree (ec);
2177                         }
2178
2179                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2180                         {
2181                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2182                                 if (c != null)
2183                                         c = new ReducedConstantExpression (c, orig_expr);
2184                                 return c;
2185                         }
2186                 }
2187
2188                 sealed class ReducedExpressionStatement : ExpressionStatement
2189                 {
2190                         readonly Expression orig_expr;
2191                         readonly ExpressionStatement stm;
2192
2193                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2194                         {
2195                                 this.orig_expr = orig;
2196                                 this.stm = stm;
2197                                 this.loc = orig.Location;
2198                         }
2199
2200                         public override Expression CreateExpressionTree (ResolveContext ec)
2201                         {
2202                                 return orig_expr.CreateExpressionTree (ec);
2203                         }
2204
2205                         protected override Expression DoResolve (ResolveContext ec)
2206                         {
2207                                 eclass = stm.eclass;
2208                                 type = stm.Type;
2209                                 return this;
2210                         }
2211
2212                         public override void Emit (EmitContext ec)
2213                         {
2214                                 stm.Emit (ec);
2215                         }
2216
2217                         public override void EmitStatement (EmitContext ec)
2218                         {
2219                                 stm.EmitStatement (ec);
2220                         }
2221
2222                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2223                         {
2224                                 stm.MutateHoistedGenericType (storey);
2225                         }
2226                 }
2227
2228                 readonly Expression expr, orig_expr;
2229
2230                 private ReducedExpression (Expression expr, Expression orig_expr)
2231                 {
2232                         this.expr = expr;
2233                         this.eclass = expr.eclass;
2234                         this.type = expr.Type;
2235                         this.orig_expr = orig_expr;
2236                         this.loc = orig_expr.Location;
2237                 }
2238
2239                 //
2240                 // Creates fully resolved expression switcher
2241                 //
2242                 public static Constant Create (Constant expr, Expression original_expr)
2243                 {
2244                         if (expr.eclass == ExprClass.Unresolved)
2245                                 throw new ArgumentException ("Unresolved expression");
2246
2247                         return new ReducedConstantExpression (expr, original_expr);
2248                 }
2249
2250                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2251                 {
2252                         return new ReducedExpressionStatement (s, orig);
2253                 }
2254
2255                 //
2256                 // Creates unresolved reduce expression. The original expression has to be
2257                 // already resolved
2258                 //
2259                 public static Expression Create (Expression expr, Expression original_expr)
2260                 {
2261                         Constant c = expr as Constant;
2262                         if (c != null)
2263                                 return Create (c, original_expr);
2264
2265                         ExpressionStatement s = expr as ExpressionStatement;
2266                         if (s != null)
2267                                 return Create (s, original_expr);
2268
2269                         if (expr.eclass == ExprClass.Unresolved)
2270                                 throw new ArgumentException ("Unresolved expression");
2271
2272                         return new ReducedExpression (expr, original_expr);
2273                 }
2274
2275                 public override Expression CreateExpressionTree (ResolveContext ec)
2276                 {
2277                         return orig_expr.CreateExpressionTree (ec);
2278                 }
2279
2280                 protected override Expression DoResolve (ResolveContext ec)
2281                 {
2282                         return this;
2283                 }
2284
2285                 public override void Emit (EmitContext ec)
2286                 {
2287                         expr.Emit (ec);
2288                 }
2289
2290                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2291                 {
2292                         expr.EmitBranchable (ec, target, on_true);
2293                 }
2294
2295                 public override SLE.Expression MakeExpression (BuilderContext ctx)
2296                 {
2297                         return orig_expr.MakeExpression (ctx);
2298                 }
2299
2300                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2301                 {
2302                         expr.MutateHoistedGenericType (storey);
2303                 }
2304         }
2305
2306         //
2307         // Standard composite pattern
2308         //
2309         public abstract class CompositeExpression : Expression
2310         {
2311                 Expression expr;
2312
2313                 protected CompositeExpression (Expression expr)
2314                 {
2315                         this.expr = expr;
2316                         this.loc = expr.Location;
2317                 }
2318
2319                 public override Expression CreateExpressionTree (ResolveContext ec)
2320                 {
2321                         return expr.CreateExpressionTree (ec);
2322                 }
2323
2324                 public Expression Child {
2325                         get { return expr; }
2326                 }
2327
2328                 protected override Expression DoResolve (ResolveContext ec)
2329                 {
2330                         expr = expr.Resolve (ec);
2331                         if (expr != null) {
2332                                 type = expr.Type;
2333                                 eclass = expr.eclass;
2334                         }
2335
2336                         return this;
2337                 }
2338
2339                 public override void Emit (EmitContext ec)
2340                 {
2341                         expr.Emit (ec);
2342                 }
2343
2344                 public override bool IsNull {
2345                         get { return expr.IsNull; }
2346                 }
2347         }
2348
2349         //
2350         // Base of expressions used only to narrow resolve flow
2351         //
2352         public abstract class ShimExpression : Expression
2353         {
2354                 protected Expression expr;
2355
2356                 protected ShimExpression (Expression expr)
2357                 {
2358                         this.expr = expr;
2359                 }
2360
2361                 protected override void CloneTo (CloneContext clonectx, Expression t)
2362                 {
2363                         if (expr == null)
2364                                 return;
2365
2366                         ShimExpression target = (ShimExpression) t;
2367                         target.expr = expr.Clone (clonectx);
2368                 }
2369
2370                 public override Expression CreateExpressionTree (ResolveContext ec)
2371                 {
2372                         throw new NotSupportedException ("ET");
2373                 }
2374
2375                 public override void Emit (EmitContext ec)
2376                 {
2377                         throw new InternalErrorException ("Missing Resolve call");
2378                 }
2379
2380                 public Expression Expr {
2381                         get { return expr; }
2382                 }
2383
2384                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2385                 {
2386                         throw new InternalErrorException ("Missing Resolve call");
2387                 }
2388         }
2389
2390         //
2391         // Unresolved type name expressions
2392         //
2393         public abstract class ATypeNameExpression : FullNamedExpression
2394         {
2395                 string name;
2396                 protected TypeArguments targs;
2397
2398                 protected ATypeNameExpression (string name, Location l)
2399                 {
2400                         this.name = name;
2401                         loc = l;
2402                 }
2403
2404                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2405                 {
2406                         this.name = name;
2407                         this.targs = targs;
2408                         loc = l;
2409                 }
2410
2411                 public bool HasTypeArguments {
2412                         get {
2413                                 return targs != null;
2414                         }
2415                 }
2416
2417                 public override bool Equals (object obj)
2418                 {
2419                         ATypeNameExpression atne = obj as ATypeNameExpression;
2420                         return atne != null && atne.Name == Name &&
2421                                 (targs == null || targs.Equals (atne.targs));
2422                 }
2423
2424                 public override int GetHashCode ()
2425                 {
2426                         return Name.GetHashCode ();
2427                 }
2428
2429                 public override string GetSignatureForError ()
2430                 {
2431                         if (targs != null) {
2432                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2433                                         targs.GetSignatureForError () + ">";
2434                         }
2435
2436                         return Name;
2437                 }
2438
2439                 public string Name {
2440                         get {
2441                                 return name;
2442                         }
2443                         set {
2444                                 name = value;
2445                         }
2446                 }
2447
2448                 public TypeArguments TypeArguments {
2449                         get {
2450                                 return targs;
2451                         }
2452                 }
2453         }
2454
2455         /// <summary>
2456         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2457         ///   of a dotted-name.
2458         /// </summary>
2459         public class SimpleName : ATypeNameExpression
2460         {
2461                 public SimpleName (string name, Location l)
2462                         : base (name, l)
2463                 {
2464                 }
2465
2466                 public SimpleName (string name, TypeArguments args, Location l)
2467                         : base (name, args, l)
2468                 {
2469                 }
2470
2471                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2472                         : base (name, l)
2473                 {
2474                         targs = new TypeArguments ();
2475                         foreach (TypeParameter type_param in type_params)
2476                                 targs.Add (new TypeParameterExpr (type_param, l));
2477                 }
2478
2479                 public static string RemoveGenericArity (string name)
2480                 {
2481                         int start = 0;
2482                         StringBuilder sb = null;
2483                         do {
2484                                 int pos = name.IndexOf ('`', start);
2485                                 if (pos < 0) {
2486                                         if (start == 0)
2487                                                 return name;
2488
2489                                         sb.Append (name.Substring (start));
2490                                         break;
2491                                 }
2492
2493                                 if (sb == null)
2494                                         sb = new StringBuilder ();
2495                                 sb.Append (name.Substring (start, pos-start));
2496
2497                                 pos++;
2498                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2499                                         pos++;
2500
2501                                 start = pos;
2502                         } while (start < name.Length);
2503
2504                         return sb.ToString ();
2505                 }
2506
2507                 public SimpleName GetMethodGroup ()
2508                 {
2509                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2510                 }
2511
2512                 public static void Error_ObjectRefRequired (ResolveContext ec, Location l, string name)
2513                 {
2514                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
2515                                 ec.Report.Error (236, l,
2516                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2517                                         name);
2518                         else
2519                                 ec.Report.Error (120, l,
2520                                         "An object reference is required to access non-static member `{0}'",
2521                                         name);
2522                 }
2523
2524                 public bool IdenticalNameAndTypeName (IMemberContext mc, Expression resolved_to, Location loc)
2525                 {
2526                         return resolved_to != null && resolved_to.Type != null &&
2527                                 resolved_to.Type.Name == Name &&
2528                                 (mc.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2529                 }
2530
2531                 protected override Expression DoResolve (ResolveContext ec)
2532                 {
2533                         return SimpleNameResolve (ec, null, false);
2534                 }
2535
2536                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
2537                 {
2538                         return SimpleNameResolve (ec, right_side, false);
2539                 }
2540
2541                 public Expression DoResolve (ResolveContext ec, bool intermediate)
2542                 {
2543                         return SimpleNameResolve (ec, null, intermediate);
2544                 }
2545
2546                 static bool IsNestedChild (Type t, Type parent)
2547                 {
2548                         while (parent != null) {
2549                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2550                                         return true;
2551
2552                                 parent = parent.BaseType;
2553                         }
2554
2555                         return false;
2556                 }
2557
2558                 FullNamedExpression ResolveNested (Type t)
2559                 {
2560                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2561                                 return null;
2562
2563                         Type ds = t;
2564                         while (ds != null && !IsNestedChild (t, ds))
2565                                 ds = ds.DeclaringType;
2566
2567                         if (ds == null)
2568                                 return null;
2569
2570                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2571
2572                         int arg_count = targs != null ? targs.Count : 0;
2573
2574                         for (; (ds != null) && TypeManager.IsGenericType (ds); ds = ds.DeclaringType) {
2575                                 Type[] gargs = TypeManager.GetTypeArguments (ds);
2576                                 if (arg_count + gargs.Length == gen_params.Length) {
2577                                         TypeArguments new_args = new TypeArguments ();
2578                                         foreach (Type param in gargs)
2579                                                 new_args.Add (new TypeExpression (param, loc));
2580
2581                                         if (targs != null)
2582                                                 new_args.Add (targs);
2583
2584                                         return new GenericTypeExpr (t, new_args, loc);
2585                                 }
2586                         }
2587
2588                         return null;
2589                 }
2590
2591                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2592                 {
2593                         int errors = ec.Compiler.Report.Errors;
2594                         FullNamedExpression fne = ec.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2595
2596                         if (fne != null) {
2597                                 if (fne.Type == null)
2598                                         return fne;
2599
2600                                 FullNamedExpression nested = ResolveNested (fne.Type);
2601                                 if (nested != null)
2602                                         return nested.ResolveAsTypeStep (ec, false);
2603
2604                                 if (targs != null) {
2605                                         if (TypeManager.IsGenericType (fne.Type)) {
2606                                                 GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2607                                                 return ct.ResolveAsTypeStep (ec, false);
2608                                         }
2609
2610                                         fne.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2611                                 }
2612
2613                                 return fne;
2614                         }
2615
2616                         if (!HasTypeArguments && Name == "dynamic" &&
2617                                 RootContext.Version > LanguageVersion.V_3 &&
2618                                 RootContext.MetadataCompatibilityVersion > MetadataVersion.v2) {
2619
2620                                 if (!PredefinedAttributes.Get.Dynamic.IsDefined) {
2621                                         ec.Compiler.Report.Error (1980, Location,
2622                                                 "Dynamic keyword requires `{0}' to be defined. Are you missing System.Core.dll assembly reference?",
2623                                                 PredefinedAttributes.Get.Dynamic.GetSignatureForError ());
2624                                 }
2625
2626                                 return new DynamicTypeExpr (loc);
2627                         }
2628
2629                         if (silent || errors != ec.Compiler.Report.Errors)
2630                                 return null;
2631
2632                         Error_TypeOrNamespaceNotFound (ec);
2633                         return null;
2634                 }
2635
2636                 protected virtual void Error_TypeOrNamespaceNotFound (IMemberContext ec)
2637                 {
2638                         if (ec.CurrentType != null) {
2639                                 if (ec.CurrentTypeDefinition != null) {
2640                                         MemberCore mc = ec.CurrentTypeDefinition.GetDefinition (Name);
2641                                         if (mc != null) {
2642                                                 Error_UnexpectedKind (ec.Compiler.Report, mc, "type", GetMemberType (mc), loc);
2643                                                 return;
2644                                         }
2645                                 }
2646
2647                                 string ns = ec.CurrentType.Namespace;
2648                                 string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2649                                 foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
2650                                         Type type = a.GetType (fullname);
2651                                         if (type != null) {
2652                                                 ec.Compiler.Report.SymbolRelatedToPreviousError (type);
2653                                                 Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type), ec.Compiler.Report);
2654                                                 return;
2655                                         }
2656                                 }
2657
2658                                 if (ec.CurrentTypeDefinition != null) {
2659                                         Type t = ec.CurrentTypeDefinition.LookupAnyGeneric (Name);
2660                                         if (t != null) {
2661                                                 Namespace.Error_InvalidNumberOfTypeArguments (ec.Compiler.Report, t, loc);
2662                                                 return;
2663                                         }
2664                                 }
2665                         }
2666
2667                         if (targs != null) {
2668                                 FullNamedExpression retval = ec.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2669                                 if (retval != null) {
2670                                         retval.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2671                                         return;
2672                                 }
2673                         }
2674
2675                         NamespaceEntry.Error_NamespaceNotFound (loc, Name, ec.Compiler.Report);
2676                 }
2677
2678                 // TODO: I am still not convinced about this. If someone else will need it
2679                 // implement this as virtual property in MemberCore hierarchy
2680                 public static string GetMemberType (MemberCore mc)
2681                 {
2682                         if (mc is Property)
2683                                 return "property";
2684                         if (mc is Indexer)
2685                                 return "indexer";
2686                         if (mc is FieldBase)
2687                                 return "field";
2688                         if (mc is MethodCore)
2689                                 return "method";
2690                         if (mc is EnumMember)
2691                                 return "enum";
2692                         if (mc is Event)
2693                                 return "event";
2694
2695                         return "type";
2696                 }
2697
2698                 Expression SimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2699                 {
2700                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2701
2702                         if (e == null)
2703                                 return null;
2704
2705                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2706                                 return e;
2707
2708                         return null;
2709                 }
2710
2711                 /// <remarks>
2712                 ///   7.5.2: Simple Names.
2713                 ///
2714                 ///   Local Variables and Parameters are handled at
2715                 ///   parse time, so they never occur as SimpleNames.
2716                 ///
2717                 ///   The `intermediate' flag is used by MemberAccess only
2718                 ///   and it is used to inform us that it is ok for us to
2719                 ///   avoid the static check, because MemberAccess might end
2720                 ///   up resolving the Name as a Type name and the access as
2721                 ///   a static type access.
2722                 ///
2723                 ///   ie: Type Type; .... { Type.GetType (""); }
2724                 ///
2725                 ///   Type is both an instance variable and a Type;  Type.GetType
2726                 ///   is the static method not an instance method of type.
2727                 /// </remarks>
2728                 Expression DoSimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2729                 {
2730                         Expression e = null;
2731
2732                         //
2733                         // Stage 1: Performed by the parser (binding to locals or parameters).
2734                         //
2735                         Block current_block = ec.CurrentBlock;
2736                         if (current_block != null){
2737                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2738                                 if (vi != null){
2739                                         e = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2740
2741                                         if (right_side != null) {
2742                                                 e = e.ResolveLValue (ec, right_side);
2743                                         } else {
2744                                                 if (intermediate) {
2745                                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
2746                                                                 e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2747                                                         }
2748                                                 } else {
2749                                                         e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2750                                                 }
2751                                         }
2752
2753                                         if (targs != null && e != null)
2754                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2755
2756                                         return e;
2757                                 }
2758
2759                                 e = current_block.Toplevel.GetParameterReference (Name, loc);
2760                                 if (e != null) {
2761                                         if (right_side != null)
2762                                                 e = e.ResolveLValue (ec, right_side);
2763                                         else
2764                                                 e = e.Resolve (ec);
2765
2766                                         if (targs != null && e != null)
2767                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2768
2769                                         return e;
2770                                 }
2771                         }
2772
2773                         //
2774                         // Stage 2: Lookup members
2775                         //
2776
2777                         Type almost_matched_type = null;
2778                         IList<MemberInfo> almost_matched = null;
2779                         for (Type lookup_ds = ec.CurrentType; lookup_ds != null; lookup_ds = lookup_ds.DeclaringType) {
2780                                 e = MemberLookup (ec.Compiler, ec.CurrentType, lookup_ds, Name, loc);
2781                                 if (e != null) {
2782                                         PropertyExpr pe = e as PropertyExpr;
2783                                         if (pe != null) {
2784                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2785
2786                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2787                                                 // it doesn't know which accessor to check permissions against
2788                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.CurrentType, right_side != null))
2789                                                         break;
2790                                         } else if (e is EventExpr) {
2791                                                 if (((EventExpr) e).IsAccessibleFrom (ec.CurrentType))
2792                                                         break;
2793                                         } else if (targs != null && e is TypeExpression) {
2794                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2795                                                 break;
2796                                         } else {
2797                                                 break;
2798                                         }
2799                                         e = null;
2800                                 }
2801
2802                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2803                                         almost_matched_type = lookup_ds;
2804                                         almost_matched = new List<MemberInfo>(almost_matched_members);
2805                                 }
2806                         }
2807
2808                         if (e == null) {
2809                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2810                                         almost_matched_type = ec.CurrentType;
2811                                         almost_matched = new List<MemberInfo> (almost_matched_members);
2812                                 }
2813                                 e = ResolveAsTypeStep (ec, true);
2814                         }
2815
2816                         if (e == null) {
2817                                 if (current_block != null) {
2818                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2819                                         if (ikv != null) {
2820                                                 LocalInfo li = ikv as LocalInfo;
2821                                                 // Supress CS0219 warning
2822                                                 if (li != null)
2823                                                         li.Used = true;
2824
2825                                                 Error_VariableIsUsedBeforeItIsDeclared (ec.Report, Name);
2826                                                 return null;
2827                                         }
2828                                 }
2829
2830                                 if (RootContext.EvalMode){
2831                                         FieldInfo fi = Evaluator.LookupField (Name);
2832                                         if (fi != null)
2833                                                 return new FieldExpr (Import.CreateField (fi), loc).Resolve (ec);
2834                                 }
2835
2836                                 if (almost_matched != null)
2837                                         almost_matched_members = almost_matched;
2838                                 if (almost_matched_type == null)
2839                                         almost_matched_type = ec.CurrentType;
2840
2841                                 string type_name = ec.MemberContext.CurrentType == null ? null : ec.MemberContext.CurrentType.Name;
2842                                 return Error_MemberLookupFailed (ec, ec.CurrentType, null, almost_matched_type, Name,
2843                                         type_name, AllMemberTypes, AllBindingFlags);
2844                         }
2845
2846                         if (e is MemberExpr) {
2847                                 MemberExpr me = (MemberExpr) e;
2848
2849                                 Expression left;
2850                                 if (me.IsInstance) {
2851                                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope)) {
2852                                                 //
2853                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2854                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2855                                                 // and each predicate is true if the MethodGroupExpr contains
2856                                                 // at least one of that kind of method.
2857                                                 //
2858
2859                                                 if (!me.IsStatic &&
2860                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2861                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2862                                                         return null;
2863                                                 }
2864
2865                                                 //
2866                                                 // Pass the buck to MemberAccess and Invocation.
2867                                                 //
2868                                                 left = EmptyExpression.Null;
2869                                         } else {
2870                                                 left = ec.GetThis (loc);
2871                                         }
2872                                 } else {
2873                                         left = new TypeExpression (ec.CurrentType, loc);
2874                                 }
2875
2876                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2877                                 if (me == null)
2878                                         return null;
2879
2880                                 if (targs != null) {
2881                                         if (!targs.Resolve (ec))
2882                                                 return null;
2883
2884                                         me.SetTypeArguments (ec, targs);
2885                                 }
2886
2887                                 if (!me.IsStatic && (me.InstanceExpression != null && me.InstanceExpression != EmptyExpression.Null) &&
2888                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2889                                     me.InstanceExpression.Type != me.DeclaringType &&
2890                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2891                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2892                                         ec.Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2893                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2894                                         return null;
2895                                 }
2896
2897                                 return (right_side != null)
2898                                         ? me.DoResolveLValue (ec, right_side)
2899                                         : me.Resolve (ec);
2900                         }
2901
2902                         return e;
2903                 }
2904         }
2905
2906         /// <summary>
2907         ///   Represents a namespace or a type.  The name of the class was inspired by
2908         ///   section 10.8.1 (Fully Qualified Names).
2909         /// </summary>
2910         public abstract class FullNamedExpression : Expression
2911         {
2912                 protected override void CloneTo (CloneContext clonectx, Expression target)
2913                 {
2914                         // Do nothing, most unresolved type expressions cannot be
2915                         // resolved to different type
2916                 }
2917
2918                 public override Expression CreateExpressionTree (ResolveContext ec)
2919                 {
2920                         throw new NotSupportedException ("ET");
2921                 }
2922
2923                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2924                 {
2925                         throw new NotSupportedException ();
2926                 }
2927
2928                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2929                 {
2930                         return this;
2931                 }
2932
2933                 public override void Emit (EmitContext ec)
2934                 {
2935                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2936                                 GetSignatureForError ());
2937                 }
2938         }
2939
2940         /// <summary>
2941         ///   Expression that evaluates to a type
2942         /// </summary>
2943         public abstract class TypeExpr : FullNamedExpression {
2944                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2945                 {
2946                         TypeExpr t = DoResolveAsTypeStep (ec);
2947                         if (t == null)
2948                                 return null;
2949
2950                         eclass = ExprClass.Type;
2951                         return t;
2952                 }
2953
2954                 protected override Expression DoResolve (ResolveContext ec)
2955                 {
2956                         return ResolveAsTypeTerminal (ec, false);
2957                 }
2958
2959                 public virtual bool CheckAccessLevel (IMemberContext mc)
2960                 {
2961                         return mc.CurrentTypeDefinition.CheckAccessLevel (Type);
2962                 }
2963
2964                 public virtual bool IsClass {
2965                         get { return Type.IsClass; }
2966                 }
2967
2968                 public virtual bool IsValueType {
2969                         get { return TypeManager.IsStruct (Type); }
2970                 }
2971
2972                 public virtual bool IsInterface {
2973                         get { return Type.IsInterface; }
2974                 }
2975
2976                 public virtual bool IsSealed {
2977                         get { return Type.IsSealed; }
2978                 }
2979
2980                 public virtual bool CanInheritFrom ()
2981                 {
2982                         if (Type == TypeManager.enum_type ||
2983                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2984                             Type == TypeManager.multicast_delegate_type ||
2985                             Type == TypeManager.delegate_type ||
2986                             Type == TypeManager.array_type)
2987                                 return false;
2988
2989                         return true;
2990                 }
2991
2992                 protected abstract TypeExpr DoResolveAsTypeStep (IMemberContext ec);
2993
2994                 public override bool Equals (object obj)
2995                 {
2996                         TypeExpr tobj = obj as TypeExpr;
2997                         if (tobj == null)
2998                                 return false;
2999
3000                         return Type == tobj.Type;
3001                 }
3002
3003                 public override int GetHashCode ()
3004                 {
3005                         return Type.GetHashCode ();
3006                 }
3007
3008                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3009                 {
3010                         type = storey.MutateType (type);
3011                 }
3012         }
3013
3014         /// <summary>
3015         ///   Fully resolved Expression that already evaluated to a type
3016         /// </summary>
3017         public class TypeExpression : TypeExpr {
3018                 public TypeExpression (Type t, Location l)
3019                 {
3020                         Type = t;
3021                         eclass = ExprClass.Type;
3022                         loc = l;
3023                 }
3024
3025                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3026                 {
3027                         return this;
3028                 }
3029
3030                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3031                 {
3032                         return this;
3033                 }
3034         }
3035
3036         //
3037         // Used to create types from a fully qualified name.  These are just used
3038         // by the parser to setup the core types.
3039         //
3040         public sealed class TypeLookupExpression : TypeExpr {
3041                 readonly string ns_name;
3042                 readonly string name;
3043
3044                 public TypeLookupExpression (string ns, string name)
3045                 {
3046                         this.name = name;
3047                         this.ns_name = ns;
3048                         eclass = ExprClass.Type;
3049                 }
3050
3051                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3052                 {
3053                         //
3054                         // It's null only during mscorlib bootstrap when DefineType
3055                         // nees to resolve base type of same type
3056                         //
3057                         // For instance struct Char : IComparable<char>
3058                         //
3059                         // TODO: it could be removed when Resolve starts to use
3060                         // DeclSpace instead of Type
3061                         //
3062                         if (type == null) {
3063                                 Namespace ns = GlobalRootNamespace.Instance.GetNamespace (ns_name, false);
3064                                 FullNamedExpression fne = ns.Lookup (ec.Compiler, name, loc);
3065                                 if (fne != null)
3066                                         type = fne.Type;
3067                         }
3068
3069                         return this;
3070                 }
3071
3072                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3073                 {
3074                         return this;
3075                 }
3076
3077                 public override string GetSignatureForError ()
3078                 {
3079                         if (type == null)
3080                                 return TypeManager.CSharpName (ns_name + "." + name, null);
3081
3082                         return base.GetSignatureForError ();
3083                 }
3084         }
3085
3086         /// <summary>
3087         ///   This class denotes an expression which evaluates to a member
3088         ///   of a struct or a class.
3089         /// </summary>
3090         public abstract class MemberExpr : Expression
3091         {
3092                 protected bool is_base;
3093
3094                 /// <summary>
3095                 ///   The name of this member.
3096                 /// </summary>
3097                 public abstract string Name {
3098                         get;
3099                 }
3100
3101                 //
3102                 // When base.member is used
3103                 //
3104                 public bool IsBase {
3105                         get { return is_base; }
3106                         set { is_base = value; }
3107                 }
3108
3109                 /// <summary>
3110                 ///   Whether this is an instance member.
3111                 /// </summary>
3112                 public abstract bool IsInstance {
3113                         get;
3114                 }
3115
3116                 /// <summary>
3117                 ///   Whether this is a static member.
3118                 /// </summary>
3119                 public abstract bool IsStatic {
3120                         get;
3121                 }
3122
3123                 /// <summary>
3124                 ///   The type which declares this member.
3125                 /// </summary>
3126                 public abstract Type DeclaringType {
3127                         get;
3128                 }
3129
3130                 /// <summary>
3131                 ///   The instance expression associated with this member, if it's a
3132                 ///   non-static member.
3133                 /// </summary>
3134                 public Expression InstanceExpression;
3135
3136                 public static void error176 (ResolveContext ec, Location loc, string name)
3137                 {
3138                         ec.Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3139                                       "with an instance reference, qualify it with a type name instead", name);
3140                 }
3141
3142                 public static void Error_BaseAccessInExpressionTree (ResolveContext ec, Location loc)
3143                 {
3144                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
3145                 }
3146
3147                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3148                 {
3149                         if (InstanceExpression != null)
3150                                 InstanceExpression.MutateHoistedGenericType (storey);
3151                 }
3152
3153                 // TODO: possible optimalization
3154                 // Cache resolved constant result in FieldBuilder <-> expression map
3155                 public virtual MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3156                                                                SimpleName original)
3157                 {
3158                         //
3159                         // Precondition:
3160                         //   original == null || original.Resolve (...) ==> left
3161                         //
3162
3163                         if (left is TypeExpr) {
3164                                 left = left.ResolveAsBaseTerminal (ec, false);
3165                                 if (left == null)
3166                                         return null;
3167
3168                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3169                                 // always do all necessary checks
3170                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3171                                 if (oa != null && !ec.IsObsolete) {
3172                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc, ec.Report);
3173                                 }
3174
3175                                 GenericTypeExpr ct = left as GenericTypeExpr;
3176                                 if (ct != null && !ct.CheckConstraints (ec))
3177                                         return null;
3178                                 //
3179
3180                                 if (!IsStatic) {
3181                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3182                                         return null;
3183                                 }
3184
3185                                 return this;
3186                         }
3187
3188                         if (!IsInstance) {
3189                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3190                                         return this;
3191
3192                                 return ResolveExtensionMemberAccess (ec, left);
3193                         }
3194
3195                         InstanceExpression = left;
3196                         return this;
3197                 }
3198
3199                 protected virtual MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3200                 {
3201                         error176 (ec, loc, GetSignatureForError ());
3202                         return this;
3203                 }
3204
3205                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3206                 {
3207                         if (IsStatic)
3208                                 return;
3209
3210                         if (InstanceExpression == EmptyExpression.Null) {
3211                                 // FIXME: This should not be here at all
3212                                 SimpleName.Error_ObjectRefRequired (new ResolveContext (ec.MemberContext), loc, GetSignatureForError ());
3213                                 return;
3214                         }
3215
3216                         if (TypeManager.IsValueType (InstanceExpression.Type)) {
3217                                 if (InstanceExpression is IMemoryLocation) {
3218                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3219                                 } else {
3220                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3221                                         InstanceExpression.Emit (ec);
3222                                         t.Store (ec);
3223                                         t.AddressOf (ec, AddressOp.Store);
3224                                 }
3225                         } else
3226                                 InstanceExpression.Emit (ec);
3227
3228                         if (prepare_for_load)
3229                                 ec.ig.Emit (OpCodes.Dup);
3230                 }
3231
3232                 public virtual void SetTypeArguments (ResolveContext ec, TypeArguments ta)
3233                 {
3234                         // TODO: need to get correct member type
3235                         ec.Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3236                                 GetSignatureForError ());
3237                 }
3238         }
3239
3240         ///
3241         /// Represents group of extension methods
3242         ///
3243         public class ExtensionMethodGroupExpr : MethodGroupExpr
3244         {
3245                 readonly NamespaceEntry namespace_entry;
3246                 public Expression ExtensionExpression;
3247                 Argument extension_argument;
3248
3249                 public ExtensionMethodGroupExpr (List<MethodSpec> list, NamespaceEntry n, Type extensionType, Location l)
3250                         : base (list, extensionType, l)
3251                 {
3252                         this.namespace_entry = n;
3253                 }
3254
3255                 public override bool IsStatic {
3256                         get { return true; }
3257                 }
3258
3259                 public bool IsTopLevel {
3260                         get { return namespace_entry == null; }
3261                 }
3262
3263                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3264                 {
3265                         extension_argument.Expr.MutateHoistedGenericType (storey);
3266                         base.MutateHoistedGenericType (storey);
3267                 }
3268
3269                 public override MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments arguments, bool may_fail, Location loc)
3270                 {
3271                         if (arguments == null)
3272                                 arguments = new Arguments (1);
3273
3274                         arguments.Insert (0, new Argument (ExtensionExpression));
3275                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, ref arguments, namespace_entry, loc);
3276
3277                         // Store resolved argument and restore original arguments
3278                         if (mg != null)
3279                                 ((ExtensionMethodGroupExpr)mg).extension_argument = arguments [0];
3280                         else
3281                                 arguments.RemoveAt (0); // Clean-up modified arguments for error reporting
3282
3283                         return mg;
3284                 }
3285
3286                 MethodGroupExpr ResolveOverloadExtensions (ResolveContext ec, ref Arguments arguments, NamespaceEntry ns, Location loc)
3287                 {
3288                         // Use normal resolve rules
3289                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3290                         if (mg != null)
3291                                 return mg;
3292
3293                         if (ns == null)
3294                                 return null;
3295
3296                         // Search continues
3297                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, Name, loc);
3298                         if (e == null)
3299                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3300
3301                         e.ExtensionExpression = ExtensionExpression;
3302                         e.SetTypeArguments (ec, type_arguments);
3303                         return e.ResolveOverloadExtensions (ec, ref arguments, e.namespace_entry, loc);
3304                 }
3305         }
3306
3307         /// <summary>
3308         ///   MethodGroupExpr represents a group of method candidates which
3309         ///   can be resolved to the best method overload
3310         /// </summary>
3311         public class MethodGroupExpr : MemberExpr
3312         {
3313                 public interface IErrorHandler
3314                 {
3315                         bool AmbiguousCall (ResolveContext ec, MethodSpec ambiguous);
3316                         bool NoExactMatch (ResolveContext ec, MethodSpec method);
3317                 }
3318
3319                 public IErrorHandler CustomErrorHandler;
3320                 public MethodSpec [] Methods;
3321                 MethodSpec best_candidate;
3322                 // TODO: make private
3323                 public TypeArguments type_arguments;
3324                 bool identical_type_name;
3325                 bool has_inaccessible_candidates_only;
3326                 Type delegate_type;
3327                 Type queried_type;
3328
3329                 public MethodGroupExpr (MethodSpec [] mi, Type type, Location l)
3330                         : this (type, l)
3331                 {
3332                         Methods = new MethodSpec[mi.Length];
3333                         mi.CopyTo (Methods, 0);
3334                 }
3335
3336                 public MethodGroupExpr (MethodSpec[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3337                         : this (mi, type, l)
3338                 {
3339                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3340                 }
3341
3342                 public MethodGroupExpr (List<MethodSpec> list, Type type, Location l)
3343                         : this (type, l)
3344                 {
3345                         try {
3346                                 Methods = list.ToArray ();
3347                         } catch {
3348                                 //foreach (MemberInfo m in list){
3349                                 //    if (!(m is MethodBase)){
3350                                 //        Console.WriteLine ("Name " + m.Name);
3351                                 //        Console.WriteLine ("Found a: " + m.GetType ().FullName);
3352                                 //    }
3353                                 //}
3354                                 throw;
3355                         }
3356
3357
3358                 }
3359
3360                 protected MethodGroupExpr (Type type, Location loc)
3361                 {
3362                         this.loc = loc;
3363                         eclass = ExprClass.MethodGroup;
3364                         this.type = InternalType.MethodGroup;
3365                         queried_type = type;
3366                 }
3367
3368                 public override Type DeclaringType {
3369                         get {
3370                                 return queried_type;
3371                         }
3372                 }
3373
3374                 public MethodSpec BestCandidate {
3375                         get {
3376                                 return best_candidate;
3377                         }
3378                 }
3379
3380                 public Type DelegateType {
3381                         set {
3382                                 delegate_type = value;
3383                         }
3384                 }
3385
3386                 public bool IdenticalTypeName {
3387                         get {
3388                                 return identical_type_name;
3389                         }
3390                 }
3391
3392                 public override string GetSignatureForError ()
3393                 {
3394                         if (best_candidate != null)
3395                                 return TypeManager.CSharpSignature (best_candidate.MetaInfo);
3396
3397                         return TypeManager.CSharpSignature (Methods [0].MetaInfo);
3398                 }
3399
3400                 public override string Name {
3401                         get {
3402                                 return Methods [0].Name;
3403                         }
3404                 }
3405
3406                 public override bool IsInstance {
3407                         get {
3408                                 if (best_candidate != null)
3409                                         return !best_candidate.IsStatic;
3410
3411                                 foreach (var mb in Methods)
3412                                         if (!mb.IsStatic)
3413                                                 return true;
3414
3415                                 return false;
3416                         }
3417                 }
3418
3419                 public override bool IsStatic {
3420                         get {
3421                                 if (best_candidate != null)
3422                                         return best_candidate.IsStatic;
3423
3424                                 foreach (var mb in Methods)
3425                                         if (mb.IsStatic)
3426                                                 return true;
3427
3428                                 return false;
3429                         }
3430                 }
3431
3432                 public static explicit operator MethodSpec (MethodGroupExpr mg)
3433                 {
3434                         return mg.best_candidate;
3435                 }
3436
3437                 //
3438                 //  7.4.3.3  Better conversion from expression
3439                 //  Returns :   1    if a->p is better,
3440                 //              2    if a->q is better,
3441                 //              0 if neither is better
3442                 //
3443                 static int BetterExpressionConversion (ResolveContext ec, Argument a, Type p, Type q)
3444                 {
3445                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3446                         if (argument_type == InternalType.AnonymousMethod && RootContext.Version > LanguageVersion.ISO_2) {
3447                                 //
3448                                 // Uwrap delegate from Expression<T>
3449                                 //
3450                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3451                                         p = TypeManager.GetTypeArguments (p) [0];
3452                                 }
3453                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3454                                         q = TypeManager.GetTypeArguments (q) [0];
3455                                 }
3456
3457                                 p = Delegate.GetInvokeMethod (ec.Compiler, null, p).ReturnType;
3458                                 q = Delegate.GetInvokeMethod (ec.Compiler, null, q).ReturnType;
3459                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3460                                         return 2;
3461                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3462                                         return 1;
3463                         } else {
3464                                 if (argument_type == p)
3465                                         return 1;
3466
3467                                 if (argument_type == q)
3468                                         return 2;
3469                         }
3470
3471                         return BetterTypeConversion (ec, p, q);
3472                 }
3473
3474                 //
3475                 // 7.4.3.4  Better conversion from type
3476                 //
3477                 public static int BetterTypeConversion (ResolveContext ec, Type p, Type q)
3478                 {
3479                         if (p == null || q == null)
3480                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3481
3482                         if (p == TypeManager.int32_type) {
3483                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3484                                         return 1;
3485                         } else if (p == TypeManager.int64_type) {
3486                                 if (q == TypeManager.uint64_type)
3487                                         return 1;
3488                         } else if (p == TypeManager.sbyte_type) {
3489                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3490                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3491                                         return 1;
3492                         } else if (p == TypeManager.short_type) {
3493                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3494                                         q == TypeManager.uint64_type)
3495                                         return 1;
3496                         } else if (p == InternalType.Dynamic) {
3497                                 if (q == TypeManager.object_type)
3498                                         return 2;
3499                         }
3500
3501                         if (q == TypeManager.int32_type) {
3502                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3503                                         return 2;
3504                         } if (q == TypeManager.int64_type) {
3505                                 if (p == TypeManager.uint64_type)
3506                                         return 2;
3507                         } else if (q == TypeManager.sbyte_type) {
3508                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3509                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3510                                         return 2;
3511                         } if (q == TypeManager.short_type) {
3512                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3513                                         p == TypeManager.uint64_type)
3514                                         return 2;
3515                         } else if (q == InternalType.Dynamic) {
3516                                 if (p == TypeManager.object_type)
3517                                         return 1;
3518                         }
3519
3520                         // TODO: this is expensive
3521                         Expression p_tmp = new EmptyExpression (p);
3522                         Expression q_tmp = new EmptyExpression (q);
3523
3524                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3525                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3526
3527                         if (p_to_q && !q_to_p)
3528                                 return 1;
3529
3530                         if (q_to_p && !p_to_q)
3531                                 return 2;
3532
3533                         return 0;
3534                 }
3535
3536                 /// <summary>
3537                 ///   Determines "Better function" between candidate
3538                 ///   and the current best match
3539                 /// </summary>
3540                 /// <remarks>
3541                 ///    Returns a boolean indicating :
3542                 ///     false if candidate ain't better
3543                 ///     true  if candidate is better than the current best match
3544                 /// </remarks>
3545                 static bool BetterFunction (ResolveContext ec, Arguments args, int argument_count,
3546                         MethodSpec candidate, bool candidate_params,
3547                         MethodSpec best, bool best_params)
3548                 {
3549                         AParametersCollection candidate_pd = candidate.Parameters;
3550                         AParametersCollection best_pd = best.Parameters;
3551
3552                         bool better_at_least_one = false;
3553                         bool same = true;
3554                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3555                         {
3556                                 Argument a = args [j];
3557
3558                                 // Provided default argument value is never better
3559                                 if (a.IsDefaultArgument && candidate_params == best_params)
3560                                         return false;
3561
3562                                 Type ct = candidate_pd.Types [c_idx];
3563                                 Type bt = best_pd.Types [b_idx];
3564
3565                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3566                                 {
3567                                         ct = TypeManager.GetElementType (ct);
3568                                         --c_idx;
3569                                 }
3570
3571                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3572                                 {
3573                                         bt = TypeManager.GetElementType (bt);
3574                                         --b_idx;
3575                                 }
3576
3577                                 if (TypeManager.IsEqual (ct, bt))
3578                                         continue;
3579
3580                                 same = false;
3581                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3582
3583                                 // for each argument, the conversion to 'ct' should be no worse than
3584                                 // the conversion to 'bt'.
3585                                 if (result == 2)
3586                                         return false;
3587
3588                                 // for at least one argument, the conversion to 'ct' should be better than
3589                                 // the conversion to 'bt'.
3590                                 if (result != 0)
3591                                         better_at_least_one = true;
3592                         }
3593
3594                         if (better_at_least_one)
3595                                 return true;
3596
3597                         //
3598                         // This handles the case
3599                         //
3600                         //   Add (float f1, float f2, float f3);
3601                         //   Add (params decimal [] foo);
3602                         //
3603                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3604                         // first candidate would've chosen as better.
3605                         //
3606                         if (!same)
3607                                 return false;
3608
3609                         //
3610                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3611                         //
3612                         if (best.IsGenericMethod) {
3613                                 if (!candidate.IsGenericMethod)
3614                                         return true;
3615                         } else if (candidate.IsGenericMethod) {
3616                                 return false;
3617                         }
3618
3619                         //
3620                         // This handles the following cases:
3621                         //
3622                         //   Trim () is better than Trim (params char[] chars)
3623                         //   Concat (string s1, string s2, string s3) is better than
3624                         //     Concat (string s1, params string [] srest)
3625                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3626                         //
3627                         if (!candidate_params && best_params)
3628                                 return true;
3629                         if (candidate_params && !best_params)
3630                                 return false;
3631
3632                         int candidate_param_count = candidate_pd.Count;
3633                         int best_param_count = best_pd.Count;
3634
3635                         if (candidate_param_count != best_param_count)
3636                                 // can only happen if (candidate_params && best_params)
3637                                 return candidate_param_count > best_param_count && best_pd.HasParams;
3638
3639                         //
3640                         // now, both methods have the same number of parameters, and the parameters have the same types
3641                         // Pick the "more specific" signature
3642                         //
3643
3644                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3645                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3646
3647                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3648                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3649
3650                         bool specific_at_least_once = false;
3651                         for (int j = 0; j < candidate_param_count; ++j)
3652                         {
3653                                 Type ct = orig_candidate_pd.Types [j];
3654                                 Type bt = orig_best_pd.Types [j];
3655                                 if (ct.Equals (bt))
3656                                         continue;
3657                                 Type specific = MoreSpecific (ct, bt);
3658                                 if (specific == bt)
3659                                         return false;
3660                                 if (specific == ct)
3661                                         specific_at_least_once = true;
3662                         }
3663
3664                         if (specific_at_least_once)
3665                                 return true;
3666
3667                         // FIXME: handle lifted operators
3668                         // ...
3669
3670                         return false;
3671                 }
3672
3673                 protected override MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3674                 {
3675                         if (!IsStatic)
3676                                 return base.ResolveExtensionMemberAccess (ec, left);
3677
3678                         //
3679                         // When left side is an expression and at least one candidate method is
3680                         // static, it can be extension method
3681                         //
3682                         InstanceExpression = left;
3683                         return this;
3684                 }
3685
3686                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3687                                                                 SimpleName original)
3688                 {
3689                         if (!(left is TypeExpr) &&
3690                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3691                                 identical_type_name = true;
3692
3693                         return base.ResolveMemberAccess (ec, left, loc, original);
3694                 }
3695
3696                 public override Expression CreateExpressionTree (ResolveContext ec)
3697                 {
3698                         if (best_candidate == null) {
3699                                 ec.Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3700                                 return null;
3701                         }
3702
3703                         IMethodData md = TypeManager.GetMethod (best_candidate.MetaInfo);
3704                         if (md != null && md.IsExcluded ())
3705                                 ec.Report.Error (765, loc,
3706                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3707
3708                         return new TypeOfMethod (best_candidate, loc);
3709                 }
3710
3711                 protected override Expression DoResolve (ResolveContext ec)
3712                 {
3713                         this.eclass = ExprClass.MethodGroup;
3714
3715                         if (InstanceExpression != null) {
3716                                 InstanceExpression = InstanceExpression.Resolve (ec);
3717                                 if (InstanceExpression == null)
3718                                         return null;
3719                         }
3720
3721                         return this;
3722                 }
3723
3724                 public void ReportUsageError (ResolveContext ec)
3725                 {
3726                         ec.Report.Error (654, loc, "Method `" + DeclaringType + "." +
3727                                       Name + "()' is referenced without parentheses");
3728                 }
3729
3730                 override public void Emit (EmitContext ec)
3731                 {
3732                         throw new NotSupportedException ();
3733                         // ReportUsageError ();
3734                 }
3735
3736                 public void EmitCall (EmitContext ec, Arguments arguments)
3737                 {
3738                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3739                 }
3740
3741                 void Error_AmbiguousCall (ResolveContext ec, MethodSpec ambiguous)
3742                 {
3743                         if (CustomErrorHandler != null && CustomErrorHandler.AmbiguousCall (ec, ambiguous))
3744                                 return;
3745
3746                         ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
3747                         ec.Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
3748                                 TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate.MetaInfo));
3749                 }
3750
3751                 protected virtual void Error_InvalidArguments (ResolveContext ec, Location loc, int idx, MethodSpec method,
3752                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3753                 {
3754                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3755
3756                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3757                                 ec.Report.SymbolRelatedToPreviousError (method.MetaInfo);
3758                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3759                                         ec.Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3760                                                 TypeManager.CSharpSignature (method));
3761                                         return;
3762                                 }
3763                                 ec.Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3764                                           TypeManager.CSharpSignature (method));
3765                         } else if (TypeManager.IsDelegateType (method.DeclaringType)) {
3766                                 ec.Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3767                                         TypeManager.CSharpName (method.DeclaringType));
3768                         } else {
3769                                 ec.Report.SymbolRelatedToPreviousError (method.MetaInfo);
3770                                 if (emg != null) {
3771                                         ec.Report.Error (1928, loc,
3772                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3773                                                 emg.ExtensionExpression.GetSignatureForError (),
3774                                                 emg.Name, TypeManager.CSharpSignature (method));
3775                                 } else {
3776                                         ec.Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3777                                                 TypeManager.CSharpSignature (method));
3778                                 }
3779                         }
3780
3781                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3782
3783                         string index = (idx + 1).ToString ();
3784                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3785                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3786                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3787                                         ec.Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3788                                                 index, Parameter.GetModifierSignature (a.Modifier));
3789                                 else
3790                                         ec.Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3791                                                 index, Parameter.GetModifierSignature (mod));
3792                         } else {
3793                                 string p1 = a.GetSignatureForError ();
3794                                 string p2 = TypeManager.CSharpName (paramType);
3795
3796                                 if (p1 == p2) {
3797                                         ec.Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3798                                         ec.Report.SymbolRelatedToPreviousError (a.Expr.Type);
3799                                         ec.Report.SymbolRelatedToPreviousError (paramType);
3800                                 }
3801
3802                                 if (idx == 0 && emg != null) {
3803                                         ec.Report.Error (1929, loc,
3804                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3805                                 } else {
3806                                         ec.Report.Error (1503, loc,
3807                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3808                                 }
3809                         }
3810                 }
3811
3812                 public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
3813                 {
3814                         ec.Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3815                                 Name, TypeManager.CSharpName (target));
3816                 }
3817
3818                 void Error_ArgumentCountWrong (ResolveContext ec, int arg_count)
3819                 {
3820                         ec.Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
3821                                       Name, arg_count.ToString ());
3822                 }
3823
3824                 protected virtual int GetApplicableParametersCount (MethodSpec method, AParametersCollection parameters)
3825                 {
3826                         return parameters.Count;
3827                 }
3828
3829                 public static bool IsAncestralType (Type first_type, Type second_type)
3830                 {
3831                         return first_type != second_type &&
3832                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3833                                 TypeManager.ImplementsInterface (second_type, first_type));
3834                 }
3835
3836                 ///
3837                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3838                 /// to the given set of arguments
3839                 /// A return value rates candidate method compatibility,
3840                 /// 0 = the best, int.MaxValue = the worst
3841                 ///
3842                 public int IsApplicable (ResolveContext ec,
3843                                                 ref Arguments arguments, int arg_count, ref MethodSpec method, ref bool params_expanded_form)
3844                 {
3845                         var candidate = method;
3846
3847                         AParametersCollection pd = candidate.Parameters;
3848                         int param_count = GetApplicableParametersCount (candidate, pd);
3849                         int optional_count = 0;
3850
3851                         if (arg_count != param_count) {
3852                                 for (int i = 0; i < pd.Count; ++i) {
3853                                         if (pd.FixedParameters [i].HasDefaultValue) {
3854                                                 optional_count = pd.Count - i;
3855                                                 break;
3856                                         }
3857                                 }
3858
3859                                 int args_gap = System.Math.Abs (arg_count - param_count);
3860                                 if (optional_count != 0) {
3861                                         if (args_gap > optional_count)
3862                                                 return int.MaxValue - 10000 + args_gap - optional_count;
3863
3864                                         // Readjust expected number when params used
3865                                         if (pd.HasParams) {
3866                                                 optional_count--;
3867                                                 if (arg_count < param_count)
3868                                                         param_count--;
3869                                         } else if (arg_count > param_count) {
3870                                                 return int.MaxValue - 10000 + args_gap;
3871                                         }
3872                                 } else if (arg_count != param_count) {
3873                                         if (!pd.HasParams)
3874                                                 return int.MaxValue - 10000 + args_gap;
3875                                         if (arg_count < param_count - 1)
3876                                                 return int.MaxValue - 10000 + args_gap;
3877                                 }
3878
3879                                 // Initialize expanded form of a method with 1 params parameter
3880                                 params_expanded_form = param_count == 1 && pd.HasParams;
3881
3882                                 // Resize to fit optional arguments
3883                                 if (optional_count != 0) {
3884                                         Arguments resized;
3885                                         if (arguments == null) {
3886                                                 resized = new Arguments (optional_count);
3887                                         } else {
3888                                                 resized = new Arguments (param_count);
3889                                                 resized.AddRange (arguments);
3890                                         }
3891
3892                                         for (int i = arg_count; i < param_count; ++i)
3893                                                 resized.Add (null);
3894                                         arguments = resized;
3895                                 }
3896                         }
3897
3898                         if (arg_count > 0) {
3899                                 //
3900                                 // Shuffle named arguments to the right positions if there are any
3901                                 //
3902                                 if (arguments [arg_count - 1] is NamedArgument) {
3903                                         arg_count = arguments.Count;
3904
3905                                         for (int i = 0; i < arg_count; ++i) {
3906                                                 bool arg_moved = false;
3907                                                 while (true) {
3908                                                         NamedArgument na = arguments[i] as NamedArgument;
3909                                                         if (na == null)
3910                                                                 break;
3911
3912                                                         int index = pd.GetParameterIndexByName (na.Name);
3913
3914                                                         // Named parameter not found or already reordered
3915                                                         if (index <= i)
3916                                                                 break;
3917
3918                                                         // When using parameters which should not be available to the user
3919                                                         if (index >= param_count)
3920                                                                 break;
3921
3922                                                         if (!arg_moved) {
3923                                                                 arguments.MarkReorderedArgument (na);
3924                                                                 arg_moved = true;
3925                                                         }
3926
3927                                                         Argument temp = arguments[index];
3928                                                         arguments[index] = arguments[i];
3929                                                         arguments[i] = temp;
3930
3931                                                         if (temp == null)
3932                                                                 break;
3933                                                 }
3934                                         }
3935                                 } else {
3936                                         arg_count = arguments.Count;
3937                                 }
3938                         } else if (arguments != null) {
3939                                 arg_count = arguments.Count;
3940                         }
3941
3942                         //
3943                         // 1. Handle generic method using type arguments when specified or type inference
3944                         //
3945                         if (candidate.IsGenericMethod) {
3946                                 if (type_arguments != null) {
3947                                         Type [] g_args = candidate.GetGenericArguments ();
3948                                         if (g_args.Length != type_arguments.Count)
3949                                                 return int.MaxValue - 20000 + System.Math.Abs (type_arguments.Count - g_args.Length);
3950
3951                                         method = candidate.Inflate (type_arguments.Arguments);
3952                                         candidate = method;
3953                                         pd = candidate.Parameters;
3954                                 } else {
3955                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3956                                         if (score != 0)
3957                                                 return score - 20000;
3958
3959                                         if (TypeManager.IsGenericMethodDefinition (candidate.MetaInfo))
3960                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3961                                                         TypeManager.CSharpSignature (candidate.MetaInfo));
3962
3963                                         pd = candidate.Parameters;
3964                                 }
3965                         } else {
3966                                 if (type_arguments != null)
3967                                         return int.MaxValue - 15000;
3968                         }
3969
3970                         //
3971                         // 2. Each argument has to be implicitly convertible to method parameter
3972                         //
3973                         method = candidate;
3974                         Parameter.Modifier p_mod = 0;
3975                         Type pt = null;
3976                         for (int i = 0; i < arg_count; i++) {
3977                                 Argument a = arguments [i];
3978                                 if (a == null) {
3979                                         if (!pd.FixedParameters [i].HasDefaultValue)
3980                                                 throw new InternalErrorException ();
3981
3982                                         Expression e = pd.FixedParameters [i].DefaultValue as Constant;
3983                                         if (e == null)
3984                                                 e = new DefaultValueExpression (new TypeExpression (pd.Types [i], loc), loc).Resolve (ec);
3985
3986                                         arguments [i] = new Argument (e, Argument.AType.Default);
3987                                         continue;
3988                                 }
3989
3990                                 if (p_mod != Parameter.Modifier.PARAMS) {
3991                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3992                                         pt = pd.Types [i];
3993                                 } else {
3994                                         params_expanded_form = true;
3995                                 }
3996
3997                                 Parameter.Modifier a_mod = a.Modifier & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3998                                 int score = 1;
3999                                 if (!params_expanded_form)
4000                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
4001
4002                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
4003                                         // It can be applicable in expanded form
4004                                         score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
4005                                         if (score == 0)
4006                                                 params_expanded_form = true;
4007                                 }
4008
4009                                 if (score != 0) {
4010                                         if (params_expanded_form)
4011                                                 ++score;
4012                                         return (arg_count - i) * 2 + score;
4013                                 }
4014                         }
4015
4016                         if (arg_count != param_count)
4017                                 params_expanded_form = true;
4018
4019                         return 0;
4020                 }
4021
4022                 int IsArgumentCompatible (ResolveContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
4023                 {
4024                         //
4025                         // Types have to be identical when ref or out modifer is used
4026                         //
4027                         if (arg_mod != 0 || param_mod != 0) {
4028                                 if (TypeManager.HasElementType (parameter))
4029                                         parameter = TypeManager.GetElementType (parameter);
4030
4031                                 Type a_type = argument.Type;
4032                                 if (TypeManager.HasElementType (a_type))
4033                                         a_type = TypeManager.GetElementType (a_type);
4034
4035                                 if (a_type != parameter) {
4036                                         if (TypeManager.IsDynamicType (a_type))
4037                                                 return 0;
4038
4039                                         return 2;
4040                                 }
4041                         } else {
4042                                 if (!Convert.ImplicitConversionExists (ec, argument.Expr, parameter)) {
4043                                         if (TypeManager.IsDynamicType (argument.Type))
4044                                                 return 0;
4045
4046                                         return 2;
4047                                 }
4048                         }
4049
4050                         if (arg_mod != param_mod)
4051                                 return 1;
4052
4053                         return 0;
4054                 }
4055
4056                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
4057                 {
4058                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
4059                                 return false;
4060
4061                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
4062                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
4063
4064                         if (cand_pd.Count != base_pd.Count)
4065                                 return false;
4066
4067                         for (int j = 0; j < cand_pd.Count; ++j)
4068                         {
4069                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
4070                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
4071                                 Type ct = cand_pd.Types [j];
4072                                 Type bt = base_pd.Types [j];
4073
4074                                 if (cm != bm || ct != bt)
4075                                         return false;
4076                         }
4077
4078                         return true;
4079                 }
4080
4081                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
4082                 {
4083                         if (mg1 == null) {
4084                                 if (mg2 == null)
4085                                         return null;
4086                                 return mg2;
4087                         }
4088
4089                         if (mg2 == null)
4090                                 return mg1;
4091
4092                         var all = new List<MethodSpec> (mg1.Methods);
4093                         foreach (var m in mg2.Methods){
4094                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods.Select (l => l.MetaInfo).ToArray (), m.MetaInfo, false))
4095                                         all.Add (m);
4096                         }
4097
4098                         return new MethodGroupExpr (all, null, loc);
4099                 }
4100
4101                 static Type MoreSpecific (Type p, Type q)
4102                 {
4103                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
4104                                 return q;
4105                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
4106                                 return p;
4107
4108                         if (TypeManager.HasElementType (p))
4109                         {
4110                                 Type pe = TypeManager.GetElementType (p);
4111                                 Type qe = TypeManager.GetElementType (q);
4112                                 Type specific = MoreSpecific (pe, qe);
4113                                 if (specific == pe)
4114                                         return p;
4115                                 if (specific == qe)
4116                                         return q;
4117                         }
4118                         else if (TypeManager.IsGenericType (p))
4119                         {
4120                                 Type[] pargs = TypeManager.GetTypeArguments (p);
4121                                 Type[] qargs = TypeManager.GetTypeArguments (q);
4122
4123                                 bool p_specific_at_least_once = false;
4124                                 bool q_specific_at_least_once = false;
4125
4126                                 for (int i = 0; i < pargs.Length; i++)
4127                                 {
4128                                         Type specific = MoreSpecific (TypeManager.TypeToCoreType (pargs [i]), TypeManager.TypeToCoreType (qargs [i]));
4129                                         if (specific == pargs [i])
4130                                                 p_specific_at_least_once = true;
4131                                         if (specific == qargs [i])
4132                                                 q_specific_at_least_once = true;
4133                                 }
4134
4135                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4136                                         return p;
4137                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4138                                         return q;
4139                         }
4140
4141                         return null;
4142                 }
4143
4144                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4145                 {
4146                         base.MutateHoistedGenericType (storey);
4147
4148                         if (best_candidate.IsConstructor) {
4149                                 storey.MutateConstructor (best_candidate);
4150                         } else {
4151                                 storey.MutateGenericMethod (best_candidate);
4152                         }
4153                 }
4154
4155                 /// <summary>
4156                 ///   Find the Applicable Function Members (7.4.2.1)
4157                 ///
4158                 ///   me: Method Group expression with the members to select.
4159                 ///       it might contain constructors or methods (or anything
4160                 ///       that maps to a method).
4161                 ///
4162                 ///   Arguments: ArrayList containing resolved Argument objects.
4163                 ///
4164                 ///   loc: The location if we want an error to be reported, or a Null
4165                 ///        location for "probing" purposes.
4166                 ///
4167                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4168                 ///            that is the best match of me on Arguments.
4169                 ///
4170                 /// </summary>
4171                 public virtual MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments Arguments,
4172                         bool may_fail, Location loc)
4173                 {
4174                         bool method_params = false;
4175                         Type applicable_type = null;
4176                         var candidates = new List<MethodSpec> (2);
4177                         List<MethodSpec> candidate_overrides = null;
4178
4179                         //
4180                         // Used to keep a map between the candidate
4181                         // and whether it is being considered in its
4182                         // normal or expanded form
4183                         //
4184                         // false is normal form, true is expanded form
4185                         //
4186                         Dictionary<MethodSpec, MethodSpec> candidate_to_form = null;
4187                         Dictionary<MethodSpec, Arguments> candidates_expanded = null;
4188                         Arguments candidate_args = Arguments;
4189
4190                         int arg_count = Arguments != null ? Arguments.Count : 0;
4191
4192                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4193                                 if (!may_fail)
4194                                         ec.Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4195                                 return null;
4196                         }
4197
4198                         int nmethods = Methods.Length;
4199
4200                         if (!IsBase) {
4201                                 //
4202                                 // Methods marked 'override' don't take part in 'applicable_type'
4203                                 // computation, nor in the actual overload resolution.
4204                                 // However, they still need to be emitted instead of a base virtual method.
4205                                 // So, we salt them away into the 'candidate_overrides' array.
4206                                 //
4207                                 // In case of reflected methods, we replace each overriding method with
4208                                 // its corresponding base virtual method.  This is to improve compatibility
4209                                 // with non-C# libraries which change the visibility of overrides (#75636)
4210                                 //
4211                                 int j = 0;
4212                                 MethodBase mb = null;
4213                                 for (int i = 0; i < Methods.Length; ++i) {
4214                                         var m = Methods [i];
4215                                         mb = m.MetaInfo;
4216                                         if (TypeManager.IsOverride (m)) {
4217                                                 if (candidate_overrides == null)
4218                                                         candidate_overrides = new List<MethodSpec> ();
4219                                                 candidate_overrides.Add (m);
4220                                                 mb = TypeManager.TryGetBaseDefinition (mb);
4221                                                 if (mb != null && Array.Exists (Methods, l => l.MetaInfo == mb))
4222                                                         continue;
4223                                         }
4224                                         if (mb != null)
4225                                                 Methods [j++] = Import.CreateMethod (mb);
4226                                 }
4227                                 nmethods = j;
4228                         }
4229
4230                         //
4231                         // Enable message recording, it's used mainly by lambda expressions
4232                         //
4233                         SessionReportPrinter msg_recorder = new SessionReportPrinter ();
4234                         ReportPrinter prev_recorder = ec.Report.SetPrinter (msg_recorder);
4235
4236                         //
4237                         // First we construct the set of applicable methods
4238                         //
4239                         bool is_sorted = true;
4240                         int best_candidate_rate = int.MaxValue;
4241                         for (int i = 0; i < nmethods; i++) {
4242                                 Type decl_type = Methods [i].DeclaringType;
4243
4244                                 //
4245                                 // If we have already found an applicable method
4246                                 // we eliminate all base types (Section 14.5.5.1)
4247                                 //
4248                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4249                                         continue;
4250
4251                                 //
4252                                 // Check if candidate is applicable (section 14.4.2.1)
4253                                 //
4254                                 bool params_expanded_form = false;
4255                                 int candidate_rate = IsApplicable (ec, ref candidate_args, arg_count, ref Methods [i], ref params_expanded_form);
4256
4257                                 if (candidate_rate < best_candidate_rate) {
4258                                         best_candidate_rate = candidate_rate;
4259                                         best_candidate = Methods [i];
4260                                 }
4261
4262                                 if (params_expanded_form) {
4263                                         if (candidate_to_form == null)
4264                                                 candidate_to_form = new Dictionary<MethodSpec, MethodSpec> (4, ReferenceEquality<MethodSpec>.Default);
4265                                         var candidate = Methods [i];
4266                                         candidate_to_form [candidate] = candidate;
4267                                 }
4268
4269                                 if (candidate_args != Arguments) {
4270                                         if (candidates_expanded == null)
4271                                                 candidates_expanded = new Dictionary<MethodSpec, Arguments> (4, ReferenceEquality<MethodSpec>.Default);
4272
4273                                         candidates_expanded.Add (Methods [i], candidate_args);
4274                                         candidate_args = Arguments;
4275                                 }
4276
4277                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4278                                         if (msg_recorder != null)
4279                                                 msg_recorder.EndSession ();
4280                                         continue;
4281                                 }
4282
4283                                 msg_recorder = null;
4284                                 candidates.Add (Methods [i]);
4285
4286                                 if (applicable_type == null)
4287                                         applicable_type = decl_type;
4288                                 else if (applicable_type != decl_type) {
4289                                         is_sorted = false;
4290                                         if (IsAncestralType (applicable_type, decl_type))
4291                                                 applicable_type = decl_type;
4292                                 }
4293                         }
4294
4295                         ec.Report.SetPrinter (prev_recorder);
4296                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4297                                 if (!may_fail)
4298                                         msg_recorder.Merge (prev_recorder);
4299
4300                                 return null;
4301                         }
4302
4303                         int candidate_top = candidates.Count;
4304
4305                         if (applicable_type == null) {
4306                                 //
4307                                 // When we found a top level method which does not match and it's
4308                                 // not an extension method. We start extension methods lookup from here
4309                                 //
4310                                 if (InstanceExpression != null) {
4311                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (type, Name, loc);
4312                                         if (ex_method_lookup != null) {
4313                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4314                                                 ex_method_lookup.SetTypeArguments (ec, type_arguments);
4315                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4316                                         }
4317                                 }
4318
4319                                 if (may_fail)
4320                                         return null;
4321
4322                                 //
4323                                 // Okay so we have failed to find exact match so we
4324                                 // return error info about the closest match
4325                                 //
4326                                 if (best_candidate != null) {
4327                                         if (CustomErrorHandler != null && !has_inaccessible_candidates_only && CustomErrorHandler.NoExactMatch (ec, best_candidate))
4328                                                 return null;
4329
4330                                         if (NoExactMatch (ec, ref Arguments, candidate_to_form))
4331                                                 return null;
4332                                 }
4333
4334                                 //
4335                                 // We failed to find any method with correct argument count
4336                                 //
4337                                 if (Name == ConstructorInfo.ConstructorName) {
4338                                         ec.Report.SymbolRelatedToPreviousError (queried_type);
4339                                         ec.Report.Error (1729, loc,
4340                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4341                                                 TypeManager.CSharpName (queried_type), arg_count);
4342                                 } else {
4343                                         Error_ArgumentCountWrong (ec, arg_count);
4344                                 }
4345
4346                                 return null;
4347                         }
4348
4349                         if (arg_count != 0 && Arguments.HasDynamic) {
4350                                 best_candidate = null;
4351                                 return this;
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                                                 var candidate = 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 = candidates [0];
4410                         method_params = candidate_to_form != null && candidate_to_form.ContainsKey (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.ContainsKey (best_candidate)) {
4417                                 candidate_args = candidates_expanded [best_candidate];
4418                                 arg_count = candidate_args.Count;
4419                         }
4420
4421                         for (int ix = 1; ix < candidate_top; ix++) {
4422                                 var candidate = candidates [ix];
4423
4424                                 if (candidate.MetaInfo == best_candidate.MetaInfo)
4425                                         continue;
4426
4427                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (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                         MethodSpec ambiguous = null;
4441                         for (int ix = 1; ix < candidate_top; ix++) {
4442                                 var candidate = candidates [ix];
4443
4444                                 if (candidate.MetaInfo == best_candidate.MetaInfo)
4445                                         continue;
4446
4447                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (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.MetaInfo);
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 (best_candidate.IsGenericMethod)
4475                                                 gen_args = TypeManager.GetGenericArguments (best_candidate.MetaInfo);
4476
4477                                         foreach (var candidate in candidate_overrides) {
4478                                                 if (candidate.IsGenericMethod) {
4479                                                         if (gen_args == null)
4480                                                                 continue;
4481
4482                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate.MetaInfo).Length)
4483                                                                 continue;
4484                                                 } else {
4485                                                         if (gen_args != null)
4486                                                                 continue;
4487                                                 }
4488
4489                                                 if (IsOverride (candidate.MetaInfo, best_candidate.MetaInfo)) {
4490                                                         gen_override = true;
4491                                                         best_candidate = candidate;
4492                                                 }
4493                                         }
4494
4495                                         if (gen_override && gen_args != null) {
4496                                                 best_candidate = best_candidate.Inflate (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.MetaInfo, 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.SetIsUsed ();
4529
4530                         Arguments = candidate_args;
4531                         return this;
4532                 }
4533
4534                 bool NoExactMatch (ResolveContext ec, ref Arguments Arguments, IDictionary<MethodSpec, MethodSpec> candidate_to_form)
4535                 {
4536                         AParametersCollection pd = best_candidate.Parameters;
4537                         int arg_count = Arguments == null ? 0 : Arguments.Count;
4538
4539                         if (arg_count == pd.Count || pd.HasParams) {
4540                                 if (TypeManager.IsGenericMethodDefinition (best_candidate.MetaInfo)) {
4541                                         if (type_arguments == null) {
4542                                                 ec.Report.Error (411, loc,
4543                                                         "The type arguments for method `{0}' cannot be inferred from " +
4544                                                         "the usage. Try specifying the type arguments explicitly",
4545                                                         TypeManager.CSharpSignature (best_candidate.MetaInfo));
4546                                                 return true;
4547                                         }
4548
4549                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate.MetaInfo);
4550                                         if (type_arguments.Count != g_args.Length) {
4551                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4552                                                 ec.Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4553                                                         TypeManager.CSharpSignature (best_candidate.MetaInfo),
4554                                                         g_args.Length.ToString ());
4555                                                 return true;
4556                                         }
4557                                 } else {
4558                                         if (type_arguments != null && !best_candidate.IsGenericMethod) {
4559                                                 Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
4560                                                 return true;
4561                                         }
4562                                 }
4563
4564                                 if (has_inaccessible_candidates_only) {
4565                                         if (InstanceExpression != null && type != ec.CurrentType && TypeManager.IsNestedFamilyAccessible (ec.CurrentType, best_candidate.DeclaringType)) {
4566                                                 // Although a derived class can access protected members of
4567                                                 // its base class it cannot do so through an instance of the
4568                                                 // base class (CS1540).  If the qualifier_type is a base of the
4569                                                 // ec.CurrentType and the lookup succeeds with the latter one,
4570                                                 // then we are in this situation.
4571                                                 Error_CannotAccessProtected (ec, loc, best_candidate.MetaInfo, queried_type, ec.CurrentType);
4572                                         } else {
4573                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4574                                                 ErrorIsInaccesible (loc, GetSignatureForError (), ec.Report);
4575                                         }
4576                                 }
4577
4578                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (best_candidate);
4579                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, false, loc))
4580                                         return true;
4581
4582                                 if (has_inaccessible_candidates_only)
4583                                         return true;
4584                         }
4585
4586                         return false;
4587                 }
4588
4589                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
4590                 {
4591                         type_arguments = ta;
4592                 }
4593
4594                 public bool VerifyArgumentsCompat (ResolveContext ec, ref Arguments arguments,
4595                                                           int arg_count, MethodSpec method,
4596                                                           bool chose_params_expanded,
4597                                                           bool may_fail, Location loc)
4598                 {
4599                         AParametersCollection pd = method.Parameters;
4600                         int param_count = GetApplicableParametersCount (method, pd);
4601
4602                         int errors = ec.Report.Errors;
4603                         Parameter.Modifier p_mod = 0;
4604                         Type pt = null;
4605                         int a_idx = 0, a_pos = 0;
4606                         Argument a = null;
4607                         ArrayInitializer params_initializers = null;
4608                         bool has_unsafe_arg = method.ReturnType.IsPointer;
4609
4610                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4611                                 a = arguments [a_idx];
4612                                 if (p_mod != Parameter.Modifier.PARAMS) {
4613                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4614                                         pt = pd.Types [a_idx];
4615                                         has_unsafe_arg |= pt.IsPointer;
4616
4617                                         if (p_mod == Parameter.Modifier.PARAMS) {
4618                                                 if (chose_params_expanded) {
4619                                                         params_initializers = new ArrayInitializer (arg_count - a_idx, a.Expr.Location);
4620                                                         pt = TypeManager.GetElementType (pt);
4621                                                 }
4622                                         }
4623                                 }
4624
4625                                 //
4626                                 // Types have to be identical when ref or out modifer is used
4627                                 //
4628                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4629                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4630                                                 break;
4631
4632                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4633                                                 break;
4634
4635                                         continue;
4636                                 } else {
4637                                         NamedArgument na = a as NamedArgument;
4638                                         if (na != null) {
4639                                                 int name_index = pd.GetParameterIndexByName (na.Name);
4640                                                 if (name_index < 0 || name_index >= param_count) {
4641                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType)) {
4642                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4643                                                                 ec.Report.Error (1746, na.Location,
4644                                                                         "The delegate `{0}' does not contain a parameter named `{1}'",
4645                                                                         TypeManager.CSharpName (DeclaringType), na.Name);
4646                                                         } else {
4647                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4648                                                                 ec.Report.Error (1739, na.Location,
4649                                                                         "The best overloaded method match for `{0}' does not contain a parameter named `{1}'",
4650                                                                         TypeManager.CSharpSignature (method.MetaInfo), na.Name);
4651                                                         }
4652                                                 } else if (arguments[name_index] != a) {
4653                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType))
4654                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4655                                                         else
4656                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4657
4658                                                         ec.Report.Error (1744, na.Location,
4659                                                                 "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
4660                                                                 na.Name);
4661                                                 }
4662                                         }
4663                                 }
4664
4665                                 if (TypeManager.IsDynamicType (a.Expr.Type))
4666                                         continue;
4667
4668                                 if (delegate_type != null && !Delegate.IsTypeCovariant (a.Expr, pt))
4669                                         break;
4670
4671                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4672                                 if (conv == null)
4673                                         break;
4674
4675                                 //
4676                                 // Convert params arguments to an array initializer
4677                                 //
4678                                 if (params_initializers != null) {
4679                                         // we choose to use 'a.Expr' rather than 'conv' so that
4680                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4681                                         params_initializers.Add (a.Expr);
4682                                         arguments.RemoveAt (a_idx--);
4683                                         --arg_count;
4684                                         continue;
4685                                 }
4686
4687                                 // Update the argument with the implicit conversion
4688                                 a.Expr = conv;
4689                         }
4690
4691                         if (a_idx != arg_count) {
4692                                 if (!may_fail && ec.Report.Errors == errors) {
4693                                         if (CustomErrorHandler != null)
4694                                                 CustomErrorHandler.NoExactMatch (ec, best_candidate);
4695                                         else
4696                                                 Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4697                                 }
4698                                 return false;
4699                         }
4700
4701                         //
4702                         // Fill not provided arguments required by params modifier
4703                         //
4704                         if (params_initializers == null && pd.HasParams && arg_count + 1 == param_count) {
4705                                 if (arguments == null)
4706                                         arguments = new Arguments (1);
4707
4708                                 pt = pd.Types [param_count - 1];
4709                                 pt = TypeManager.GetElementType (pt);
4710                                 has_unsafe_arg |= pt.IsPointer;
4711                                 params_initializers = new ArrayInitializer (0, loc);
4712                         }
4713
4714                         //
4715                         // Append an array argument with all params arguments
4716                         //
4717                         if (params_initializers != null) {
4718                                 arguments.Add (new Argument (
4719                                         new ArrayCreation (new TypeExpression (pt, loc), "[]", params_initializers, loc).Resolve (ec)));
4720                                 arg_count++;
4721                         }
4722
4723                         if (arg_count < param_count) {
4724                                 if (!may_fail)
4725                                         Error_ArgumentCountWrong (ec, arg_count);
4726                                 return false;
4727                         }
4728
4729                         if (has_unsafe_arg && !ec.IsUnsafe) {
4730                                 if (!may_fail)
4731                                         UnsafeError (ec, loc);
4732                                 return false;
4733                         }
4734
4735                         return true;
4736                 }
4737         }
4738
4739         public class ConstantExpr : MemberExpr
4740         {
4741                 ConstSpec constant;
4742
4743                 public ConstantExpr (ConstSpec constant, Location loc)
4744                 {
4745                         this.constant = constant;
4746                         this.loc = loc;
4747                 }
4748
4749                 public override string Name {
4750                         get { throw new NotImplementedException (); }
4751                 }
4752
4753                 public override bool IsInstance {
4754                         get { return !IsStatic; }
4755                 }
4756
4757                 public override bool IsStatic {
4758                         get { return true; }
4759                 }
4760
4761                 public override Type DeclaringType {
4762                         get { return constant.DeclaringType; }
4763                 }
4764
4765                 public override Expression CreateExpressionTree (ResolveContext ec)
4766                 {
4767                         throw new NotSupportedException ("ET");
4768                 }
4769
4770                 protected override Expression DoResolve (ResolveContext rc)
4771                 {
4772                         constant.MemberDefinition.SetIsUsed ();
4773
4774                         if (!rc.IsObsolete) {
4775                                 var oa = constant.GetObsoleteAttribute ();
4776                                 if (oa != null)
4777                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (constant.MetaInfo), loc, rc.Report);
4778                         }
4779
4780                         // Constants are resolved on-demand
4781                         var c = constant.Value.Resolve (rc) as Constant;
4782
4783                         // Creates reference expression to the constant value
4784                         return Constant.CreateConstant (rc, c.Type, c.GetValue (), loc);
4785                 }
4786
4787                 public override void Emit (EmitContext ec)
4788                 {
4789                         throw new NotSupportedException ();
4790                 }
4791
4792                 public override string GetSignatureForError ()
4793                 {
4794                         return TypeManager.GetFullNameSignature (constant.MetaInfo);
4795                 }
4796         }
4797
4798         /// <summary>
4799         ///   Fully resolved expression that evaluates to a Field
4800         /// </summary>
4801         public class FieldExpr : MemberExpr, IDynamicAssign, IMemoryLocation, IVariableReference {
4802                 protected FieldSpec spec;
4803                 readonly Type constructed_generic_type;
4804                 VariableInfo variable_info;
4805
4806                 LocalTemporary temp;
4807                 bool prepared;
4808
4809                 protected FieldExpr (Location l)
4810                 {
4811                         loc = l;
4812                 }
4813
4814                 public FieldExpr (FieldSpec spec, Location loc)
4815                 {
4816                         this.spec = spec;
4817                         this.loc = loc;
4818
4819                         type = TypeManager.TypeToCoreType (spec.FieldType);
4820                 }
4821
4822                 public FieldExpr (FieldBase fi, Location l)
4823                         : this (fi.Spec, l)
4824                 {
4825                         loc = l;
4826                 }
4827
4828                 public FieldExpr (Field fi, Type genericType, Location l)
4829                         : this (fi, l)
4830                 {
4831                         if (TypeManager.IsGenericTypeDefinition (genericType))
4832                                 return;
4833                         this.constructed_generic_type = genericType;
4834                 }
4835
4836                 public override string Name {
4837                         get {
4838                                 return spec.Name;
4839                         }
4840                 }
4841
4842                 public override bool IsInstance {
4843                         get {
4844                                 return !spec.IsStatic;
4845                         }
4846                 }
4847
4848                 public override bool IsStatic {
4849                         get {
4850                                 return spec.IsStatic;
4851                         }
4852                 }
4853
4854                 public FieldSpec Spec {
4855                         get {
4856                                 return spec;
4857                         }
4858                 }
4859
4860                 public override Type DeclaringType {
4861                         get {
4862                                 return spec.MetaInfo.DeclaringType;
4863                         }
4864                 }
4865
4866                 public override string GetSignatureForError ()
4867                 {
4868                         return TypeManager.GetFullNameSignature (spec.MetaInfo);
4869                 }
4870
4871                 public VariableInfo VariableInfo {
4872                         get {
4873                                 return variable_info;
4874                         }
4875                 }
4876
4877                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
4878                                                                 SimpleName original)
4879                 {
4880                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (spec.MetaInfo);
4881                         Type t = fi.FieldType;
4882
4883                         if (t.IsPointer && !ec.IsUnsafe) {
4884                                 UnsafeError (ec, loc);
4885                         }
4886
4887                         return base.ResolveMemberAccess (ec, left, loc, original);
4888                 }
4889
4890                 public void SetHasAddressTaken ()
4891                 {
4892                         IVariableReference vr = InstanceExpression as IVariableReference;
4893                         if (vr != null)
4894                                 vr.SetHasAddressTaken ();
4895                 }
4896
4897                 public override Expression CreateExpressionTree (ResolveContext ec)
4898                 {
4899                         Expression instance;
4900                         if (InstanceExpression == null) {
4901                                 instance = new NullLiteral (loc);
4902                         } else {
4903                                 instance = InstanceExpression.CreateExpressionTree (ec);
4904                         }
4905
4906                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
4907                                 instance,
4908                                 CreateTypeOfExpression ());
4909
4910                         return CreateExpressionFactoryCall (ec, "Field", args);
4911                 }
4912
4913                 public Expression CreateTypeOfExpression ()
4914                 {
4915                         return new TypeOfField (Import.CreateField (GetConstructedFieldInfo ()), loc);
4916                 }
4917
4918                 protected override Expression DoResolve (ResolveContext ec)
4919                 {
4920                         return DoResolve (ec, false, false);
4921                 }
4922
4923                 Expression DoResolve (ResolveContext ec, bool lvalue_instance, bool out_access)
4924                 {
4925                         if (!IsStatic){
4926                                 if (InstanceExpression == null){
4927                                         //
4928                                         // This can happen when referencing an instance field using
4929                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4930                                         //
4931                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4932                                         return null;
4933                                 }
4934
4935                                 // Resolve the field's instance expression while flow analysis is turned
4936                                 // off: when accessing a field "a.b", we must check whether the field
4937                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4938
4939                                 if (lvalue_instance) {
4940                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
4941                                                 Expression right_side =
4942                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4943
4944                                                 if (InstanceExpression != EmptyExpression.Null)
4945                                                         InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side);
4946                                         }
4947                                 } else {
4948                                         if (InstanceExpression != EmptyExpression.Null) {
4949                                                 using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
4950                                                         InstanceExpression = InstanceExpression.Resolve (ec, ResolveFlags.VariableOrValue);
4951                                                 }
4952                                         }
4953                                 }
4954
4955                                 if (InstanceExpression == null)
4956                                         return null;
4957
4958                                 using (ec.Set (ResolveContext.Options.OmitStructFlowAnalysis)) {
4959                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4960                                 }
4961                         }
4962
4963                         if (!ec.IsObsolete) {
4964                                 FieldBase f = TypeManager.GetField (spec.MetaInfo);
4965                                 if (f != null) {
4966                                         f.CheckObsoleteness (loc);
4967                                 } else {
4968                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
4969                                         if (oa != null)
4970                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (spec.MetaInfo), loc, ec.Report);
4971                                 }
4972                         }
4973
4974                         var fb = spec as FixedFieldSpec;
4975                         IVariableReference var = InstanceExpression as IVariableReference;
4976
4977                         if (fb != null) {
4978                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4979                                 if (!ec.HasSet (ResolveContext.Options.FixedInitializerScope) && (fe == null || !fe.IsFixed)) {
4980                                         ec.Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4981                                 }
4982
4983                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4984                                         ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
4985                                         ec.Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4986                                                 TypeManager.GetFullNameSignature (spec.MetaInfo));
4987                                 } else if (var != null && var.IsHoisted) {
4988                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, var, loc);
4989                                 }
4990
4991                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4992                         }
4993
4994                         eclass = ExprClass.Variable;
4995
4996                         // If the instance expression is a local variable or parameter.
4997                         if (var == null || var.VariableInfo == null)
4998                                 return this;
4999
5000                         VariableInfo vi = var.VariableInfo;
5001                         if (!vi.IsFieldAssigned (ec, Name, loc))
5002                                 return null;
5003
5004                         variable_info = vi.GetSubStruct (Name);
5005                         return this;
5006                 }
5007
5008                 static readonly int [] codes = {
5009                         191,    // instance, write access
5010                         192,    // instance, out access
5011                         198,    // static, write access
5012                         199,    // static, out access
5013                         1648,   // member of value instance, write access
5014                         1649,   // member of value instance, out access
5015                         1650,   // member of value static, write access
5016                         1651    // member of value static, out access
5017                 };
5018
5019                 static readonly string [] msgs = {
5020                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
5021                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
5022                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
5023                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
5024                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
5025                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
5026                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
5027                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
5028                 };
5029
5030                 // The return value is always null.  Returning a value simplifies calling code.
5031                 Expression Report_AssignToReadonly (ResolveContext ec, Expression right_side)
5032                 {
5033                         int i = 0;
5034                         if (right_side == EmptyExpression.OutAccess.Instance || right_side == EmptyExpression.LValueMemberOutAccess)
5035                                 i += 1;
5036                         if (IsStatic)
5037                                 i += 2;
5038                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
5039                                 i += 4;
5040                         ec.Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
5041
5042                         return null;
5043                 }
5044
5045                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5046                 {
5047                         IVariableReference var = InstanceExpression as IVariableReference;
5048                         if (var != null && var.VariableInfo != null)
5049                                 var.VariableInfo.SetFieldAssigned (ec, Name);
5050
5051                         bool lvalue_instance = !spec.IsStatic && TypeManager.IsValueType (spec.MetaInfo.DeclaringType);
5052                         bool out_access = right_side == EmptyExpression.OutAccess.Instance || right_side == EmptyExpression.LValueMemberOutAccess;
5053
5054                         Expression e = DoResolve (ec, lvalue_instance, out_access);
5055
5056                         if (e == null)
5057                                 return null;
5058
5059                         FieldBase fb = TypeManager.GetField (spec.MetaInfo);
5060                         if (fb != null) {
5061                                 fb.SetAssigned ();
5062
5063                                 if ((right_side == EmptyExpression.UnaryAddress || right_side == EmptyExpression.OutAccess.Instance) &&
5064                                         (fb.ModFlags & Modifiers.VOLATILE) != 0) {
5065                                         ec.Report.Warning (420, 1, loc,
5066                                                 "`{0}': A volatile field references will not be treated as volatile",
5067                                                 fb.GetSignatureForError ());
5068                                 }
5069                         }
5070
5071                         if (spec.IsReadOnly) {
5072                                 // InitOnly fields can only be assigned in constructors or initializers
5073                                 if (!ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.ConstructorScope))
5074                                         return Report_AssignToReadonly (ec, right_side);
5075
5076                                 if (ec.HasSet (ResolveContext.Options.ConstructorScope)) {
5077                                         Type ctype = ec.CurrentType;
5078
5079                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
5080                                         if (!TypeManager.IsEqual (ctype, DeclaringType))
5081                                                 return Report_AssignToReadonly (ec, right_side);
5082                                         // static InitOnly fields cannot be assigned-to in an instance constructor
5083                                         if (IsStatic && !ec.IsStatic)
5084                                                 return Report_AssignToReadonly (ec, right_side);
5085                                         // instance constructors can't modify InitOnly fields of other instances of the same type
5086                                         if (!IsStatic && !(InstanceExpression is This))
5087                                                 return Report_AssignToReadonly (ec, right_side);
5088                                 }
5089                         }
5090
5091                         if (right_side == EmptyExpression.OutAccess.Instance &&
5092                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
5093                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5094                                 ec.Report.Warning (197, 1, loc,
5095                                                 "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",
5096                                                 GetSignatureForError ());
5097                         }
5098
5099                         eclass = ExprClass.Variable;
5100                         return this;
5101                 }
5102
5103                 bool is_marshal_by_ref ()
5104                 {
5105                         return !IsStatic && TypeManager.IsStruct (Type) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
5106                 }
5107
5108                 public override void CheckMarshalByRefAccess (ResolveContext ec)
5109                 {
5110                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
5111                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5112                                 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",
5113                                                 GetSignatureForError ());
5114                         }
5115                 }
5116
5117                 public override int GetHashCode ()
5118                 {
5119                         return spec.GetHashCode ();
5120                 }
5121
5122                 public bool IsFixed {
5123                         get {
5124                                 //
5125                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type
5126                                 //
5127                                 IVariableReference variable = InstanceExpression as IVariableReference;
5128                                 if (variable != null)
5129                                         return TypeManager.IsStruct (InstanceExpression.Type) && variable.IsFixed;
5130
5131                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
5132                                 return fe != null && fe.IsFixed;
5133                         }
5134                 }
5135
5136                 public bool IsHoisted {
5137                         get {
5138                                 IVariableReference hv = InstanceExpression as IVariableReference;
5139                                 return hv != null && hv.IsHoisted;
5140                         }
5141                 }
5142
5143                 public override bool Equals (object obj)
5144                 {
5145                         FieldExpr fe = obj as FieldExpr;
5146                         if (fe == null)
5147                                 return false;
5148
5149                         if (spec.MetaInfo != fe.spec.MetaInfo)
5150                                 return false;
5151
5152                         if (InstanceExpression == null || fe.InstanceExpression == null)
5153                                 return true;
5154
5155                         return InstanceExpression.Equals (fe.InstanceExpression);
5156                 }
5157
5158                 public void Emit (EmitContext ec, bool leave_copy)
5159                 {
5160                         ILGenerator ig = ec.ig;
5161                         bool is_volatile = false;
5162
5163                         var f = TypeManager.GetField (spec.MetaInfo);
5164                         if (f != null){
5165                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5166                                         is_volatile = true;
5167
5168                                 f.SetIsUsed ();
5169                         }
5170
5171                         if (IsStatic){
5172                                 if (is_volatile)
5173                                         ig.Emit (OpCodes.Volatile);
5174
5175                                 ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
5176                         } else {
5177                                 if (!prepared)
5178                                         EmitInstance (ec, false);
5179
5180                                 // Optimization for build-in types
5181                                 if (TypeManager.IsStruct (type) && TypeManager.IsEqual (type, ec.MemberContext.CurrentType) && TypeManager.IsEqual (InstanceExpression.Type, type)) {
5182                                         LoadFromPtr (ig, type);
5183                                 } else {
5184                                         var ff = spec as FixedFieldSpec;
5185                                         if (ff != null) {
5186                                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5187                                                 ig.Emit (OpCodes.Ldflda, ff.Element);
5188                                         } else {
5189                                                 if (is_volatile)
5190                                                         ig.Emit (OpCodes.Volatile);
5191
5192                                                 ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
5193                                         }
5194                                 }
5195                         }
5196
5197                         if (leave_copy) {
5198                                 ec.ig.Emit (OpCodes.Dup);
5199                                 if (!IsStatic) {
5200                                         temp = new LocalTemporary (this.Type);
5201                                         temp.Store (ec);
5202                                 }
5203                         }
5204                 }
5205
5206                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5207                 {
5208                         //FieldAttributes fa = FieldInfo.Attributes;
5209                         //bool is_static = (fa & FieldAttributes.Static) != 0;
5210                         ILGenerator ig = ec.ig;
5211
5212                         prepared = prepare_for_load;
5213                         EmitInstance (ec, prepared);
5214
5215                         source.Emit (ec);
5216                         if (leave_copy) {
5217                                 ec.ig.Emit (OpCodes.Dup);
5218                                 if (!IsStatic) {
5219                                         temp = new LocalTemporary (this.Type);
5220                                         temp.Store (ec);
5221                                 }
5222                         }
5223
5224                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5225                         if (f != null){
5226                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5227                                         ig.Emit (OpCodes.Volatile);
5228
5229                                 f.SetAssigned ();
5230                         }
5231
5232                         if (IsStatic)
5233                                 ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
5234                         else
5235                                 ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
5236
5237                         if (temp != null) {
5238                                 temp.Emit (ec);
5239                                 temp.Release (ec);
5240                                 temp = null;
5241                         }
5242                 }
5243
5244                 public override void Emit (EmitContext ec)
5245                 {
5246                         Emit (ec, false);
5247                 }
5248
5249                 public override void EmitSideEffect (EmitContext ec)
5250                 {
5251                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5252                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
5253
5254                         if (is_volatile || is_marshal_by_ref ())
5255                                 base.EmitSideEffect (ec);
5256                 }
5257
5258                 public override void Error_VariableIsUsedBeforeItIsDeclared (Report r, string name)
5259                 {
5260                         r.Error (844, loc,
5261                                 "A local variable `{0}' cannot be used before it is declared. Consider renaming the local variable when it hides the field `{1}'",
5262                                 name, GetSignatureForError ());
5263                 }
5264
5265                 public void AddressOf (EmitContext ec, AddressOp mode)
5266                 {
5267                         ILGenerator ig = ec.ig;
5268
5269                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5270                         if (f != null){
5271                                 if ((mode & AddressOp.Store) != 0)
5272                                         f.SetAssigned ();
5273                                 if ((mode & AddressOp.Load) != 0)
5274                                         f.SetIsUsed ();
5275                         }
5276
5277                         //
5278                         // Handle initonly fields specially: make a copy and then
5279                         // get the address of the copy.
5280                         //
5281                         bool need_copy;
5282                         if (spec.IsReadOnly){
5283                                 need_copy = true;
5284                                 if (ec.HasSet (EmitContext.Options.ConstructorScope)){
5285                                         if (IsStatic){
5286                                                 if (ec.IsStatic)
5287                                                         need_copy = false;
5288                                         } else
5289                                                 need_copy = false;
5290                                 }
5291                         } else
5292                                 need_copy = false;
5293
5294                         if (need_copy){
5295                                 LocalBuilder local;
5296                                 Emit (ec);
5297                                 local = ig.DeclareLocal (type);
5298                                 ig.Emit (OpCodes.Stloc, local);
5299                                 ig.Emit (OpCodes.Ldloca, local);
5300                                 return;
5301                         }
5302
5303
5304                         if (IsStatic){
5305                                 ig.Emit (OpCodes.Ldsflda, GetConstructedFieldInfo ());
5306                         } else {
5307                                 if (!prepared)
5308                                         EmitInstance (ec, false);
5309                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5310                         }
5311                 }
5312
5313                 FieldInfo GetConstructedFieldInfo ()
5314                 {
5315                         if (constructed_generic_type == null)
5316                                 return spec.MetaInfo;
5317
5318                         return TypeBuilder.GetField (constructed_generic_type, spec.MetaInfo);
5319                 }
5320
5321                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5322                 {
5323                         return MakeExpression (ctx);
5324                 }
5325
5326                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5327                 {
5328                         return SLE.Expression.Field (InstanceExpression.MakeExpression (ctx), spec.MetaInfo);
5329                 }
5330
5331                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5332                 {
5333                         storey.MutateField (spec);
5334                         base.MutateHoistedGenericType (storey);
5335                 }
5336         }
5337
5338
5339         /// <summary>
5340         ///   Expression that evaluates to a Property.  The Assign class
5341         ///   might set the `Value' expression if we are in an assignment.
5342         ///
5343         ///   This is not an LValue because we need to re-write the expression, we
5344         ///   can not take data from the stack and store it.
5345         /// </summary>
5346         public class PropertyExpr : MemberExpr, IDynamicAssign
5347         {
5348                 PropertySpec spec;
5349                 MethodSpec getter, setter;
5350                 bool is_static;
5351
5352                 TypeArguments targs;
5353
5354                 LocalTemporary temp;
5355                 bool prepared;
5356
5357                 public PropertyExpr (Type container_type, PropertySpec spec, Location l)
5358                 {
5359                         this.spec = spec;
5360                         loc = l;
5361
5362                         type = TypeManager.TypeToCoreType (spec.PropertyType);
5363
5364                         ResolveAccessors (container_type);
5365                 }
5366
5367                 public override string Name {
5368                         get {
5369                                 return spec.Name;
5370                         }
5371                 }
5372
5373                 public override bool IsInstance {
5374                         get {
5375                                 return !is_static;
5376                         }
5377                 }
5378
5379                 public override bool IsStatic {
5380                         get {
5381                                 return is_static;
5382                         }
5383                 }
5384
5385                 public override Expression CreateExpressionTree (ResolveContext ec)
5386                 {
5387                         Arguments args;
5388                         if (IsSingleDimensionalArrayLength ()) {
5389                                 args = new Arguments (1);
5390                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5391                                 return CreateExpressionFactoryCall (ec, "ArrayLength", args);
5392                         }
5393
5394                         if (is_base) {
5395                                 Error_BaseAccessInExpressionTree (ec, loc);
5396                                 return null;
5397                         }
5398
5399                         args = new Arguments (2);
5400                         if (InstanceExpression == null)
5401                                 args.Add (new Argument (new NullLiteral (loc)));
5402                         else
5403                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5404                         args.Add (new Argument (new TypeOfMethod (getter, loc)));
5405                         return CreateExpressionFactoryCall (ec, "Property", args);
5406                 }
5407
5408                 public Expression CreateSetterTypeOfExpression ()
5409                 {
5410                         return new TypeOfMethod (setter, loc);
5411                 }
5412
5413                 public override Type DeclaringType {
5414                         get {
5415                                 return spec.DeclaringType;
5416                         }
5417                 }
5418
5419                 public override string GetSignatureForError ()
5420                 {
5421                         return TypeManager.GetFullNameSignature (spec.MetaInfo);
5422                 }
5423
5424                 void FindAccessors (Type invocation_type)
5425                 {
5426                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5427                                 BindingFlags.Static | BindingFlags.Instance |
5428                                 BindingFlags.DeclaredOnly;
5429
5430                         Type current = spec.DeclaringType;
5431                         for (; current != null; current = current.BaseType) {
5432                                 MemberInfo[] group = TypeManager.MemberLookup (
5433                                         invocation_type, invocation_type, current,
5434                                         MemberTypes.Property, flags, spec.Name, null);
5435
5436                                 if (group == null)
5437                                         continue;
5438
5439                                 if (group.Length != 1)
5440                                         // Oooops, can this ever happen ?
5441                                         return;
5442
5443                                 PropertyInfo pi = (PropertyInfo) group [0];
5444
5445                                 if (getter == null) {
5446                                         var m = pi.GetGetMethod (true);
5447                                         if (m != null)
5448                                                 getter = Import.CreateMethod (m);
5449                                 }
5450
5451                                 if (setter == null) {
5452                                         var m = pi.GetSetMethod (true);
5453                                         if (m != null)
5454                                                 setter = Import.CreateMethod (m);
5455                                 }
5456
5457                                 var accessor = getter != null ? getter : setter;
5458
5459                                 if (!accessor.IsVirtual)
5460                                         return;
5461                         }
5462                 }
5463
5464                 //
5465                 // We also perform the permission checking here, as the PropertyInfo does not
5466                 // hold the information for the accessibility of its setter/getter
5467                 //
5468                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5469                 void ResolveAccessors (Type container_type)
5470                 {
5471                         FindAccessors (container_type);
5472
5473                         if (getter != null) {
5474                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5475                                 IMethodData md = TypeManager.GetMethod (the_getter);
5476                                 if (md != null)
5477                                         md.SetIsUsed ();
5478
5479                                 is_static = getter.IsStatic;
5480                         }
5481
5482                         if (setter != null) {
5483                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5484                                 IMethodData md = TypeManager.GetMethod (the_setter);
5485                                 if (md != null)
5486                                         md.SetIsUsed ();
5487
5488                                 is_static = setter.IsStatic;
5489                         }
5490                 }
5491
5492                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5493                 {
5494                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), (MethodInfo) setter.MetaInfo);
5495                 }
5496
5497                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5498                 {
5499                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), (MethodInfo) getter.MetaInfo);
5500                 }
5501
5502                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5503                 {
5504                         if (InstanceExpression != null)
5505                                 InstanceExpression.MutateHoistedGenericType (storey);
5506
5507                         type = storey.MutateType (type);
5508                         if (getter != null)
5509                                 storey.MutateGenericMethod (getter);
5510                         if (setter != null)
5511                                 storey.MutateGenericMethod (setter);
5512                 }
5513
5514                 public PropertyInfo PropertyInfo {
5515                         get {
5516                                 return spec.MetaInfo;
5517                         }
5518                 }
5519
5520                 bool InstanceResolve (ResolveContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5521                 {
5522                         if (is_static) {
5523                                 InstanceExpression = null;
5524                                 return true;
5525                         }
5526
5527                         if (InstanceExpression == null) {
5528                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5529                                 return false;
5530                         }
5531
5532                         InstanceExpression = InstanceExpression.Resolve (ec);
5533                         if (lvalue_instance && InstanceExpression != null)
5534                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess);
5535
5536                         if (InstanceExpression == null)
5537                                 return false;
5538
5539                         InstanceExpression.CheckMarshalByRefAccess (ec);
5540
5541                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5542                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5543                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5544                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5545                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
5546                                 Error_CannotAccessProtected (ec, loc, spec.MetaInfo, InstanceExpression.Type, ec.CurrentType);
5547                                 return false;
5548                         }
5549
5550                         return true;
5551                 }
5552
5553                 void Error_PropertyNotFound (ResolveContext ec, MethodSpec mi, bool getter)
5554                 {
5555                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5556                         if (mi.MetaInfo is MethodBuilder) {
5557                                 Error_TypeDoesNotContainDefinition (ec, loc, spec.DeclaringType, Name);
5558                                 return;
5559                         }
5560
5561                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5562                         sig.Append ('.');
5563                         AParametersCollection iparams = mi.Parameters;
5564                         sig.Append (getter ? "get_" : "set_");
5565                         sig.Append (Name);
5566                         sig.Append (iparams.GetSignatureForError ());
5567
5568                         ec.Report.SymbolRelatedToPreviousError (mi.MetaInfo);
5569                         ec.Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5570                                 Name, sig.ToString ());
5571                 }
5572
5573                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5574                 {
5575                         bool dummy;
5576                         var accessor = lvalue ? setter : getter;
5577                         if (accessor == null && lvalue)
5578                                 accessor = getter;
5579                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5580                 }
5581
5582                 bool IsSingleDimensionalArrayLength ()
5583                 {
5584                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5585                                 return false;
5586
5587                         string t_name = InstanceExpression.Type.Name;
5588                         int t_name_len = t_name.Length;
5589                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5590                 }
5591
5592                 protected override Expression DoResolve (ResolveContext ec)
5593                 {
5594                         eclass = ExprClass.PropertyAccess;
5595
5596                         bool must_do_cs1540_check = false;
5597                         ec.Report.DisableReporting ();
5598                         bool res = ResolveGetter (ec, ref must_do_cs1540_check);
5599                         ec.Report.EnableReporting ();
5600
5601                         if (!res) {
5602                                 if (InstanceExpression != null) {
5603                                         Type expr_type = InstanceExpression.Type;
5604                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (expr_type, Name, loc);
5605                                         if (ex_method_lookup != null) {
5606                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
5607                                                 ex_method_lookup.SetTypeArguments (ec, targs);
5608                                                 return ex_method_lookup.Resolve (ec);
5609                                         }
5610                                 }
5611
5612                                 ResolveGetter (ec, ref must_do_cs1540_check);
5613                                 return null;
5614                         }
5615
5616                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5617                                 return null;
5618
5619                         //
5620                         // Only base will allow this invocation to happen.
5621                         //
5622                         if (IsBase && getter.IsAbstract) {
5623                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (spec.MetaInfo));
5624                         }
5625
5626                         if (spec.PropertyType.IsPointer && !ec.IsUnsafe){
5627                                 UnsafeError (ec, loc);
5628                         }
5629
5630                         if (!ec.IsObsolete) {
5631                                 PropertyBase pb = TypeManager.GetProperty (spec.MetaInfo);
5632                                 if (pb != null) {
5633                                         pb.CheckObsoleteness (loc);
5634                                 } else {
5635                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
5636                                         if (oa != null)
5637                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5638                                 }
5639                         }
5640
5641                         return this;
5642                 }
5643
5644                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5645                 {
5646                         eclass = ExprClass.PropertyAccess;
5647
5648                         if (right_side == EmptyExpression.OutAccess.Instance) {
5649                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (spec.Name, loc) is MemberAccess) {
5650                                         ec.Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5651                                             spec.Name);
5652                                 } else {
5653                                         right_side.DoResolveLValue (ec, this);
5654                                 }
5655                                 return null;
5656                         }
5657
5658                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5659                                 Error_CannotModifyIntermediateExpressionValue (ec);
5660                         }
5661
5662                         if (setter == null){
5663                                 //
5664                                 // The following condition happens if the PropertyExpr was
5665                                 // created, but is invalid (ie, the property is inaccessible),
5666                                 // and we did not want to embed the knowledge about this in
5667                                 // the caller routine.  This only avoids double error reporting.
5668                                 //
5669                                 if (getter == null)
5670                                         return null;
5671
5672                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (spec.Name, loc) is MemberAccess) {
5673                                         ec.Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5674                                                 spec.Name);
5675                                 } else {
5676                                         ec.Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5677                                                 GetSignatureForError ());
5678                                 }
5679                                 return null;
5680                         }
5681
5682                         if (targs != null) {
5683                                 base.SetTypeArguments (ec, targs);
5684                                 return null;
5685                         }
5686
5687                         if (setter.Parameters.Count != 1){
5688                                 Error_PropertyNotFound (ec, setter, false);
5689                                 return null;
5690                         }
5691
5692                         bool must_do_cs1540_check;
5693                         if (!IsAccessorAccessible (ec.CurrentType, setter, out must_do_cs1540_check)) {
5694                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter.MetaInfo) as PropertyBase.PropertyMethod;
5695                                 if (pm != null && pm.HasCustomAccessModifier) {
5696                                         ec.Report.SymbolRelatedToPreviousError (pm);
5697                                         ec.Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5698                                                 TypeManager.CSharpSignature (setter));
5699                                 }
5700                                 else {
5701                                         ec.Report.SymbolRelatedToPreviousError (setter.MetaInfo);
5702                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter), ec.Report);
5703                                 }
5704                                 return null;
5705                         }
5706
5707                         if (!InstanceResolve (ec, TypeManager.IsStruct (spec.DeclaringType), must_do_cs1540_check))
5708                                 return null;
5709
5710                         //
5711                         // Only base will allow this invocation to happen.
5712                         //
5713                         if (IsBase && setter.IsAbstract){
5714                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (spec.MetaInfo));
5715                         }
5716
5717                         if (spec.PropertyType.IsPointer && !ec.IsUnsafe) {
5718                                 UnsafeError (ec, loc);
5719                         }
5720
5721                         if (!ec.IsObsolete) {
5722                                 PropertyBase pb = TypeManager.GetProperty (spec.MetaInfo);
5723                                 if (pb != null) {
5724                                         pb.CheckObsoleteness (loc);
5725                                 } else {
5726                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
5727                                         if (oa != null)
5728                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5729                                 }
5730                         }
5731
5732                         return this;
5733                 }
5734
5735                 public override void Emit (EmitContext ec)
5736                 {
5737                         Emit (ec, false);
5738                 }
5739
5740                 public void Emit (EmitContext ec, bool leave_copy)
5741                 {
5742                         //
5743                         // Special case: length of single dimension array property is turned into ldlen
5744                         //
5745                         if (IsSingleDimensionalArrayLength ()) {
5746                                 if (!prepared)
5747                                         EmitInstance (ec, false);
5748                                 ec.ig.Emit (OpCodes.Ldlen);
5749                                 ec.ig.Emit (OpCodes.Conv_I4);
5750                                 return;
5751                         }
5752
5753                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5754
5755                         if (leave_copy) {
5756                                 ec.ig.Emit (OpCodes.Dup);
5757                                 if (!is_static) {
5758                                         temp = new LocalTemporary (this.Type);
5759                                         temp.Store (ec);
5760                                 }
5761                         }
5762                 }
5763
5764                 //
5765                 // Implements the IAssignMethod interface for assignments
5766                 //
5767                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5768                 {
5769                         Expression my_source = source;
5770
5771                         if (prepare_for_load) {
5772                                 prepared = true;
5773                                 source.Emit (ec);
5774
5775                                 if (leave_copy) {
5776                                         ec.ig.Emit (OpCodes.Dup);
5777                                         if (!is_static) {
5778                                                 temp = new LocalTemporary (this.Type);
5779                                                 temp.Store (ec);
5780                                         }
5781                                 }
5782                         } else if (leave_copy) {
5783                                 source.Emit (ec);
5784                                 temp = new LocalTemporary (this.Type);
5785                                 temp.Store (ec);
5786                                 my_source = temp;
5787                         }
5788
5789                         Arguments args = new Arguments (1);
5790                         args.Add (new Argument (my_source));
5791
5792                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5793
5794                         if (temp != null) {
5795                                 temp.Emit (ec);
5796                                 temp.Release (ec);
5797                         }
5798                 }
5799
5800                 bool ResolveGetter (ResolveContext ec, ref bool must_do_cs1540_check)
5801                 {
5802                         if (targs != null) {
5803                                 base.SetTypeArguments (ec, targs);
5804                                 return false;
5805                         }
5806
5807                         if (getter != null) {
5808                                 if (!getter.Parameters.IsEmpty) {
5809                                         Error_PropertyNotFound (ec, getter, true);
5810                                         return false;
5811                                 }
5812                         }
5813
5814                         if (getter == null) {
5815                                 //
5816                                 // The following condition happens if the PropertyExpr was
5817                                 // created, but is invalid (ie, the property is inaccessible),
5818                                 // and we did not want to embed the knowledge about this in
5819                                 // the caller routine.  This only avoids double error reporting.
5820                                 //
5821                                 if (setter == null)
5822                                         return false;
5823
5824                                 if (InstanceExpression != EmptyExpression.Null) {
5825                                         ec.Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5826                                                 TypeManager.GetFullNameSignature (spec.MetaInfo));
5827                                         return false;
5828                                 }
5829                         }
5830
5831                         if (getter != null &&
5832                                 !IsAccessorAccessible (ec.CurrentType, getter, out must_do_cs1540_check)) {
5833                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter.MetaInfo) as PropertyBase.PropertyMethod;
5834                                 if (pm != null && pm.HasCustomAccessModifier) {
5835                                         ec.Report.SymbolRelatedToPreviousError (pm);
5836                                         ec.Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5837                                                 TypeManager.CSharpSignature (getter.MetaInfo));
5838                                 } else {
5839                                         ec.Report.SymbolRelatedToPreviousError (getter.MetaInfo);
5840                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter.MetaInfo), ec.Report);
5841                                 }
5842
5843                                 return false;
5844                         }
5845
5846                         return true;
5847                 }
5848
5849                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
5850                 {
5851                         targs = ta;
5852                 }
5853         }
5854
5855         /// <summary>
5856         ///   Fully resolved expression that evaluates to an Event
5857         /// </summary>
5858         public class EventExpr : MemberExpr
5859         {
5860                 readonly EventSpec spec;
5861
5862                 public EventExpr (EventSpec spec, Location loc)
5863                 {
5864                         this.spec = spec;
5865                         this.loc = loc;
5866                 }
5867
5868                 public override string Name {
5869                         get {
5870                                 return spec.Name;
5871                         }
5872                 }
5873
5874                 public override bool IsInstance {
5875                         get {
5876                                 return !spec.IsStatic;
5877                         }
5878                 }
5879
5880                 public override bool IsStatic {
5881                         get {
5882                                 return spec.IsStatic;
5883                         }
5884                 }
5885
5886                 public override Type DeclaringType {
5887                         get {
5888                                 return spec.DeclaringType;
5889                         }
5890                 }
5891
5892                 public void Error_AssignmentEventOnly (ResolveContext ec)
5893                 {
5894                         ec.Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5895                                 GetSignatureForError ());
5896                 }
5897
5898                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
5899                                                                 SimpleName original)
5900                 {
5901                         //
5902                         // If the event is local to this class, we transform ourselves into a FieldExpr
5903                         //
5904
5905                         if (spec.DeclaringType == ec.CurrentType ||
5906                             TypeManager.IsNestedChildOf(ec.CurrentType, spec.DeclaringType)) {
5907
5908                                 // TODO: Breaks dynamic binder as currect context fields are imported and not compiled
5909                                 EventField mi = TypeManager.GetEventField (spec.MetaInfo).MemberDefinition as EventField;
5910
5911                                 if (mi != null && mi.HasBackingField) {
5912                                         mi.SetIsUsed ();
5913                                         if (!ec.IsObsolete)
5914                                                 mi.CheckObsoleteness (loc);
5915
5916                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5917                                                 Error_AssignmentEventOnly (ec);
5918
5919                                         FieldExpr ml = new FieldExpr (mi.BackingField, loc);
5920
5921                                         InstanceExpression = null;
5922
5923                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5924                                 }
5925                         }
5926
5927                         if (left is This && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5928                                 Error_AssignmentEventOnly (ec);
5929
5930                         return base.ResolveMemberAccess (ec, left, loc, original);
5931                 }
5932
5933                 bool InstanceResolve (ResolveContext ec, bool must_do_cs1540_check)
5934                 {
5935                         if (IsStatic) {
5936                                 InstanceExpression = null;
5937                                 return true;
5938                         }
5939
5940                         if (InstanceExpression == null) {
5941                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5942                                 return false;
5943                         }
5944
5945                         InstanceExpression = InstanceExpression.Resolve (ec);
5946                         if (InstanceExpression == null)
5947                                 return false;
5948
5949                         if (IsBase && spec.IsAbstract) {
5950                                 Error_CannotCallAbstractBase (ec, TypeManager.CSharpSignature(spec.MetaInfo));
5951                                 return false;
5952                         }
5953
5954                         //
5955                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5956                         // However, in the Event case, we reported a CS0122 instead.
5957                         //
5958                         // TODO: Exact copy from PropertyExpr
5959                         //
5960                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5961                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5962                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5963                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5964                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
5965                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (spec.MetaInfo), ec.Report);
5966                                 return false;
5967                         }
5968
5969                         return true;
5970                 }
5971
5972                 public bool IsAccessibleFrom (Type invocation_type)
5973                 {
5974                         bool dummy;
5975                         return IsAccessorAccessible (invocation_type, spec.AccessorAdd, out dummy) &&
5976                                 IsAccessorAccessible (invocation_type, spec.AccessorRemove, out dummy);
5977                 }
5978
5979                 public override Expression CreateExpressionTree (ResolveContext ec)
5980                 {
5981                         throw new NotSupportedException ("ET");
5982                 }
5983
5984                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5985                 {
5986                         // contexts where an LValue is valid have already devolved to FieldExprs
5987                         Error_CannotAssign (ec);
5988                         return null;
5989                 }
5990
5991                 protected override Expression DoResolve (ResolveContext ec)
5992                 {
5993                         eclass = ExprClass.EventAccess;
5994
5995                         bool must_do_cs1540_check;
5996                         if (!(IsAccessorAccessible (ec.CurrentType, spec.AccessorAdd, out must_do_cs1540_check) &&
5997                               IsAccessorAccessible (ec.CurrentType, spec.AccessorRemove, out must_do_cs1540_check))) {
5998                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
5999                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (spec.MetaInfo), ec.Report);
6000                                 return null;
6001                         }
6002
6003                         if (!InstanceResolve (ec, must_do_cs1540_check))
6004                                 return null;
6005
6006                         if (!ec.HasSet (ResolveContext.Options.CompoundAssignmentScope)) {
6007                                 Error_CannotAssign (ec);
6008                                 return null;
6009                         }
6010
6011                         if (!ec.IsObsolete) {
6012                                 var oa = spec.GetObsoleteAttribute ();
6013                                 if (oa != null)
6014                                         AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
6015                         }
6016
6017                         spec.MemberDefinition.SetIsUsed ();
6018                         type = spec.EventType;
6019
6020                         return this;
6021                 }
6022
6023                 public override void Emit (EmitContext ec)
6024                 {
6025                         throw new NotSupportedException ();
6026                         //Error_CannotAssign ();
6027                 }
6028
6029                 public void Error_CannotAssign (ResolveContext ec)
6030                 {
6031                         ec.Report.Error (70, loc,
6032                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
6033                                 GetSignatureForError (), TypeManager.CSharpName (spec.DeclaringType));
6034                 }
6035
6036                 public override string GetSignatureForError ()
6037                 {
6038                         return TypeManager.CSharpSignature (spec.MetaInfo);
6039                 }
6040
6041                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
6042                 {
6043                         Arguments args = new Arguments (1);
6044                         args.Add (new Argument (source));
6045                         Invocation.EmitCall (ec, IsBase, InstanceExpression,
6046                                 is_add ? spec.AccessorAdd : spec.AccessorRemove,
6047                                 args, loc);
6048                 }
6049         }
6050
6051         public class TemporaryVariable : VariableReference
6052         {
6053                 LocalInfo li;
6054
6055                 public TemporaryVariable (Type type, Location loc)
6056                 {
6057                         this.type = type;
6058                         this.loc = loc;
6059                 }
6060
6061                 public override Expression CreateExpressionTree (ResolveContext ec)
6062                 {
6063                         throw new NotSupportedException ("ET");
6064                 }
6065
6066                 protected override Expression DoResolve (ResolveContext ec)
6067                 {
6068                         eclass = ExprClass.Variable;
6069
6070                         TypeExpr te = new TypeExpression (type, loc);
6071                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
6072                         if (!li.Resolve (ec))
6073                                 return null;
6074
6075                         //
6076                         // Don't capture temporary variables except when using
6077                         // iterator redirection
6078                         //
6079                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
6080                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
6081                                 storey.CaptureLocalVariable (ec, li);
6082                         }
6083
6084                         return this;
6085                 }
6086
6087                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6088                 {
6089                         return Resolve (ec);
6090                 }
6091
6092                 public override void Emit (EmitContext ec)
6093                 {
6094                         Emit (ec, false);
6095                 }
6096
6097                 public void EmitAssign (EmitContext ec, Expression source)
6098                 {
6099                         EmitAssign (ec, source, false, false);
6100                 }
6101
6102                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6103                 {
6104                         return li.HoistedVariant;
6105                 }
6106
6107                 public override bool IsFixed {
6108                         get { return true; }
6109                 }
6110
6111                 public override bool IsRef {
6112                         get { return false; }
6113                 }
6114
6115                 public override string Name {
6116                         get { throw new NotImplementedException (); }
6117                 }
6118
6119                 public override void SetHasAddressTaken ()
6120                 {
6121                         throw new NotImplementedException ();
6122                 }
6123
6124                 protected override ILocalVariable Variable {
6125                         get { return li; }
6126                 }
6127
6128                 public override VariableInfo VariableInfo {
6129                         get { throw new NotImplementedException (); }
6130                 }
6131         }
6132
6133         ///
6134         /// Handles `var' contextual keyword; var becomes a keyword only
6135         /// if no type called var exists in a variable scope
6136         ///
6137         class VarExpr : SimpleName
6138         {
6139                 // Used for error reporting only
6140                 int initializers_count;
6141
6142                 public VarExpr (Location loc)
6143                         : base ("var", loc)
6144                 {
6145                         initializers_count = 1;
6146                 }
6147
6148                 public int VariableInitializersCount {
6149                         set {
6150                                 this.initializers_count = value;
6151                         }
6152                 }
6153
6154                 public bool InferType (ResolveContext ec, Expression right_side)
6155                 {
6156                         if (type != null)
6157                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
6158
6159                         type = right_side.Type;
6160                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == InternalType.AnonymousMethod || type == InternalType.MethodGroup) {
6161                                 ec.Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
6162                                               right_side.GetSignatureForError ());
6163                                 return false;
6164                         }
6165
6166                         eclass = ExprClass.Variable;
6167                         return true;
6168                 }
6169
6170                 protected override void Error_TypeOrNamespaceNotFound (IMemberContext ec)
6171                 {
6172                         if (RootContext.Version < LanguageVersion.V_3)
6173                                 base.Error_TypeOrNamespaceNotFound (ec);
6174                         else
6175                                 ec.Compiler.Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
6176                 }
6177
6178                 public override TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
6179                 {
6180                         TypeExpr te = base.ResolveAsContextualType (rc, true);
6181                         if (te != null)
6182                                 return te;
6183
6184                         if (RootContext.Version < LanguageVersion.V_3)
6185                                 rc.Compiler.Report.FeatureIsNotAvailable (loc, "implicitly typed local variable");
6186
6187                         if (initializers_count == 1)
6188                                 return null;
6189
6190                         if (initializers_count > 1) {
6191                                 rc.Compiler.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
6192                                 initializers_count = 1;
6193                                 return null;
6194                         }
6195
6196                         if (initializers_count == 0) {
6197                                 initializers_count = 1;
6198                                 rc.Compiler.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
6199                                 return null;
6200                         }
6201
6202                         return null;
6203                 }
6204         }
6205 }