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 bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
 141                 {
 142                         Attribute.Error_AttributeArgumentNotValid (ec, loc);
 143                         value = null;
 144                         return false;
 145                 }
 146
 147                 public virtual string GetSignatureForError ()
 148                 {
 149                         return TypeManager.CSharpName (type);
 150                 }
 151
 152                 public static bool IsAccessorAccessible (Type invocation_type, MethodSpec mi, out bool must_do_cs1540_check)
 153                 {
 154                         var ma = mi.Modifiers & Modifiers.AccessibilityMask;
 155
 156                         must_do_cs1540_check = false; // by default we do not check for this
 157
 158                         if (ma == Modifiers.PUBLIC)
 159                                 return true;
 160
 161                         //
 162                         // If only accessible to the current class or children
 163                         //
 164                         if (ma == Modifiers.PRIVATE)
 165                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 166                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 167
 168                         if ((ma & Modifiers.INTERNAL) != 0) {
 169                                 var b = TypeManager.IsThisOrFriendAssembly (invocation_type.Assembly, mi.DeclaringType.Assembly);
 170                                 if (b || ma == Modifiers.INTERNAL)
 171                                         return b;
 172                         }
 173
 174                         // Family and FamANDAssem require that we derive.
 175                         // FamORAssem requires that we derive if in different assemblies.
 176                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 177                                 return false;
 178
 179                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 180                                 must_do_cs1540_check = true;
 181
 182                         return true;
 183                 }
 184
 185                 public virtual bool IsNull {
 186                         get {
 187                                 return false;
 188                         }
 189                 }
 190
 191                 /// <summary>
 192                 ///   Performs semantic analysis on the Expression
 193                 /// </summary>
 194                 ///
 195                 /// <remarks>
 196                 ///   The Resolve method is invoked to perform the semantic analysis
 197                 ///   on the node.
 198                 ///
 199                 ///   The return value is an expression (it can be the
 200                 ///   same expression in some cases) or a new
 201                 ///   expression that better represents this node.
 202                 ///
 203                 ///   For example, optimizations of Unary (LiteralInt)
 204                 ///   would return a new LiteralInt with a negated
 205                 ///   value.
 206                 ///
 207                 ///   If there is an error during semantic analysis,
 208                 ///   then an error should be reported (using Report)
 209                 ///   and a null value should be returned.
 210                 ///
 211                 ///   There are two side effects expected from calling
 212                 ///   Resolve(): the the field variable "eclass" should
 213                 ///   be set to any value of the enumeration
 214                 ///   `ExprClass' and the type variable should be set
 215                 ///   to a valid type (this is the type of the
 216                 ///   expression).
 217                 /// </remarks>
 218                 protected abstract Expression DoResolve (ResolveContext rc);
 219
 220                 public virtual Expression DoResolveLValue (ResolveContext rc, Expression right_side)
 221                 {
 222                         return null;
 223                 }
 224
 225                 //
 226                 // This is used if the expression should be resolved as a type or namespace name.
 227                 // the default implementation fails.
 228                 //
 229                 public virtual FullNamedExpression ResolveAsTypeStep (IMemberContext rc,  bool silent)
 230                 {
 231                         if (!silent) {
 232                                 ResolveContext ec = new ResolveContext (rc);
 233                                 Expression e = Resolve (ec);
 234                                 if (e != null)
 235                                         e.Error_UnexpectedKind (ec, ResolveFlags.Type, loc);
 236                         }
 237
 238                         return null;
 239                 }
 240
 241                 //
 242                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 243                 // same name exists or as a keyword when no type was found
 244                 //
 245                 public virtual TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
 246                 {
 247                         return ResolveAsTypeTerminal (rc, silent);
 248                 }
 249
 250                 //
 251                 // This is used to resolve the expression as a type, a null
 252                 // value will be returned if the expression is not a type
 253                 // reference
 254                 //
 255                 public virtual TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
 256                 {
 257                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 258                         if (te == null)
 259                                 return null;
 260
 261                         if (!silent) { // && !(te is TypeParameterExpr)) {
 262                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 263                                 if (obsolete_attr != null && !ec.IsObsolete) {
 264                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location, ec.Compiler.Report);
 265                                 }
 266                         }
 267
 268                         GenericTypeExpr ct = te as GenericTypeExpr;
 269                         if (ct != null) {
 270                                 //
 271                                 // TODO: Constrained type parameters check for parameters of generic method overrides is broken
 272                                 // There are 2 solutions.
 273                                 // 1, Skip this check completely when we are in override/explicit impl scope
 274                                 // 2, Copy type parameters constraints from base implementation and pass (they have to be emitted anyway)
 275                                 //
 276                                 MemberCore gm = ec as GenericMethod;
 277                                 if (gm == null)
 278                                         gm = ec as Method;
 279                                 if (gm != null && ((gm.ModFlags & Modifiers.OVERRIDE) != 0 || gm.MemberName.Left != null)) {
 280                                         te.loc = loc;
 281                                         return te;
 282                                 }
 283
 284                                 // TODO: silent flag is ignored
 285                                 ct.CheckConstraints (ec);
 286                         }
 287
 288                         return te;
 289                 }
 290
 291                 public TypeExpr ResolveAsBaseTerminal (IMemberContext ec, bool silent)
 292                 {
 293                         int errors = ec.Compiler.Report.Errors;
 294
 295                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 296
 297                         if (fne == null)
 298                                 return null;
 299
 300                         TypeExpr te = fne as TypeExpr;
 301                         if (te == null) {
 302                                 if (!silent && errors == ec.Compiler.Report.Errors)
 303                                         fne.Error_UnexpectedKind (ec.Compiler.Report, null, "type", loc);
 304                                 return null;
 305                         }
 306
 307                         if (!te.CheckAccessLevel (ec)) {
 308                                 ec.Compiler.Report.SymbolRelatedToPreviousError (te.Type);
 309                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type), ec.Compiler.Report);
 310                                 return null;
 311                         }
 312
 313                         te.loc = loc;
 314                         return te;
 315                 }
 316
 317                 public static void ErrorIsInaccesible (Location loc, string name, Report Report)
 318                 {
 319                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 320                 }
 321
 322                 protected static void Error_CannotAccessProtected (ResolveContext ec, Location loc, MemberInfo m, Type qualifier, Type container)
 323                 {
 324                         ec.Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 325                                 + " The qualifier must be of type `{2}' or derived from it",
 326                                 TypeManager.GetFullNameSignature (m),
 327                                 TypeManager.CSharpName (qualifier),
 328                                 TypeManager.CSharpName (container));
 329
 330                 }
 331
 332                 public void Error_ExpressionMustBeConstant (ResolveContext rc, Location loc, string e_name)
 333                 {
 334                         rc.Report.Error (133, loc, "The expression being assigned to `{0}' must be constant", e_name);
 335                 }
 336
 337                 public void Error_ConstantCanBeInitializedWithNullOnly (ResolveContext rc, Type type, Location loc, string name)
 338                 {
 339                         rc.Report.Error (134, loc, "A constant `{0}' of reference type `{1}' can only be initialized with null",
 340                                 name, TypeManager.CSharpName (type));
 341                 }
 342
 343                 public static void Error_InvalidExpressionStatement (Report Report, Location loc)
 344                 {
 345                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 346                                        "expressions can be used as a statement");
 347                 }
 348
 349                 public void Error_InvalidExpressionStatement (BlockContext ec)
 350                 {
 351                         Error_InvalidExpressionStatement (ec.Report, loc);
 352                 }
 353
 354                 public static void Error_VoidInvalidInTheContext (Location loc, Report Report)
 355                 {
 356                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 357                 }
 358
 359                 public virtual void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
 360                 {
 361                         Error_ValueCannotBeConvertedCore (ec, loc, target, expl);
 362                 }
 363
 364                 protected void Error_ValueCannotBeConvertedCore (ResolveContext ec, Location loc, Type target, bool expl)
 365                 {
 366                         // The error was already reported as CS1660
 367                         if (type == InternalType.AnonymousMethod)
 368                                 return;
 369
 370                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 371                                 string sig1 = type.DeclaringMethod == null ?
 372                                         TypeManager.CSharpName (type.DeclaringType) :
 373                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 374                                 string sig2 = target.DeclaringMethod == null ?
 375                                         TypeManager.CSharpName (target.DeclaringType) :
 376                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 377                                 ec.Report.ExtraInformation (loc,
 378                                         String.Format (
 379                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 380                                                 Type.Name, sig1, sig2));
 381                         } else if (Type.FullName == target.FullName){
 382                                 ec.Report.ExtraInformation (loc,
 383                                         String.Format (
 384                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 385                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 386                         }
 387
 388                         if (expl) {
 389                                 ec.Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 390                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 391                                 return;
 392                         }
 393
 394                         ec.Report.DisableReporting ();
 395                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 396                         ec.Report.EnableReporting ();
 397
 398                         if (expl_exists) {
 399                                 ec.Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 400                                               "An explicit conversion exists (are you missing a cast?)",
 401                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 402                                 return;
 403                         }
 404
 405                         ec.Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 406                                 TypeManager.CSharpName (type),
 407                                 TypeManager.CSharpName (target));
 408                 }
 409
 410                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (Report Report, string name)
 411                 {
 412                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 413                 }
 414
 415                 public void Error_TypeArgumentsCannotBeUsed (Report report, Location loc)
 416                 {
 417                         // Better message for possible generic expressions
 418                         if (eclass == ExprClass.MethodGroup || eclass == ExprClass.Type) {
 419                                 if (this is TypeExpr)
 420                                         report.SymbolRelatedToPreviousError (type);
 421
 422                                 string name = eclass == ExprClass.Type ? ExprClassName : "method";
 423                                 report.Error (308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 424                                         name, GetSignatureForError ());
 425                         } else {
 426                                 report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
 427                                         ExprClassName, GetSignatureForError ());
 428                         }
 429                 }
 430
 431                 protected virtual void Error_TypeDoesNotContainDefinition (ResolveContext ec, Type type, string name)
 432                 {
 433                         Error_TypeDoesNotContainDefinition (ec, loc, type, name);
 434                 }
 435
 436                 public static void Error_TypeDoesNotContainDefinition (ResolveContext ec, Location loc, Type type, string name)
 437                 {
 438                         ec.Report.SymbolRelatedToPreviousError (type);
 439                         ec.Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 440                                 TypeManager.CSharpName (type), name);
 441                 }
 442
 443                 protected static void Error_ValueAssignment (ResolveContext ec, Location loc)
 444                 {
 445                         ec.Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 446                 }
 447
 448                 ResolveFlags ExprClassToResolveFlags {
 449                         get {
 450                                 switch (eclass) {
 451                                 case ExprClass.Type:
 452                                 case ExprClass.Namespace:
 453                                         return ResolveFlags.Type;
 454
 455                                 case ExprClass.MethodGroup:
 456                                         return ResolveFlags.MethodGroup;
 457
 458                                 case ExprClass.TypeParameter:
 459                                         return ResolveFlags.TypeParameter;
 460
 461                                 case ExprClass.Value:
 462                                 case ExprClass.Variable:
 463                                 case ExprClass.PropertyAccess:
 464                                 case ExprClass.EventAccess:
 465                                 case ExprClass.IndexerAccess:
 466                                         return ResolveFlags.VariableOrValue;
 467
 468                                 default:
 469                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 470                                 }
 471                         }
 472                 }
 473
 474                 /// <summary>
 475                 ///   Resolves an expression and performs semantic analysis on it.
 476                 /// </summary>
 477                 ///
 478                 /// <remarks>
 479                 ///   Currently Resolve wraps DoResolve to perform sanity
 480                 ///   checking and assertion checking on what we expect from Resolve.
 481                 /// </remarks>
 482                 public Expression Resolve (ResolveContext ec, ResolveFlags flags)
 483                 {
 484                         if (eclass != ExprClass.Unresolved)
 485                                 return this;
 486
 487                         Expression e;
 488                         if (this is SimpleName) {
 489                                 e = ((SimpleName) this).DoResolve (ec, (flags & ResolveFlags.Intermediate) != 0);
 490                         } else {
 491                                 e = DoResolve (ec);
 492                         }
 493
 494                         if (e == null)
 495                                 return null;
 496
 497                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 498                                 e.Error_UnexpectedKind (ec, flags, loc);
 499                                 return null;
 500                         }
 501
 502                         if (e.type == null)
 503                                 throw new InternalErrorException ("Expression `{0}' didn't set its type in DoResolve", e.GetType ());
 504
 505                         return e;
 506                 }
 507
 508                 /// <summary>
 509                 ///   Resolves an expression and performs semantic analysis on it.
 510                 /// </summary>
 511                 public Expression Resolve (ResolveContext rc)
 512                 {
 513                         return Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 514                 }
 515
 516                 /// <summary>
 517                 ///   Resolves an expression for LValue assignment
 518                 /// </summary>
 519                 ///
 520                 /// <remarks>
 521                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 522                 ///   checking and assertion checking on what we expect from Resolve
 523                 /// </remarks>
 524                 public Expression ResolveLValue (ResolveContext ec, Expression right_side)
 525                 {
 526                         int errors = ec.Report.Errors;
 527                         bool out_access = right_side == EmptyExpression.OutAccess.Instance;
 528
 529                         Expression e = DoResolveLValue (ec, right_side);
 530
 531                         if (e != null && out_access && !(e is IMemoryLocation)) {
 532                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 533                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 534
 535                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 536                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 537                                 e = null;
 538                         }
 539
 540                         if (e == null) {
 541                                 if (errors == ec.Report.Errors) {
 542                                         if (out_access)
 543                                                 ec.Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 544                                         else
 545                                                 Error_ValueAssignment (ec, loc);
 546                                 }
 547                                 return null;
 548                         }
 549
 550                         if (e.eclass == ExprClass.Unresolved)
 551                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 552
 553                         if ((e.type == null) && !(e is GenericTypeExpr))
 554                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 555
 556                         return e;
 557                 }
 558
 559                 /// <summary>
 560                 ///   Emits the code for the expression
 561                 /// </summary>
 562                 ///
 563                 /// <remarks>
 564                 ///   The Emit method is invoked to generate the code
 565                 ///   for the expression.
 566                 /// </remarks>
 567                 public abstract void Emit (EmitContext ec);
 568
 569                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 570                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 571                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 572                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 573                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 574                 {
 575                         Emit (ec);
 576                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 577                 }
 578
 579                 // Emit this expression for its side effects, not for its value.
 580                 // The default implementation is to emit the value, and then throw it away.
 581                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 582                 public virtual void EmitSideEffect (EmitContext ec)
 583                 {
 584                         Emit (ec);
 585                         ec.ig.Emit (OpCodes.Pop);
 586                 }
 587
 588                 /// <summary>
 589                 ///   Protected constructor.  Only derivate types should
 590                 ///   be able to be created
 591                 /// </summary>
 592
 593                 protected Expression ()
 594                 {
 595                 }
 596
 597                 /// <summary>
 598                 ///   Returns a fully formed expression after a MemberLookup
 599                 /// </summary>
 600                 ///
 601                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 602                 {
 603                         if (mi is EventInfo)
 604                                 return new EventExpr (Import.CreateEvent ((EventInfo) mi), loc);
 605                         else if (mi is FieldInfo) {
 606                                 FieldInfo fi = (FieldInfo) mi;
 607                                 var spec = Import.CreateField (fi);
 608                                 if (spec is ConstSpec)
 609                                         return new ConstantExpr ((ConstSpec) spec, loc);
 610                                 return new FieldExpr (spec, loc);
 611                         } else if (mi is PropertyInfo)
 612                                 return new PropertyExpr (container_type, Import.CreateProperty ((PropertyInfo) mi), loc);
 613                         else if (mi is Type) {
 614                                 return new TypeExpression ((System.Type) mi, loc);
 615                         }
 616
 617                         return null;
 618                 }
 619
 620                 // TODO: [Obsolete ("Can be removed")]
 621                 protected static IList<MemberInfo> almost_matched_members = new List<MemberInfo> (4);
 622
 623                 //
 624                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 625                 //
 626                 // This code could use some optimizations, but we need to do some
 627                 // measurements.  For example, we could use a delegate to `flag' when
 628                 // something can not any longer be a method-group (because it is something
 629                 // else).
 630                 //
 631                 // Return values:
 632                 //     If the return value is an Array, then it is an array of
 633                 //     MethodBases
 634                 //
 635                 //     If the return value is an MemberInfo, it is anything, but a Method
 636                 //
 637                 //     null on error.
 638                 //
 639                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 640                 // the arguments here and have MemberLookup return only the methods that
 641                 // match the argument count/type, unlike we are doing now (we delay this
 642                 // decision).
 643                 //
 644                 // This is so we can catch correctly attempts to invoke instance methods
 645                 // from a static body (scan for error 120 in ResolveSimpleName).
 646                 //
 647                 //
 648                 // FIXME: Potential optimization, have a static ArrayList
 649                 //
 650
 651                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type, string name,
 652                                                        MemberTypes mt, BindingFlags bf, Location loc)
 653                 {
 654                         return MemberLookup (ctx, container_type, null, queried_type, name, mt, bf, loc);
 655                 }
 656
 657                 //
 658                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 659                 // `qualifier_type' or null to lookup members in the current class.
 660                 //
 661
 662                 public static Expression MemberLookup (CompilerContext ctx, Type container_type,
 663                                                        Type qualifier_type, Type queried_type,
 664                                                        string name, MemberTypes mt,
 665                                                        BindingFlags bf, Location loc)
 666                 {
 667                         almost_matched_members.Clear ();
 668
 669                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 670                                                                      queried_type, mt, bf, name, almost_matched_members);
 671
 672                         if (mi == null)
 673                                 return null;
 674
 675                         if (mi.Length > 1) {
 676                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 677                                 var methods = new List<MethodSpec> (2);
 678                                 List<MemberInfo> non_methods = null;
 679
 680                                 foreach (var m in mi) {
 681                                         if (m is MethodBase) {
 682                                                 methods.Add (Import.CreateMethod ((MethodBase) m));
 683                                                 continue;
 684                                         }
 685
 686                                         if (non_methods == null)
 687                                                 non_methods = new List<MemberInfo> (2);
 688
 689                                         bool is_candidate = true;
 690                                         for (int i = 0; i < non_methods.Count; ++i) {
 691                                                 MemberInfo n_m = non_methods [i];
 692                                                 if (n_m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType)) {
 693                                                         non_methods.Remove (n_m);
 694                                                         --i;
 695                                                 } else if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (n_m.DeclaringType, m.DeclaringType)) {
 696                                                         is_candidate = false;
 697                                                         break;
 698                                                 }
 699                                         }
 700
 701                                         if (is_candidate) {
 702                                                 non_methods.Add (m);
 703                                         }
 704                                 }
 705
 706                                 if (methods.Count == 0 && non_methods != null && non_methods.Count > 1) {
 707                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [1]);
 708                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [0]);
 709                                         ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 710                                                 TypeManager.GetFullNameSignature (non_methods [1]),
 711                                                 TypeManager.GetFullNameSignature (non_methods [0]));
 712                                         return null;
 713                                 }
 714
 715                                 if (methods.Count == 0)
 716                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 717
 718                                 if (non_methods != null && non_methods.Count > 0) {
 719                                         var method = methods [0];
 720                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 721                                         if (method.DeclaringType == non_method.DeclaringType) {
 722                                                 // Cannot happen with C# code, but is valid in IL
 723                                                 ctx.Report.SymbolRelatedToPreviousError (method.MetaInfo);
 724                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 725                                                 ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 726                                                               TypeManager.GetFullNameSignature (non_method),
 727                                                               TypeManager.CSharpSignature (method.MetaInfo));
 728                                                 return null;
 729                                         }
 730
 731                                         if (is_interface) {
 732                                                 ctx.Report.SymbolRelatedToPreviousError (method.MetaInfo);
 733                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 734                                                 ctx.Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 735                                                                 TypeManager.CSharpSignature (method.MetaInfo), TypeManager.GetFullNameSignature (non_method));
 736                                         }
 737                                 }
 738
 739                                 return new MethodGroupExpr (methods, queried_type, loc);
 740                         }
 741
 742                         if (mi [0] is MethodBase)
 743                                 return new MethodGroupExpr (mi.Select (l => Import.CreateMethod ((MethodBase) l)).ToArray (), queried_type, loc);
 744
 745                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 746                 }
 747
 748                 public const MemberTypes AllMemberTypes =
 749                         MemberTypes.Constructor |
 750                         MemberTypes.Event       |
 751                         MemberTypes.Field       |
 752                         MemberTypes.Method      |
 753                         MemberTypes.NestedType  |
 754                         MemberTypes.Property;
 755
 756                 public const BindingFlags AllBindingFlags =
 757                         BindingFlags.Public |
 758                         BindingFlags.Static |
 759                         BindingFlags.Instance;
 760
 761                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type,
 762                                                        string name, Location loc)
 763                 {
 764                         return MemberLookup (ctx, container_type, null, queried_type, name,
 765                                              AllMemberTypes, AllBindingFlags, loc);
 766                 }
 767
 768                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type qualifier_type,
 769                                                        Type queried_type, string name, Location loc)
 770                 {
 771                         return MemberLookup (ctx, container_type, qualifier_type, queried_type,
 772                                              name, AllMemberTypes, AllBindingFlags, loc);
 773                 }
 774
 775                 public static MethodGroupExpr MethodLookup (CompilerContext ctx, Type container_type, Type queried_type,
 776                                                        string name, Location loc)
 777                 {
 778                         return (MethodGroupExpr)MemberLookup (ctx, container_type, null, queried_type, name,
 779                                              MemberTypes.Method, AllBindingFlags, loc);
 780                 }
 781
 782                 /// <summary>
 783                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 784                 ///   to find a final definition.  If the final definition is not found, we
 785                 ///   look for private members and display a useful debugging message if we
 786                 ///   find it.
 787                 /// </summary>
 788                 protected Expression MemberLookupFinal (ResolveContext ec, Type qualifier_type,
 789                                                             Type queried_type, string name,
 790                                                             MemberTypes mt, BindingFlags bf,
 791                                                             Location loc)
 792                 {
 793                         Expression e;
 794
 795                         int errors = ec.Report.Errors;
 796                         e = MemberLookup (ec.Compiler, ec.CurrentType, qualifier_type, queried_type, name, mt, bf, loc);
 797
 798                         if (e != null || errors != ec.Report.Errors)
 799                                 return e;
 800
 801                         // No errors were reported by MemberLookup, but there was an error.
 802                         return Error_MemberLookupFailed (ec, ec.CurrentType, qualifier_type, queried_type,
 803                                         name, null, mt, bf);
 804                 }
 805
 806                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type container_type, Type qualifier_type,
 807                                                        Type queried_type, string name, string class_name,
 808                                                            MemberTypes mt, BindingFlags bf)
 809                 {
 810                         MemberInfo[] lookup = null;
 811                         if (queried_type == null) {
 812                                 class_name = "global::";
 813                         } else {
 814                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 815                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 816                                         name, null);
 817
 818                                 if (lookup != null) {
 819                                         Expression e = Error_MemberLookupFailed (ec, queried_type, lookup);
 820
 821                                         //
 822                                         // FIXME: This is still very wrong, it should be done inside
 823                                         // OverloadResolve to do correct arguments matching.
 824                                         // Requires MemberLookup accessiblity check removal
 825                                         //
 826                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 827                                                 MemberInfo mi = lookup[0];
 828                                                 ec.Report.SymbolRelatedToPreviousError (mi);
 829                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 830                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 831                                                         // Although a derived class can access protected members of
 832                                                         // its base class it cannot do so through an instance of the
 833                                                         // base class (CS1540).  If the qualifier_type is a base of the
 834                                                         // ec.CurrentType and the lookup succeeds with the latter one,
 835                                                         // then we are in this situation.
 836                                                         Error_CannotAccessProtected (ec, loc, mi, qualifier_type, container_type);
 837                                                 } else {
 838                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi), ec.Report);
 839                                                 }
 840                                         }
 841
 842                                         return e;
 843                                 }
 844
 845                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 846                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 847                                         name, null);
 848                         }
 849
 850                         if (lookup == null) {
 851                                 if (class_name != null) {
 852                                         ec.Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 853                                                 name);
 854                                 } else {
 855                                         Error_TypeDoesNotContainDefinition (ec, queried_type, name);
 856                                 }
 857                                 return null;
 858                         }
 859
 860                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 861                                                       AllMemberTypes, AllBindingFlags |
 862                                                       BindingFlags.NonPublic, name, null) == null) {
 863                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 864                                         Type t = (Type) lookup [0];
 865
 866                                         ec.Report.Error (305, loc,
 867                                                       "Using the generic type `{0}' " +
 868                                                       "requires {1} type arguments",
 869                                                       TypeManager.CSharpName (t),
 870                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 871                                         return null;
 872                                 }
 873                         }
 874
 875                         return Error_MemberLookupFailed (ec, queried_type, lookup);
 876                 }
 877
 878                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type type, MemberInfo[] members)
 879                 {
 880                         List<MethodSpec> methods = new List<MethodSpec> ();
 881                         for (int i = 0; i < members.Length; ++i) {
 882                                 if (!(members [i] is MethodBase))
 883                                         return null;
 884
 885                                 methods.Add (Import.CreateMethod (members[i] as MethodBase));
 886                         }
 887
 888                         // By default propagate the closest candidates upwards
 889                         return new MethodGroupExpr (methods.ToArray (), type, loc, true);
 890                 }
 891
 892                 protected virtual void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
 893                 {
 894                         throw new NotImplementedException ();
 895                 }
 896
 897                 protected void Error_PointerInsideExpressionTree (ResolveContext ec)
 898                 {
 899                         ec.Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 900                 }
 901
 902                 /// <summary>
 903                 ///   Returns an expression that can be used to invoke operator true
 904                 ///   on the expression if it exists.
 905                 /// </summary>
 906                 protected static Expression GetOperatorTrue (ResolveContext ec, Expression e, Location loc)
 907                 {
 908                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 909                 }
 910
 911                 /// <summary>
 912                 ///   Returns an expression that can be used to invoke operator false
 913                 ///   on the expression if it exists.
 914                 /// </summary>
 915                 static public Expression GetOperatorFalse (ResolveContext ec, Expression e, Location loc)
 916                 {
 917                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 918                 }
 919
 920                 static Expression GetOperatorTrueOrFalse (ResolveContext ec, Expression e, bool is_true, Location loc)
 921                 {
 922                         MethodGroupExpr operator_group;
 923                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 924                         operator_group = MethodLookup (ec.Compiler, ec.CurrentType, e.Type, mname, loc) as MethodGroupExpr;
 925                         if (operator_group == null)
 926                                 return null;
 927
 928                         Arguments arguments = new Arguments (1);
 929                         arguments.Add (new Argument (e));
 930                         operator_group = operator_group.OverloadResolve (
 931                                 ec, ref arguments, false, loc);
 932
 933                         if (operator_group == null)
 934                                 return null;
 935
 936                         return new UserOperatorCall (operator_group, arguments, null, loc);
 937                 }
 938
 939                 public virtual string ExprClassName
 940                 {
 941                         get {
 942                                 switch (eclass){
 943                                 case ExprClass.Unresolved:
 944                                         return "Unresolved";
 945                                 case ExprClass.Value:
 946                                         return "value";
 947                                 case ExprClass.Variable:
 948                                         return "variable";
 949                                 case ExprClass.Namespace:
 950                                         return "namespace";
 951                                 case ExprClass.Type:
 952                                         return "type";
 953                                 case ExprClass.MethodGroup:
 954                                         return "method group";
 955                                 case ExprClass.PropertyAccess:
 956                                         return "property access";
 957                                 case ExprClass.EventAccess:
 958                                         return "event access";
 959                                 case ExprClass.IndexerAccess:
 960                                         return "indexer access";
 961                                 case ExprClass.Nothing:
 962                                         return "null";
 963                                 case ExprClass.TypeParameter:
 964                                         return "type parameter";
 965                                 }
 966                                 throw new Exception ("Should not happen");
 967                         }
 968                 }
 969
 970                 /// <summary>
 971                 ///   Reports that we were expecting `expr' to be of class `expected'
 972                 /// </summary>
 973                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, Location loc)
 974                 {
 975                         Error_UnexpectedKind (r, mc, expected, ExprClassName, loc);
 976                 }
 977
 978                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, string was, Location loc)
 979                 {
 980                         string name;
 981                         if (mc != null)
 982                                 name = mc.GetSignatureForError ();
 983                         else
 984                                 name = GetSignatureForError ();
 985
 986                         r.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
 987                               name, was, expected);
 988                 }
 989
 990                 public void Error_UnexpectedKind (ResolveContext ec, ResolveFlags flags, Location loc)
 991                 {
 992                         string [] valid = new string [4];
 993                         int count = 0;
 994
 995                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 996                                 valid [count++] = "variable";
 997                                 valid [count++] = "value";
 998                         }
 999
1000                         if ((flags & ResolveFlags.Type) != 0)
1001                                 valid [count++] = "type";
1002
1003                         if ((flags & ResolveFlags.MethodGroup) != 0)
1004                                 valid [count++] = "method group";
1005
1006                         if (count == 0)
1007                                 valid [count++] = "unknown";
1008
1009                         StringBuilder sb = new StringBuilder (valid [0]);
1010                         for (int i = 1; i < count - 1; i++) {
1011                                 sb.Append ("', `");
1012                                 sb.Append (valid [i]);
1013                         }
1014                         if (count > 1) {
1015                                 sb.Append ("' or `");
1016                                 sb.Append (valid [count - 1]);
1017                         }
1018
1019                         ec.Report.Error (119, loc,
1020                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1021                 }
1022
1023                 public static void UnsafeError (ResolveContext ec, Location loc)
1024                 {
1025                         UnsafeError (ec.Report, loc);
1026                 }
1027
1028                 public static void UnsafeError (Report Report, Location loc)
1029                 {
1030                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1031                 }
1032
1033                 //
1034                 // Load the object from the pointer.
1035                 //
1036                 public static void LoadFromPtr (ILGenerator ig, Type t)
1037                 {
1038                         if (t == TypeManager.int32_type)
1039                                 ig.Emit (OpCodes.Ldind_I4);
1040                         else if (t == TypeManager.uint32_type)
1041                                 ig.Emit (OpCodes.Ldind_U4);
1042                         else if (t == TypeManager.short_type)
1043                                 ig.Emit (OpCodes.Ldind_I2);
1044                         else if (t == TypeManager.ushort_type)
1045                                 ig.Emit (OpCodes.Ldind_U2);
1046                         else if (t == TypeManager.char_type)
1047                                 ig.Emit (OpCodes.Ldind_U2);
1048                         else if (t == TypeManager.byte_type)
1049                                 ig.Emit (OpCodes.Ldind_U1);
1050                         else if (t == TypeManager.sbyte_type)
1051                                 ig.Emit (OpCodes.Ldind_I1);
1052                         else if (t == TypeManager.uint64_type)
1053                                 ig.Emit (OpCodes.Ldind_I8);
1054                         else if (t == TypeManager.int64_type)
1055                                 ig.Emit (OpCodes.Ldind_I8);
1056                         else if (t == TypeManager.float_type)
1057                                 ig.Emit (OpCodes.Ldind_R4);
1058                         else if (t == TypeManager.double_type)
1059                                 ig.Emit (OpCodes.Ldind_R8);
1060                         else if (t == TypeManager.bool_type)
1061                                 ig.Emit (OpCodes.Ldind_I1);
1062                         else if (t == TypeManager.intptr_type)
1063                                 ig.Emit (OpCodes.Ldind_I);
1064                         else if (TypeManager.IsEnumType (t)) {
1065                                 if (t == TypeManager.enum_type)
1066                                         ig.Emit (OpCodes.Ldind_Ref);
1067                                 else
1068                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1069                         } else if (TypeManager.IsStruct (t) || TypeManager.IsGenericParameter (t))
1070                                 ig.Emit (OpCodes.Ldobj, t);
1071                         else if (t.IsPointer)
1072                                 ig.Emit (OpCodes.Ldind_I);
1073                         else
1074                                 ig.Emit (OpCodes.Ldind_Ref);
1075                 }
1076
1077                 //
1078                 // The stack contains the pointer and the value of type `type'
1079                 //
1080                 public static void StoreFromPtr (ILGenerator ig, Type type)
1081                 {
1082                         if (TypeManager.IsEnumType (type))
1083                                 type = TypeManager.GetEnumUnderlyingType (type);
1084                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1085                                 ig.Emit (OpCodes.Stind_I4);
1086                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1087                                 ig.Emit (OpCodes.Stind_I8);
1088                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1089                                  type == TypeManager.ushort_type)
1090                                 ig.Emit (OpCodes.Stind_I2);
1091                         else if (type == TypeManager.float_type)
1092                                 ig.Emit (OpCodes.Stind_R4);
1093                         else if (type == TypeManager.double_type)
1094                                 ig.Emit (OpCodes.Stind_R8);
1095                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1096                                  type == TypeManager.bool_type)
1097                                 ig.Emit (OpCodes.Stind_I1);
1098                         else if (type == TypeManager.intptr_type)
1099                                 ig.Emit (OpCodes.Stind_I);
1100                         else if (TypeManager.IsStruct (type) || TypeManager.IsGenericParameter (type))
1101                                 ig.Emit (OpCodes.Stobj, type);
1102                         else
1103                                 ig.Emit (OpCodes.Stind_Ref);
1104                 }
1105
1106                 //
1107                 // Returns the size of type `t' if known, otherwise, 0
1108                 //
1109                 public static int GetTypeSize (Type t)
1110                 {
1111                         t = TypeManager.TypeToCoreType (t);
1112                         if (t == TypeManager.int32_type ||
1113                             t == TypeManager.uint32_type ||
1114                             t == TypeManager.float_type)
1115                                 return 4;
1116                         else if (t == TypeManager.int64_type ||
1117                                  t == TypeManager.uint64_type ||
1118                                  t == TypeManager.double_type)
1119                                 return 8;
1120                         else if (t == TypeManager.byte_type ||
1121                                  t == TypeManager.sbyte_type ||
1122                                  t == TypeManager.bool_type)
1123                                 return 1;
1124                         else if (t == TypeManager.short_type ||
1125                                  t == TypeManager.char_type ||
1126                                  t == TypeManager.ushort_type)
1127                                 return 2;
1128                         else if (t == TypeManager.decimal_type)
1129                                 return 16;
1130                         else
1131                                 return 0;
1132                 }
1133
1134                 protected void Error_CannotCallAbstractBase (ResolveContext ec, string name)
1135                 {
1136                         ec.Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1137                 }
1138
1139                 protected void Error_CannotModifyIntermediateExpressionValue (ResolveContext ec)
1140                 {
1141                         ec.Report.SymbolRelatedToPreviousError (type);
1142                         if (ec.CurrentInitializerVariable != null) {
1143                                 ec.Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1144                                         TypeManager.CSharpName (type), GetSignatureForError ());
1145                         } else {
1146                                 ec.Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1147                                         GetSignatureForError ());
1148                         }
1149                 }
1150
1151                 //
1152                 // Converts `source' to an int, uint, long or ulong.
1153                 //
1154                 protected Expression ConvertExpressionToArrayIndex (ResolveContext ec, Expression source)
1155                 {
1156                         if (TypeManager.IsDynamicType (source.type)) {
1157                                 Arguments args = new Arguments (1);
1158                                 args.Add (new Argument (source));
1159                                 return new DynamicConversion (TypeManager.int32_type, CSharpBinderFlags.ConvertArrayIndex, args, loc).Resolve (ec);
1160                         }
1161
1162                         Expression converted;
1163
1164                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
1165                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1166                                 if (converted == null)
1167                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1168                                 if (converted == null)
1169                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1170                                 if (converted == null)
1171                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1172
1173                                 if (converted == null) {
1174                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1175                                         return null;
1176                                 }
1177                         }
1178
1179                         //
1180                         // Only positive constants are allowed at compile time
1181                         //
1182                         Constant c = converted as Constant;
1183                         if (c != null && c.IsNegative)
1184                                 Error_NegativeArrayIndex (ec, source.loc);
1185
1186                         // No conversion needed to array index
1187                         if (converted.Type == TypeManager.int32_type)
1188                                 return converted;
1189
1190                         return new ArrayIndexCast (converted).Resolve (ec);
1191                 }
1192
1193                 //
1194                 // Derived classes implement this method by cloning the fields that
1195                 // could become altered during the Resolve stage
1196                 //
1197                 // Only expressions that are created for the parser need to implement
1198                 // this.
1199                 //
1200                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1201                 {
1202                         throw new NotImplementedException (
1203                                 String.Format (
1204                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1205                 }
1206
1207                 //
1208                 // Clones an expression created by the parser.
1209                 //
1210                 // We only support expressions created by the parser so far, not
1211                 // expressions that have been resolved (many more classes would need
1212                 // to implement CloneTo).
1213                 //
1214                 // This infrastructure is here merely for Lambda expressions which
1215                 // compile the same code using different type values for the same
1216                 // arguments to find the correct overload
1217                 //
1218                 public Expression Clone (CloneContext clonectx)
1219                 {
1220                         Expression cloned = (Expression) MemberwiseClone ();
1221                         CloneTo (clonectx, cloned);
1222
1223                         return cloned;
1224                 }
1225
1226                 //
1227                 // Implementation of expression to expression tree conversion
1228                 //
1229                 public abstract Expression CreateExpressionTree (ResolveContext ec);
1230
1231                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, Arguments args)
1232                 {
1233                         return CreateExpressionFactoryCall (ec, name, null, args, loc);
1234                 }
1235
1236                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args)
1237                 {
1238                         return CreateExpressionFactoryCall (ec, name, typeArguments, args, loc);
1239                 }
1240
1241                 public static Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args, Location loc)
1242                 {
1243                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (ec, loc), name, typeArguments, loc), args);
1244                 }
1245
1246                 protected static TypeExpr CreateExpressionTypeExpression (ResolveContext ec, Location loc)
1247                 {
1248                         TypeExpr texpr = TypeManager.expression_type_expr;
1249                         if (texpr == null) {
1250                                 Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Linq.Expressions", "Expression", MemberKind.Class, true);
1251                                 if (t == null)
1252                                         return null;
1253
1254                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1255                         }
1256
1257                         return texpr;
1258                 }
1259
1260                 //
1261                 // Implemented by all expressions which support conversion from
1262                 // compiler expression to invokable runtime expression. Used by
1263                 // dynamic C# binder.
1264                 //
1265                 public virtual SLE.Expression MakeExpression (BuilderContext ctx)
1266                 {
1267                         throw new NotImplementedException ("MakeExpression for " + GetType ());
1268                 }
1269
1270                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1271                 {
1272                         // TODO: It should probably be type = storey.MutateType (type);
1273                 }
1274         }
1275
1276         /// <summary>
1277         ///   This is just a base class for expressions that can
1278         ///   appear on statements (invocations, object creation,
1279         ///   assignments, post/pre increment and decrement).  The idea
1280         ///   being that they would support an extra Emition interface that
1281         ///   does not leave a result on the stack.
1282         /// </summary>
1283         public abstract class ExpressionStatement : Expression {
1284
1285                 public virtual ExpressionStatement ResolveStatement (BlockContext ec)
1286                 {
1287                         Expression e = Resolve (ec);
1288                         if (e == null)
1289                                 return null;
1290
1291                         ExpressionStatement es = e as ExpressionStatement;
1292                         if (es == null)
1293                                 Error_InvalidExpressionStatement (ec);
1294
1295                         return es;
1296                 }
1297
1298                 /// <summary>
1299                 ///   Requests the expression to be emitted in a `statement'
1300                 ///   context.  This means that no new value is left on the
1301                 ///   stack after invoking this method (constrasted with
1302                 ///   Emit that will always leave a value on the stack).
1303                 /// </summary>
1304                 public abstract void EmitStatement (EmitContext ec);
1305
1306                 public override void EmitSideEffect (EmitContext ec)
1307                 {
1308                         EmitStatement (ec);
1309                 }
1310         }
1311
1312         /// <summary>
1313         ///   This kind of cast is used to encapsulate the child
1314         ///   whose type is child.Type into an expression that is
1315         ///   reported to return "return_type".  This is used to encapsulate
1316         ///   expressions which have compatible types, but need to be dealt
1317         ///   at higher levels with.
1318         ///
1319         ///   For example, a "byte" expression could be encapsulated in one
1320         ///   of these as an "unsigned int".  The type for the expression
1321         ///   would be "unsigned int".
1322         ///
1323         /// </summary>
1324         public abstract class TypeCast : Expression
1325         {
1326                 protected readonly Expression child;
1327
1328                 protected TypeCast (Expression child, Type return_type)
1329                 {
1330                         eclass = child.eclass;
1331                         loc = child.Location;
1332                         type = return_type;
1333                         this.child = child;
1334                 }
1335
1336                 public override Expression CreateExpressionTree (ResolveContext ec)
1337                 {
1338                         Arguments args = new Arguments (2);
1339                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1340                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1341
1342                         if (type.IsPointer || child.Type.IsPointer)
1343                                 Error_PointerInsideExpressionTree (ec);
1344
1345                         return CreateExpressionFactoryCall (ec, ec.HasSet (ResolveContext.Options.CheckedScope) ? "ConvertChecked" : "Convert", args);
1346                 }
1347
1348                 protected override Expression DoResolve (ResolveContext ec)
1349                 {
1350                         // This should never be invoked, we are born in fully
1351                         // initialized state.
1352
1353                         return this;
1354                 }
1355
1356                 public override void Emit (EmitContext ec)
1357                 {
1358                         child.Emit (ec);
1359                 }
1360
1361                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1362                 {
1363                         return child.GetAttributableValue (ec, value_type, out value);
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 EmitBranchable (EmitContext ec, Label label, bool on_true)
1672                 {
1673                         Child.EmitBranchable (ec, label, on_true);
1674                 }
1675
1676                 public override void EmitSideEffect (EmitContext ec)
1677                 {
1678                         Child.EmitSideEffect (ec);
1679                 }
1680
1681                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1682                 {
1683                         value = GetTypedValue ();
1684                         return true;
1685                 }
1686
1687                 public override string GetSignatureForError()
1688                 {
1689                         return TypeManager.CSharpName (Type);
1690                 }
1691
1692                 public override object GetValue ()
1693                 {
1694                         return Child.GetValue ();
1695                 }
1696
1697                 public override object GetTypedValue ()
1698                 {
1699                         // FIXME: runtime is not ready to work with just emited enums
1700                         if (!RootContext.StdLib) {
1701                                 return Child.GetValue ();
1702                         }
1703
1704 #if MS_COMPATIBLE
1705                         // Small workaround for big problem
1706                         // System.Enum.ToObject cannot be called on dynamic types
1707                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1708                         // because it does not properly support generics
1709                         //
1710                         // This works only sometimes
1711                         //
1712                         if (TypeManager.IsBeingCompiled (type))
1713                                 return Child.GetValue ();
1714 #endif
1715
1716                         return System.Enum.ToObject (type, Child.GetValue ());
1717                 }
1718
1719                 public override string AsString ()
1720                 {
1721                         return Child.AsString ();
1722                 }
1723
1724                 public EnumConstant Increment()
1725                 {
1726                         return new EnumConstant (((IntegralConstant) Child).Increment (), type);
1727                 }
1728
1729                 public override bool IsDefaultValue {
1730                         get {
1731                                 return Child.IsDefaultValue;
1732                         }
1733                 }
1734
1735                 public override bool IsZeroInteger {
1736                         get { return Child.IsZeroInteger; }
1737                 }
1738
1739                 public override bool IsNegative {
1740                         get {
1741                                 return Child.IsNegative;
1742                         }
1743                 }
1744
1745                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1746                 {
1747                         if (Child.Type == target_type)
1748                                 return Child;
1749
1750                         return Child.ConvertExplicitly (in_checked_context, target_type);
1751                 }
1752
1753                 public override Constant ConvertImplicitly (ResolveContext rc, Type type)
1754                 {
1755                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1756                         type = TypeManager.DropGenericTypeArguments (type);
1757
1758                         if (this_type == type) {
1759                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1760                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1761                                         return this;
1762
1763                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1764                                 if (type.UnderlyingSystemType != child_type)
1765                                         Child = Child.ConvertImplicitly (rc, type.UnderlyingSystemType);
1766                                 return this;
1767                         }
1768
1769                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1770                                 return null;
1771                         }
1772
1773                         return Child.ConvertImplicitly (rc, type);
1774                 }
1775         }
1776
1777         /// <summary>
1778         ///   This kind of cast is used to encapsulate Value Types in objects.
1779         ///
1780         ///   The effect of it is to box the value type emitted by the previous
1781         ///   operation.
1782         /// </summary>
1783         public class BoxedCast : TypeCast {
1784
1785                 public BoxedCast (Expression expr, Type target_type)
1786                         : base (expr, target_type)
1787                 {
1788                         eclass = ExprClass.Value;
1789                 }
1790
1791                 protected override Expression DoResolve (ResolveContext ec)
1792                 {
1793                         // This should never be invoked, we are born in fully
1794                         // initialized state.
1795
1796                         return this;
1797                 }
1798
1799                 public override void Emit (EmitContext ec)
1800                 {
1801                         base.Emit (ec);
1802
1803                         ec.ig.Emit (OpCodes.Box, child.Type);
1804                 }
1805
1806                 public override void EmitSideEffect (EmitContext ec)
1807                 {
1808                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1809                         // so, we need to emit the box+pop instructions in most cases
1810                         if (TypeManager.IsStruct (child.Type) &&
1811                             (type == TypeManager.object_type || type == TypeManager.value_type))
1812                                 child.EmitSideEffect (ec);
1813                         else
1814                                 base.EmitSideEffect (ec);
1815                 }
1816         }
1817
1818         public class UnboxCast : TypeCast {
1819                 public UnboxCast (Expression expr, Type return_type)
1820                         : base (expr, return_type)
1821                 {
1822                 }
1823
1824                 protected override Expression DoResolve (ResolveContext ec)
1825                 {
1826                         // This should never be invoked, we are born in fully
1827                         // initialized state.
1828
1829                         return this;
1830                 }
1831
1832                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1833                 {
1834                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1835                                 ec.Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1836                         return base.DoResolveLValue (ec, right_side);
1837                 }
1838
1839                 public override void Emit (EmitContext ec)
1840                 {
1841                         base.Emit (ec);
1842
1843                         ILGenerator ig = ec.ig;
1844                         ig.Emit (OpCodes.Unbox_Any, type);
1845                 }
1846
1847                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1848                 {
1849                         type = storey.MutateType (type);
1850                         base.MutateHoistedGenericType (storey);
1851                 }
1852         }
1853
1854         /// <summary>
1855         ///   This is used to perform explicit numeric conversions.
1856         ///
1857         ///   Explicit numeric conversions might trigger exceptions in a checked
1858         ///   context, so they should generate the conv.ovf opcodes instead of
1859         ///   conv opcodes.
1860         /// </summary>
1861         public class ConvCast : TypeCast {
1862                 public enum Mode : byte {
1863                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1864                         U1_I1, U1_CH,
1865                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1866                         U2_I1, U2_U1, U2_I2, U2_CH,
1867                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1868                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1869                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH, I8_I,
1870                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH, U8_I,
1871                         CH_I1, CH_U1, CH_I2,
1872                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1873                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4,
1874                         I_I8,
1875                 }
1876
1877                 Mode mode;
1878
1879                 public ConvCast (Expression child, Type return_type, Mode m)
1880                         : base (child, return_type)
1881                 {
1882                         mode = m;
1883                 }
1884
1885                 protected override Expression DoResolve (ResolveContext ec)
1886                 {
1887                         // This should never be invoked, we are born in fully
1888                         // initialized state.
1889
1890                         return this;
1891                 }
1892
1893                 public override string ToString ()
1894                 {
1895                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1896                 }
1897
1898                 public override void Emit (EmitContext ec)
1899                 {
1900                         ILGenerator ig = ec.ig;
1901
1902                         base.Emit (ec);
1903
1904                         if (ec.HasSet (EmitContext.Options.CheckedScope)) {
1905                                 switch (mode){
1906                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1907                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1908                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1909                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1910                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1911
1912                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1913                                 case Mode.U1_CH: /* nothing */ break;
1914
1915                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1916                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1917                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1918                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1919                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1920                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1921
1922                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1923                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1924                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1925                                 case Mode.U2_CH: /* nothing */ break;
1926
1927                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1928                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1929                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1930                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1931                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1932                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1933                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1934
1935                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1936                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1937                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1938                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1939                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1940                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1941
1942                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1943                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1944                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1945                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1946                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1947                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1948                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1949                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1950                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_Ovf_U); break;
1951
1952                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1953                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1954                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1955                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1956                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1957                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1958                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1959                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1960                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_Ovf_U_Un); break;
1961
1962                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1963                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1964                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1965
1966                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1967                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1968                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1969                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1970                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1971                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1972                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1973                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1974                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1975
1976                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1977                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1978                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1979                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1980                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1981                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1982                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1983                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1984                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1985                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1986
1987                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1988                                 }
1989                         } else {
1990                                 switch (mode){
1991                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1992                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1993                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1994                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1995                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1996
1997                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1998                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1999
2000                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2001                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2002                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2003                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2004                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2005                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2006
2007                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2008                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2009                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2010                                 case Mode.U2_CH: /* nothing */ break;
2011
2012                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2013                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2014                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2015                                 case Mode.I4_U4: /* nothing */ break;
2016                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2017                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2018                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2019
2020                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2021                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2022                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2023                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2024                                 case Mode.U4_I4: /* nothing */ break;
2025                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2026
2027                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2028                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2029                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2030                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2031                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2032                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2033                                 case Mode.I8_U8: /* nothing */ break;
2034                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2035                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_U); break;
2036
2037                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2038                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2039                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2040                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2041                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2042                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2043                                 case Mode.U8_I8: /* nothing */ break;
2044                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2045                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_U); break;
2046
2047                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2048                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2049                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2050
2051                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2052                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2053                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2054                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2055                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2056                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2057                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2058                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2059                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2060
2061                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2062                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2063                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2064                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2065                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2066                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2067                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2068                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2069                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2070                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2071
2072                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_U8); break;
2073                                 }
2074                         }
2075                 }
2076         }
2077
2078         public class OpcodeCast : TypeCast {
2079                 readonly OpCode op;
2080
2081                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2082                         : base (child, return_type)
2083                 {
2084                         this.op = op;
2085                 }
2086
2087                 protected override Expression DoResolve (ResolveContext ec)
2088                 {
2089                         // This should never be invoked, we are born in fully
2090                         // initialized state.
2091
2092                         return this;
2093                 }
2094
2095                 public override void Emit (EmitContext ec)
2096                 {
2097                         base.Emit (ec);
2098                         ec.ig.Emit (op);
2099                 }
2100
2101                 public Type UnderlyingType {
2102                         get { return child.Type; }
2103                 }
2104         }
2105
2106         /// <summary>
2107         ///   This kind of cast is used to encapsulate a child and cast it
2108         ///   to the class requested
2109         /// </summary>
2110         public sealed class ClassCast : TypeCast {
2111                 readonly bool forced;
2112
2113                 public ClassCast (Expression child, Type return_type)
2114                         : base (child, return_type)
2115                 {
2116                 }
2117
2118                 public ClassCast (Expression child, Type return_type, bool forced)
2119                         : base (child, return_type)
2120                 {
2121                         this.forced = forced;
2122                 }
2123
2124                 public override void Emit (EmitContext ec)
2125                 {
2126                         base.Emit (ec);
2127
2128                         bool gen = TypeManager.IsGenericParameter (child.Type);
2129                         if (gen)
2130                                 ec.ig.Emit (OpCodes.Box, child.Type);
2131
2132                         if (type.IsGenericParameter) {
2133                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2134                                 return;
2135                         }
2136
2137                         if (gen && !forced)
2138                                 return;
2139
2140                         ec.ig.Emit (OpCodes.Castclass, type);
2141                 }
2142         }
2143
2144         //
2145         // Created during resolving pahse when an expression is wrapped or constantified
2146         // and original expression can be used later (e.g. for expression trees)
2147         //
2148         public class ReducedExpression : Expression
2149         {
2150                 sealed class ReducedConstantExpression : EmptyConstantCast
2151                 {
2152                         readonly Expression orig_expr;
2153
2154                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2155                                 : base (expr, expr.Type)
2156                         {
2157                                 this.orig_expr = orig_expr;
2158                         }
2159
2160                         public override Constant ConvertImplicitly (ResolveContext rc, Type target_type)
2161                         {
2162                                 Constant c = base.ConvertImplicitly (rc, target_type);
2163                                 if (c != null)
2164                                         c = new ReducedConstantExpression (c, orig_expr);
2165
2166                                 return c;
2167                         }
2168
2169                         public override Expression CreateExpressionTree (ResolveContext ec)
2170                         {
2171                                 return orig_expr.CreateExpressionTree (ec);
2172                         }
2173
2174                         public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
2175                         {
2176                                 //
2177                                 // Even if resolved result is a constant original expression was not
2178                                 // and attribute accepts constants only
2179                                 //
2180                                 Attribute.Error_AttributeArgumentNotValid (ec, orig_expr.Location);
2181                                 value = null;
2182                                 return false;
2183                         }
2184
2185                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2186                         {
2187                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2188                                 if (c != null)
2189                                         c = new ReducedConstantExpression (c, orig_expr);
2190                                 return c;
2191                         }
2192                 }
2193
2194                 sealed class ReducedExpressionStatement : ExpressionStatement
2195                 {
2196                         readonly Expression orig_expr;
2197                         readonly ExpressionStatement stm;
2198
2199                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2200                         {
2201                                 this.orig_expr = orig;
2202                                 this.stm = stm;
2203                                 this.loc = orig.Location;
2204                         }
2205
2206                         public override Expression CreateExpressionTree (ResolveContext ec)
2207                         {
2208                                 return orig_expr.CreateExpressionTree (ec);
2209                         }
2210
2211                         protected override Expression DoResolve (ResolveContext ec)
2212                         {
2213                                 eclass = stm.eclass;
2214                                 type = stm.Type;
2215                                 return this;
2216                         }
2217
2218                         public override void Emit (EmitContext ec)
2219                         {
2220                                 stm.Emit (ec);
2221                         }
2222
2223                         public override void EmitStatement (EmitContext ec)
2224                         {
2225                                 stm.EmitStatement (ec);
2226                         }
2227
2228                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2229                         {
2230                                 stm.MutateHoistedGenericType (storey);
2231                         }
2232                 }
2233
2234                 readonly Expression expr, orig_expr;
2235
2236                 private ReducedExpression (Expression expr, Expression orig_expr)
2237                 {
2238                         this.expr = expr;
2239                         this.eclass = expr.eclass;
2240                         this.type = expr.Type;
2241                         this.orig_expr = orig_expr;
2242                         this.loc = orig_expr.Location;
2243                 }
2244
2245                 //
2246                 // Creates fully resolved expression switcher
2247                 //
2248                 public static Constant Create (Constant expr, Expression original_expr)
2249                 {
2250                         if (expr.eclass == ExprClass.Unresolved)
2251                                 throw new ArgumentException ("Unresolved expression");
2252
2253                         return new ReducedConstantExpression (expr, original_expr);
2254                 }
2255
2256                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2257                 {
2258                         return new ReducedExpressionStatement (s, orig);
2259                 }
2260
2261                 //
2262                 // Creates unresolved reduce expression. The original expression has to be
2263                 // already resolved
2264                 //
2265                 public static Expression Create (Expression expr, Expression original_expr)
2266                 {
2267                         Constant c = expr as Constant;
2268                         if (c != null)
2269                                 return Create (c, original_expr);
2270
2271                         ExpressionStatement s = expr as ExpressionStatement;
2272                         if (s != null)
2273                                 return Create (s, original_expr);
2274
2275                         if (expr.eclass == ExprClass.Unresolved)
2276                                 throw new ArgumentException ("Unresolved expression");
2277
2278                         return new ReducedExpression (expr, original_expr);
2279                 }
2280
2281                 public override Expression CreateExpressionTree (ResolveContext ec)
2282                 {
2283                         return orig_expr.CreateExpressionTree (ec);
2284                 }
2285
2286                 protected override Expression DoResolve (ResolveContext ec)
2287                 {
2288                         return this;
2289                 }
2290
2291                 public override void Emit (EmitContext ec)
2292                 {
2293                         expr.Emit (ec);
2294                 }
2295
2296                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2297                 {
2298                         expr.EmitBranchable (ec, target, on_true);
2299                 }
2300
2301                 public override SLE.Expression MakeExpression (BuilderContext ctx)
2302                 {
2303                         return orig_expr.MakeExpression (ctx);
2304                 }
2305
2306                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2307                 {
2308                         expr.MutateHoistedGenericType (storey);
2309                 }
2310         }
2311
2312         //
2313         // Standard composite pattern
2314         //
2315         public abstract class CompositeExpression : Expression
2316         {
2317                 Expression expr;
2318
2319                 protected CompositeExpression (Expression expr)
2320                 {
2321                         this.expr = expr;
2322                         this.loc = expr.Location;
2323                 }
2324
2325                 public override Expression CreateExpressionTree (ResolveContext ec)
2326                 {
2327                         return expr.CreateExpressionTree (ec);
2328                 }
2329
2330                 public Expression Child {
2331                         get { return expr; }
2332                 }
2333
2334                 protected override Expression DoResolve (ResolveContext ec)
2335                 {
2336                         expr = expr.Resolve (ec);
2337                         if (expr != null) {
2338                                 type = expr.Type;
2339                                 eclass = expr.eclass;
2340                         }
2341
2342                         return this;
2343                 }
2344
2345                 public override void Emit (EmitContext ec)
2346                 {
2347                         expr.Emit (ec);
2348                 }
2349
2350                 public override bool IsNull {
2351                         get { return expr.IsNull; }
2352                 }
2353         }
2354
2355         //
2356         // Base of expressions used only to narrow resolve flow
2357         //
2358         public abstract class ShimExpression : Expression
2359         {
2360                 protected Expression expr;
2361
2362                 protected ShimExpression (Expression expr)
2363                 {
2364                         this.expr = expr;
2365                 }
2366
2367                 protected override void CloneTo (CloneContext clonectx, Expression t)
2368                 {
2369                         if (expr == null)
2370                                 return;
2371
2372                         ShimExpression target = (ShimExpression) t;
2373                         target.expr = expr.Clone (clonectx);
2374                 }
2375
2376                 public override Expression CreateExpressionTree (ResolveContext ec)
2377                 {
2378                         throw new NotSupportedException ("ET");
2379                 }
2380
2381                 public override void Emit (EmitContext ec)
2382                 {
2383                         throw new InternalErrorException ("Missing Resolve call");
2384                 }
2385
2386                 public Expression Expr {
2387                         get { return expr; }
2388                 }
2389
2390                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2391                 {
2392                         throw new InternalErrorException ("Missing Resolve call");
2393                 }
2394         }
2395
2396         //
2397         // Unresolved type name expressions
2398         //
2399         public abstract class ATypeNameExpression : FullNamedExpression
2400         {
2401                 string name;
2402                 protected TypeArguments targs;
2403
2404                 protected ATypeNameExpression (string name, Location l)
2405                 {
2406                         this.name = name;
2407                         loc = l;
2408                 }
2409
2410                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2411                 {
2412                         this.name = name;
2413                         this.targs = targs;
2414                         loc = l;
2415                 }
2416
2417                 public bool HasTypeArguments {
2418                         get {
2419                                 return targs != null;
2420                         }
2421                 }
2422
2423                 public override bool Equals (object obj)
2424                 {
2425                         ATypeNameExpression atne = obj as ATypeNameExpression;
2426                         return atne != null && atne.Name == Name &&
2427                                 (targs == null || targs.Equals (atne.targs));
2428                 }
2429
2430                 public override int GetHashCode ()
2431                 {
2432                         return Name.GetHashCode ();
2433                 }
2434
2435                 public override string GetSignatureForError ()
2436                 {
2437                         if (targs != null) {
2438                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2439                                         targs.GetSignatureForError () + ">";
2440                         }
2441
2442                         return Name;
2443                 }
2444
2445                 public string Name {
2446                         get {
2447                                 return name;
2448                         }
2449                         set {
2450                                 name = value;
2451                         }
2452                 }
2453
2454                 public TypeArguments TypeArguments {
2455                         get {
2456                                 return targs;
2457                         }
2458                 }
2459         }
2460
2461         /// <summary>
2462         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2463         ///   of a dotted-name.
2464         /// </summary>
2465         public class SimpleName : ATypeNameExpression
2466         {
2467                 public SimpleName (string name, Location l)
2468                         : base (name, l)
2469                 {
2470                 }
2471
2472                 public SimpleName (string name, TypeArguments args, Location l)
2473                         : base (name, args, l)
2474                 {
2475                 }
2476
2477                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2478                         : base (name, l)
2479                 {
2480                         targs = new TypeArguments ();
2481                         foreach (TypeParameter type_param in type_params)
2482                                 targs.Add (new TypeParameterExpr (type_param, l));
2483                 }
2484
2485                 public static string RemoveGenericArity (string name)
2486                 {
2487                         int start = 0;
2488                         StringBuilder sb = null;
2489                         do {
2490                                 int pos = name.IndexOf ('`', start);
2491                                 if (pos < 0) {
2492                                         if (start == 0)
2493                                                 return name;
2494
2495                                         sb.Append (name.Substring (start));
2496                                         break;
2497                                 }
2498
2499                                 if (sb == null)
2500                                         sb = new StringBuilder ();
2501                                 sb.Append (name.Substring (start, pos-start));
2502
2503                                 pos++;
2504                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2505                                         pos++;
2506
2507                                 start = pos;
2508                         } while (start < name.Length);
2509
2510                         return sb.ToString ();
2511                 }
2512
2513                 public SimpleName GetMethodGroup ()
2514                 {
2515                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2516                 }
2517
2518                 public static void Error_ObjectRefRequired (ResolveContext ec, Location l, string name)
2519                 {
2520                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
2521                                 ec.Report.Error (236, l,
2522                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2523                                         name);
2524                         else
2525                                 ec.Report.Error (120, l,
2526                                         "An object reference is required to access non-static member `{0}'",
2527                                         name);
2528                 }
2529
2530                 public bool IdenticalNameAndTypeName (IMemberContext mc, Expression resolved_to, Location loc)
2531                 {
2532                         return resolved_to != null && resolved_to.Type != null &&
2533                                 resolved_to.Type.Name == Name &&
2534                                 (mc.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2535                 }
2536
2537                 protected override Expression DoResolve (ResolveContext ec)
2538                 {
2539                         return SimpleNameResolve (ec, null, false);
2540                 }
2541
2542                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
2543                 {
2544                         return SimpleNameResolve (ec, right_side, false);
2545                 }
2546
2547                 public Expression DoResolve (ResolveContext ec, bool intermediate)
2548                 {
2549                         return SimpleNameResolve (ec, null, intermediate);
2550                 }
2551
2552                 static bool IsNestedChild (Type t, Type parent)
2553                 {
2554                         while (parent != null) {
2555                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2556                                         return true;
2557
2558                                 parent = parent.BaseType;
2559                         }
2560
2561                         return false;
2562                 }
2563
2564                 FullNamedExpression ResolveNested (Type t)
2565                 {
2566                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2567                                 return null;
2568
2569                         Type ds = t;
2570                         while (ds != null && !IsNestedChild (t, ds))
2571                                 ds = ds.DeclaringType;
2572
2573                         if (ds == null)
2574                                 return null;
2575
2576                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2577
2578                         int arg_count = targs != null ? targs.Count : 0;
2579
2580                         for (; (ds != null) && TypeManager.IsGenericType (ds); ds = ds.DeclaringType) {
2581                                 Type[] gargs = TypeManager.GetTypeArguments (ds);
2582                                 if (arg_count + gargs.Length == gen_params.Length) {
2583                                         TypeArguments new_args = new TypeArguments ();
2584                                         foreach (Type param in gargs)
2585                                                 new_args.Add (new TypeExpression (param, loc));
2586
2587                                         if (targs != null)
2588                                                 new_args.Add (targs);
2589
2590                                         return new GenericTypeExpr (t, new_args, loc);
2591                                 }
2592                         }
2593
2594                         return null;
2595                 }
2596
2597                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2598                 {
2599                         int errors = ec.Compiler.Report.Errors;
2600                         FullNamedExpression fne = ec.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2601
2602                         if (fne != null) {
2603                                 if (fne.Type == null)
2604                                         return fne;
2605
2606                                 FullNamedExpression nested = ResolveNested (fne.Type);
2607                                 if (nested != null)
2608                                         return nested.ResolveAsTypeStep (ec, false);
2609
2610                                 if (targs != null) {
2611                                         if (TypeManager.IsGenericType (fne.Type)) {
2612                                                 GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2613                                                 return ct.ResolveAsTypeStep (ec, false);
2614                                         }
2615
2616                                         fne.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2617                                 }
2618
2619                                 return fne;
2620                         }
2621
2622                         if (!HasTypeArguments && Name == "dynamic" &&
2623                                 RootContext.Version > LanguageVersion.V_3 &&
2624                                 RootContext.MetadataCompatibilityVersion > MetadataVersion.v2) {
2625
2626                                 if (!PredefinedAttributes.Get.Dynamic.IsDefined) {
2627                                         ec.Compiler.Report.Error (1980, Location,
2628                                                 "Dynamic keyword requires `{0}' to be defined. Are you missing System.Core.dll assembly reference?",
2629                                                 PredefinedAttributes.Get.Dynamic.GetSignatureForError ());
2630                                 }
2631
2632                                 return new DynamicTypeExpr (loc);
2633                         }
2634
2635                         if (silent || errors != ec.Compiler.Report.Errors)
2636                                 return null;
2637
2638                         Error_TypeOrNamespaceNotFound (ec);
2639                         return null;
2640                 }
2641
2642                 protected virtual void Error_TypeOrNamespaceNotFound (IMemberContext ec)
2643                 {
2644                         if (ec.CurrentType != null) {
2645                                 if (ec.CurrentTypeDefinition != null) {
2646                                         MemberCore mc = ec.CurrentTypeDefinition.GetDefinition (Name);
2647                                         if (mc != null) {
2648                                                 Error_UnexpectedKind (ec.Compiler.Report, mc, "type", GetMemberType (mc), loc);
2649                                                 return;
2650                                         }
2651                                 }
2652
2653                                 string ns = ec.CurrentType.Namespace;
2654                                 string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2655                                 foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
2656                                         Type type = a.GetType (fullname);
2657                                         if (type != null) {
2658                                                 ec.Compiler.Report.SymbolRelatedToPreviousError (type);
2659                                                 Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type), ec.Compiler.Report);
2660                                                 return;
2661                                         }
2662                                 }
2663
2664                                 if (ec.CurrentTypeDefinition != null) {
2665                                         Type t = ec.CurrentTypeDefinition.LookupAnyGeneric (Name);
2666                                         if (t != null) {
2667                                                 Namespace.Error_InvalidNumberOfTypeArguments (ec.Compiler.Report, t, loc);
2668                                                 return;
2669                                         }
2670                                 }
2671                         }
2672
2673                         if (targs != null) {
2674                                 FullNamedExpression retval = ec.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2675                                 if (retval != null) {
2676                                         retval.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2677                                         return;
2678                                 }
2679                         }
2680
2681                         NamespaceEntry.Error_NamespaceNotFound (loc, Name, ec.Compiler.Report);
2682                 }
2683
2684                 // TODO: I am still not convinced about this. If someone else will need it
2685                 // implement this as virtual property in MemberCore hierarchy
2686                 public static string GetMemberType (MemberCore mc)
2687                 {
2688                         if (mc is Property)
2689                                 return "property";
2690                         if (mc is Indexer)
2691                                 return "indexer";
2692                         if (mc is FieldBase)
2693                                 return "field";
2694                         if (mc is MethodCore)
2695                                 return "method";
2696                         if (mc is EnumMember)
2697                                 return "enum";
2698                         if (mc is Event)
2699                                 return "event";
2700
2701                         return "type";
2702                 }
2703
2704                 Expression SimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2705                 {
2706                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2707
2708                         if (e == null)
2709                                 return null;
2710
2711                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2712                                 return e;
2713
2714                         return null;
2715                 }
2716
2717                 /// <remarks>
2718                 ///   7.5.2: Simple Names.
2719                 ///
2720                 ///   Local Variables and Parameters are handled at
2721                 ///   parse time, so they never occur as SimpleNames.
2722                 ///
2723                 ///   The `intermediate' flag is used by MemberAccess only
2724                 ///   and it is used to inform us that it is ok for us to
2725                 ///   avoid the static check, because MemberAccess might end
2726                 ///   up resolving the Name as a Type name and the access as
2727                 ///   a static type access.
2728                 ///
2729                 ///   ie: Type Type; .... { Type.GetType (""); }
2730                 ///
2731                 ///   Type is both an instance variable and a Type;  Type.GetType
2732                 ///   is the static method not an instance method of type.
2733                 /// </remarks>
2734                 Expression DoSimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2735                 {
2736                         Expression e = null;
2737
2738                         //
2739                         // Stage 1: Performed by the parser (binding to locals or parameters).
2740                         //
2741                         Block current_block = ec.CurrentBlock;
2742                         if (current_block != null){
2743                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2744                                 if (vi != null){
2745                                         e = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2746
2747                                         if (right_side != null) {
2748                                                 e = e.ResolveLValue (ec, right_side);
2749                                         } else {
2750                                                 if (intermediate) {
2751                                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
2752                                                                 e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2753                                                         }
2754                                                 } else {
2755                                                         e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2756                                                 }
2757                                         }
2758
2759                                         if (targs != null && e != null)
2760                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2761
2762                                         return e;
2763                                 }
2764
2765                                 e = current_block.Toplevel.GetParameterReference (Name, loc);
2766                                 if (e != null) {
2767                                         if (right_side != null)
2768                                                 e = e.ResolveLValue (ec, right_side);
2769                                         else
2770                                                 e = e.Resolve (ec);
2771
2772                                         if (targs != null && e != null)
2773                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2774
2775                                         return e;
2776                                 }
2777                         }
2778
2779                         //
2780                         // Stage 2: Lookup members
2781                         //
2782
2783                         Type almost_matched_type = null;
2784                         IList<MemberInfo> almost_matched = null;
2785                         for (Type lookup_ds = ec.CurrentType; lookup_ds != null; lookup_ds = lookup_ds.DeclaringType) {
2786                                 e = MemberLookup (ec.Compiler, ec.CurrentType, lookup_ds, Name, loc);
2787                                 if (e != null) {
2788                                         PropertyExpr pe = e as PropertyExpr;
2789                                         if (pe != null) {
2790                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2791
2792                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2793                                                 // it doesn't know which accessor to check permissions against
2794                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.CurrentType, right_side != null))
2795                                                         break;
2796                                         } else if (e is EventExpr) {
2797                                                 if (((EventExpr) e).IsAccessibleFrom (ec.CurrentType))
2798                                                         break;
2799                                         } else if (targs != null && e is TypeExpression) {
2800                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2801                                                 break;
2802                                         } else {
2803                                                 break;
2804                                         }
2805                                         e = null;
2806                                 }
2807
2808                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2809                                         almost_matched_type = lookup_ds;
2810                                         almost_matched = new List<MemberInfo>(almost_matched_members);
2811                                 }
2812                         }
2813
2814                         if (e == null) {
2815                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2816                                         almost_matched_type = ec.CurrentType;
2817                                         almost_matched = new List<MemberInfo> (almost_matched_members);
2818                                 }
2819                                 e = ResolveAsTypeStep (ec, true);
2820                         }
2821
2822                         if (e == null) {
2823                                 if (current_block != null) {
2824                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2825                                         if (ikv != null) {
2826                                                 LocalInfo li = ikv as LocalInfo;
2827                                                 // Supress CS0219 warning
2828                                                 if (li != null)
2829                                                         li.Used = true;
2830
2831                                                 Error_VariableIsUsedBeforeItIsDeclared (ec.Report, Name);
2832                                                 return null;
2833                                         }
2834                                 }
2835
2836                                 if (RootContext.EvalMode){
2837                                         FieldInfo fi = Evaluator.LookupField (Name);
2838                                         if (fi != null)
2839                                                 return new FieldExpr (Import.CreateField (fi), loc).Resolve (ec);
2840                                 }
2841
2842                                 if (almost_matched != null)
2843                                         almost_matched_members = almost_matched;
2844                                 if (almost_matched_type == null)
2845                                         almost_matched_type = ec.CurrentType;
2846
2847                                 string type_name = ec.MemberContext.CurrentType == null ? null : ec.MemberContext.CurrentType.Name;
2848                                 return Error_MemberLookupFailed (ec, ec.CurrentType, null, almost_matched_type, Name,
2849                                         type_name, AllMemberTypes, AllBindingFlags);
2850                         }
2851
2852                         if (e is MemberExpr) {
2853                                 MemberExpr me = (MemberExpr) e;
2854
2855                                 Expression left;
2856                                 if (me.IsInstance) {
2857                                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope)) {
2858                                                 //
2859                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2860                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2861                                                 // and each predicate is true if the MethodGroupExpr contains
2862                                                 // at least one of that kind of method.
2863                                                 //
2864
2865                                                 if (!me.IsStatic &&
2866                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2867                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2868                                                         return null;
2869                                                 }
2870
2871                                                 //
2872                                                 // Pass the buck to MemberAccess and Invocation.
2873                                                 //
2874                                                 left = EmptyExpression.Null;
2875                                         } else {
2876                                                 left = ec.GetThis (loc);
2877                                         }
2878                                 } else {
2879                                         left = new TypeExpression (ec.CurrentType, loc);
2880                                 }
2881
2882                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2883                                 if (me == null)
2884                                         return null;
2885
2886                                 if (targs != null) {
2887                                         if (!targs.Resolve (ec))
2888                                                 return null;
2889
2890                                         me.SetTypeArguments (ec, targs);
2891                                 }
2892
2893                                 if (!me.IsStatic && (me.InstanceExpression != null && me.InstanceExpression != EmptyExpression.Null) &&
2894                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2895                                     me.InstanceExpression.Type != me.DeclaringType &&
2896                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2897                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2898                                         ec.Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2899                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2900                                         return null;
2901                                 }
2902
2903                                 return (right_side != null)
2904                                         ? me.DoResolveLValue (ec, right_side)
2905                                         : me.Resolve (ec);
2906                         }
2907
2908                         return e;
2909                 }
2910         }
2911
2912         /// <summary>
2913         ///   Represents a namespace or a type.  The name of the class was inspired by
2914         ///   section 10.8.1 (Fully Qualified Names).
2915         /// </summary>
2916         public abstract class FullNamedExpression : Expression
2917         {
2918                 protected override void CloneTo (CloneContext clonectx, Expression target)
2919                 {
2920                         // Do nothing, most unresolved type expressions cannot be
2921                         // resolved to different type
2922                 }
2923
2924                 public override Expression CreateExpressionTree (ResolveContext ec)
2925                 {
2926                         throw new NotSupportedException ("ET");
2927                 }
2928
2929                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2930                 {
2931                         throw new NotSupportedException ();
2932                 }
2933
2934                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2935                 {
2936                         return this;
2937                 }
2938
2939                 public override void Emit (EmitContext ec)
2940                 {
2941                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2942                                 GetSignatureForError ());
2943                 }
2944         }
2945
2946         /// <summary>
2947         ///   Expression that evaluates to a type
2948         /// </summary>
2949         public abstract class TypeExpr : FullNamedExpression {
2950                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2951                 {
2952                         TypeExpr t = DoResolveAsTypeStep (ec);
2953                         if (t == null)
2954                                 return null;
2955
2956                         eclass = ExprClass.Type;
2957                         return t;
2958                 }
2959
2960                 protected override Expression DoResolve (ResolveContext ec)
2961                 {
2962                         return ResolveAsTypeTerminal (ec, false);
2963                 }
2964
2965                 public virtual bool CheckAccessLevel (IMemberContext mc)
2966                 {
2967                         return mc.CurrentTypeDefinition.CheckAccessLevel (Type);
2968                 }
2969
2970                 public virtual bool IsClass {
2971                         get { return Type.IsClass; }
2972                 }
2973
2974                 public virtual bool IsValueType {
2975                         get { return TypeManager.IsStruct (Type); }
2976                 }
2977
2978                 public virtual bool IsInterface {
2979                         get { return Type.IsInterface; }
2980                 }
2981
2982                 public virtual bool IsSealed {
2983                         get { return Type.IsSealed; }
2984                 }
2985
2986                 public virtual bool CanInheritFrom ()
2987                 {
2988                         if (Type == TypeManager.enum_type ||
2989                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2990                             Type == TypeManager.multicast_delegate_type ||
2991                             Type == TypeManager.delegate_type ||
2992                             Type == TypeManager.array_type)
2993                                 return false;
2994
2995                         return true;
2996                 }
2997
2998                 protected abstract TypeExpr DoResolveAsTypeStep (IMemberContext ec);
2999
3000                 public override bool Equals (object obj)
3001                 {
3002                         TypeExpr tobj = obj as TypeExpr;
3003                         if (tobj == null)
3004                                 return false;
3005
3006                         return Type == tobj.Type;
3007                 }
3008
3009                 public override int GetHashCode ()
3010                 {
3011                         return Type.GetHashCode ();
3012                 }
3013
3014                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3015                 {
3016                         type = storey.MutateType (type);
3017                 }
3018         }
3019
3020         /// <summary>
3021         ///   Fully resolved Expression that already evaluated to a type
3022         /// </summary>
3023         public class TypeExpression : TypeExpr {
3024                 public TypeExpression (Type t, Location l)
3025                 {
3026                         Type = t;
3027                         eclass = ExprClass.Type;
3028                         loc = l;
3029                 }
3030
3031                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3032                 {
3033                         return this;
3034                 }
3035
3036                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3037                 {
3038                         return this;
3039                 }
3040         }
3041
3042         //
3043         // Used to create types from a fully qualified name.  These are just used
3044         // by the parser to setup the core types.
3045         //
3046         public sealed class TypeLookupExpression : TypeExpr {
3047                 readonly string ns_name;
3048                 readonly string name;
3049
3050                 public TypeLookupExpression (string ns, string name)
3051                 {
3052                         this.name = name;
3053                         this.ns_name = ns;
3054                         eclass = ExprClass.Type;
3055                 }
3056
3057                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3058                 {
3059                         //
3060                         // It's null only during mscorlib bootstrap when DefineType
3061                         // nees to resolve base type of same type
3062                         //
3063                         // For instance struct Char : IComparable<char>
3064                         //
3065                         // TODO: it could be removed when Resolve starts to use
3066                         // DeclSpace instead of Type
3067                         //
3068                         if (type == null) {
3069                                 Namespace ns = GlobalRootNamespace.Instance.GetNamespace (ns_name, false);
3070                                 FullNamedExpression fne = ns.Lookup (ec.Compiler, name, loc);
3071                                 if (fne != null)
3072                                         type = fne.Type;
3073                         }
3074
3075                         return this;
3076                 }
3077
3078                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3079                 {
3080                         return this;
3081                 }
3082
3083                 public override string GetSignatureForError ()
3084                 {
3085                         if (type == null)
3086                                 return TypeManager.CSharpName (ns_name + "." + name, null);
3087
3088                         return base.GetSignatureForError ();
3089                 }
3090         }
3091
3092         /// <summary>
3093         ///   This class denotes an expression which evaluates to a member
3094         ///   of a struct or a class.
3095         /// </summary>
3096         public abstract class MemberExpr : Expression
3097         {
3098                 protected bool is_base;
3099
3100                 /// <summary>
3101                 ///   The name of this member.
3102                 /// </summary>
3103                 public abstract string Name {
3104                         get;
3105                 }
3106
3107                 //
3108                 // When base.member is used
3109                 //
3110                 public bool IsBase {
3111                         get { return is_base; }
3112                         set { is_base = value; }
3113                 }
3114
3115                 /// <summary>
3116                 ///   Whether this is an instance member.
3117                 /// </summary>
3118                 public abstract bool IsInstance {
3119                         get;
3120                 }
3121
3122                 /// <summary>
3123                 ///   Whether this is a static member.
3124                 /// </summary>
3125                 public abstract bool IsStatic {
3126                         get;
3127                 }
3128
3129                 /// <summary>
3130                 ///   The type which declares this member.
3131                 /// </summary>
3132                 public abstract Type DeclaringType {
3133                         get;
3134                 }
3135
3136                 /// <summary>
3137                 ///   The instance expression associated with this member, if it's a
3138                 ///   non-static member.
3139                 /// </summary>
3140                 public Expression InstanceExpression;
3141
3142                 public static void error176 (ResolveContext ec, Location loc, string name)
3143                 {
3144                         ec.Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3145                                       "with an instance reference, qualify it with a type name instead", name);
3146                 }
3147
3148                 public static void Error_BaseAccessInExpressionTree (ResolveContext ec, Location loc)
3149                 {
3150                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
3151                 }
3152
3153                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3154                 {
3155                         if (InstanceExpression != null)
3156                                 InstanceExpression.MutateHoistedGenericType (storey);
3157                 }
3158
3159                 // TODO: possible optimalization
3160                 // Cache resolved constant result in FieldBuilder <-> expression map
3161                 public virtual MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3162                                                                SimpleName original)
3163                 {
3164                         //
3165                         // Precondition:
3166                         //   original == null || original.Resolve (...) ==> left
3167                         //
3168
3169                         if (left is TypeExpr) {
3170                                 left = left.ResolveAsBaseTerminal (ec, false);
3171                                 if (left == null)
3172                                         return null;
3173
3174                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3175                                 // always do all necessary checks
3176                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3177                                 if (oa != null && !ec.IsObsolete) {
3178                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc, ec.Report);
3179                                 }
3180
3181                                 GenericTypeExpr ct = left as GenericTypeExpr;
3182                                 if (ct != null && !ct.CheckConstraints (ec))
3183                                         return null;
3184                                 //
3185
3186                                 if (!IsStatic) {
3187                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3188                                         return null;
3189                                 }
3190
3191                                 return this;
3192                         }
3193
3194                         if (!IsInstance) {
3195                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3196                                         return this;
3197
3198                                 return ResolveExtensionMemberAccess (ec, left);
3199                         }
3200
3201                         InstanceExpression = left;
3202                         return this;
3203                 }
3204
3205                 protected virtual MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3206                 {
3207                         error176 (ec, loc, GetSignatureForError ());
3208                         return this;
3209                 }
3210
3211                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3212                 {
3213                         if (IsStatic)
3214                                 return;
3215
3216                         if (InstanceExpression == EmptyExpression.Null) {
3217                                 // FIXME: This should not be here at all
3218                                 SimpleName.Error_ObjectRefRequired (new ResolveContext (ec.MemberContext), loc, GetSignatureForError ());
3219                                 return;
3220                         }
3221
3222                         if (TypeManager.IsValueType (InstanceExpression.Type)) {
3223                                 if (InstanceExpression is IMemoryLocation) {
3224                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3225                                 } else {
3226                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3227                                         InstanceExpression.Emit (ec);
3228                                         t.Store (ec);
3229                                         t.AddressOf (ec, AddressOp.Store);
3230                                 }
3231                         } else
3232                                 InstanceExpression.Emit (ec);
3233
3234                         if (prepare_for_load)
3235                                 ec.ig.Emit (OpCodes.Dup);
3236                 }
3237
3238                 public virtual void SetTypeArguments (ResolveContext ec, TypeArguments ta)
3239                 {
3240                         // TODO: need to get correct member type
3241                         ec.Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3242                                 GetSignatureForError ());
3243                 }
3244         }
3245
3246         ///
3247         /// Represents group of extension methods
3248         ///
3249         public class ExtensionMethodGroupExpr : MethodGroupExpr
3250         {
3251                 readonly NamespaceEntry namespace_entry;
3252                 public Expression ExtensionExpression;
3253                 Argument extension_argument;
3254
3255                 public ExtensionMethodGroupExpr (List<MethodSpec> list, NamespaceEntry n, Type extensionType, Location l)
3256                         : base (list, extensionType, l)
3257                 {
3258                         this.namespace_entry = n;
3259                 }
3260
3261                 public override bool IsStatic {
3262                         get { return true; }
3263                 }
3264
3265                 public bool IsTopLevel {
3266                         get { return namespace_entry == null; }
3267                 }
3268
3269                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3270                 {
3271                         extension_argument.Expr.MutateHoistedGenericType (storey);
3272                         base.MutateHoistedGenericType (storey);
3273                 }
3274
3275                 public override MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments arguments, bool may_fail, Location loc)
3276                 {
3277                         if (arguments == null)
3278                                 arguments = new Arguments (1);
3279
3280                         arguments.Insert (0, new Argument (ExtensionExpression));
3281                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, ref arguments, namespace_entry, loc);
3282
3283                         // Store resolved argument and restore original arguments
3284                         if (mg != null)
3285                                 ((ExtensionMethodGroupExpr)mg).extension_argument = arguments [0];
3286                         else
3287                                 arguments.RemoveAt (0); // Clean-up modified arguments for error reporting
3288
3289                         return mg;
3290                 }
3291
3292                 MethodGroupExpr ResolveOverloadExtensions (ResolveContext ec, ref Arguments arguments, NamespaceEntry ns, Location loc)
3293                 {
3294                         // Use normal resolve rules
3295                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3296                         if (mg != null)
3297                                 return mg;
3298
3299                         if (ns == null)
3300                                 return null;
3301
3302                         // Search continues
3303                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, Name, loc);
3304                         if (e == null)
3305                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3306
3307                         e.ExtensionExpression = ExtensionExpression;
3308                         e.SetTypeArguments (ec, type_arguments);
3309                         return e.ResolveOverloadExtensions (ec, ref arguments, e.namespace_entry, loc);
3310                 }
3311         }
3312
3313         /// <summary>
3314         ///   MethodGroupExpr represents a group of method candidates which
3315         ///   can be resolved to the best method overload
3316         /// </summary>
3317         public class MethodGroupExpr : MemberExpr
3318         {
3319                 public interface IErrorHandler
3320                 {
3321                         bool AmbiguousCall (ResolveContext ec, MethodSpec ambiguous);
3322                         bool NoExactMatch (ResolveContext ec, MethodSpec method);
3323                 }
3324
3325                 public IErrorHandler CustomErrorHandler;
3326                 public MethodSpec [] Methods;
3327                 MethodSpec best_candidate;
3328                 // TODO: make private
3329                 public TypeArguments type_arguments;
3330                 bool identical_type_name;
3331                 bool has_inaccessible_candidates_only;
3332                 Type delegate_type;
3333                 Type queried_type;
3334
3335                 public MethodGroupExpr (MethodSpec [] mi, Type type, Location l)
3336                         : this (type, l)
3337                 {
3338                         Methods = new MethodSpec[mi.Length];
3339                         mi.CopyTo (Methods, 0);
3340                 }
3341
3342                 public MethodGroupExpr (MethodSpec[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3343                         : this (mi, type, l)
3344                 {
3345                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3346                 }
3347
3348                 public MethodGroupExpr (List<MethodSpec> list, Type type, Location l)
3349                         : this (type, l)
3350                 {
3351                         try {
3352                                 Methods = list.ToArray ();
3353                         } catch {
3354                                 //foreach (MemberInfo m in list){
3355                                 //    if (!(m is MethodBase)){
3356                                 //        Console.WriteLine ("Name " + m.Name);
3357                                 //        Console.WriteLine ("Found a: " + m.GetType ().FullName);
3358                                 //    }
3359                                 //}
3360                                 throw;
3361                         }
3362
3363
3364                 }
3365
3366                 protected MethodGroupExpr (Type type, Location loc)
3367                 {
3368                         this.loc = loc;
3369                         eclass = ExprClass.MethodGroup;
3370                         this.type = InternalType.MethodGroup;
3371                         queried_type = type;
3372                 }
3373
3374                 public override Type DeclaringType {
3375                         get {
3376                                 return queried_type;
3377                         }
3378                 }
3379
3380                 public MethodSpec BestCandidate {
3381                         get {
3382                                 return best_candidate;
3383                         }
3384                 }
3385
3386                 public Type DelegateType {
3387                         set {
3388                                 delegate_type = value;
3389                         }
3390                 }
3391
3392                 public bool IdenticalTypeName {
3393                         get {
3394                                 return identical_type_name;
3395                         }
3396                 }
3397
3398                 public override string GetSignatureForError ()
3399                 {
3400                         if (best_candidate != null)
3401                                 return TypeManager.CSharpSignature (best_candidate.MetaInfo);
3402
3403                         return TypeManager.CSharpSignature (Methods [0].MetaInfo);
3404                 }
3405
3406                 public override string Name {
3407                         get {
3408                                 return Methods [0].Name;
3409                         }
3410                 }
3411
3412                 public override bool IsInstance {
3413                         get {
3414                                 if (best_candidate != null)
3415                                         return !best_candidate.IsStatic;
3416
3417                                 foreach (var mb in Methods)
3418                                         if (!mb.IsStatic)
3419                                                 return true;
3420
3421                                 return false;
3422                         }
3423                 }
3424
3425                 public override bool IsStatic {
3426                         get {
3427                                 if (best_candidate != null)
3428                                         return best_candidate.IsStatic;
3429
3430                                 foreach (var mb in Methods)
3431                                         if (mb.IsStatic)
3432                                                 return true;
3433
3434                                 return false;
3435                         }
3436                 }
3437
3438                 public static explicit operator MethodSpec (MethodGroupExpr mg)
3439                 {
3440                         return mg.best_candidate;
3441                 }
3442
3443                 //
3444                 //  7.4.3.3  Better conversion from expression
3445                 //  Returns :   1    if a->p is better,
3446                 //              2    if a->q is better,
3447                 //              0 if neither is better
3448                 //
3449                 static int BetterExpressionConversion (ResolveContext ec, Argument a, Type p, Type q)
3450                 {
3451                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3452                         if (argument_type == InternalType.AnonymousMethod && RootContext.Version > LanguageVersion.ISO_2) {
3453                                 //
3454                                 // Uwrap delegate from Expression<T>
3455                                 //
3456                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3457                                         p = TypeManager.GetTypeArguments (p) [0];
3458                                 }
3459                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3460                                         q = TypeManager.GetTypeArguments (q) [0];
3461                                 }
3462
3463                                 p = Delegate.GetInvokeMethod (ec.Compiler, null, p).ReturnType;
3464                                 q = Delegate.GetInvokeMethod (ec.Compiler, null, q).ReturnType;
3465                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3466                                         return 2;
3467                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3468                                         return 1;
3469                         } else {
3470                                 if (argument_type == p)
3471                                         return 1;
3472
3473                                 if (argument_type == q)
3474                                         return 2;
3475                         }
3476
3477                         return BetterTypeConversion (ec, p, q);
3478                 }
3479
3480                 //
3481                 // 7.4.3.4  Better conversion from type
3482                 //
3483                 public static int BetterTypeConversion (ResolveContext ec, Type p, Type q)
3484                 {
3485                         if (p == null || q == null)
3486                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3487
3488                         if (p == TypeManager.int32_type) {
3489                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3490                                         return 1;
3491                         } else if (p == TypeManager.int64_type) {
3492                                 if (q == TypeManager.uint64_type)
3493                                         return 1;
3494                         } else if (p == TypeManager.sbyte_type) {
3495                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3496                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3497                                         return 1;
3498                         } else if (p == TypeManager.short_type) {
3499                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3500                                         q == TypeManager.uint64_type)
3501                                         return 1;
3502                         } else if (p == InternalType.Dynamic) {
3503                                 if (q == TypeManager.object_type)
3504                                         return 2;
3505                         }
3506
3507                         if (q == TypeManager.int32_type) {
3508                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3509                                         return 2;
3510                         } if (q == TypeManager.int64_type) {
3511                                 if (p == TypeManager.uint64_type)
3512                                         return 2;
3513                         } else if (q == TypeManager.sbyte_type) {
3514                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3515                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3516                                         return 2;
3517                         } if (q == TypeManager.short_type) {
3518                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3519                                         p == TypeManager.uint64_type)
3520                                         return 2;
3521                         } else if (q == InternalType.Dynamic) {
3522                                 if (p == TypeManager.object_type)
3523                                         return 1;
3524                         }
3525
3526                         // TODO: this is expensive
3527                         Expression p_tmp = new EmptyExpression (p);
3528                         Expression q_tmp = new EmptyExpression (q);
3529
3530                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3531                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3532
3533                         if (p_to_q && !q_to_p)
3534                                 return 1;
3535
3536                         if (q_to_p && !p_to_q)
3537                                 return 2;
3538
3539                         return 0;
3540                 }
3541
3542                 /// <summary>
3543                 ///   Determines "Better function" between candidate
3544                 ///   and the current best match
3545                 /// </summary>
3546                 /// <remarks>
3547                 ///    Returns a boolean indicating :
3548                 ///     false if candidate ain't better
3549                 ///     true  if candidate is better than the current best match
3550                 /// </remarks>
3551                 static bool BetterFunction (ResolveContext ec, Arguments args, int argument_count,
3552                         MethodSpec candidate, bool candidate_params,
3553                         MethodSpec best, bool best_params)
3554                 {
3555                         AParametersCollection candidate_pd = candidate.Parameters;
3556                         AParametersCollection best_pd = best.Parameters;
3557
3558                         bool better_at_least_one = false;
3559                         bool same = true;
3560                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3561                         {
3562                                 Argument a = args [j];
3563
3564                                 // Provided default argument value is never better
3565                                 if (a.IsDefaultArgument && candidate_params == best_params)
3566                                         return false;
3567
3568                                 Type ct = candidate_pd.Types [c_idx];
3569                                 Type bt = best_pd.Types [b_idx];
3570
3571                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3572                                 {
3573                                         ct = TypeManager.GetElementType (ct);
3574                                         --c_idx;
3575                                 }
3576
3577                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3578                                 {
3579                                         bt = TypeManager.GetElementType (bt);
3580                                         --b_idx;
3581                                 }
3582
3583                                 if (TypeManager.IsEqual (ct, bt))
3584                                         continue;
3585
3586                                 same = false;
3587                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3588
3589                                 // for each argument, the conversion to 'ct' should be no worse than
3590                                 // the conversion to 'bt'.
3591                                 if (result == 2)
3592                                         return false;
3593
3594                                 // for at least one argument, the conversion to 'ct' should be better than
3595                                 // the conversion to 'bt'.
3596                                 if (result != 0)
3597                                         better_at_least_one = true;
3598                         }
3599
3600                         if (better_at_least_one)
3601                                 return true;
3602
3603                         //
3604                         // This handles the case
3605                         //
3606                         //   Add (float f1, float f2, float f3);
3607                         //   Add (params decimal [] foo);
3608                         //
3609                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3610                         // first candidate would've chosen as better.
3611                         //
3612                         if (!same)
3613                                 return false;
3614
3615                         //
3616                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3617                         //
3618                         if (best.IsGenericMethod) {
3619                                 if (!candidate.IsGenericMethod)
3620                                         return true;
3621                         } else if (candidate.IsGenericMethod) {
3622                                 return false;
3623                         }
3624
3625                         //
3626                         // This handles the following cases:
3627                         //
3628                         //   Trim () is better than Trim (params char[] chars)
3629                         //   Concat (string s1, string s2, string s3) is better than
3630                         //     Concat (string s1, params string [] srest)
3631                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3632                         //
3633                         if (!candidate_params && best_params)
3634                                 return true;
3635                         if (candidate_params && !best_params)
3636                                 return false;
3637
3638                         int candidate_param_count = candidate_pd.Count;
3639                         int best_param_count = best_pd.Count;
3640
3641                         if (candidate_param_count != best_param_count)
3642                                 // can only happen if (candidate_params && best_params)
3643                                 return candidate_param_count > best_param_count && best_pd.HasParams;
3644
3645                         //
3646                         // now, both methods have the same number of parameters, and the parameters have the same types
3647                         // Pick the "more specific" signature
3648                         //
3649
3650                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3651                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3652
3653                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3654                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3655
3656                         bool specific_at_least_once = false;
3657                         for (int j = 0; j < candidate_param_count; ++j)
3658                         {
3659                                 Type ct = orig_candidate_pd.Types [j];
3660                                 Type bt = orig_best_pd.Types [j];
3661                                 if (ct.Equals (bt))
3662                                         continue;
3663                                 Type specific = MoreSpecific (ct, bt);
3664                                 if (specific == bt)
3665                                         return false;
3666                                 if (specific == ct)
3667                                         specific_at_least_once = true;
3668                         }
3669
3670                         if (specific_at_least_once)
3671                                 return true;
3672
3673                         // FIXME: handle lifted operators
3674                         // ...
3675
3676                         return false;
3677                 }
3678
3679                 protected override MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3680                 {
3681                         if (!IsStatic)
3682                                 return base.ResolveExtensionMemberAccess (ec, left);
3683
3684                         //
3685                         // When left side is an expression and at least one candidate method is
3686                         // static, it can be extension method
3687                         //
3688                         InstanceExpression = left;
3689                         return this;
3690                 }
3691
3692                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3693                                                                 SimpleName original)
3694                 {
3695                         if (!(left is TypeExpr) &&
3696                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3697                                 identical_type_name = true;
3698
3699                         return base.ResolveMemberAccess (ec, left, loc, original);
3700                 }
3701
3702                 public override Expression CreateExpressionTree (ResolveContext ec)
3703                 {
3704                         if (best_candidate == null) {
3705                                 ec.Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3706                                 return null;
3707                         }
3708
3709                         IMethodData md = TypeManager.GetMethod (best_candidate.MetaInfo);
3710                         if (md != null && md.IsExcluded ())
3711                                 ec.Report.Error (765, loc,
3712                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3713
3714                         return new TypeOfMethod (best_candidate, loc);
3715                 }
3716
3717                 protected override Expression DoResolve (ResolveContext ec)
3718                 {
3719                         this.eclass = ExprClass.MethodGroup;
3720
3721                         if (InstanceExpression != null) {
3722                                 InstanceExpression = InstanceExpression.Resolve (ec);
3723                                 if (InstanceExpression == null)
3724                                         return null;
3725                         }
3726
3727                         return this;
3728                 }
3729
3730                 public void ReportUsageError (ResolveContext ec)
3731                 {
3732                         ec.Report.Error (654, loc, "Method `" + DeclaringType + "." +
3733                                       Name + "()' is referenced without parentheses");
3734                 }
3735
3736                 override public void Emit (EmitContext ec)
3737                 {
3738                         throw new NotSupportedException ();
3739                         // ReportUsageError ();
3740                 }
3741
3742                 public void EmitCall (EmitContext ec, Arguments arguments)
3743                 {
3744                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3745                 }
3746
3747                 void Error_AmbiguousCall (ResolveContext ec, MethodSpec ambiguous)
3748                 {
3749                         if (CustomErrorHandler != null && CustomErrorHandler.AmbiguousCall (ec, ambiguous))
3750                                 return;
3751
3752                         ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
3753                         ec.Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
3754                                 TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate.MetaInfo));
3755                 }
3756
3757                 protected virtual void Error_InvalidArguments (ResolveContext ec, Location loc, int idx, MethodSpec method,
3758                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3759                 {
3760                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3761
3762                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3763                                 ec.Report.SymbolRelatedToPreviousError (method.MetaInfo);
3764                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3765                                         ec.Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3766                                                 TypeManager.CSharpSignature (method));
3767                                         return;
3768                                 }
3769                                 ec.Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3770                                           TypeManager.CSharpSignature (method));
3771                         } else if (TypeManager.IsDelegateType (method.DeclaringType)) {
3772                                 ec.Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3773                                         TypeManager.CSharpName (method.DeclaringType));
3774                         } else {
3775                                 ec.Report.SymbolRelatedToPreviousError (method.MetaInfo);
3776                                 if (emg != null) {
3777                                         ec.Report.Error (1928, loc,
3778                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3779                                                 emg.ExtensionExpression.GetSignatureForError (),
3780                                                 emg.Name, TypeManager.CSharpSignature (method));
3781                                 } else {
3782                                         ec.Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3783                                                 TypeManager.CSharpSignature (method));
3784                                 }
3785                         }
3786
3787                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3788
3789                         string index = (idx + 1).ToString ();
3790                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3791                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3792                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3793                                         ec.Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3794                                                 index, Parameter.GetModifierSignature (a.Modifier));
3795                                 else
3796                                         ec.Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3797                                                 index, Parameter.GetModifierSignature (mod));
3798                         } else {
3799                                 string p1 = a.GetSignatureForError ();
3800                                 string p2 = TypeManager.CSharpName (paramType);
3801
3802                                 if (p1 == p2) {
3803                                         ec.Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3804                                         ec.Report.SymbolRelatedToPreviousError (a.Expr.Type);
3805                                         ec.Report.SymbolRelatedToPreviousError (paramType);
3806                                 }
3807
3808                                 if (idx == 0 && emg != null) {
3809                                         ec.Report.Error (1929, loc,
3810                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3811                                 } else {
3812                                         ec.Report.Error (1503, loc,
3813                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3814                                 }
3815                         }
3816                 }
3817
3818                 public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
3819                 {
3820                         ec.Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3821                                 Name, TypeManager.CSharpName (target));
3822                 }
3823
3824                 void Error_ArgumentCountWrong (ResolveContext ec, int arg_count)
3825                 {
3826                         ec.Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
3827                                       Name, arg_count.ToString ());
3828                 }
3829
3830                 protected virtual int GetApplicableParametersCount (MethodSpec method, AParametersCollection parameters)
3831                 {
3832                         return parameters.Count;
3833                 }
3834
3835                 public static bool IsAncestralType (Type first_type, Type second_type)
3836                 {
3837                         return first_type != second_type &&
3838                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3839                                 TypeManager.ImplementsInterface (second_type, first_type));
3840                 }
3841
3842                 ///
3843                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3844                 /// to the given set of arguments
3845                 /// A return value rates candidate method compatibility,
3846                 /// 0 = the best, int.MaxValue = the worst
3847                 ///
3848                 public int IsApplicable (ResolveContext ec,
3849                                                 ref Arguments arguments, int arg_count, ref MethodSpec method, ref bool params_expanded_form)
3850                 {
3851                         var candidate = method;
3852
3853                         AParametersCollection pd = candidate.Parameters;
3854                         int param_count = GetApplicableParametersCount (candidate, pd);
3855                         int optional_count = 0;
3856
3857                         if (arg_count != param_count) {
3858                                 for (int i = 0; i < pd.Count; ++i) {
3859                                         if (pd.FixedParameters [i].HasDefaultValue) {
3860                                                 optional_count = pd.Count - i;
3861                                                 break;
3862                                         }
3863                                 }
3864
3865                                 int args_gap = System.Math.Abs (arg_count - param_count);
3866                                 if (optional_count != 0) {
3867                                         if (args_gap > optional_count)
3868                                                 return int.MaxValue - 10000 + args_gap - optional_count;
3869
3870                                         // Readjust expected number when params used
3871                                         if (pd.HasParams) {
3872                                                 optional_count--;
3873                                                 if (arg_count < param_count)
3874                                                         param_count--;
3875                                         } else if (arg_count > param_count) {
3876                                                 return int.MaxValue - 10000 + args_gap;
3877                                         }
3878                                 } else if (arg_count != param_count) {
3879                                         if (!pd.HasParams)
3880                                                 return int.MaxValue - 10000 + args_gap;
3881                                         if (arg_count < param_count - 1)
3882                                                 return int.MaxValue - 10000 + args_gap;
3883                                 }
3884
3885                                 // Initialize expanded form of a method with 1 params parameter
3886                                 params_expanded_form = param_count == 1 && pd.HasParams;
3887
3888                                 // Resize to fit optional arguments
3889                                 if (optional_count != 0) {
3890                                         Arguments resized;
3891                                         if (arguments == null) {
3892                                                 resized = new Arguments (optional_count);
3893                                         } else {
3894                                                 resized = new Arguments (param_count);
3895                                                 resized.AddRange (arguments);
3896                                         }
3897
3898                                         for (int i = arg_count; i < param_count; ++i)
3899                                                 resized.Add (null);
3900                                         arguments = resized;
3901                                 }
3902                         }
3903
3904                         if (arg_count > 0) {
3905                                 //
3906                                 // Shuffle named arguments to the right positions if there are any
3907                                 //
3908                                 if (arguments [arg_count - 1] is NamedArgument) {
3909                                         arg_count = arguments.Count;
3910
3911                                         for (int i = 0; i < arg_count; ++i) {
3912                                                 bool arg_moved = false;
3913                                                 while (true) {
3914                                                         NamedArgument na = arguments[i] as NamedArgument;
3915                                                         if (na == null)
3916                                                                 break;
3917
3918                                                         int index = pd.GetParameterIndexByName (na.Name);
3919
3920                                                         // Named parameter not found or already reordered
3921                                                         if (index <= i)
3922                                                                 break;
3923
3924                                                         // When using parameters which should not be available to the user
3925                                                         if (index >= param_count)
3926                                                                 break;
3927
3928                                                         if (!arg_moved) {
3929                                                                 arguments.MarkReorderedArgument (na);
3930                                                                 arg_moved = true;
3931                                                         }
3932
3933                                                         Argument temp = arguments[index];
3934                                                         arguments[index] = arguments[i];
3935                                                         arguments[i] = temp;
3936
3937                                                         if (temp == null)
3938                                                                 break;
3939                                                 }
3940                                         }
3941                                 } else {
3942                                         arg_count = arguments.Count;
3943                                 }
3944                         } else if (arguments != null) {
3945                                 arg_count = arguments.Count;
3946                         }
3947
3948                         //
3949                         // 1. Handle generic method using type arguments when specified or type inference
3950                         //
3951                         if (candidate.IsGenericMethod) {
3952                                 if (type_arguments != null) {
3953                                         Type [] g_args = candidate.GetGenericArguments ();
3954                                         if (g_args.Length != type_arguments.Count)
3955                                                 return int.MaxValue - 20000 + System.Math.Abs (type_arguments.Count - g_args.Length);
3956
3957                                         method = candidate.Inflate (type_arguments.Arguments);
3958                                         candidate = method;
3959                                         pd = candidate.Parameters;
3960                                 } else {
3961                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3962                                         if (score != 0)
3963                                                 return score - 20000;
3964
3965                                         if (TypeManager.IsGenericMethodDefinition (candidate.MetaInfo))
3966                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3967                                                         TypeManager.CSharpSignature (candidate.MetaInfo));
3968
3969                                         pd = candidate.Parameters;
3970                                 }
3971                         } else {
3972                                 if (type_arguments != null)
3973                                         return int.MaxValue - 15000;
3974                         }
3975
3976                         //
3977                         // 2. Each argument has to be implicitly convertible to method parameter
3978                         //
3979                         method = candidate;
3980                         Parameter.Modifier p_mod = 0;
3981                         Type pt = null;
3982                         for (int i = 0; i < arg_count; i++) {
3983                                 Argument a = arguments [i];
3984                                 if (a == null) {
3985                                         if (!pd.FixedParameters [i].HasDefaultValue)
3986                                                 throw new InternalErrorException ();
3987
3988                                         Expression e = pd.FixedParameters [i].DefaultValue as Constant;
3989                                         if (e == null)
3990                                                 e = new DefaultValueExpression (new TypeExpression (pd.Types [i], loc), loc).Resolve (ec);
3991
3992                                         arguments [i] = new Argument (e, Argument.AType.Default);
3993                                         continue;
3994                                 }
3995
3996                                 if (p_mod != Parameter.Modifier.PARAMS) {
3997                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3998                                         pt = pd.Types [i];
3999                                 } else {
4000                                         params_expanded_form = true;
4001                                 }
4002
4003                                 Parameter.Modifier a_mod = a.Modifier & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
4004                                 int score = 1;
4005                                 if (!params_expanded_form)
4006                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
4007
4008                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
4009                                         // It can be applicable in expanded form
4010                                         score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
4011                                         if (score == 0)
4012                                                 params_expanded_form = true;
4013                                 }
4014
4015                                 if (score != 0) {
4016                                         if (params_expanded_form)
4017                                                 ++score;
4018                                         return (arg_count - i) * 2 + score;
4019                                 }
4020                         }
4021
4022                         if (arg_count != param_count)
4023                                 params_expanded_form = true;
4024
4025                         return 0;
4026                 }
4027
4028                 int IsArgumentCompatible (ResolveContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
4029                 {
4030                         //
4031                         // Types have to be identical when ref or out modifer is used
4032                         //
4033                         if (arg_mod != 0 || param_mod != 0) {
4034                                 if (TypeManager.HasElementType (parameter))
4035                                         parameter = TypeManager.GetElementType (parameter);
4036
4037                                 Type a_type = argument.Type;
4038                                 if (TypeManager.HasElementType (a_type))
4039                                         a_type = TypeManager.GetElementType (a_type);
4040
4041                                 if (a_type != parameter) {
4042                                         if (TypeManager.IsDynamicType (a_type))
4043                                                 return 0;
4044
4045                                         return 2;
4046                                 }
4047                         } else {
4048                                 if (!Convert.ImplicitConversionExists (ec, argument.Expr, parameter)) {
4049                                         if (TypeManager.IsDynamicType (argument.Type))
4050                                                 return 0;
4051
4052                                         return 2;
4053                                 }
4054                         }
4055
4056                         if (arg_mod != param_mod)
4057                                 return 1;
4058
4059                         return 0;
4060                 }
4061
4062                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
4063                 {
4064                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
4065                                 return false;
4066
4067                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
4068                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
4069
4070                         if (cand_pd.Count != base_pd.Count)
4071                                 return false;
4072
4073                         for (int j = 0; j < cand_pd.Count; ++j)
4074                         {
4075                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
4076                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
4077                                 Type ct = cand_pd.Types [j];
4078                                 Type bt = base_pd.Types [j];
4079
4080                                 if (cm != bm || ct != bt)
4081                                         return false;
4082                         }
4083
4084                         return true;
4085                 }
4086
4087                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
4088                 {
4089                         if (mg1 == null) {
4090                                 if (mg2 == null)
4091                                         return null;
4092                                 return mg2;
4093                         }
4094
4095                         if (mg2 == null)
4096                                 return mg1;
4097
4098                         var all = new List<MethodSpec> (mg1.Methods);
4099                         foreach (var m in mg2.Methods){
4100                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods.Select (l => l.MetaInfo).ToArray (), m.MetaInfo, false))
4101                                         all.Add (m);
4102                         }
4103
4104                         return new MethodGroupExpr (all, null, loc);
4105                 }
4106
4107                 static Type MoreSpecific (Type p, Type q)
4108                 {
4109                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
4110                                 return q;
4111                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
4112                                 return p;
4113
4114                         if (TypeManager.HasElementType (p))
4115                         {
4116                                 Type pe = TypeManager.GetElementType (p);
4117                                 Type qe = TypeManager.GetElementType (q);
4118                                 Type specific = MoreSpecific (pe, qe);
4119                                 if (specific == pe)
4120                                         return p;
4121                                 if (specific == qe)
4122                                         return q;
4123                         }
4124                         else if (TypeManager.IsGenericType (p))
4125                         {
4126                                 Type[] pargs = TypeManager.GetTypeArguments (p);
4127                                 Type[] qargs = TypeManager.GetTypeArguments (q);
4128
4129                                 bool p_specific_at_least_once = false;
4130                                 bool q_specific_at_least_once = false;
4131
4132                                 for (int i = 0; i < pargs.Length; i++)
4133                                 {
4134                                         Type specific = MoreSpecific (TypeManager.TypeToCoreType (pargs [i]), TypeManager.TypeToCoreType (qargs [i]));
4135                                         if (specific == pargs [i])
4136                                                 p_specific_at_least_once = true;
4137                                         if (specific == qargs [i])
4138                                                 q_specific_at_least_once = true;
4139                                 }
4140
4141                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4142                                         return p;
4143                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4144                                         return q;
4145                         }
4146
4147                         return null;
4148                 }
4149
4150                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4151                 {
4152                         base.MutateHoistedGenericType (storey);
4153
4154                         if (best_candidate.IsConstructor) {
4155                                 storey.MutateConstructor (best_candidate);
4156                         } else {
4157                                 storey.MutateGenericMethod (best_candidate);
4158                         }
4159                 }
4160
4161                 /// <summary>
4162                 ///   Find the Applicable Function Members (7.4.2.1)
4163                 ///
4164                 ///   me: Method Group expression with the members to select.
4165                 ///       it might contain constructors or methods (or anything
4166                 ///       that maps to a method).
4167                 ///
4168                 ///   Arguments: ArrayList containing resolved Argument objects.
4169                 ///
4170                 ///   loc: The location if we want an error to be reported, or a Null
4171                 ///        location for "probing" purposes.
4172                 ///
4173                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4174                 ///            that is the best match of me on Arguments.
4175                 ///
4176                 /// </summary>
4177                 public virtual MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments Arguments,
4178                         bool may_fail, Location loc)
4179                 {
4180                         bool method_params = false;
4181                         Type applicable_type = null;
4182                         var candidates = new List<MethodSpec> (2);
4183                         List<MethodSpec> candidate_overrides = null;
4184
4185                         //
4186                         // Used to keep a map between the candidate
4187                         // and whether it is being considered in its
4188                         // normal or expanded form
4189                         //
4190                         // false is normal form, true is expanded form
4191                         //
4192                         Dictionary<MethodSpec, MethodSpec> candidate_to_form = null;
4193                         Dictionary<MethodSpec, Arguments> candidates_expanded = null;
4194                         Arguments candidate_args = Arguments;
4195
4196                         int arg_count = Arguments != null ? Arguments.Count : 0;
4197
4198                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4199                                 if (!may_fail)
4200                                         ec.Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4201                                 return null;
4202                         }
4203
4204                         int nmethods = Methods.Length;
4205
4206                         if (!IsBase) {
4207                                 //
4208                                 // Methods marked 'override' don't take part in 'applicable_type'
4209                                 // computation, nor in the actual overload resolution.
4210                                 // However, they still need to be emitted instead of a base virtual method.
4211                                 // So, we salt them away into the 'candidate_overrides' array.
4212                                 //
4213                                 // In case of reflected methods, we replace each overriding method with
4214                                 // its corresponding base virtual method.  This is to improve compatibility
4215                                 // with non-C# libraries which change the visibility of overrides (#75636)
4216                                 //
4217                                 int j = 0;
4218                                 MethodBase mb = null;
4219                                 for (int i = 0; i < Methods.Length; ++i) {
4220                                         var m = Methods [i];
4221                                         mb = m.MetaInfo;
4222                                         if (TypeManager.IsOverride (m)) {
4223                                                 if (candidate_overrides == null)
4224                                                         candidate_overrides = new List<MethodSpec> ();
4225                                                 candidate_overrides.Add (m);
4226                                                 mb = TypeManager.TryGetBaseDefinition (mb);
4227                                                 if (mb != null && Array.Exists (Methods, l => l.MetaInfo == mb))
4228                                                         continue;
4229                                         }
4230                                         if (mb != null)
4231                                                 Methods [j++] = Import.CreateMethod (mb);
4232                                 }
4233                                 nmethods = j;
4234                         }
4235
4236                         //
4237                         // Enable message recording, it's used mainly by lambda expressions
4238                         //
4239                         SessionReportPrinter msg_recorder = new SessionReportPrinter ();
4240                         ReportPrinter prev_recorder = ec.Report.SetPrinter (msg_recorder);
4241
4242                         //
4243                         // First we construct the set of applicable methods
4244                         //
4245                         bool is_sorted = true;
4246                         int best_candidate_rate = int.MaxValue;
4247                         for (int i = 0; i < nmethods; i++) {
4248                                 Type decl_type = Methods [i].DeclaringType;
4249
4250                                 //
4251                                 // If we have already found an applicable method
4252                                 // we eliminate all base types (Section 14.5.5.1)
4253                                 //
4254                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4255                                         continue;
4256
4257                                 //
4258                                 // Check if candidate is applicable (section 14.4.2.1)
4259                                 //
4260                                 bool params_expanded_form = false;
4261                                 int candidate_rate = IsApplicable (ec, ref candidate_args, arg_count, ref Methods [i], ref params_expanded_form);
4262
4263                                 if (candidate_rate < best_candidate_rate) {
4264                                         best_candidate_rate = candidate_rate;
4265                                         best_candidate = Methods [i];
4266                                 }
4267
4268                                 if (params_expanded_form) {
4269                                         if (candidate_to_form == null)
4270                                                 candidate_to_form = new Dictionary<MethodSpec, MethodSpec> (4, ReferenceEquality<MethodSpec>.Default);
4271                                         var candidate = Methods [i];
4272                                         candidate_to_form [candidate] = candidate;
4273                                 }
4274
4275                                 if (candidate_args != Arguments) {
4276                                         if (candidates_expanded == null)
4277                                                 candidates_expanded = new Dictionary<MethodSpec, Arguments> (4, ReferenceEquality<MethodSpec>.Default);
4278
4279                                         candidates_expanded.Add (Methods [i], candidate_args);
4280                                         candidate_args = Arguments;
4281                                 }
4282
4283                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4284                                         if (msg_recorder != null)
4285                                                 msg_recorder.EndSession ();
4286                                         continue;
4287                                 }
4288
4289                                 msg_recorder = null;
4290                                 candidates.Add (Methods [i]);
4291
4292                                 if (applicable_type == null)
4293                                         applicable_type = decl_type;
4294                                 else if (applicable_type != decl_type) {
4295                                         is_sorted = false;
4296                                         if (IsAncestralType (applicable_type, decl_type))
4297                                                 applicable_type = decl_type;
4298                                 }
4299                         }
4300
4301                         ec.Report.SetPrinter (prev_recorder);
4302                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4303                                 if (!may_fail)
4304                                         msg_recorder.Merge (prev_recorder);
4305
4306                                 return null;
4307                         }
4308
4309                         int candidate_top = candidates.Count;
4310
4311                         if (applicable_type == null) {
4312                                 //
4313                                 // When we found a top level method which does not match and it's
4314                                 // not an extension method. We start extension methods lookup from here
4315                                 //
4316                                 if (InstanceExpression != null) {
4317                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (type, Name, loc);
4318                                         if (ex_method_lookup != null) {
4319                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4320                                                 ex_method_lookup.SetTypeArguments (ec, type_arguments);
4321                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4322                                         }
4323                                 }
4324
4325                                 if (may_fail)
4326                                         return null;
4327
4328                                 //
4329                                 // Okay so we have failed to find exact match so we
4330                                 // return error info about the closest match
4331                                 //
4332                                 if (best_candidate != null) {
4333                                         if (CustomErrorHandler != null && !has_inaccessible_candidates_only && CustomErrorHandler.NoExactMatch (ec, best_candidate))
4334                                                 return null;
4335
4336                                         if (NoExactMatch (ec, ref Arguments, candidate_to_form))
4337                                                 return null;
4338                                 }
4339
4340                                 //
4341                                 // We failed to find any method with correct argument count
4342                                 //
4343                                 if (Name == ConstructorInfo.ConstructorName) {
4344                                         ec.Report.SymbolRelatedToPreviousError (queried_type);
4345                                         ec.Report.Error (1729, loc,
4346                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4347                                                 TypeManager.CSharpName (queried_type), arg_count);
4348                                 } else {
4349                                         Error_ArgumentCountWrong (ec, arg_count);
4350                                 }
4351
4352                                 return null;
4353                         }
4354
4355                         if (arg_count != 0 && Arguments.HasDynamic) {
4356                                 best_candidate = null;
4357                                 return this;
4358                         }
4359
4360                         if (!is_sorted) {
4361                                 //
4362                                 // At this point, applicable_type is _one_ of the most derived types
4363                                 // in the set of types containing the methods in this MethodGroup.
4364                                 // Filter the candidates so that they only contain methods from the
4365                                 // most derived types.
4366                                 //
4367
4368                                 int finalized = 0; // Number of finalized candidates
4369
4370                                 do {
4371                                         // Invariant: applicable_type is a most derived type
4372
4373                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4374                                         // eliminating all it's base types.  At the same time, we'll also move
4375                                         // every unrelated type to the end of the array, and pick the next
4376                                         // 'applicable_type'.
4377
4378                                         Type next_applicable_type = null;
4379                                         int j = finalized; // where to put the next finalized candidate
4380                                         int k = finalized; // where to put the next undiscarded candidate
4381                                         for (int i = finalized; i < candidate_top; ++i) {
4382                                                 var candidate = candidates [i];
4383                                                 Type decl_type = candidate.DeclaringType;
4384
4385                                                 if (decl_type == applicable_type) {
4386                                                         candidates [k++] = candidates [j];
4387                                                         candidates [j++] = candidates [i];
4388                                                         continue;
4389                                                 }
4390
4391                                                 if (IsAncestralType (decl_type, applicable_type))
4392                                                         continue;
4393
4394                                                 if (next_applicable_type != null &&
4395                                                         IsAncestralType (decl_type, next_applicable_type))
4396                                                         continue;
4397
4398                                                 candidates [k++] = candidates [i];
4399
4400                                                 if (next_applicable_type == null ||
4401                                                         IsAncestralType (next_applicable_type, decl_type))
4402                                                         next_applicable_type = decl_type;
4403                                         }
4404
4405                                         applicable_type = next_applicable_type;
4406                                         finalized = j;
4407                                         candidate_top = k;
4408                                 } while (applicable_type != null);
4409                         }
4410
4411                         //
4412                         // Now we actually find the best method
4413                         //
4414
4415                         best_candidate = candidates [0];
4416                         method_params = candidate_to_form != null && candidate_to_form.ContainsKey (best_candidate);
4417
4418                         //
4419                         // TODO: Broken inverse order of candidates logic does not work with optional
4420                         // parameters used for method overrides and I am not going to fix it for SRE
4421                         //
4422                         if (candidates_expanded != null && candidates_expanded.ContainsKey (best_candidate)) {
4423                                 candidate_args = candidates_expanded [best_candidate];
4424                                 arg_count = candidate_args.Count;
4425                         }
4426
4427                         for (int ix = 1; ix < candidate_top; ix++) {
4428                                 var candidate = candidates [ix];
4429
4430                                 if (candidate.MetaInfo == best_candidate.MetaInfo)
4431                                         continue;
4432
4433                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (candidate);
4434
4435                                 if (BetterFunction (ec, candidate_args, arg_count,
4436                                         candidate, cand_params,
4437                                         best_candidate, method_params)) {
4438                                         best_candidate = candidate;
4439                                         method_params = cand_params;
4440                                 }
4441                         }
4442                         //
4443                         // Now check that there are no ambiguities i.e the selected method
4444                         // should be better than all the others
4445                         //
4446                         MethodSpec ambiguous = null;
4447                         for (int ix = 1; ix < candidate_top; ix++) {
4448                                 var candidate = candidates [ix];
4449
4450                                 if (candidate.MetaInfo == best_candidate.MetaInfo)
4451                                         continue;
4452
4453                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (candidate);
4454                                 if (!BetterFunction (ec, candidate_args, arg_count,
4455                                         best_candidate, method_params,
4456                                         candidate, cand_params))
4457                                 {
4458                                         if (!may_fail)
4459                                                 ec.Report.SymbolRelatedToPreviousError (candidate.MetaInfo);
4460                                         ambiguous = candidate;
4461                                 }
4462                         }
4463
4464                         if (ambiguous != null) {
4465                                 Error_AmbiguousCall (ec, ambiguous);
4466                                 return this;
4467                         }
4468
4469                         //
4470                         // If the method is a virtual function, pick an override closer to the LHS type.
4471                         //
4472                         if (!IsBase && best_candidate.IsVirtual) {
4473                                 if (TypeManager.IsOverride (best_candidate))
4474                                         throw new InternalErrorException (
4475                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4476
4477                                 if (candidate_overrides != null) {
4478                                         Type[] gen_args = null;
4479                                         bool gen_override = false;
4480                                         if (best_candidate.IsGenericMethod)
4481                                                 gen_args = TypeManager.GetGenericArguments (best_candidate.MetaInfo);
4482
4483                                         foreach (var candidate in candidate_overrides) {
4484                                                 if (candidate.IsGenericMethod) {
4485                                                         if (gen_args == null)
4486                                                                 continue;
4487
4488                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate.MetaInfo).Length)
4489                                                                 continue;
4490                                                 } else {
4491                                                         if (gen_args != null)
4492                                                                 continue;
4493                                                 }
4494
4495                                                 if (IsOverride (candidate.MetaInfo, best_candidate.MetaInfo)) {
4496                                                         gen_override = true;
4497                                                         best_candidate = candidate;
4498                                                 }
4499                                         }
4500
4501                                         if (gen_override && gen_args != null) {
4502                                                 best_candidate = best_candidate.Inflate (gen_args);
4503                                         }
4504                                 }
4505                         }
4506
4507                         //
4508                         // And now check if the arguments are all
4509                         // compatible, perform conversions if
4510                         // necessary etc. and return if everything is
4511                         // all right
4512                         //
4513                         if (!VerifyArgumentsCompat (ec, ref candidate_args, arg_count, best_candidate,
4514                                 method_params, may_fail, loc))
4515                                 return null;
4516
4517                         if (best_candidate == null)
4518                                 return null;
4519
4520                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4521                         if (TypeManager.IsGenericMethodDefinition (the_method) &&
4522                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate.MetaInfo, loc))
4523                                 return null;
4524
4525                         //
4526                         // Check ObsoleteAttribute on the best method
4527                         //
4528                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4529                         if (oa != null && !ec.IsObsolete)
4530                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
4531
4532                         IMethodData data = TypeManager.GetMethod (the_method);
4533                         if (data != null)
4534                                 data.SetIsUsed ();
4535
4536                         Arguments = candidate_args;
4537                         return this;
4538                 }
4539
4540                 bool NoExactMatch (ResolveContext ec, ref Arguments Arguments, IDictionary<MethodSpec, MethodSpec> candidate_to_form)
4541                 {
4542                         AParametersCollection pd = best_candidate.Parameters;
4543                         int arg_count = Arguments == null ? 0 : Arguments.Count;
4544
4545                         if (arg_count == pd.Count || pd.HasParams) {
4546                                 if (TypeManager.IsGenericMethodDefinition (best_candidate.MetaInfo)) {
4547                                         if (type_arguments == null) {
4548                                                 ec.Report.Error (411, loc,
4549                                                         "The type arguments for method `{0}' cannot be inferred from " +
4550                                                         "the usage. Try specifying the type arguments explicitly",
4551                                                         TypeManager.CSharpSignature (best_candidate.MetaInfo));
4552                                                 return true;
4553                                         }
4554
4555                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate.MetaInfo);
4556                                         if (type_arguments.Count != g_args.Length) {
4557                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4558                                                 ec.Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4559                                                         TypeManager.CSharpSignature (best_candidate.MetaInfo),
4560                                                         g_args.Length.ToString ());
4561                                                 return true;
4562                                         }
4563                                 } else {
4564                                         if (type_arguments != null && !best_candidate.IsGenericMethod) {
4565                                                 Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
4566                                                 return true;
4567                                         }
4568                                 }
4569
4570                                 if (has_inaccessible_candidates_only) {
4571                                         if (InstanceExpression != null && type != ec.CurrentType && TypeManager.IsNestedFamilyAccessible (ec.CurrentType, best_candidate.DeclaringType)) {
4572                                                 // Although a derived class can access protected members of
4573                                                 // its base class it cannot do so through an instance of the
4574                                                 // base class (CS1540).  If the qualifier_type is a base of the
4575                                                 // ec.CurrentType and the lookup succeeds with the latter one,
4576                                                 // then we are in this situation.
4577                                                 Error_CannotAccessProtected (ec, loc, best_candidate.MetaInfo, queried_type, ec.CurrentType);
4578                                         } else {
4579                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4580                                                 ErrorIsInaccesible (loc, GetSignatureForError (), ec.Report);
4581                                         }
4582                                 }
4583
4584                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (best_candidate);
4585                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, false, loc))
4586                                         return true;
4587
4588                                 if (has_inaccessible_candidates_only)
4589                                         return true;
4590                         }
4591
4592                         return false;
4593                 }
4594
4595                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
4596                 {
4597                         type_arguments = ta;
4598                 }
4599
4600                 public bool VerifyArgumentsCompat (ResolveContext ec, ref Arguments arguments,
4601                                                           int arg_count, MethodSpec method,
4602                                                           bool chose_params_expanded,
4603                                                           bool may_fail, Location loc)
4604                 {
4605                         AParametersCollection pd = method.Parameters;
4606                         int param_count = GetApplicableParametersCount (method, pd);
4607
4608                         int errors = ec.Report.Errors;
4609                         Parameter.Modifier p_mod = 0;
4610                         Type pt = null;
4611                         int a_idx = 0, a_pos = 0;
4612                         Argument a = null;
4613                         ArrayInitializer params_initializers = null;
4614                         bool has_unsafe_arg = method.ReturnType.IsPointer;
4615
4616                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4617                                 a = arguments [a_idx];
4618                                 if (p_mod != Parameter.Modifier.PARAMS) {
4619                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4620                                         pt = pd.Types [a_idx];
4621                                         has_unsafe_arg |= pt.IsPointer;
4622
4623                                         if (p_mod == Parameter.Modifier.PARAMS) {
4624                                                 if (chose_params_expanded) {
4625                                                         params_initializers = new ArrayInitializer (arg_count - a_idx, a.Expr.Location);
4626                                                         pt = TypeManager.GetElementType (pt);
4627                                                 }
4628                                         }
4629                                 }
4630
4631                                 //
4632                                 // Types have to be identical when ref or out modifer is used
4633                                 //
4634                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4635                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4636                                                 break;
4637
4638                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4639                                                 break;
4640
4641                                         continue;
4642                                 } else {
4643                                         NamedArgument na = a as NamedArgument;
4644                                         if (na != null) {
4645                                                 int name_index = pd.GetParameterIndexByName (na.Name);
4646                                                 if (name_index < 0 || name_index >= param_count) {
4647                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType)) {
4648                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4649                                                                 ec.Report.Error (1746, na.Location,
4650                                                                         "The delegate `{0}' does not contain a parameter named `{1}'",
4651                                                                         TypeManager.CSharpName (DeclaringType), na.Name);
4652                                                         } else {
4653                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4654                                                                 ec.Report.Error (1739, na.Location,
4655                                                                         "The best overloaded method match for `{0}' does not contain a parameter named `{1}'",
4656                                                                         TypeManager.CSharpSignature (method.MetaInfo), na.Name);
4657                                                         }
4658                                                 } else if (arguments[name_index] != a) {
4659                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType))
4660                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4661                                                         else
4662                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate.MetaInfo);
4663
4664                                                         ec.Report.Error (1744, na.Location,
4665                                                                 "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
4666                                                                 na.Name);
4667                                                 }
4668                                         }
4669                                 }
4670
4671                                 if (TypeManager.IsDynamicType (a.Expr.Type))
4672                                         continue;
4673
4674                                 if (delegate_type != null && !Delegate.IsTypeCovariant (a.Expr, pt))
4675                                         break;
4676
4677                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4678                                 if (conv == null)
4679                                         break;
4680
4681                                 //
4682                                 // Convert params arguments to an array initializer
4683                                 //
4684                                 if (params_initializers != null) {
4685                                         // we choose to use 'a.Expr' rather than 'conv' so that
4686                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4687                                         params_initializers.Add (a.Expr);
4688                                         arguments.RemoveAt (a_idx--);
4689                                         --arg_count;
4690                                         continue;
4691                                 }
4692
4693                                 // Update the argument with the implicit conversion
4694                                 a.Expr = conv;
4695                         }
4696
4697                         if (a_idx != arg_count) {
4698                                 if (!may_fail && ec.Report.Errors == errors) {
4699                                         if (CustomErrorHandler != null)
4700                                                 CustomErrorHandler.NoExactMatch (ec, best_candidate);
4701                                         else
4702                                                 Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4703                                 }
4704                                 return false;
4705                         }
4706
4707                         //
4708                         // Fill not provided arguments required by params modifier
4709                         //
4710                         if (params_initializers == null && pd.HasParams && arg_count + 1 == param_count) {
4711                                 if (arguments == null)
4712                                         arguments = new Arguments (1);
4713
4714                                 pt = pd.Types [param_count - 1];
4715                                 pt = TypeManager.GetElementType (pt);
4716                                 has_unsafe_arg |= pt.IsPointer;
4717                                 params_initializers = new ArrayInitializer (0, loc);
4718                         }
4719
4720                         //
4721                         // Append an array argument with all params arguments
4722                         //
4723                         if (params_initializers != null) {
4724                                 arguments.Add (new Argument (
4725                                         new ArrayCreation (new TypeExpression (pt, loc), "[]", params_initializers, loc).Resolve (ec)));
4726                                 arg_count++;
4727                         }
4728
4729                         if (arg_count < param_count) {
4730                                 if (!may_fail)
4731                                         Error_ArgumentCountWrong (ec, arg_count);
4732                                 return false;
4733                         }
4734
4735                         if (has_unsafe_arg && !ec.IsUnsafe) {
4736                                 if (!may_fail)
4737                                         UnsafeError (ec, loc);
4738                                 return false;
4739                         }
4740
4741                         return true;
4742                 }
4743         }
4744
4745         public class ConstantExpr : MemberExpr
4746         {
4747                 ConstSpec constant;
4748
4749                 public ConstantExpr (ConstSpec constant, Location loc)
4750                 {
4751                         this.constant = constant;
4752                         this.loc = loc;
4753                 }
4754
4755                 public override string Name {
4756                         get { throw new NotImplementedException (); }
4757                 }
4758
4759                 public override bool IsInstance {
4760                         get { return !IsStatic; }
4761                 }
4762
4763                 public override bool IsStatic {
4764                         get { return true; }
4765                 }
4766
4767                 public override Type DeclaringType {
4768                         get { return constant.DeclaringType; }
4769                 }
4770
4771                 public override Expression CreateExpressionTree (ResolveContext ec)
4772                 {
4773                         throw new NotSupportedException ("ET");
4774                 }
4775
4776                 protected override Expression DoResolve (ResolveContext rc)
4777                 {
4778                         constant.MemberDefinition.SetIsUsed ();
4779
4780                         if (!rc.IsObsolete) {
4781                                 var oa = constant.GetObsoleteAttribute ();
4782                                 if (oa != null)
4783                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (constant.MetaInfo), loc, rc.Report);
4784                         }
4785
4786                         // Constants are resolved on-demand
4787                         var c = constant.Value.Resolve (rc) as Constant;
4788
4789                         // Creates reference expression to the constant value
4790                         return Constant.CreateConstant (rc, c.Type, c.GetValue (), loc);
4791                 }
4792
4793                 public override void Emit (EmitContext ec)
4794                 {
4795                         throw new NotSupportedException ();
4796                 }
4797
4798                 public override string GetSignatureForError ()
4799                 {
4800                         return TypeManager.GetFullNameSignature (constant.MetaInfo);
4801                 }
4802         }
4803
4804         /// <summary>
4805         ///   Fully resolved expression that evaluates to a Field
4806         /// </summary>
4807         public class FieldExpr : MemberExpr, IDynamicAssign, IMemoryLocation, IVariableReference {
4808                 protected FieldSpec spec;
4809                 readonly Type constructed_generic_type;
4810                 VariableInfo variable_info;
4811
4812                 LocalTemporary temp;
4813                 bool prepared;
4814
4815                 protected FieldExpr (Location l)
4816                 {
4817                         loc = l;
4818                 }
4819
4820                 public FieldExpr (FieldSpec spec, Location loc)
4821                 {
4822                         this.spec = spec;
4823                         this.loc = loc;
4824
4825                         type = TypeManager.TypeToCoreType (spec.FieldType);
4826                 }
4827
4828                 public FieldExpr (FieldBase fi, Location l)
4829                         : this (fi.Spec, l)
4830                 {
4831                         loc = l;
4832                 }
4833
4834                 public FieldExpr (Field fi, Type genericType, Location l)
4835                         : this (fi, l)
4836                 {
4837                         if (TypeManager.IsGenericTypeDefinition (genericType))
4838                                 return;
4839                         this.constructed_generic_type = genericType;
4840                 }
4841
4842                 public override string Name {
4843                         get {
4844                                 return spec.Name;
4845                         }
4846                 }
4847
4848                 public override bool IsInstance {
4849                         get {
4850                                 return !spec.IsStatic;
4851                         }
4852                 }
4853
4854                 public override bool IsStatic {
4855                         get {
4856                                 return spec.IsStatic;
4857                         }
4858                 }
4859
4860                 public FieldSpec Spec {
4861                         get {
4862                                 return spec;
4863                         }
4864                 }
4865
4866                 public override Type DeclaringType {
4867                         get {
4868                                 return spec.MetaInfo.DeclaringType;
4869                         }
4870                 }
4871
4872                 public override string GetSignatureForError ()
4873                 {
4874                         return TypeManager.GetFullNameSignature (spec.MetaInfo);
4875                 }
4876
4877                 public VariableInfo VariableInfo {
4878                         get {
4879                                 return variable_info;
4880                         }
4881                 }
4882
4883                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
4884                                                                 SimpleName original)
4885                 {
4886                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (spec.MetaInfo);
4887                         Type t = fi.FieldType;
4888
4889                         if (t.IsPointer && !ec.IsUnsafe) {
4890                                 UnsafeError (ec, loc);
4891                         }
4892
4893                         return base.ResolveMemberAccess (ec, left, loc, original);
4894                 }
4895
4896                 public void SetHasAddressTaken ()
4897                 {
4898                         IVariableReference vr = InstanceExpression as IVariableReference;
4899                         if (vr != null)
4900                                 vr.SetHasAddressTaken ();
4901                 }
4902
4903                 public override Expression CreateExpressionTree (ResolveContext ec)
4904                 {
4905                         Expression instance;
4906                         if (InstanceExpression == null) {
4907                                 instance = new NullLiteral (loc);
4908                         } else {
4909                                 instance = InstanceExpression.CreateExpressionTree (ec);
4910                         }
4911
4912                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
4913                                 instance,
4914                                 CreateTypeOfExpression ());
4915
4916                         return CreateExpressionFactoryCall (ec, "Field", args);
4917                 }
4918
4919                 public Expression CreateTypeOfExpression ()
4920                 {
4921                         return new TypeOfField (Import.CreateField (GetConstructedFieldInfo ()), loc);
4922                 }
4923
4924                 protected override Expression DoResolve (ResolveContext ec)
4925                 {
4926                         return DoResolve (ec, false, false);
4927                 }
4928
4929                 Expression DoResolve (ResolveContext ec, bool lvalue_instance, bool out_access)
4930                 {
4931                         if (!IsStatic){
4932                                 if (InstanceExpression == null){
4933                                         //
4934                                         // This can happen when referencing an instance field using
4935                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4936                                         //
4937                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4938                                         return null;
4939                                 }
4940
4941                                 // Resolve the field's instance expression while flow analysis is turned
4942                                 // off: when accessing a field "a.b", we must check whether the field
4943                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4944
4945                                 if (lvalue_instance) {
4946                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
4947                                                 Expression right_side =
4948                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4949
4950                                                 if (InstanceExpression != EmptyExpression.Null)
4951                                                         InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side);
4952                                         }
4953                                 } else {
4954                                         if (InstanceExpression != EmptyExpression.Null) {
4955                                                 using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
4956                                                         InstanceExpression = InstanceExpression.Resolve (ec, ResolveFlags.VariableOrValue);
4957                                                 }
4958                                         }
4959                                 }
4960
4961                                 if (InstanceExpression == null)
4962                                         return null;
4963
4964                                 using (ec.Set (ResolveContext.Options.OmitStructFlowAnalysis)) {
4965                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4966                                 }
4967                         }
4968
4969                         if (!ec.IsObsolete) {
4970                                 FieldBase f = TypeManager.GetField (spec.MetaInfo);
4971                                 if (f != null) {
4972                                         f.CheckObsoleteness (loc);
4973                                 } else {
4974                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
4975                                         if (oa != null)
4976                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (spec.MetaInfo), loc, ec.Report);
4977                                 }
4978                         }
4979
4980                         var fb = spec as FixedFieldSpec;
4981                         IVariableReference var = InstanceExpression as IVariableReference;
4982
4983                         if (fb != null) {
4984                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4985                                 if (!ec.HasSet (ResolveContext.Options.FixedInitializerScope) && (fe == null || !fe.IsFixed)) {
4986                                         ec.Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4987                                 }
4988
4989                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4990                                         ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
4991                                         ec.Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4992                                                 TypeManager.GetFullNameSignature (spec.MetaInfo));
4993                                 } else if (var != null && var.IsHoisted) {
4994                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (ec, var, loc);
4995                                 }
4996
4997                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4998                         }
4999
5000                         eclass = ExprClass.Variable;
5001
5002                         // If the instance expression is a local variable or parameter.
5003                         if (var == null || var.VariableInfo == null)
5004                                 return this;
5005
5006                         VariableInfo vi = var.VariableInfo;
5007                         if (!vi.IsFieldAssigned (ec, Name, loc))
5008                                 return null;
5009
5010                         variable_info = vi.GetSubStruct (Name);
5011                         return this;
5012                 }
5013
5014                 static readonly int [] codes = {
5015                         191,    // instance, write access
5016                         192,    // instance, out access
5017                         198,    // static, write access
5018                         199,    // static, out access
5019                         1648,   // member of value instance, write access
5020                         1649,   // member of value instance, out access
5021                         1650,   // member of value static, write access
5022                         1651    // member of value static, out access
5023                 };
5024
5025                 static readonly string [] msgs = {
5026                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
5027                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
5028                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
5029                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
5030                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
5031                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
5032                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
5033                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
5034                 };
5035
5036                 // The return value is always null.  Returning a value simplifies calling code.
5037                 Expression Report_AssignToReadonly (ResolveContext ec, Expression right_side)
5038                 {
5039                         int i = 0;
5040                         if (right_side == EmptyExpression.OutAccess.Instance || right_side == EmptyExpression.LValueMemberOutAccess)
5041                                 i += 1;
5042                         if (IsStatic)
5043                                 i += 2;
5044                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
5045                                 i += 4;
5046                         ec.Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
5047
5048                         return null;
5049                 }
5050
5051                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5052                 {
5053                         IVariableReference var = InstanceExpression as IVariableReference;
5054                         if (var != null && var.VariableInfo != null)
5055                                 var.VariableInfo.SetFieldAssigned (ec, Name);
5056
5057                         bool lvalue_instance = !spec.IsStatic && TypeManager.IsValueType (spec.MetaInfo.DeclaringType);
5058                         bool out_access = right_side == EmptyExpression.OutAccess.Instance || right_side == EmptyExpression.LValueMemberOutAccess;
5059
5060                         Expression e = DoResolve (ec, lvalue_instance, out_access);
5061
5062                         if (e == null)
5063                                 return null;
5064
5065                         FieldBase fb = TypeManager.GetField (spec.MetaInfo);
5066                         if (fb != null) {
5067                                 fb.SetAssigned ();
5068
5069                                 if ((right_side == EmptyExpression.UnaryAddress || right_side == EmptyExpression.OutAccess.Instance) &&
5070                                         (fb.ModFlags & Modifiers.VOLATILE) != 0) {
5071                                         ec.Report.Warning (420, 1, loc,
5072                                                 "`{0}': A volatile field references will not be treated as volatile",
5073                                                 fb.GetSignatureForError ());
5074                                 }
5075                         }
5076
5077                         if (spec.IsReadOnly) {
5078                                 // InitOnly fields can only be assigned in constructors or initializers
5079                                 if (!ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.ConstructorScope))
5080                                         return Report_AssignToReadonly (ec, right_side);
5081
5082                                 if (ec.HasSet (ResolveContext.Options.ConstructorScope)) {
5083                                         Type ctype = ec.CurrentType;
5084
5085                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
5086                                         if (!TypeManager.IsEqual (ctype, DeclaringType))
5087                                                 return Report_AssignToReadonly (ec, right_side);
5088                                         // static InitOnly fields cannot be assigned-to in an instance constructor
5089                                         if (IsStatic && !ec.IsStatic)
5090                                                 return Report_AssignToReadonly (ec, right_side);
5091                                         // instance constructors can't modify InitOnly fields of other instances of the same type
5092                                         if (!IsStatic && !(InstanceExpression is This))
5093                                                 return Report_AssignToReadonly (ec, right_side);
5094                                 }
5095                         }
5096
5097                         if (right_side == EmptyExpression.OutAccess.Instance &&
5098                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
5099                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5100                                 ec.Report.Warning (197, 1, loc,
5101                                                 "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",
5102                                                 GetSignatureForError ());
5103                         }
5104
5105                         eclass = ExprClass.Variable;
5106                         return this;
5107                 }
5108
5109                 bool is_marshal_by_ref ()
5110                 {
5111                         return !IsStatic && TypeManager.IsStruct (Type) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
5112                 }
5113
5114                 public override void CheckMarshalByRefAccess (ResolveContext ec)
5115                 {
5116                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
5117                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
5118                                 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",
5119                                                 GetSignatureForError ());
5120                         }
5121                 }
5122
5123                 public override int GetHashCode ()
5124                 {
5125                         return spec.GetHashCode ();
5126                 }
5127
5128                 public bool IsFixed {
5129                         get {
5130                                 //
5131                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type
5132                                 //
5133                                 IVariableReference variable = InstanceExpression as IVariableReference;
5134                                 if (variable != null)
5135                                         return TypeManager.IsStruct (InstanceExpression.Type) && variable.IsFixed;
5136
5137                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
5138                                 return fe != null && fe.IsFixed;
5139                         }
5140                 }
5141
5142                 public bool IsHoisted {
5143                         get {
5144                                 IVariableReference hv = InstanceExpression as IVariableReference;
5145                                 return hv != null && hv.IsHoisted;
5146                         }
5147                 }
5148
5149                 public override bool Equals (object obj)
5150                 {
5151                         FieldExpr fe = obj as FieldExpr;
5152                         if (fe == null)
5153                                 return false;
5154
5155                         if (spec.MetaInfo != fe.spec.MetaInfo)
5156                                 return false;
5157
5158                         if (InstanceExpression == null || fe.InstanceExpression == null)
5159                                 return true;
5160
5161                         return InstanceExpression.Equals (fe.InstanceExpression);
5162                 }
5163
5164                 public void Emit (EmitContext ec, bool leave_copy)
5165                 {
5166                         ILGenerator ig = ec.ig;
5167                         bool is_volatile = false;
5168
5169                         var f = TypeManager.GetField (spec.MetaInfo);
5170                         if (f != null){
5171                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5172                                         is_volatile = true;
5173
5174                                 f.SetIsUsed ();
5175                         }
5176
5177                         if (IsStatic){
5178                                 if (is_volatile)
5179                                         ig.Emit (OpCodes.Volatile);
5180
5181                                 ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
5182                         } else {
5183                                 if (!prepared)
5184                                         EmitInstance (ec, false);
5185
5186                                 // Optimization for build-in types
5187                                 if (TypeManager.IsStruct (type) && TypeManager.IsEqual (type, ec.MemberContext.CurrentType)) {
5188                                         LoadFromPtr (ig, type);
5189                                 } else {
5190                                         var ff = spec as FixedFieldSpec;
5191                                         if (ff != null) {
5192                                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5193                                                 ig.Emit (OpCodes.Ldflda, ff.Element);
5194                                         } else {
5195                                                 if (is_volatile)
5196                                                         ig.Emit (OpCodes.Volatile);
5197
5198                                                 ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
5199                                         }
5200                                 }
5201                         }
5202
5203                         if (leave_copy) {
5204                                 ec.ig.Emit (OpCodes.Dup);
5205                                 if (!IsStatic) {
5206                                         temp = new LocalTemporary (this.Type);
5207                                         temp.Store (ec);
5208                                 }
5209                         }
5210                 }
5211
5212                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5213                 {
5214                         //FieldAttributes fa = FieldInfo.Attributes;
5215                         //bool is_static = (fa & FieldAttributes.Static) != 0;
5216                         ILGenerator ig = ec.ig;
5217
5218                         prepared = prepare_for_load;
5219                         EmitInstance (ec, prepared);
5220
5221                         source.Emit (ec);
5222                         if (leave_copy) {
5223                                 ec.ig.Emit (OpCodes.Dup);
5224                                 if (!IsStatic) {
5225                                         temp = new LocalTemporary (this.Type);
5226                                         temp.Store (ec);
5227                                 }
5228                         }
5229
5230                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5231                         if (f != null){
5232                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5233                                         ig.Emit (OpCodes.Volatile);
5234
5235                                 f.SetAssigned ();
5236                         }
5237
5238                         if (IsStatic)
5239                                 ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
5240                         else
5241                                 ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
5242
5243                         if (temp != null) {
5244                                 temp.Emit (ec);
5245                                 temp.Release (ec);
5246                                 temp = null;
5247                         }
5248                 }
5249
5250                 public override void Emit (EmitContext ec)
5251                 {
5252                         Emit (ec, false);
5253                 }
5254
5255                 public override void EmitSideEffect (EmitContext ec)
5256                 {
5257                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5258                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
5259
5260                         if (is_volatile || is_marshal_by_ref ())
5261                                 base.EmitSideEffect (ec);
5262                 }
5263
5264                 public override void Error_VariableIsUsedBeforeItIsDeclared (Report r, string name)
5265                 {
5266                         r.Error (844, loc,
5267                                 "A local variable `{0}' cannot be used before it is declared. Consider renaming the local variable when it hides the field `{1}'",
5268                                 name, GetSignatureForError ());
5269                 }
5270
5271                 public void AddressOf (EmitContext ec, AddressOp mode)
5272                 {
5273                         ILGenerator ig = ec.ig;
5274
5275                         FieldBase f = TypeManager.GetField (spec.MetaInfo);
5276                         if (f != null){
5277                                 if ((mode & AddressOp.Store) != 0)
5278                                         f.SetAssigned ();
5279                                 if ((mode & AddressOp.Load) != 0)
5280                                         f.SetIsUsed ();
5281                         }
5282
5283                         //
5284                         // Handle initonly fields specially: make a copy and then
5285                         // get the address of the copy.
5286                         //
5287                         bool need_copy;
5288                         if (spec.IsReadOnly){
5289                                 need_copy = true;
5290                                 if (ec.HasSet (EmitContext.Options.ConstructorScope)){
5291                                         if (IsStatic){
5292                                                 if (ec.IsStatic)
5293                                                         need_copy = false;
5294                                         } else
5295                                                 need_copy = false;
5296                                 }
5297                         } else
5298                                 need_copy = false;
5299
5300                         if (need_copy){
5301                                 LocalBuilder local;
5302                                 Emit (ec);
5303                                 local = ig.DeclareLocal (type);
5304                                 ig.Emit (OpCodes.Stloc, local);
5305                                 ig.Emit (OpCodes.Ldloca, local);
5306                                 return;
5307                         }
5308
5309
5310                         if (IsStatic){
5311                                 ig.Emit (OpCodes.Ldsflda, GetConstructedFieldInfo ());
5312                         } else {
5313                                 if (!prepared)
5314                                         EmitInstance (ec, false);
5315                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5316                         }
5317                 }
5318
5319                 FieldInfo GetConstructedFieldInfo ()
5320                 {
5321                         if (constructed_generic_type == null)
5322                                 return spec.MetaInfo;
5323
5324                         return TypeBuilder.GetField (constructed_generic_type, spec.MetaInfo);
5325                 }
5326
5327                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5328                 {
5329                         return MakeExpression (ctx);
5330                 }
5331
5332                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5333                 {
5334                         return SLE.Expression.Field (InstanceExpression.MakeExpression (ctx), spec.MetaInfo);
5335                 }
5336
5337                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5338                 {
5339                         storey.MutateField (spec);
5340                         base.MutateHoistedGenericType (storey);
5341                 }
5342         }
5343
5344
5345         /// <summary>
5346         ///   Expression that evaluates to a Property.  The Assign class
5347         ///   might set the `Value' expression if we are in an assignment.
5348         ///
5349         ///   This is not an LValue because we need to re-write the expression, we
5350         ///   can not take data from the stack and store it.
5351         /// </summary>
5352         public class PropertyExpr : MemberExpr, IDynamicAssign
5353         {
5354                 PropertySpec spec;
5355                 MethodSpec getter, setter;
5356                 bool is_static;
5357
5358                 TypeArguments targs;
5359
5360                 LocalTemporary temp;
5361                 bool prepared;
5362
5363                 public PropertyExpr (Type container_type, PropertySpec spec, Location l)
5364                 {
5365                         this.spec = spec;
5366                         loc = l;
5367
5368                         type = TypeManager.TypeToCoreType (spec.PropertyType);
5369
5370                         ResolveAccessors (container_type);
5371                 }
5372
5373                 public override string Name {
5374                         get {
5375                                 return spec.Name;
5376                         }
5377                 }
5378
5379                 public override bool IsInstance {
5380                         get {
5381                                 return !is_static;
5382                         }
5383                 }
5384
5385                 public override bool IsStatic {
5386                         get {
5387                                 return is_static;
5388                         }
5389                 }
5390
5391                 public override Expression CreateExpressionTree (ResolveContext ec)
5392                 {
5393                         Arguments args;
5394                         if (IsSingleDimensionalArrayLength ()) {
5395                                 args = new Arguments (1);
5396                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5397                                 return CreateExpressionFactoryCall (ec, "ArrayLength", args);
5398                         }
5399
5400                         if (is_base) {
5401                                 Error_BaseAccessInExpressionTree (ec, loc);
5402                                 return null;
5403                         }
5404
5405                         args = new Arguments (2);
5406                         if (InstanceExpression == null)
5407                                 args.Add (new Argument (new NullLiteral (loc)));
5408                         else
5409                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5410                         args.Add (new Argument (new TypeOfMethod (getter, loc)));
5411                         return CreateExpressionFactoryCall (ec, "Property", args);
5412                 }
5413
5414                 public Expression CreateSetterTypeOfExpression ()
5415                 {
5416                         return new TypeOfMethod (setter, loc);
5417                 }
5418
5419                 public override Type DeclaringType {
5420                         get {
5421                                 return spec.DeclaringType;
5422                         }
5423                 }
5424
5425                 public override string GetSignatureForError ()
5426                 {
5427                         return TypeManager.GetFullNameSignature (spec.MetaInfo);
5428                 }
5429
5430                 void FindAccessors (Type invocation_type)
5431                 {
5432                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5433                                 BindingFlags.Static | BindingFlags.Instance |
5434                                 BindingFlags.DeclaredOnly;
5435
5436                         Type current = spec.DeclaringType;
5437                         for (; current != null; current = current.BaseType) {
5438                                 MemberInfo[] group = TypeManager.MemberLookup (
5439                                         invocation_type, invocation_type, current,
5440                                         MemberTypes.Property, flags, spec.Name, null);
5441
5442                                 if (group == null)
5443                                         continue;
5444
5445                                 if (group.Length != 1)
5446                                         // Oooops, can this ever happen ?
5447                                         return;
5448
5449                                 PropertyInfo pi = (PropertyInfo) group [0];
5450
5451                                 if (getter == null) {
5452                                         var m = pi.GetGetMethod (true);
5453                                         if (m != null)
5454                                                 getter = Import.CreateMethod (m);
5455                                 }
5456
5457                                 if (setter == null) {
5458                                         var m = pi.GetSetMethod (true);
5459                                         if (m != null)
5460                                                 setter = Import.CreateMethod (m);
5461                                 }
5462
5463                                 var accessor = getter != null ? getter : setter;
5464
5465                                 if (!accessor.IsVirtual)
5466                                         return;
5467                         }
5468                 }
5469
5470                 //
5471                 // We also perform the permission checking here, as the PropertyInfo does not
5472                 // hold the information for the accessibility of its setter/getter
5473                 //
5474                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5475                 void ResolveAccessors (Type container_type)
5476                 {
5477                         FindAccessors (container_type);
5478
5479                         if (getter != null) {
5480                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5481                                 IMethodData md = TypeManager.GetMethod (the_getter);
5482                                 if (md != null)
5483                                         md.SetIsUsed ();
5484
5485                                 is_static = getter.IsStatic;
5486                         }
5487
5488                         if (setter != null) {
5489                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5490                                 IMethodData md = TypeManager.GetMethod (the_setter);
5491                                 if (md != null)
5492                                         md.SetIsUsed ();
5493
5494                                 is_static = setter.IsStatic;
5495                         }
5496                 }
5497
5498                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5499                 {
5500                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), (MethodInfo) setter.MetaInfo);
5501                 }
5502
5503                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5504                 {
5505                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), (MethodInfo) getter.MetaInfo);
5506                 }
5507
5508                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5509                 {
5510                         if (InstanceExpression != null)
5511                                 InstanceExpression.MutateHoistedGenericType (storey);
5512
5513                         type = storey.MutateType (type);
5514                         if (getter != null)
5515                                 storey.MutateGenericMethod (getter);
5516                         if (setter != null)
5517                                 storey.MutateGenericMethod (setter);
5518                 }
5519
5520                 public PropertyInfo PropertyInfo {
5521                         get {
5522                                 return spec.MetaInfo;
5523                         }
5524                 }
5525
5526                 bool InstanceResolve (ResolveContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5527                 {
5528                         if (is_static) {
5529                                 InstanceExpression = null;
5530                                 return true;
5531                         }
5532
5533                         if (InstanceExpression == null) {
5534                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5535                                 return false;
5536                         }
5537
5538                         InstanceExpression = InstanceExpression.Resolve (ec);
5539                         if (lvalue_instance && InstanceExpression != null)
5540                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess);
5541
5542                         if (InstanceExpression == null)
5543                                 return false;
5544
5545                         InstanceExpression.CheckMarshalByRefAccess (ec);
5546
5547                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5548                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5549                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5550                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5551                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
5552                                 Error_CannotAccessProtected (ec, loc, spec.MetaInfo, InstanceExpression.Type, ec.CurrentType);
5553                                 return false;
5554                         }
5555
5556                         return true;
5557                 }
5558
5559                 void Error_PropertyNotFound (ResolveContext ec, MethodSpec mi, bool getter)
5560                 {
5561                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5562                         if (mi.MetaInfo is MethodBuilder) {
5563                                 Error_TypeDoesNotContainDefinition (ec, loc, spec.DeclaringType, Name);
5564                                 return;
5565                         }
5566
5567                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5568                         sig.Append ('.');
5569                         AParametersCollection iparams = mi.Parameters;
5570                         sig.Append (getter ? "get_" : "set_");
5571                         sig.Append (Name);
5572                         sig.Append (iparams.GetSignatureForError ());
5573
5574                         ec.Report.SymbolRelatedToPreviousError (mi.MetaInfo);
5575                         ec.Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5576                                 Name, sig.ToString ());
5577                 }
5578
5579                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5580                 {
5581                         bool dummy;
5582                         var accessor = lvalue ? setter : getter;
5583                         if (accessor == null && lvalue)
5584                                 accessor = getter;
5585                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5586                 }
5587
5588                 bool IsSingleDimensionalArrayLength ()
5589                 {
5590                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5591                                 return false;
5592
5593                         string t_name = InstanceExpression.Type.Name;
5594                         int t_name_len = t_name.Length;
5595                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5596                 }
5597
5598                 protected override Expression DoResolve (ResolveContext ec)
5599                 {
5600                         eclass = ExprClass.PropertyAccess;
5601
5602                         bool must_do_cs1540_check = false;
5603                         ec.Report.DisableReporting ();
5604                         bool res = ResolveGetter (ec, ref must_do_cs1540_check);
5605                         ec.Report.EnableReporting ();
5606
5607                         if (!res) {
5608                                 if (InstanceExpression != null) {
5609                                         Type expr_type = InstanceExpression.Type;
5610                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (expr_type, Name, loc);
5611                                         if (ex_method_lookup != null) {
5612                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
5613                                                 ex_method_lookup.SetTypeArguments (ec, targs);
5614                                                 return ex_method_lookup.Resolve (ec);
5615                                         }
5616                                 }
5617
5618                                 ResolveGetter (ec, ref must_do_cs1540_check);
5619                                 return null;
5620                         }
5621
5622                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5623                                 return null;
5624
5625                         //
5626                         // Only base will allow this invocation to happen.
5627                         //
5628                         if (IsBase && getter.IsAbstract) {
5629                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (spec.MetaInfo));
5630                         }
5631
5632                         if (spec.PropertyType.IsPointer && !ec.IsUnsafe){
5633                                 UnsafeError (ec, loc);
5634                         }
5635
5636                         if (!ec.IsObsolete) {
5637                                 PropertyBase pb = TypeManager.GetProperty (spec.MetaInfo);
5638                                 if (pb != null) {
5639                                         pb.CheckObsoleteness (loc);
5640                                 } else {
5641                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
5642                                         if (oa != null)
5643                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5644                                 }
5645                         }
5646
5647                         return this;
5648                 }
5649
5650                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5651                 {
5652                         eclass = ExprClass.PropertyAccess;
5653
5654                         if (right_side == EmptyExpression.OutAccess.Instance) {
5655                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (spec.Name, loc) is MemberAccess) {
5656                                         ec.Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5657                                             spec.Name);
5658                                 } else {
5659                                         right_side.DoResolveLValue (ec, this);
5660                                 }
5661                                 return null;
5662                         }
5663
5664                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5665                                 Error_CannotModifyIntermediateExpressionValue (ec);
5666                         }
5667
5668                         if (setter == null){
5669                                 //
5670                                 // The following condition happens if the PropertyExpr was
5671                                 // created, but is invalid (ie, the property is inaccessible),
5672                                 // and we did not want to embed the knowledge about this in
5673                                 // the caller routine.  This only avoids double error reporting.
5674                                 //
5675                                 if (getter == null)
5676                                         return null;
5677
5678                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (spec.Name, loc) is MemberAccess) {
5679                                         ec.Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5680                                                 spec.Name);
5681                                 } else {
5682                                         ec.Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5683                                                 GetSignatureForError ());
5684                                 }
5685                                 return null;
5686                         }
5687
5688                         if (targs != null) {
5689                                 base.SetTypeArguments (ec, targs);
5690                                 return null;
5691                         }
5692
5693                         if (setter.Parameters.Count != 1){
5694                                 Error_PropertyNotFound (ec, setter, false);
5695                                 return null;
5696                         }
5697
5698                         bool must_do_cs1540_check;
5699                         if (!IsAccessorAccessible (ec.CurrentType, setter, out must_do_cs1540_check)) {
5700                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter.MetaInfo) as PropertyBase.PropertyMethod;
5701                                 if (pm != null && pm.HasCustomAccessModifier) {
5702                                         ec.Report.SymbolRelatedToPreviousError (pm);
5703                                         ec.Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5704                                                 TypeManager.CSharpSignature (setter));
5705                                 }
5706                                 else {
5707                                         ec.Report.SymbolRelatedToPreviousError (setter.MetaInfo);
5708                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter), ec.Report);
5709                                 }
5710                                 return null;
5711                         }
5712
5713                         if (!InstanceResolve (ec, TypeManager.IsStruct (spec.DeclaringType), must_do_cs1540_check))
5714                                 return null;
5715
5716                         //
5717                         // Only base will allow this invocation to happen.
5718                         //
5719                         if (IsBase && setter.IsAbstract){
5720                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (spec.MetaInfo));
5721                         }
5722
5723                         if (spec.PropertyType.IsPointer && !ec.IsUnsafe) {
5724                                 UnsafeError (ec, loc);
5725                         }
5726
5727                         if (!ec.IsObsolete) {
5728                                 PropertyBase pb = TypeManager.GetProperty (spec.MetaInfo);
5729                                 if (pb != null) {
5730                                         pb.CheckObsoleteness (loc);
5731                                 } else {
5732                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (spec.MetaInfo);
5733                                         if (oa != null)
5734                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5735                                 }
5736                         }
5737
5738                         return this;
5739                 }
5740
5741                 public override void Emit (EmitContext ec)
5742                 {
5743                         Emit (ec, false);
5744                 }
5745
5746                 public void Emit (EmitContext ec, bool leave_copy)
5747                 {
5748                         //
5749                         // Special case: length of single dimension array property is turned into ldlen
5750                         //
5751                         if (IsSingleDimensionalArrayLength ()) {
5752                                 if (!prepared)
5753                                         EmitInstance (ec, false);
5754                                 ec.ig.Emit (OpCodes.Ldlen);
5755                                 ec.ig.Emit (OpCodes.Conv_I4);
5756                                 return;
5757                         }
5758
5759                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5760
5761                         if (leave_copy) {
5762                                 ec.ig.Emit (OpCodes.Dup);
5763                                 if (!is_static) {
5764                                         temp = new LocalTemporary (this.Type);
5765                                         temp.Store (ec);
5766                                 }
5767                         }
5768                 }
5769
5770                 //
5771                 // Implements the IAssignMethod interface for assignments
5772                 //
5773                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5774                 {
5775                         Expression my_source = source;
5776
5777                         if (prepare_for_load) {
5778                                 prepared = true;
5779                                 source.Emit (ec);
5780
5781                                 if (leave_copy) {
5782                                         ec.ig.Emit (OpCodes.Dup);
5783                                         if (!is_static) {
5784                                                 temp = new LocalTemporary (this.Type);
5785                                                 temp.Store (ec);
5786                                         }
5787                                 }
5788                         } else if (leave_copy) {
5789                                 source.Emit (ec);
5790                                 temp = new LocalTemporary (this.Type);
5791                                 temp.Store (ec);
5792                                 my_source = temp;
5793                         }
5794
5795                         Arguments args = new Arguments (1);
5796                         args.Add (new Argument (my_source));
5797
5798                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5799
5800                         if (temp != null) {
5801                                 temp.Emit (ec);
5802                                 temp.Release (ec);
5803                         }
5804                 }
5805
5806                 bool ResolveGetter (ResolveContext ec, ref bool must_do_cs1540_check)
5807                 {
5808                         if (targs != null) {
5809                                 base.SetTypeArguments (ec, targs);
5810                                 return false;
5811                         }
5812
5813                         if (getter != null) {
5814                                 if (!getter.Parameters.IsEmpty) {
5815                                         Error_PropertyNotFound (ec, getter, true);
5816                                         return false;
5817                                 }
5818                         }
5819
5820                         if (getter == null) {
5821                                 //
5822                                 // The following condition happens if the PropertyExpr was
5823                                 // created, but is invalid (ie, the property is inaccessible),
5824                                 // and we did not want to embed the knowledge about this in
5825                                 // the caller routine.  This only avoids double error reporting.
5826                                 //
5827                                 if (setter == null)
5828                                         return false;
5829
5830                                 if (InstanceExpression != EmptyExpression.Null) {
5831                                         ec.Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5832                                                 TypeManager.GetFullNameSignature (spec.MetaInfo));
5833                                         return false;
5834                                 }
5835                         }
5836
5837                         if (getter != null &&
5838                                 !IsAccessorAccessible (ec.CurrentType, getter, out must_do_cs1540_check)) {
5839                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter.MetaInfo) as PropertyBase.PropertyMethod;
5840                                 if (pm != null && pm.HasCustomAccessModifier) {
5841                                         ec.Report.SymbolRelatedToPreviousError (pm);
5842                                         ec.Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5843                                                 TypeManager.CSharpSignature (getter.MetaInfo));
5844                                 } else {
5845                                         ec.Report.SymbolRelatedToPreviousError (getter.MetaInfo);
5846                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter.MetaInfo), ec.Report);
5847                                 }
5848
5849                                 return false;
5850                         }
5851
5852                         return true;
5853                 }
5854
5855                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
5856                 {
5857                         targs = ta;
5858                 }
5859         }
5860
5861         /// <summary>
5862         ///   Fully resolved expression that evaluates to an Event
5863         /// </summary>
5864         public class EventExpr : MemberExpr
5865         {
5866                 readonly EventSpec spec;
5867
5868                 public EventExpr (EventSpec spec, Location loc)
5869                 {
5870                         this.spec = spec;
5871                         this.loc = loc;
5872                 }
5873
5874                 public override string Name {
5875                         get {
5876                                 return spec.Name;
5877                         }
5878                 }
5879
5880                 public override bool IsInstance {
5881                         get {
5882                                 return !spec.IsStatic;
5883                         }
5884                 }
5885
5886                 public override bool IsStatic {
5887                         get {
5888                                 return spec.IsStatic;
5889                         }
5890                 }
5891
5892                 public override Type DeclaringType {
5893                         get {
5894                                 return spec.DeclaringType;
5895                         }
5896                 }
5897
5898                 public void Error_AssignmentEventOnly (ResolveContext ec)
5899                 {
5900                         ec.Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5901                                 GetSignatureForError ());
5902                 }
5903
5904                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
5905                                                                 SimpleName original)
5906                 {
5907                         //
5908                         // If the event is local to this class, we transform ourselves into a FieldExpr
5909                         //
5910
5911                         if (spec.DeclaringType == ec.CurrentType ||
5912                             TypeManager.IsNestedChildOf(ec.CurrentType, spec.DeclaringType)) {
5913
5914                                 // TODO: Breaks dynamic binder as currect context fields are imported and not compiled
5915                                 EventField mi = TypeManager.GetEventField (spec.MetaInfo).MemberDefinition as EventField;
5916
5917                                 if (mi != null && mi.HasBackingField) {
5918                                         mi.SetIsUsed ();
5919                                         if (!ec.IsObsolete)
5920                                                 mi.CheckObsoleteness (loc);
5921
5922                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5923                                                 Error_AssignmentEventOnly (ec);
5924
5925                                         FieldExpr ml = new FieldExpr (mi.BackingField, loc);
5926
5927                                         InstanceExpression = null;
5928
5929                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5930                                 }
5931                         }
5932
5933                         if (left is This && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5934                                 Error_AssignmentEventOnly (ec);
5935
5936                         return base.ResolveMemberAccess (ec, left, loc, original);
5937                 }
5938
5939                 bool InstanceResolve (ResolveContext ec, bool must_do_cs1540_check)
5940                 {
5941                         if (IsStatic) {
5942                                 InstanceExpression = null;
5943                                 return true;
5944                         }
5945
5946                         if (InstanceExpression == null) {
5947                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5948                                 return false;
5949                         }
5950
5951                         InstanceExpression = InstanceExpression.Resolve (ec);
5952                         if (InstanceExpression == null)
5953                                 return false;
5954
5955                         if (IsBase && spec.IsAbstract) {
5956                                 Error_CannotCallAbstractBase (ec, TypeManager.CSharpSignature(spec.MetaInfo));
5957                                 return false;
5958                         }
5959
5960                         //
5961                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5962                         // However, in the Event case, we reported a CS0122 instead.
5963                         //
5964                         // TODO: Exact copy from PropertyExpr
5965                         //
5966                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5967                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5968                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5969                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5970                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
5971                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (spec.MetaInfo), ec.Report);
5972                                 return false;
5973                         }
5974
5975                         return true;
5976                 }
5977
5978                 public bool IsAccessibleFrom (Type invocation_type)
5979                 {
5980                         bool dummy;
5981                         return IsAccessorAccessible (invocation_type, spec.AccessorAdd, out dummy) &&
5982                                 IsAccessorAccessible (invocation_type, spec.AccessorRemove, out dummy);
5983                 }
5984
5985                 public override Expression CreateExpressionTree (ResolveContext ec)
5986                 {
5987                         throw new NotSupportedException ("ET");
5988                 }
5989
5990                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5991                 {
5992                         // contexts where an LValue is valid have already devolved to FieldExprs
5993                         Error_CannotAssign (ec);
5994                         return null;
5995                 }
5996
5997                 protected override Expression DoResolve (ResolveContext ec)
5998                 {
5999                         eclass = ExprClass.EventAccess;
6000
6001                         bool must_do_cs1540_check;
6002                         if (!(IsAccessorAccessible (ec.CurrentType, spec.AccessorAdd, out must_do_cs1540_check) &&
6003                               IsAccessorAccessible (ec.CurrentType, spec.AccessorRemove, out must_do_cs1540_check))) {
6004                                 ec.Report.SymbolRelatedToPreviousError (spec.MetaInfo);
6005                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (spec.MetaInfo), ec.Report);
6006                                 return null;
6007                         }
6008
6009                         if (!InstanceResolve (ec, must_do_cs1540_check))
6010                                 return null;
6011
6012                         if (!ec.HasSet (ResolveContext.Options.CompoundAssignmentScope)) {
6013                                 Error_CannotAssign (ec);
6014                                 return null;
6015                         }
6016
6017                         if (!ec.IsObsolete) {
6018                                 var oa = spec.GetObsoleteAttribute ();
6019                                 if (oa != null)
6020                                         AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
6021                         }
6022
6023                         spec.MemberDefinition.SetIsUsed ();
6024                         type = spec.EventType;
6025
6026                         return this;
6027                 }
6028
6029                 public override void Emit (EmitContext ec)
6030                 {
6031                         throw new NotSupportedException ();
6032                         //Error_CannotAssign ();
6033                 }
6034
6035                 public void Error_CannotAssign (ResolveContext ec)
6036                 {
6037                         ec.Report.Error (70, loc,
6038                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
6039                                 GetSignatureForError (), TypeManager.CSharpName (spec.DeclaringType));
6040                 }
6041
6042                 public override string GetSignatureForError ()
6043                 {
6044                         return TypeManager.CSharpSignature (spec.MetaInfo);
6045                 }
6046
6047                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
6048                 {
6049                         Arguments args = new Arguments (1);
6050                         args.Add (new Argument (source));
6051                         Invocation.EmitCall (ec, IsBase, InstanceExpression,
6052                                 is_add ? spec.AccessorAdd : spec.AccessorRemove,
6053                                 args, loc);
6054                 }
6055         }
6056
6057         public class TemporaryVariable : VariableReference
6058         {
6059                 LocalInfo li;
6060
6061                 public TemporaryVariable (Type type, Location loc)
6062                 {
6063                         this.type = type;
6064                         this.loc = loc;
6065                 }
6066
6067                 public override Expression CreateExpressionTree (ResolveContext ec)
6068                 {
6069                         throw new NotSupportedException ("ET");
6070                 }
6071
6072                 protected override Expression DoResolve (ResolveContext ec)
6073                 {
6074                         eclass = ExprClass.Variable;
6075
6076                         TypeExpr te = new TypeExpression (type, loc);
6077                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
6078                         if (!li.Resolve (ec))
6079                                 return null;
6080
6081                         //
6082                         // Don't capture temporary variables except when using
6083                         // iterator redirection
6084                         //
6085                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
6086                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
6087                                 storey.CaptureLocalVariable (ec, li);
6088                         }
6089
6090                         return this;
6091                 }
6092
6093                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6094                 {
6095                         return Resolve (ec);
6096                 }
6097
6098                 public override void Emit (EmitContext ec)
6099                 {
6100                         Emit (ec, false);
6101                 }
6102
6103                 public void EmitAssign (EmitContext ec, Expression source)
6104                 {
6105                         EmitAssign (ec, source, false, false);
6106                 }
6107
6108                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6109                 {
6110                         return li.HoistedVariant;
6111                 }
6112
6113                 public override bool IsFixed {
6114                         get { return true; }
6115                 }
6116
6117                 public override bool IsRef {
6118                         get { return false; }
6119                 }
6120
6121                 public override string Name {
6122                         get { throw new NotImplementedException (); }
6123                 }
6124
6125                 public override void SetHasAddressTaken ()
6126                 {
6127                         throw new NotImplementedException ();
6128                 }
6129
6130                 protected override ILocalVariable Variable {
6131                         get { return li; }
6132                 }
6133
6134                 public override VariableInfo VariableInfo {
6135                         get { throw new NotImplementedException (); }
6136                 }
6137         }
6138
6139         ///
6140         /// Handles `var' contextual keyword; var becomes a keyword only
6141         /// if no type called var exists in a variable scope
6142         ///
6143         class VarExpr : SimpleName
6144         {
6145                 // Used for error reporting only
6146                 int initializers_count;
6147
6148                 public VarExpr (Location loc)
6149                         : base ("var", loc)
6150                 {
6151                         initializers_count = 1;
6152                 }
6153
6154                 public int VariableInitializersCount {
6155                         set {
6156                                 this.initializers_count = value;
6157                         }
6158                 }
6159
6160                 public bool InferType (ResolveContext ec, Expression right_side)
6161                 {
6162                         if (type != null)
6163                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
6164
6165                         type = right_side.Type;
6166                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == InternalType.AnonymousMethod || type == InternalType.MethodGroup) {
6167                                 ec.Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
6168                                               right_side.GetSignatureForError ());
6169                                 return false;
6170                         }
6171
6172                         eclass = ExprClass.Variable;
6173                         return true;
6174                 }
6175
6176                 protected override void Error_TypeOrNamespaceNotFound (IMemberContext ec)
6177                 {
6178                         if (RootContext.Version < LanguageVersion.V_3)
6179                                 base.Error_TypeOrNamespaceNotFound (ec);
6180                         else
6181                                 ec.Compiler.Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
6182                 }
6183
6184                 public override TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
6185                 {
6186                         TypeExpr te = base.ResolveAsContextualType (rc, true);
6187                         if (te != null)
6188                                 return te;
6189
6190                         if (RootContext.Version < LanguageVersion.V_3)
6191                                 rc.Compiler.Report.FeatureIsNotAvailable (loc, "implicitly typed local variable");
6192
6193                         if (initializers_count == 1)
6194                                 return null;
6195
6196                         if (initializers_count > 1) {
6197                                 rc.Compiler.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
6198                                 initializers_count = 1;
6199                                 return null;
6200                         }
6201
6202                         if (initializers_count == 0) {
6203                                 initializers_count = 1;
6204                                 rc.Compiler.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
6205                                 return null;
6206                         }
6207
6208                         return null;
6209                 }
6210         }
6211 }