mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 //
  12
  13 namespace Mono.CSharp {
  14         using System;
  15         using System.Collections.Generic;
  16         using System.Diagnostics;
  17         using System.Reflection;
  18         using System.Reflection.Emit;
  19         using System.Text;
  20         using SLE = System.Linq.Expressions;
  21
  22         /// <remarks>
  23         ///   The ExprClass class contains the is used to pass the
  24         ///   classification of an expression (value, variable, namespace,
  25         ///   type, method group, property access, event access, indexer access,
  26         ///   nothing).
  27         /// </remarks>
  28         public enum ExprClass : byte {
  29                 Unresolved      = 0,
  30
  31                 Value,
  32                 Variable,
  33                 Namespace,
  34                 Type,
  35                 TypeParameter,
  36                 MethodGroup,
  37                 PropertyAccess,
  38                 EventAccess,
  39                 IndexerAccess,
  40                 Nothing,
  41         }
  42
  43         /// <remarks>
  44         ///   This is used to tell Resolve in which types of expressions we're
  45         ///   interested.
  46         /// </remarks>
  47         [Flags]
  48         public enum ResolveFlags {
  49                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  50                 VariableOrValue         = 1,
  51
  52                 // Returns a type expression.
  53                 Type                    = 1 << 1,
  54
  55                 // Returns a method group.
  56                 MethodGroup             = 1 << 2,
  57
  58                 TypeParameter   = 1 << 3,
  59
  60                 // Mask of all the expression class flags.
  61                 MaskExprClass = VariableOrValue | Type | MethodGroup | TypeParameter,
  62
  63                 // Set if this is resolving the first part of a MemberAccess.
  64                 Intermediate            = 1 << 11,
  65         }
  66
  67         //
  68         // This is just as a hint to AddressOf of what will be done with the
  69         // address.
  70         [Flags]
  71         public enum AddressOp {
  72                 Store = 1,
  73                 Load  = 2,
  74                 LoadStore = 3
  75         };
  76
  77         /// <summary>
  78         ///   This interface is implemented by variables
  79         /// </summary>
  80         public interface IMemoryLocation {
  81                 /// <summary>
  82                 ///   The AddressOf method should generate code that loads
  83                 ///   the address of the object and leaves it on the stack.
  84                 ///
  85                 ///   The `mode' argument is used to notify the expression
  86                 ///   of whether this will be used to read from the address or
  87                 ///   write to the address.
  88                 ///
  89                 ///   This is just a hint that can be used to provide good error
  90                 ///   reporting, and should have no other side effects.
  91                 /// </summary>
  92                 void AddressOf (EmitContext ec, AddressOp mode);
  93         }
  94
  95         //
  96         // An expressions resolved as a direct variable reference
  97         //
  98         public interface IVariableReference : IFixedExpression
  99         {
 100                 bool IsHoisted { get; }
 101                 string Name { get; }
 102                 VariableInfo VariableInfo { get; }
 103
 104                 void SetHasAddressTaken ();
 105         }
 106
 107         //
 108         // Implemented by an expression which could be or is always
 109         // fixed
 110         //
 111         public interface IFixedExpression
 112         {
 113                 bool IsFixed { get; }
 114         }
 115
 116         /// <remarks>
 117         ///   Base class for expressions
 118         /// </remarks>
 119         public abstract class Expression {
 120                 public ExprClass eclass;
 121                 protected Type type;
 122                 protected Location loc;
 123
 124                 public Type Type {
 125                         get { return type; }
 126                         set { type = value; }
 127                 }
 128
 129                 public virtual Location Location {
 130                         get { return loc; }
 131                 }
 132
 133                 // Not nice but we have broken hierarchy.
 134                 public virtual void CheckMarshalByRefAccess (ResolveContext ec)
 135                 {
 136                 }
 137
 138                 public virtual bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
 139                 {
 140                         Attribute.Error_AttributeArgumentNotValid (ec, loc);
 141                         value = null;
 142                         return false;
 143                 }
 144
 145                 public virtual string GetSignatureForError ()
 146                 {
 147                         return TypeManager.CSharpName (type);
 148                 }
 149
 150                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 151                 {
 152                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 153
 154                         must_do_cs1540_check = false; // by default we do not check for this
 155
 156                         if (ma == MethodAttributes.Public)
 157                                 return true;
 158
 159                         //
 160                         // If only accessible to the current class or children
 161                         //
 162                         if (ma == MethodAttributes.Private)
 163                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 164                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 165
 166                         if (TypeManager.IsThisOrFriendAssembly (invocation_type.Assembly, mi.DeclaringType.Assembly)) {
 167                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 168                                         return true;
 169                         } else {
 170                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 171                                         return false;
 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 static void Error_InvalidExpressionStatement (Report Report, Location loc)
 333                 {
 334                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 335                                        "expressions can be used as a statement");
 336                 }
 337
 338                 public void Error_InvalidExpressionStatement (BlockContext ec)
 339                 {
 340                         Error_InvalidExpressionStatement (ec.Report, loc);
 341                 }
 342
 343                 public static void Error_VoidInvalidInTheContext (Location loc, Report Report)
 344                 {
 345                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 346                 }
 347
 348                 public virtual void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
 349                 {
 350                         Error_ValueCannotBeConvertedCore (ec, loc, target, expl);
 351                 }
 352
 353                 protected void Error_ValueCannotBeConvertedCore (ResolveContext ec, Location loc, Type target, bool expl)
 354                 {
 355                         // The error was already reported as CS1660
 356                         if (type == InternalType.AnonymousMethod)
 357                                 return;
 358
 359                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 360                                 string sig1 = type.DeclaringMethod == null ?
 361                                         TypeManager.CSharpName (type.DeclaringType) :
 362                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 363                                 string sig2 = target.DeclaringMethod == null ?
 364                                         TypeManager.CSharpName (target.DeclaringType) :
 365                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 366                                 ec.Report.ExtraInformation (loc,
 367                                         String.Format (
 368                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 369                                                 Type.Name, sig1, sig2));
 370                         } else if (Type.FullName == target.FullName){
 371                                 ec.Report.ExtraInformation (loc,
 372                                         String.Format (
 373                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 374                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 375                         }
 376
 377                         if (expl) {
 378                                 ec.Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 379                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 380                                 return;
 381                         }
 382
 383                         ec.Report.DisableReporting ();
 384                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 385                         ec.Report.EnableReporting ();
 386
 387                         if (expl_exists) {
 388                                 ec.Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 389                                               "An explicit conversion exists (are you missing a cast?)",
 390                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 391                                 return;
 392                         }
 393
 394                         ec.Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 395                                 TypeManager.CSharpName (type),
 396                                 TypeManager.CSharpName (target));
 397                 }
 398
 399                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (Report Report, string name)
 400                 {
 401                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 402                 }
 403
 404                 public void Error_TypeArgumentsCannotBeUsed (Report report, Location loc)
 405                 {
 406                         // Better message for possible generic expressions
 407                         if (eclass == ExprClass.MethodGroup || eclass == ExprClass.Type) {
 408                                 if (this is TypeExpr)
 409                                         report.SymbolRelatedToPreviousError (type);
 410
 411                                 string name = eclass == ExprClass.Type ? ExprClassName : "method";
 412                                 report.Error (308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 413                                         name, GetSignatureForError ());
 414                         } else {
 415                                 report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
 416                                         ExprClassName, GetSignatureForError ());
 417                         }
 418                 }
 419
 420                 protected virtual void Error_TypeDoesNotContainDefinition (ResolveContext ec, Type type, string name)
 421                 {
 422                         Error_TypeDoesNotContainDefinition (ec, loc, type, name);
 423                 }
 424
 425                 public static void Error_TypeDoesNotContainDefinition (ResolveContext ec, Location loc, Type type, string name)
 426                 {
 427                         ec.Report.SymbolRelatedToPreviousError (type);
 428                         ec.Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 429                                 TypeManager.CSharpName (type), name);
 430                 }
 431
 432                 protected static void Error_ValueAssignment (ResolveContext ec, Location loc)
 433                 {
 434                         ec.Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 435                 }
 436
 437                 ResolveFlags ExprClassToResolveFlags {
 438                         get {
 439                                 switch (eclass) {
 440                                 case ExprClass.Type:
 441                                 case ExprClass.Namespace:
 442                                         return ResolveFlags.Type;
 443
 444                                 case ExprClass.MethodGroup:
 445                                         return ResolveFlags.MethodGroup;
 446
 447                                 case ExprClass.TypeParameter:
 448                                         return ResolveFlags.TypeParameter;
 449
 450                                 case ExprClass.Value:
 451                                 case ExprClass.Variable:
 452                                 case ExprClass.PropertyAccess:
 453                                 case ExprClass.EventAccess:
 454                                 case ExprClass.IndexerAccess:
 455                                         return ResolveFlags.VariableOrValue;
 456
 457                                 default:
 458                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 459                                 }
 460                         }
 461                 }
 462
 463                 /// <summary>
 464                 ///   Resolves an expression and performs semantic analysis on it.
 465                 /// </summary>
 466                 ///
 467                 /// <remarks>
 468                 ///   Currently Resolve wraps DoResolve to perform sanity
 469                 ///   checking and assertion checking on what we expect from Resolve.
 470                 /// </remarks>
 471                 public Expression Resolve (ResolveContext ec, ResolveFlags flags)
 472                 {
 473                         if (eclass != ExprClass.Unresolved)
 474                                 return this;
 475
 476                         Expression e;
 477                         if (this is SimpleName) {
 478                                 e = ((SimpleName) this).DoResolve (ec, (flags & ResolveFlags.Intermediate) != 0);
 479                         } else {
 480                                 e = DoResolve (ec);
 481                         }
 482
 483                         if (e == null)
 484                                 return null;
 485
 486                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 487                                 e.Error_UnexpectedKind (ec, flags, loc);
 488                                 return null;
 489                         }
 490
 491                         if (e.type == null)
 492                                 throw new InternalErrorException ("Expression `{0}' didn't set its type in DoResolve", e.GetType ());
 493
 494                         return e;
 495                 }
 496
 497                 /// <summary>
 498                 ///   Resolves an expression and performs semantic analysis on it.
 499                 /// </summary>
 500                 public Expression Resolve (ResolveContext rc)
 501                 {
 502                         return Resolve (rc, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 503                 }
 504
 505                 public Constant ResolveAsConstant (ResolveContext ec, MemberCore mc)
 506                 {
 507                         Expression e = Resolve (ec);
 508                         if (e == null)
 509                                 return null;
 510
 511                         Constant c = e as Constant;
 512                         if (c != null)
 513                                 return c;
 514
 515                         if (type != null && TypeManager.IsReferenceType (type))
 516                                 Const.Error_ConstantCanBeInitializedWithNullOnly (type, loc, mc.GetSignatureForError (), ec.Report);
 517                         else
 518                                 Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError (), ec.Report);
 519
 520                         return null;
 521                 }
 522
 523                 /// <summary>
 524                 ///   Resolves an expression for LValue assignment
 525                 /// </summary>
 526                 ///
 527                 /// <remarks>
 528                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 529                 ///   checking and assertion checking on what we expect from Resolve
 530                 /// </remarks>
 531                 public Expression ResolveLValue (ResolveContext ec, Expression right_side)
 532                 {
 533                         int errors = ec.Report.Errors;
 534                         bool out_access = right_side == EmptyExpression.OutAccess.Instance;
 535
 536                         Expression e = DoResolveLValue (ec, right_side);
 537
 538                         if (e != null && out_access && !(e is IMemoryLocation)) {
 539                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 540                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 541
 542                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 543                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 544                                 e = null;
 545                         }
 546
 547                         if (e == null) {
 548                                 if (errors == ec.Report.Errors) {
 549                                         if (out_access)
 550                                                 ec.Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 551                                         else
 552                                                 Error_ValueAssignment (ec, loc);
 553                                 }
 554                                 return null;
 555                         }
 556
 557                         if (e.eclass == ExprClass.Unresolved)
 558                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 559
 560                         if ((e.type == null) && !(e is GenericTypeExpr))
 561                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 562
 563                         return e;
 564                 }
 565
 566                 /// <summary>
 567                 ///   Emits the code for the expression
 568                 /// </summary>
 569                 ///
 570                 /// <remarks>
 571                 ///   The Emit method is invoked to generate the code
 572                 ///   for the expression.
 573                 /// </remarks>
 574                 public abstract void Emit (EmitContext ec);
 575
 576                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 577                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 578                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 579                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 580                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 581                 {
 582                         Emit (ec);
 583                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 584                 }
 585
 586                 // Emit this expression for its side effects, not for its value.
 587                 // The default implementation is to emit the value, and then throw it away.
 588                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 589                 public virtual void EmitSideEffect (EmitContext ec)
 590                 {
 591                         Emit (ec);
 592                         ec.ig.Emit (OpCodes.Pop);
 593                 }
 594
 595                 /// <summary>
 596                 ///   Protected constructor.  Only derivate types should
 597                 ///   be able to be created
 598                 /// </summary>
 599
 600                 protected Expression ()
 601                 {
 602                 }
 603
 604                 /// <summary>
 605                 ///   Returns a fully formed expression after a MemberLookup
 606                 /// </summary>
 607                 ///
 608                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 609                 {
 610                         if (mi is EventInfo)
 611                                 return new EventExpr ((EventInfo) mi, loc);
 612                         else if (mi is FieldInfo) {
 613                                 FieldInfo fi = (FieldInfo) mi;
 614                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 615                                         return new ConstantExpr (fi, loc);
 616                                 return new FieldExpr (fi, loc);
 617                         } else if (mi is PropertyInfo)
 618                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 619                         else if (mi is Type) {
 620                                 return new TypeExpression ((System.Type) mi, loc);
 621                         }
 622
 623                         return null;
 624                 }
 625
 626                 // TODO: [Obsolete ("Can be removed")]
 627                 protected static IList<MemberInfo> almost_matched_members = new List<MemberInfo> (4);
 628
 629                 //
 630                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 631                 //
 632                 // This code could use some optimizations, but we need to do some
 633                 // measurements.  For example, we could use a delegate to `flag' when
 634                 // something can not any longer be a method-group (because it is something
 635                 // else).
 636                 //
 637                 // Return values:
 638                 //     If the return value is an Array, then it is an array of
 639                 //     MethodBases
 640                 //
 641                 //     If the return value is an MemberInfo, it is anything, but a Method
 642                 //
 643                 //     null on error.
 644                 //
 645                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 646                 // the arguments here and have MemberLookup return only the methods that
 647                 // match the argument count/type, unlike we are doing now (we delay this
 648                 // decision).
 649                 //
 650                 // This is so we can catch correctly attempts to invoke instance methods
 651                 // from a static body (scan for error 120 in ResolveSimpleName).
 652                 //
 653                 //
 654                 // FIXME: Potential optimization, have a static ArrayList
 655                 //
 656
 657                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type, string name,
 658                                                        MemberTypes mt, BindingFlags bf, Location loc)
 659                 {
 660                         return MemberLookup (ctx, container_type, null, queried_type, name, mt, bf, loc);
 661                 }
 662
 663                 //
 664                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 665                 // `qualifier_type' or null to lookup members in the current class.
 666                 //
 667
 668                 public static Expression MemberLookup (CompilerContext ctx, Type container_type,
 669                                                        Type qualifier_type, Type queried_type,
 670                                                        string name, MemberTypes mt,
 671                                                        BindingFlags bf, Location loc)
 672                 {
 673                         almost_matched_members.Clear ();
 674
 675                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 676                                                                      queried_type, mt, bf, name, almost_matched_members);
 677
 678                         if (mi == null)
 679                                 return null;
 680
 681                         if (mi.Length > 1) {
 682                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 683                                 var methods = new List<MethodBase> (2);
 684                                 List<MemberInfo> non_methods = null;
 685
 686                                 foreach (MemberInfo m in mi) {
 687                                         if (m is MethodBase) {
 688                                                 methods.Add ((MethodBase) m);
 689                                                 continue;
 690                                         }
 691
 692                                         if (non_methods == null)
 693                                                 non_methods = new List<MemberInfo> (2);
 694
 695                                         bool is_candidate = true;
 696                                         for (int i = 0; i < non_methods.Count; ++i) {
 697                                                 MemberInfo n_m = non_methods [i];
 698                                                 if (n_m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType)) {
 699                                                         non_methods.Remove (n_m);
 700                                                         --i;
 701                                                 } else if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (n_m.DeclaringType, m.DeclaringType)) {
 702                                                         is_candidate = false;
 703                                                         break;
 704                                                 }
 705                                         }
 706
 707                                         if (is_candidate) {
 708                                                 non_methods.Add (m);
 709                                         }
 710                                 }
 711
 712                                 if (methods.Count == 0 && non_methods != null && non_methods.Count > 1) {
 713                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [1]);
 714                                         ctx.Report.SymbolRelatedToPreviousError (non_methods [0]);
 715                                         ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 716                                                 TypeManager.GetFullNameSignature (non_methods [1]),
 717                                                 TypeManager.GetFullNameSignature (non_methods [0]));
 718                                         return null;
 719                                 }
 720
 721                                 if (methods.Count == 0)
 722                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 723
 724                                 if (non_methods != null && non_methods.Count > 0) {
 725                                         MethodBase method = (MethodBase) methods [0];
 726                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 727                                         if (method.DeclaringType == non_method.DeclaringType) {
 728                                                 // Cannot happen with C# code, but is valid in IL
 729                                                 ctx.Report.SymbolRelatedToPreviousError (method);
 730                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 731                                                 ctx.Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 732                                                               TypeManager.GetFullNameSignature (non_method),
 733                                                               TypeManager.CSharpSignature (method));
 734                                                 return null;
 735                                         }
 736
 737                                         if (is_interface) {
 738                                                 ctx.Report.SymbolRelatedToPreviousError (method);
 739                                                 ctx.Report.SymbolRelatedToPreviousError (non_method);
 740                                                 ctx.Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 741                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 742                                         }
 743                                 }
 744
 745                                 return new MethodGroupExpr (methods, queried_type, loc);
 746                         }
 747
 748                         if (mi [0] is MethodBase)
 749                                 return new MethodGroupExpr (mi, queried_type, loc);
 750
 751                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 752                 }
 753
 754                 public const MemberTypes AllMemberTypes =
 755                         MemberTypes.Constructor |
 756                         MemberTypes.Event       |
 757                         MemberTypes.Field       |
 758                         MemberTypes.Method      |
 759                         MemberTypes.NestedType  |
 760                         MemberTypes.Property;
 761
 762                 public const BindingFlags AllBindingFlags =
 763                         BindingFlags.Public |
 764                         BindingFlags.Static |
 765                         BindingFlags.Instance;
 766
 767                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type queried_type,
 768                                                        string name, Location loc)
 769                 {
 770                         return MemberLookup (ctx, container_type, null, queried_type, name,
 771                                              AllMemberTypes, AllBindingFlags, loc);
 772                 }
 773
 774                 public static Expression MemberLookup (CompilerContext ctx, Type container_type, Type qualifier_type,
 775                                                        Type queried_type, string name, Location loc)
 776                 {
 777                         return MemberLookup (ctx, container_type, qualifier_type, queried_type,
 778                                              name, AllMemberTypes, AllBindingFlags, loc);
 779                 }
 780
 781                 public static MethodGroupExpr MethodLookup (CompilerContext ctx, Type container_type, Type queried_type,
 782                                                        string name, Location loc)
 783                 {
 784                         return (MethodGroupExpr)MemberLookup (ctx, container_type, null, queried_type, name,
 785                                              MemberTypes.Method, AllBindingFlags, loc);
 786                 }
 787
 788                 /// <summary>
 789                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 790                 ///   to find a final definition.  If the final definition is not found, we
 791                 ///   look for private members and display a useful debugging message if we
 792                 ///   find it.
 793                 /// </summary>
 794                 protected Expression MemberLookupFinal (ResolveContext ec, Type qualifier_type,
 795                                                             Type queried_type, string name,
 796                                                             MemberTypes mt, BindingFlags bf,
 797                                                             Location loc)
 798                 {
 799                         Expression e;
 800
 801                         int errors = ec.Report.Errors;
 802                         e = MemberLookup (ec.Compiler, ec.CurrentType, qualifier_type, queried_type, name, mt, bf, loc);
 803
 804                         if (e != null || errors != ec.Report.Errors)
 805                                 return e;
 806
 807                         // No errors were reported by MemberLookup, but there was an error.
 808                         return Error_MemberLookupFailed (ec, ec.CurrentType, qualifier_type, queried_type,
 809                                         name, null, mt, bf);
 810                 }
 811
 812                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type container_type, Type qualifier_type,
 813                                                        Type queried_type, string name, string class_name,
 814                                                            MemberTypes mt, BindingFlags bf)
 815                 {
 816                         MemberInfo[] lookup = null;
 817                         if (queried_type == null) {
 818                                 class_name = "global::";
 819                         } else {
 820                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 821                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 822                                         name, null);
 823
 824                                 if (lookup != null) {
 825                                         Expression e = Error_MemberLookupFailed (ec, queried_type, lookup);
 826
 827                                         //
 828                                         // FIXME: This is still very wrong, it should be done inside
 829                                         // OverloadResolve to do correct arguments matching.
 830                                         // Requires MemberLookup accessiblity check removal
 831                                         //
 832                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 833                                                 MemberInfo mi = lookup[0];
 834                                                 ec.Report.SymbolRelatedToPreviousError (mi);
 835                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 836                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 837                                                         // Although a derived class can access protected members of
 838                                                         // its base class it cannot do so through an instance of the
 839                                                         // base class (CS1540).  If the qualifier_type is a base of the
 840                                                         // ec.CurrentType and the lookup succeeds with the latter one,
 841                                                         // then we are in this situation.
 842                                                         Error_CannotAccessProtected (ec, loc, mi, qualifier_type, container_type);
 843                                                 } else {
 844                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi), ec.Report);
 845                                                 }
 846                                         }
 847
 848                                         return e;
 849                                 }
 850
 851                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 852                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 853                                         name, null);
 854                         }
 855
 856                         if (lookup == null) {
 857                                 if (class_name != null) {
 858                                         ec.Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 859                                                 name);
 860                                 } else {
 861                                         Error_TypeDoesNotContainDefinition (ec, queried_type, name);
 862                                 }
 863                                 return null;
 864                         }
 865
 866                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 867                                                       AllMemberTypes, AllBindingFlags |
 868                                                       BindingFlags.NonPublic, name, null) == null) {
 869                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 870                                         Type t = (Type) lookup [0];
 871
 872                                         ec.Report.Error (305, loc,
 873                                                       "Using the generic type `{0}' " +
 874                                                       "requires {1} type arguments",
 875                                                       TypeManager.CSharpName (t),
 876                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 877                                         return null;
 878                                 }
 879                         }
 880
 881                         return Error_MemberLookupFailed (ec, queried_type, lookup);
 882                 }
 883
 884                 protected virtual Expression Error_MemberLookupFailed (ResolveContext ec, Type type, MemberInfo[] members)
 885                 {
 886                         for (int i = 0; i < members.Length; ++i) {
 887                                 if (!(members [i] is MethodBase))
 888                                         return null;
 889                         }
 890
 891                         // By default propagate the closest candidates upwards
 892                         return new MethodGroupExpr (members, type, loc, true);
 893                 }
 894
 895                 protected virtual void Error_NegativeArrayIndex (ResolveContext ec, Location loc)
 896                 {
 897                         throw new NotImplementedException ();
 898                 }
 899
 900                 protected void Error_PointerInsideExpressionTree (ResolveContext ec)
 901                 {
 902                         ec.Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 903                 }
 904
 905                 /// <summary>
 906                 ///   Returns an expression that can be used to invoke operator true
 907                 ///   on the expression if it exists.
 908                 /// </summary>
 909                 protected static Expression GetOperatorTrue (ResolveContext ec, Expression e, Location loc)
 910                 {
 911                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 912                 }
 913
 914                 /// <summary>
 915                 ///   Returns an expression that can be used to invoke operator false
 916                 ///   on the expression if it exists.
 917                 /// </summary>
 918                 static public Expression GetOperatorFalse (ResolveContext ec, Expression e, Location loc)
 919                 {
 920                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 921                 }
 922
 923                 static Expression GetOperatorTrueOrFalse (ResolveContext ec, Expression e, bool is_true, Location loc)
 924                 {
 925                         MethodGroupExpr operator_group;
 926                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 927                         operator_group = MethodLookup (ec.Compiler, ec.CurrentType, e.Type, mname, loc) as MethodGroupExpr;
 928                         if (operator_group == null)
 929                                 return null;
 930
 931                         Arguments arguments = new Arguments (1);
 932                         arguments.Add (new Argument (e));
 933                         operator_group = operator_group.OverloadResolve (
 934                                 ec, ref arguments, false, loc);
 935
 936                         if (operator_group == null)
 937                                 return null;
 938
 939                         return new UserOperatorCall (operator_group, arguments, null, loc);
 940                 }
 941
 942                 public virtual string ExprClassName
 943                 {
 944                         get {
 945                                 switch (eclass){
 946                                 case ExprClass.Unresolved:
 947                                         return "Unresolved";
 948                                 case ExprClass.Value:
 949                                         return "value";
 950                                 case ExprClass.Variable:
 951                                         return "variable";
 952                                 case ExprClass.Namespace:
 953                                         return "namespace";
 954                                 case ExprClass.Type:
 955                                         return "type";
 956                                 case ExprClass.MethodGroup:
 957                                         return "method group";
 958                                 case ExprClass.PropertyAccess:
 959                                         return "property access";
 960                                 case ExprClass.EventAccess:
 961                                         return "event access";
 962                                 case ExprClass.IndexerAccess:
 963                                         return "indexer access";
 964                                 case ExprClass.Nothing:
 965                                         return "null";
 966                                 case ExprClass.TypeParameter:
 967                                         return "type parameter";
 968                                 }
 969                                 throw new Exception ("Should not happen");
 970                         }
 971                 }
 972
 973                 /// <summary>
 974                 ///   Reports that we were expecting `expr' to be of class `expected'
 975                 /// </summary>
 976                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, Location loc)
 977                 {
 978                         Error_UnexpectedKind (r, mc, expected, ExprClassName, loc);
 979                 }
 980
 981                 public void Error_UnexpectedKind (Report r, MemberCore mc, string expected, string was, Location loc)
 982                 {
 983                         string name;
 984                         if (mc != null)
 985                                 name = mc.GetSignatureForError ();
 986                         else
 987                                 name = GetSignatureForError ();
 988
 989                         r.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
 990                               name, was, expected);
 991                 }
 992
 993                 public void Error_UnexpectedKind (ResolveContext ec, ResolveFlags flags, Location loc)
 994                 {
 995                         string [] valid = new string [4];
 996                         int count = 0;
 997
 998                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 999                                 valid [count++] = "variable";
1000                                 valid [count++] = "value";
1001                         }
1002
1003                         if ((flags & ResolveFlags.Type) != 0)
1004                                 valid [count++] = "type";
1005
1006                         if ((flags & ResolveFlags.MethodGroup) != 0)
1007                                 valid [count++] = "method group";
1008
1009                         if (count == 0)
1010                                 valid [count++] = "unknown";
1011
1012                         StringBuilder sb = new StringBuilder (valid [0]);
1013                         for (int i = 1; i < count - 1; i++) {
1014                                 sb.Append ("', `");
1015                                 sb.Append (valid [i]);
1016                         }
1017                         if (count > 1) {
1018                                 sb.Append ("' or `");
1019                                 sb.Append (valid [count - 1]);
1020                         }
1021
1022                         ec.Report.Error (119, loc,
1023                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1024                 }
1025
1026                 public static void UnsafeError (ResolveContext ec, Location loc)
1027                 {
1028                         UnsafeError (ec.Report, loc);
1029                 }
1030
1031                 public static void UnsafeError (Report Report, Location loc)
1032                 {
1033                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1034                 }
1035
1036                 //
1037                 // Load the object from the pointer.
1038                 //
1039                 public static void LoadFromPtr (ILGenerator ig, Type t)
1040                 {
1041                         if (t == TypeManager.int32_type)
1042                                 ig.Emit (OpCodes.Ldind_I4);
1043                         else if (t == TypeManager.uint32_type)
1044                                 ig.Emit (OpCodes.Ldind_U4);
1045                         else if (t == TypeManager.short_type)
1046                                 ig.Emit (OpCodes.Ldind_I2);
1047                         else if (t == TypeManager.ushort_type)
1048                                 ig.Emit (OpCodes.Ldind_U2);
1049                         else if (t == TypeManager.char_type)
1050                                 ig.Emit (OpCodes.Ldind_U2);
1051                         else if (t == TypeManager.byte_type)
1052                                 ig.Emit (OpCodes.Ldind_U1);
1053                         else if (t == TypeManager.sbyte_type)
1054                                 ig.Emit (OpCodes.Ldind_I1);
1055                         else if (t == TypeManager.uint64_type)
1056                                 ig.Emit (OpCodes.Ldind_I8);
1057                         else if (t == TypeManager.int64_type)
1058                                 ig.Emit (OpCodes.Ldind_I8);
1059                         else if (t == TypeManager.float_type)
1060                                 ig.Emit (OpCodes.Ldind_R4);
1061                         else if (t == TypeManager.double_type)
1062                                 ig.Emit (OpCodes.Ldind_R8);
1063                         else if (t == TypeManager.bool_type)
1064                                 ig.Emit (OpCodes.Ldind_I1);
1065                         else if (t == TypeManager.intptr_type)
1066                                 ig.Emit (OpCodes.Ldind_I);
1067                         else if (TypeManager.IsEnumType (t)) {
1068                                 if (t == TypeManager.enum_type)
1069                                         ig.Emit (OpCodes.Ldind_Ref);
1070                                 else
1071                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1072                         } else if (TypeManager.IsStruct (t) || TypeManager.IsGenericParameter (t))
1073                                 ig.Emit (OpCodes.Ldobj, t);
1074                         else if (t.IsPointer)
1075                                 ig.Emit (OpCodes.Ldind_I);
1076                         else
1077                                 ig.Emit (OpCodes.Ldind_Ref);
1078                 }
1079
1080                 //
1081                 // The stack contains the pointer and the value of type `type'
1082                 //
1083                 public static void StoreFromPtr (ILGenerator ig, Type type)
1084                 {
1085                         if (TypeManager.IsEnumType (type))
1086                                 type = TypeManager.GetEnumUnderlyingType (type);
1087                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1088                                 ig.Emit (OpCodes.Stind_I4);
1089                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1090                                 ig.Emit (OpCodes.Stind_I8);
1091                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1092                                  type == TypeManager.ushort_type)
1093                                 ig.Emit (OpCodes.Stind_I2);
1094                         else if (type == TypeManager.float_type)
1095                                 ig.Emit (OpCodes.Stind_R4);
1096                         else if (type == TypeManager.double_type)
1097                                 ig.Emit (OpCodes.Stind_R8);
1098                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1099                                  type == TypeManager.bool_type)
1100                                 ig.Emit (OpCodes.Stind_I1);
1101                         else if (type == TypeManager.intptr_type)
1102                                 ig.Emit (OpCodes.Stind_I);
1103                         else if (TypeManager.IsStruct (type) || TypeManager.IsGenericParameter (type))
1104                                 ig.Emit (OpCodes.Stobj, type);
1105                         else
1106                                 ig.Emit (OpCodes.Stind_Ref);
1107                 }
1108
1109                 //
1110                 // Returns the size of type `t' if known, otherwise, 0
1111                 //
1112                 public static int GetTypeSize (Type t)
1113                 {
1114                         t = TypeManager.TypeToCoreType (t);
1115                         if (t == TypeManager.int32_type ||
1116                             t == TypeManager.uint32_type ||
1117                             t == TypeManager.float_type)
1118                                 return 4;
1119                         else if (t == TypeManager.int64_type ||
1120                                  t == TypeManager.uint64_type ||
1121                                  t == TypeManager.double_type)
1122                                 return 8;
1123                         else if (t == TypeManager.byte_type ||
1124                                  t == TypeManager.sbyte_type ||
1125                                  t == TypeManager.bool_type)
1126                                 return 1;
1127                         else if (t == TypeManager.short_type ||
1128                                  t == TypeManager.char_type ||
1129                                  t == TypeManager.ushort_type)
1130                                 return 2;
1131                         else if (t == TypeManager.decimal_type)
1132                                 return 16;
1133                         else
1134                                 return 0;
1135                 }
1136
1137                 protected void Error_CannotCallAbstractBase (ResolveContext ec, string name)
1138                 {
1139                         ec.Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1140                 }
1141
1142                 protected void Error_CannotModifyIntermediateExpressionValue (ResolveContext ec)
1143                 {
1144                         ec.Report.SymbolRelatedToPreviousError (type);
1145                         if (ec.CurrentInitializerVariable != null) {
1146                                 ec.Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1147                                         TypeManager.CSharpName (type), GetSignatureForError ());
1148                         } else {
1149                                 ec.Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1150                                         GetSignatureForError ());
1151                         }
1152                 }
1153
1154                 //
1155                 // Converts `source' to an int, uint, long or ulong.
1156                 //
1157                 protected Expression ConvertExpressionToArrayIndex (ResolveContext ec, Expression source)
1158                 {
1159                         if (TypeManager.IsDynamicType (source.type)) {
1160                                 Arguments args = new Arguments (1);
1161                                 args.Add (new Argument (source));
1162                                 return new DynamicConversion (TypeManager.int32_type, CSharpBinderFlags.ConvertArrayIndex, args, loc).Resolve (ec);
1163                         }
1164
1165                         Expression converted;
1166
1167                         using (ec.Set (ResolveContext.Options.CheckedScope)) {
1168                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1169                                 if (converted == null)
1170                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1171                                 if (converted == null)
1172                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1173                                 if (converted == null)
1174                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1175
1176                                 if (converted == null) {
1177                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1178                                         return null;
1179                                 }
1180                         }
1181
1182                         //
1183                         // Only positive constants are allowed at compile time
1184                         //
1185                         Constant c = converted as Constant;
1186                         if (c != null && c.IsNegative)
1187                                 Error_NegativeArrayIndex (ec, source.loc);
1188
1189                         // No conversion needed to array index
1190                         if (converted.Type == TypeManager.int32_type)
1191                                 return converted;
1192
1193                         return new ArrayIndexCast (converted).Resolve (ec);
1194                 }
1195
1196                 //
1197                 // Derived classes implement this method by cloning the fields that
1198                 // could become altered during the Resolve stage
1199                 //
1200                 // Only expressions that are created for the parser need to implement
1201                 // this.
1202                 //
1203                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1204                 {
1205                         throw new NotImplementedException (
1206                                 String.Format (
1207                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1208                 }
1209
1210                 //
1211                 // Clones an expression created by the parser.
1212                 //
1213                 // We only support expressions created by the parser so far, not
1214                 // expressions that have been resolved (many more classes would need
1215                 // to implement CloneTo).
1216                 //
1217                 // This infrastructure is here merely for Lambda expressions which
1218                 // compile the same code using different type values for the same
1219                 // arguments to find the correct overload
1220                 //
1221                 public Expression Clone (CloneContext clonectx)
1222                 {
1223                         Expression cloned = (Expression) MemberwiseClone ();
1224                         CloneTo (clonectx, cloned);
1225
1226                         return cloned;
1227                 }
1228
1229                 //
1230                 // Implementation of expression to expression tree conversion
1231                 //
1232                 public abstract Expression CreateExpressionTree (ResolveContext ec);
1233
1234                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, Arguments args)
1235                 {
1236                         return CreateExpressionFactoryCall (ec, name, null, args, loc);
1237                 }
1238
1239                 protected Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args)
1240                 {
1241                         return CreateExpressionFactoryCall (ec, name, typeArguments, args, loc);
1242                 }
1243
1244                 public static Expression CreateExpressionFactoryCall (ResolveContext ec, string name, TypeArguments typeArguments, Arguments args, Location loc)
1245                 {
1246                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (ec, loc), name, typeArguments, loc), args);
1247                 }
1248
1249                 protected static TypeExpr CreateExpressionTypeExpression (ResolveContext ec, Location loc)
1250                 {
1251                         TypeExpr texpr = TypeManager.expression_type_expr;
1252                         if (texpr == null) {
1253                                 Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Linq.Expressions", "Expression", Kind.Class, true);
1254                                 if (t == null)
1255                                         return null;
1256
1257                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1258                         }
1259
1260                         return texpr;
1261                 }
1262
1263                 //
1264                 // Implemented by all expressions which support conversion from
1265                 // compiler expression to invokable runtime expression. Used by
1266                 // dynamic C# binder.
1267                 //
1268                 public virtual SLE.Expression MakeExpression (BuilderContext ctx)
1269                 {
1270                         throw new NotImplementedException ("MakeExpression for " + GetType ());
1271                 }
1272
1273                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1274                 {
1275                         // TODO: It should probably be type = storey.MutateType (type);
1276                 }
1277         }
1278
1279         /// <summary>
1280         ///   This is just a base class for expressions that can
1281         ///   appear on statements (invocations, object creation,
1282         ///   assignments, post/pre increment and decrement).  The idea
1283         ///   being that they would support an extra Emition interface that
1284         ///   does not leave a result on the stack.
1285         /// </summary>
1286         public abstract class ExpressionStatement : Expression {
1287
1288                 public virtual ExpressionStatement ResolveStatement (BlockContext ec)
1289                 {
1290                         Expression e = Resolve (ec);
1291                         if (e == null)
1292                                 return null;
1293
1294                         ExpressionStatement es = e as ExpressionStatement;
1295                         if (es == null)
1296                                 Error_InvalidExpressionStatement (ec);
1297
1298                         return es;
1299                 }
1300
1301                 /// <summary>
1302                 ///   Requests the expression to be emitted in a `statement'
1303                 ///   context.  This means that no new value is left on the
1304                 ///   stack after invoking this method (constrasted with
1305                 ///   Emit that will always leave a value on the stack).
1306                 /// </summary>
1307                 public abstract void EmitStatement (EmitContext ec);
1308
1309                 public override void EmitSideEffect (EmitContext ec)
1310                 {
1311                         EmitStatement (ec);
1312                 }
1313         }
1314
1315         /// <summary>
1316         ///   This kind of cast is used to encapsulate the child
1317         ///   whose type is child.Type into an expression that is
1318         ///   reported to return "return_type".  This is used to encapsulate
1319         ///   expressions which have compatible types, but need to be dealt
1320         ///   at higher levels with.
1321         ///
1322         ///   For example, a "byte" expression could be encapsulated in one
1323         ///   of these as an "unsigned int".  The type for the expression
1324         ///   would be "unsigned int".
1325         ///
1326         /// </summary>
1327         public abstract class TypeCast : Expression
1328         {
1329                 protected readonly Expression child;
1330
1331                 protected TypeCast (Expression child, Type return_type)
1332                 {
1333                         eclass = child.eclass;
1334                         loc = child.Location;
1335                         type = return_type;
1336                         this.child = child;
1337                 }
1338
1339                 public override Expression CreateExpressionTree (ResolveContext ec)
1340                 {
1341                         Arguments args = new Arguments (2);
1342                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1343                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1344
1345                         if (type.IsPointer || child.Type.IsPointer)
1346                                 Error_PointerInsideExpressionTree (ec);
1347
1348                         return CreateExpressionFactoryCall (ec, ec.HasSet (ResolveContext.Options.CheckedScope) ? "ConvertChecked" : "Convert", args);
1349                 }
1350
1351                 protected override Expression DoResolve (ResolveContext ec)
1352                 {
1353                         // This should never be invoked, we are born in fully
1354                         // initialized state.
1355
1356                         return this;
1357                 }
1358
1359                 public override void Emit (EmitContext ec)
1360                 {
1361                         child.Emit (ec);
1362                 }
1363
1364                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1365                 {
1366                         return child.GetAttributableValue (ec, value_type, out value);
1367                 }
1368
1369                 public override SLE.Expression MakeExpression (BuilderContext ctx)
1370                 {
1371                         return ctx.HasSet (BuilderContext.Options.CheckedScope) ?
1372                                 SLE.Expression.ConvertChecked (child.MakeExpression (ctx), type) :
1373                                 SLE.Expression.Convert (child.MakeExpression (ctx), type);
1374                 }
1375
1376                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1377                 {
1378                         type = storey.MutateType (type);
1379                         child.MutateHoistedGenericType (storey);
1380                 }
1381
1382                 protected override void CloneTo (CloneContext clonectx, Expression t)
1383                 {
1384                         // Nothing to clone
1385                 }
1386
1387                 public override bool IsNull {
1388                         get { return child.IsNull; }
1389                 }
1390         }
1391
1392         public class EmptyCast : TypeCast {
1393                 EmptyCast (Expression child, Type target_type)
1394                         : base (child, target_type)
1395                 {
1396                 }
1397
1398                 public static Expression Create (Expression child, Type type)
1399                 {
1400                         Constant c = child as Constant;
1401                         if (c != null)
1402                                 return new EmptyConstantCast (c, type);
1403
1404                         EmptyCast e = child as EmptyCast;
1405                         if (e != null)
1406                                 return new EmptyCast (e.child, type);
1407
1408                         return new EmptyCast (child, type);
1409                 }
1410
1411                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1412                 {
1413                         child.EmitBranchable (ec, label, on_true);
1414                 }
1415
1416                 public override void EmitSideEffect (EmitContext ec)
1417                 {
1418                         child.EmitSideEffect (ec);
1419                 }
1420         }
1421
1422         //
1423         // Used for predefined class library user casts (no obsolete check, etc.)
1424         //
1425         public class OperatorCast : TypeCast {
1426                 MethodInfo conversion_operator;
1427
1428                 public OperatorCast (Expression child, Type target_type)
1429                         : this (child, target_type, false)
1430                 {
1431                 }
1432
1433                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1434                         : base (child, target_type)
1435                 {
1436                         conversion_operator = GetConversionOperator (find_explicit);
1437                         if (conversion_operator == null)
1438                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1439                 }
1440
1441                 // Returns the implicit operator that converts from
1442                 // 'child.Type' to our target type (type)
1443                 MethodInfo GetConversionOperator (bool find_explicit)
1444                 {
1445                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1446
1447                         MemberInfo [] mi;
1448
1449                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1450                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1451
1452                         if (mi == null){
1453                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1454                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1455                         }
1456
1457                         foreach (MethodInfo oper in mi) {
1458                                 AParametersCollection pd = TypeManager.GetParameterData (oper);
1459
1460                                 if (pd.Types [0] == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1461                                         return oper;
1462                         }
1463
1464                         return null;
1465                 }
1466
1467                 public override void Emit (EmitContext ec)
1468                 {
1469                         child.Emit (ec);
1470                         ec.ig.Emit (OpCodes.Call, conversion_operator);
1471                 }
1472         }
1473
1474         /// <summary>
1475         ///     This is a numeric cast to a Decimal
1476         /// </summary>
1477         public class CastToDecimal : OperatorCast {
1478                 public CastToDecimal (Expression child)
1479                         : this (child, false)
1480                 {
1481                 }
1482
1483                 public CastToDecimal (Expression child, bool find_explicit)
1484                         : base (child, TypeManager.decimal_type, find_explicit)
1485                 {
1486                 }
1487         }
1488
1489         /// <summary>
1490         ///     This is an explicit numeric cast from a Decimal
1491         /// </summary>
1492         public class CastFromDecimal : TypeCast
1493         {
1494                 static Dictionary<Type, MethodInfo> operators;
1495
1496                 public CastFromDecimal (Expression child, Type return_type)
1497                         : base (child, return_type)
1498                 {
1499                         if (child.Type != TypeManager.decimal_type)
1500                                 throw new InternalErrorException (
1501                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1502                 }
1503
1504                 // Returns the explicit operator that converts from an
1505                 // express of type System.Decimal to 'type'.
1506                 public Expression Resolve ()
1507                 {
1508                         if (operators == null) {
1509                                 MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1510                                    TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1511                                    BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1512
1513                                 operators = new Dictionary<Type, MethodInfo> (ReferenceEquality<Type>.Default);
1514                                 foreach (MethodInfo oper in all_oper) {
1515                                         AParametersCollection pd = TypeManager.GetParameterData (oper);
1516                                         if (pd.Types [0] == TypeManager.decimal_type)
1517                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1518                                 }
1519                         }
1520
1521                         return operators.ContainsKey (type) ? this : null;
1522                 }
1523
1524                 public override void Emit (EmitContext ec)
1525                 {
1526                         ILGenerator ig = ec.ig;
1527                         child.Emit (ec);
1528
1529                         ig.Emit (OpCodes.Call, operators [type]);
1530                 }
1531         }
1532
1533
1534         //
1535         // Constant specialization of EmptyCast.
1536         // We need to special case this since an empty cast of
1537         // a constant is still a constant.
1538         //
1539         public class EmptyConstantCast : Constant
1540         {
1541                 public Constant child;
1542
1543                 public EmptyConstantCast (Constant child, Type type)
1544                         : base (child.Location)
1545                 {
1546                         if (child == null)
1547                                 throw new ArgumentNullException ("child");
1548
1549                         this.child = child;
1550                         this.eclass = child.eclass;
1551                         this.type = type;
1552                 }
1553
1554                 public override string AsString ()
1555                 {
1556                         return child.AsString ();
1557                 }
1558
1559                 public override object GetValue ()
1560                 {
1561                         return child.GetValue ();
1562                 }
1563
1564                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1565                 {
1566                         if (child.Type == target_type)
1567                                 return child;
1568
1569                         // FIXME: check that 'type' can be converted to 'target_type' first
1570                         return child.ConvertExplicitly (in_checked_context, target_type);
1571                 }
1572
1573                 public override Expression CreateExpressionTree (ResolveContext ec)
1574                 {
1575                         Arguments args = Arguments.CreateForExpressionTree (ec, null,
1576                                 child.CreateExpressionTree (ec),
1577                                 new TypeOf (new TypeExpression (type, loc), loc));
1578
1579                         if (type.IsPointer)
1580                                 Error_PointerInsideExpressionTree (ec);
1581
1582                         return CreateExpressionFactoryCall (ec, "Convert", args);
1583                 }
1584
1585                 public override bool IsDefaultValue {
1586                         get { return child.IsDefaultValue; }
1587                 }
1588
1589                 public override bool IsNegative {
1590                         get { return child.IsNegative; }
1591                 }
1592
1593                 public override bool IsNull {
1594                         get { return child.IsNull; }
1595                 }
1596
1597                 public override bool IsZeroInteger {
1598                         get { return child.IsZeroInteger; }
1599                 }
1600
1601                 protected override Expression DoResolve (ResolveContext rc)
1602                 {
1603                         return this;
1604                 }
1605
1606                 public override void Emit (EmitContext ec)
1607                 {
1608                         child.Emit (ec);
1609                 }
1610
1611                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1612                 {
1613                         child.EmitBranchable (ec, label, on_true);
1614
1615                         // Only to make verifier happy
1616                         if (TypeManager.IsGenericParameter (type) && child.IsNull)
1617                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1618                 }
1619
1620                 public override void EmitSideEffect (EmitContext ec)
1621                 {
1622                         child.EmitSideEffect (ec);
1623                 }
1624
1625                 public override Constant ConvertImplicitly (ResolveContext rc, Type target_type)
1626                 {
1627                         // FIXME: Do we need to check user conversions?
1628                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1629                                 return null;
1630                         return child.ConvertImplicitly (rc, target_type);
1631                 }
1632
1633                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1634                 {
1635                         child.MutateHoistedGenericType (storey);
1636                 }
1637         }
1638
1639         /// <summary>
1640         ///  This class is used to wrap literals which belong inside Enums
1641         /// </summary>
1642         public class EnumConstant : Constant
1643         {
1644                 public Constant Child;
1645
1646                 public EnumConstant (Constant child, Type enum_type)
1647                         : base (child.Location)
1648                 {
1649                         this.Child = child;
1650                         this.type = enum_type;
1651                 }
1652
1653                 protected EnumConstant (Location loc)
1654                         : base (loc)
1655                 {
1656                 }
1657
1658                 protected override Expression DoResolve (ResolveContext rc)
1659                 {
1660                         Child = Child.Resolve (rc);
1661                         this.eclass = ExprClass.Value;
1662                         return this;
1663                 }
1664
1665                 public override void Emit (EmitContext ec)
1666                 {
1667                         Child.Emit (ec);
1668                 }
1669
1670                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1671                 {
1672                         Child.EmitBranchable (ec, label, on_true);
1673                 }
1674
1675                 public override void EmitSideEffect (EmitContext ec)
1676                 {
1677                         Child.EmitSideEffect (ec);
1678                 }
1679
1680                 public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
1681                 {
1682                         value = GetTypedValue ();
1683                         return true;
1684                 }
1685
1686                 public override string GetSignatureForError()
1687                 {
1688                         return TypeManager.CSharpName (Type);
1689                 }
1690
1691                 public override object GetValue ()
1692                 {
1693                         return Child.GetValue ();
1694                 }
1695
1696                 public override object GetTypedValue ()
1697                 {
1698                         // FIXME: runtime is not ready to work with just emited enums
1699                         if (!RootContext.StdLib) {
1700                                 return Child.GetValue ();
1701                         }
1702
1703 #if MS_COMPATIBLE
1704                         // Small workaround for big problem
1705                         // System.Enum.ToObject cannot be called on dynamic types
1706                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1707                         // because it does not properly support generics
1708                         //
1709                         // This works only sometimes
1710                         //
1711                         if (TypeManager.IsBeingCompiled (type))
1712                                 return Child.GetValue ();
1713 #endif
1714
1715                         return System.Enum.ToObject (type, Child.GetValue ());
1716                 }
1717
1718                 public override string AsString ()
1719                 {
1720                         return Child.AsString ();
1721                 }
1722
1723                 public EnumConstant Increment()
1724                 {
1725                         return new EnumConstant (((IntegralConstant) Child).Increment (), type);
1726                 }
1727
1728                 public override bool IsDefaultValue {
1729                         get {
1730                                 return Child.IsDefaultValue;
1731                         }
1732                 }
1733
1734                 public override bool IsZeroInteger {
1735                         get { return Child.IsZeroInteger; }
1736                 }
1737
1738                 public override bool IsNegative {
1739                         get {
1740                                 return Child.IsNegative;
1741                         }
1742                 }
1743
1744                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1745                 {
1746                         if (Child.Type == target_type)
1747                                 return Child;
1748
1749                         return Child.ConvertExplicitly (in_checked_context, target_type);
1750                 }
1751
1752                 public override Constant ConvertImplicitly (ResolveContext rc, Type type)
1753                 {
1754                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1755                         type = TypeManager.DropGenericTypeArguments (type);
1756
1757                         if (this_type == type) {
1758                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1759                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1760                                         return this;
1761
1762                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1763                                 if (type.UnderlyingSystemType != child_type)
1764                                         Child = Child.ConvertImplicitly (rc, type.UnderlyingSystemType);
1765                                 return this;
1766                         }
1767
1768                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1769                                 return null;
1770                         }
1771
1772                         return Child.ConvertImplicitly (rc, type);
1773                 }
1774         }
1775
1776         /// <summary>
1777         ///   This kind of cast is used to encapsulate Value Types in objects.
1778         ///
1779         ///   The effect of it is to box the value type emitted by the previous
1780         ///   operation.
1781         /// </summary>
1782         public class BoxedCast : TypeCast {
1783
1784                 public BoxedCast (Expression expr, Type target_type)
1785                         : base (expr, target_type)
1786                 {
1787                         eclass = ExprClass.Value;
1788                 }
1789
1790                 protected override Expression DoResolve (ResolveContext ec)
1791                 {
1792                         // This should never be invoked, we are born in fully
1793                         // initialized state.
1794
1795                         return this;
1796                 }
1797
1798                 public override void Emit (EmitContext ec)
1799                 {
1800                         base.Emit (ec);
1801
1802                         ec.ig.Emit (OpCodes.Box, child.Type);
1803                 }
1804
1805                 public override void EmitSideEffect (EmitContext ec)
1806                 {
1807                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1808                         // so, we need to emit the box+pop instructions in most cases
1809                         if (TypeManager.IsStruct (child.Type) &&
1810                             (type == TypeManager.object_type || type == TypeManager.value_type))
1811                                 child.EmitSideEffect (ec);
1812                         else
1813                                 base.EmitSideEffect (ec);
1814                 }
1815         }
1816
1817         public class UnboxCast : TypeCast {
1818                 public UnboxCast (Expression expr, Type return_type)
1819                         : base (expr, return_type)
1820                 {
1821                 }
1822
1823                 protected override Expression DoResolve (ResolveContext ec)
1824                 {
1825                         // This should never be invoked, we are born in fully
1826                         // initialized state.
1827
1828                         return this;
1829                 }
1830
1831                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1832                 {
1833                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1834                                 ec.Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1835                         return base.DoResolveLValue (ec, right_side);
1836                 }
1837
1838                 public override void Emit (EmitContext ec)
1839                 {
1840                         base.Emit (ec);
1841
1842                         ILGenerator ig = ec.ig;
1843                         ig.Emit (OpCodes.Unbox_Any, type);
1844                 }
1845
1846                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1847                 {
1848                         type = storey.MutateType (type);
1849                         base.MutateHoistedGenericType (storey);
1850                 }
1851         }
1852
1853         /// <summary>
1854         ///   This is used to perform explicit numeric conversions.
1855         ///
1856         ///   Explicit numeric conversions might trigger exceptions in a checked
1857         ///   context, so they should generate the conv.ovf opcodes instead of
1858         ///   conv opcodes.
1859         /// </summary>
1860         public class ConvCast : TypeCast {
1861                 public enum Mode : byte {
1862                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1863                         U1_I1, U1_CH,
1864                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1865                         U2_I1, U2_U1, U2_I2, U2_CH,
1866                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1867                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1868                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH, I8_I,
1869                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH, U8_I,
1870                         CH_I1, CH_U1, CH_I2,
1871                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1872                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4,
1873                         I_I8,
1874                 }
1875
1876                 Mode mode;
1877
1878                 public ConvCast (Expression child, Type return_type, Mode m)
1879                         : base (child, return_type)
1880                 {
1881                         mode = m;
1882                 }
1883
1884                 protected override Expression DoResolve (ResolveContext ec)
1885                 {
1886                         // This should never be invoked, we are born in fully
1887                         // initialized state.
1888
1889                         return this;
1890                 }
1891
1892                 public override string ToString ()
1893                 {
1894                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1895                 }
1896
1897                 public override void Emit (EmitContext ec)
1898                 {
1899                         ILGenerator ig = ec.ig;
1900
1901                         base.Emit (ec);
1902
1903                         if (ec.HasSet (EmitContext.Options.CheckedScope)) {
1904                                 switch (mode){
1905                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1906                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1907                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1908                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1909                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1910
1911                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1912                                 case Mode.U1_CH: /* nothing */ break;
1913
1914                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1915                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1916                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1917                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1918                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1919                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1920
1921                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1922                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1923                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1924                                 case Mode.U2_CH: /* nothing */ break;
1925
1926                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1927                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1928                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1929                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1930                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1931                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1932                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1933
1934                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1935                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1936                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1937                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1938                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1939                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1940
1941                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1942                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1943                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1944                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1945                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1946                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1947                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1948                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1949                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_Ovf_U); break;
1950
1951                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1952                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1953                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1954                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1955                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1956                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1957                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1958                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1959                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_Ovf_U_Un); break;
1960
1961                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1962                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1963                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1964
1965                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1966                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1967                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1968                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1969                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1970                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1971                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1972                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1973                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1974
1975                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1976                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1977                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1978                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1979                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1980                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1981                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1982                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1983                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1984                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1985
1986                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1987                                 }
1988                         } else {
1989                                 switch (mode){
1990                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1991                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1992                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1993                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1994                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1995
1996                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1997                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1998
1999                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2000                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2001                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2002                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2003                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2004                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2005
2006                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2007                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2008                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2009                                 case Mode.U2_CH: /* nothing */ break;
2010
2011                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2012                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2013                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2014                                 case Mode.I4_U4: /* nothing */ break;
2015                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2016                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2017                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2018
2019                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2020                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2021                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2022                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2023                                 case Mode.U4_I4: /* nothing */ break;
2024                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2025
2026                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2027                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2028                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2029                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2030                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2031                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2032                                 case Mode.I8_U8: /* nothing */ break;
2033                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2034                                 case Mode.I8_I: ig.Emit (OpCodes.Conv_U); break;
2035
2036                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2037                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2038                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2039                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2040                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2041                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2042                                 case Mode.U8_I8: /* nothing */ break;
2043                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2044                                 case Mode.U8_I: ig.Emit (OpCodes.Conv_U); break;
2045
2046                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2047                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2048                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2049
2050                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2051                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2052                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2053                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2054                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2055                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2056                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2057                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2058                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2059
2060                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2061                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2062                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2063                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2064                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2065                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2066                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2067                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2068                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2069                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2070
2071                                 case Mode.I_I8: ig.Emit (OpCodes.Conv_U8); break;
2072                                 }
2073                         }
2074                 }
2075         }
2076
2077         public class OpcodeCast : TypeCast {
2078                 readonly OpCode op;
2079
2080                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2081                         : base (child, return_type)
2082                 {
2083                         this.op = op;
2084                 }
2085
2086                 protected override Expression DoResolve (ResolveContext ec)
2087                 {
2088                         // This should never be invoked, we are born in fully
2089                         // initialized state.
2090
2091                         return this;
2092                 }
2093
2094                 public override void Emit (EmitContext ec)
2095                 {
2096                         base.Emit (ec);
2097                         ec.ig.Emit (op);
2098                 }
2099
2100                 public Type UnderlyingType {
2101                         get { return child.Type; }
2102                 }
2103         }
2104
2105         /// <summary>
2106         ///   This kind of cast is used to encapsulate a child and cast it
2107         ///   to the class requested
2108         /// </summary>
2109         public sealed class ClassCast : TypeCast {
2110                 readonly bool forced;
2111
2112                 public ClassCast (Expression child, Type return_type)
2113                         : base (child, return_type)
2114                 {
2115                 }
2116
2117                 public ClassCast (Expression child, Type return_type, bool forced)
2118                         : base (child, return_type)
2119                 {
2120                         this.forced = forced;
2121                 }
2122
2123                 public override void Emit (EmitContext ec)
2124                 {
2125                         base.Emit (ec);
2126
2127                         bool gen = TypeManager.IsGenericParameter (child.Type);
2128                         if (gen)
2129                                 ec.ig.Emit (OpCodes.Box, child.Type);
2130
2131                         if (type.IsGenericParameter) {
2132                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2133                                 return;
2134                         }
2135
2136                         if (gen && !forced)
2137                                 return;
2138
2139                         ec.ig.Emit (OpCodes.Castclass, type);
2140                 }
2141         }
2142
2143         //
2144         // Created during resolving pahse when an expression is wrapped or constantified
2145         // and original expression can be used later (e.g. for expression trees)
2146         //
2147         public class ReducedExpression : Expression
2148         {
2149                 sealed class ReducedConstantExpression : EmptyConstantCast
2150                 {
2151                         readonly Expression orig_expr;
2152
2153                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2154                                 : base (expr, expr.Type)
2155                         {
2156                                 this.orig_expr = orig_expr;
2157                         }
2158
2159                         public override Constant ConvertImplicitly (ResolveContext rc, Type target_type)
2160                         {
2161                                 Constant c = base.ConvertImplicitly (rc, target_type);
2162                                 if (c != null)
2163                                         c = new ReducedConstantExpression (c, orig_expr);
2164
2165                                 return c;
2166                         }
2167
2168                         public override Expression CreateExpressionTree (ResolveContext ec)
2169                         {
2170                                 return orig_expr.CreateExpressionTree (ec);
2171                         }
2172
2173                         public override bool GetAttributableValue (ResolveContext ec, Type value_type, out object value)
2174                         {
2175                                 //
2176                                 // Even if resolved result is a constant original expression was not
2177                                 // and attribute accepts constants only
2178                                 //
2179                                 Attribute.Error_AttributeArgumentNotValid (ec, orig_expr.Location);
2180                                 value = null;
2181                                 return false;
2182                         }
2183
2184                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2185                         {
2186                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2187                                 if (c != null)
2188                                         c = new ReducedConstantExpression (c, orig_expr);
2189                                 return c;
2190                         }
2191                 }
2192
2193                 sealed class ReducedExpressionStatement : ExpressionStatement
2194                 {
2195                         readonly Expression orig_expr;
2196                         readonly ExpressionStatement stm;
2197
2198                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2199                         {
2200                                 this.orig_expr = orig;
2201                                 this.stm = stm;
2202                                 this.loc = orig.Location;
2203                         }
2204
2205                         public override Expression CreateExpressionTree (ResolveContext ec)
2206                         {
2207                                 return orig_expr.CreateExpressionTree (ec);
2208                         }
2209
2210                         protected override Expression DoResolve (ResolveContext ec)
2211                         {
2212                                 eclass = stm.eclass;
2213                                 type = stm.Type;
2214                                 return this;
2215                         }
2216
2217                         public override void Emit (EmitContext ec)
2218                         {
2219                                 stm.Emit (ec);
2220                         }
2221
2222                         public override void EmitStatement (EmitContext ec)
2223                         {
2224                                 stm.EmitStatement (ec);
2225                         }
2226
2227                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2228                         {
2229                                 stm.MutateHoistedGenericType (storey);
2230                         }
2231                 }
2232
2233                 readonly Expression expr, orig_expr;
2234
2235                 private ReducedExpression (Expression expr, Expression orig_expr)
2236                 {
2237                         this.expr = expr;
2238                         this.eclass = expr.eclass;
2239                         this.type = expr.Type;
2240                         this.orig_expr = orig_expr;
2241                         this.loc = orig_expr.Location;
2242                 }
2243
2244                 //
2245                 // Creates fully resolved expression switcher
2246                 //
2247                 public static Constant Create (Constant expr, Expression original_expr)
2248                 {
2249                         if (expr.eclass == ExprClass.Unresolved)
2250                                 throw new ArgumentException ("Unresolved expression");
2251
2252                         return new ReducedConstantExpression (expr, original_expr);
2253                 }
2254
2255                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2256                 {
2257                         return new ReducedExpressionStatement (s, orig);
2258                 }
2259
2260                 //
2261                 // Creates unresolved reduce expression. The original expression has to be
2262                 // already resolved
2263                 //
2264                 public static Expression Create (Expression expr, Expression original_expr)
2265                 {
2266                         Constant c = expr as Constant;
2267                         if (c != null)
2268                                 return Create (c, original_expr);
2269
2270                         ExpressionStatement s = expr as ExpressionStatement;
2271                         if (s != null)
2272                                 return Create (s, original_expr);
2273
2274                         if (expr.eclass == ExprClass.Unresolved)
2275                                 throw new ArgumentException ("Unresolved expression");
2276
2277                         return new ReducedExpression (expr, original_expr);
2278                 }
2279
2280                 public override Expression CreateExpressionTree (ResolveContext ec)
2281                 {
2282                         return orig_expr.CreateExpressionTree (ec);
2283                 }
2284
2285                 protected override Expression DoResolve (ResolveContext ec)
2286                 {
2287                         return this;
2288                 }
2289
2290                 public override void Emit (EmitContext ec)
2291                 {
2292                         expr.Emit (ec);
2293                 }
2294
2295                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2296                 {
2297                         expr.EmitBranchable (ec, target, on_true);
2298                 }
2299
2300                 public override SLE.Expression MakeExpression (BuilderContext ctx)
2301                 {
2302                         return orig_expr.MakeExpression (ctx);
2303                 }
2304
2305                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2306                 {
2307                         expr.MutateHoistedGenericType (storey);
2308                 }
2309         }
2310
2311         //
2312         // Standard composite pattern
2313         //
2314         public abstract class CompositeExpression : Expression
2315         {
2316                 Expression expr;
2317
2318                 protected CompositeExpression (Expression expr)
2319                 {
2320                         this.expr = expr;
2321                         this.loc = expr.Location;
2322                 }
2323
2324                 public override Expression CreateExpressionTree (ResolveContext ec)
2325                 {
2326                         return expr.CreateExpressionTree (ec);
2327                 }
2328
2329                 public Expression Child {
2330                         get { return expr; }
2331                 }
2332
2333                 protected override Expression DoResolve (ResolveContext ec)
2334                 {
2335                         expr = expr.Resolve (ec);
2336                         if (expr != null) {
2337                                 type = expr.Type;
2338                                 eclass = expr.eclass;
2339                         }
2340
2341                         return this;
2342                 }
2343
2344                 public override void Emit (EmitContext ec)
2345                 {
2346                         expr.Emit (ec);
2347                 }
2348
2349                 public override bool IsNull {
2350                         get { return expr.IsNull; }
2351                 }
2352         }
2353
2354         //
2355         // Base of expressions used only to narrow resolve flow
2356         //
2357         public abstract class ShimExpression : Expression
2358         {
2359                 protected Expression expr;
2360
2361                 protected ShimExpression (Expression expr)
2362                 {
2363                         this.expr = expr;
2364                 }
2365
2366                 protected override void CloneTo (CloneContext clonectx, Expression t)
2367                 {
2368                         if (expr == null)
2369                                 return;
2370
2371                         ShimExpression target = (ShimExpression) t;
2372                         target.expr = expr.Clone (clonectx);
2373                 }
2374
2375                 public override Expression CreateExpressionTree (ResolveContext ec)
2376                 {
2377                         throw new NotSupportedException ("ET");
2378                 }
2379
2380                 public override void Emit (EmitContext ec)
2381                 {
2382                         throw new InternalErrorException ("Missing Resolve call");
2383                 }
2384
2385                 public Expression Expr {
2386                         get { return expr; }
2387                 }
2388
2389                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2390                 {
2391                         throw new InternalErrorException ("Missing Resolve call");
2392                 }
2393         }
2394
2395         //
2396         // Unresolved type name expressions
2397         //
2398         public abstract class ATypeNameExpression : FullNamedExpression
2399         {
2400                 string name;
2401                 protected TypeArguments targs;
2402
2403                 protected ATypeNameExpression (string name, Location l)
2404                 {
2405                         this.name = name;
2406                         loc = l;
2407                 }
2408
2409                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2410                 {
2411                         this.name = name;
2412                         this.targs = targs;
2413                         loc = l;
2414                 }
2415
2416                 public bool HasTypeArguments {
2417                         get {
2418                                 return targs != null;
2419                         }
2420                 }
2421
2422                 public override bool Equals (object obj)
2423                 {
2424                         ATypeNameExpression atne = obj as ATypeNameExpression;
2425                         return atne != null && atne.Name == Name &&
2426                                 (targs == null || targs.Equals (atne.targs));
2427                 }
2428
2429                 public override int GetHashCode ()
2430                 {
2431                         return Name.GetHashCode ();
2432                 }
2433
2434                 public override string GetSignatureForError ()
2435                 {
2436                         if (targs != null) {
2437                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2438                                         targs.GetSignatureForError () + ">";
2439                         }
2440
2441                         return Name;
2442                 }
2443
2444                 public string Name {
2445                         get {
2446                                 return name;
2447                         }
2448                         set {
2449                                 name = value;
2450                         }
2451                 }
2452
2453                 public TypeArguments TypeArguments {
2454                         get {
2455                                 return targs;
2456                         }
2457                 }
2458         }
2459
2460         /// <summary>
2461         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2462         ///   of a dotted-name.
2463         /// </summary>
2464         public class SimpleName : ATypeNameExpression
2465         {
2466                 public SimpleName (string name, Location l)
2467                         : base (name, l)
2468                 {
2469                 }
2470
2471                 public SimpleName (string name, TypeArguments args, Location l)
2472                         : base (name, args, l)
2473                 {
2474                 }
2475
2476                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2477                         : base (name, l)
2478                 {
2479                         targs = new TypeArguments ();
2480                         foreach (TypeParameter type_param in type_params)
2481                                 targs.Add (new TypeParameterExpr (type_param, l));
2482                 }
2483
2484                 public static string RemoveGenericArity (string name)
2485                 {
2486                         int start = 0;
2487                         StringBuilder sb = null;
2488                         do {
2489                                 int pos = name.IndexOf ('`', start);
2490                                 if (pos < 0) {
2491                                         if (start == 0)
2492                                                 return name;
2493
2494                                         sb.Append (name.Substring (start));
2495                                         break;
2496                                 }
2497
2498                                 if (sb == null)
2499                                         sb = new StringBuilder ();
2500                                 sb.Append (name.Substring (start, pos-start));
2501
2502                                 pos++;
2503                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2504                                         pos++;
2505
2506                                 start = pos;
2507                         } while (start < name.Length);
2508
2509                         return sb.ToString ();
2510                 }
2511
2512                 public SimpleName GetMethodGroup ()
2513                 {
2514                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2515                 }
2516
2517                 public static void Error_ObjectRefRequired (ResolveContext ec, Location l, string name)
2518                 {
2519                         if (ec.HasSet (ResolveContext.Options.FieldInitializerScope))
2520                                 ec.Report.Error (236, l,
2521                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2522                                         name);
2523                         else
2524                                 ec.Report.Error (120, l,
2525                                         "An object reference is required to access non-static member `{0}'",
2526                                         name);
2527                 }
2528
2529                 public bool IdenticalNameAndTypeName (IMemberContext mc, Expression resolved_to, Location loc)
2530                 {
2531                         return resolved_to != null && resolved_to.Type != null &&
2532                                 resolved_to.Type.Name == Name &&
2533                                 (mc.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2534                 }
2535
2536                 protected override Expression DoResolve (ResolveContext ec)
2537                 {
2538                         return SimpleNameResolve (ec, null, false);
2539                 }
2540
2541                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
2542                 {
2543                         return SimpleNameResolve (ec, right_side, false);
2544                 }
2545
2546                 public Expression DoResolve (ResolveContext ec, bool intermediate)
2547                 {
2548                         return SimpleNameResolve (ec, null, intermediate);
2549                 }
2550
2551                 static bool IsNestedChild (Type t, Type parent)
2552                 {
2553                         while (parent != null) {
2554                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2555                                         return true;
2556
2557                                 parent = parent.BaseType;
2558                         }
2559
2560                         return false;
2561                 }
2562
2563                 FullNamedExpression ResolveNested (Type t)
2564                 {
2565                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2566                                 return null;
2567
2568                         Type ds = t;
2569                         while (ds != null && !IsNestedChild (t, ds))
2570                                 ds = ds.DeclaringType;
2571
2572                         if (ds == null)
2573                                 return null;
2574
2575                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2576
2577                         int arg_count = targs != null ? targs.Count : 0;
2578
2579                         for (; (ds != null) && TypeManager.IsGenericType (ds); ds = ds.DeclaringType) {
2580                                 Type[] gargs = TypeManager.GetTypeArguments (ds);
2581                                 if (arg_count + gargs.Length == gen_params.Length) {
2582                                         TypeArguments new_args = new TypeArguments ();
2583                                         foreach (Type param in gargs)
2584                                                 new_args.Add (new TypeExpression (param, loc));
2585
2586                                         if (targs != null)
2587                                                 new_args.Add (targs);
2588
2589                                         return new GenericTypeExpr (t, new_args, loc);
2590                                 }
2591                         }
2592
2593                         return null;
2594                 }
2595
2596                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2597                 {
2598                         int errors = ec.Compiler.Report.Errors;
2599                         FullNamedExpression fne = ec.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2600
2601                         if (fne != null) {
2602                                 if (fne.Type == null)
2603                                         return fne;
2604
2605                                 FullNamedExpression nested = ResolveNested (fne.Type);
2606                                 if (nested != null)
2607                                         return nested.ResolveAsTypeStep (ec, false);
2608
2609                                 if (targs != null) {
2610                                         if (TypeManager.IsGenericType (fne.Type)) {
2611                                                 GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2612                                                 return ct.ResolveAsTypeStep (ec, false);
2613                                         }
2614
2615                                         fne.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2616                                 }
2617
2618                                 return fne;
2619                         }
2620
2621                         if (!HasTypeArguments && Name == "dynamic" &&
2622                                 RootContext.Version > LanguageVersion.V_3 &&
2623                                 RootContext.MetadataCompatibilityVersion > MetadataVersion.v2) {
2624
2625                                 if (!PredefinedAttributes.Get.Dynamic.IsDefined) {
2626                                         ec.Compiler.Report.Error (1980, Location,
2627                                                 "Dynamic keyword requires `{0}' to be defined. Are you missing System.Core.dll assembly reference?",
2628                                                 PredefinedAttributes.Get.Dynamic.GetSignatureForError ());
2629                                 }
2630
2631                                 return new DynamicTypeExpr (loc);
2632                         }
2633
2634                         if (silent || errors != ec.Compiler.Report.Errors)
2635                                 return null;
2636
2637                         Error_TypeOrNamespaceNotFound (ec);
2638                         return null;
2639                 }
2640
2641                 protected virtual void Error_TypeOrNamespaceNotFound (IMemberContext ec)
2642                 {
2643                         if (ec.CurrentType != null) {
2644                                 if (ec.CurrentTypeDefinition != null) {
2645                                         MemberCore mc = ec.CurrentTypeDefinition.GetDefinition (Name);
2646                                         if (mc != null) {
2647                                                 Error_UnexpectedKind (ec.Compiler.Report, mc, "type", GetMemberType (mc), loc);
2648                                                 return;
2649                                         }
2650                                 }
2651
2652                                 string ns = ec.CurrentType.Namespace;
2653                                 string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2654                                 foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
2655                                         Type type = a.GetType (fullname);
2656                                         if (type != null) {
2657                                                 ec.Compiler.Report.SymbolRelatedToPreviousError (type);
2658                                                 Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type), ec.Compiler.Report);
2659                                                 return;
2660                                         }
2661                                 }
2662
2663                                 if (ec.CurrentTypeDefinition != null) {
2664                                         Type t = ec.CurrentTypeDefinition.LookupAnyGeneric (Name);
2665                                         if (t != null) {
2666                                                 Namespace.Error_InvalidNumberOfTypeArguments (ec.Compiler.Report, t, loc);
2667                                                 return;
2668                                         }
2669                                 }
2670                         }
2671
2672                         if (targs != null) {
2673                                 FullNamedExpression retval = ec.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2674                                 if (retval != null) {
2675                                         retval.Error_TypeArgumentsCannotBeUsed (ec.Compiler.Report, loc);
2676                                         return;
2677                                 }
2678                         }
2679
2680                         NamespaceEntry.Error_NamespaceNotFound (loc, Name, ec.Compiler.Report);
2681                 }
2682
2683                 // TODO: I am still not convinced about this. If someone else will need it
2684                 // implement this as virtual property in MemberCore hierarchy
2685                 public static string GetMemberType (MemberCore mc)
2686                 {
2687                         if (mc is Property)
2688                                 return "property";
2689                         if (mc is Indexer)
2690                                 return "indexer";
2691                         if (mc is FieldBase)
2692                                 return "field";
2693                         if (mc is MethodCore)
2694                                 return "method";
2695                         if (mc is EnumMember)
2696                                 return "enum";
2697                         if (mc is Event)
2698                                 return "event";
2699
2700                         return "type";
2701                 }
2702
2703                 Expression SimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2704                 {
2705                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2706
2707                         if (e == null)
2708                                 return null;
2709
2710                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2711                                 return e;
2712
2713                         return null;
2714                 }
2715
2716                 /// <remarks>
2717                 ///   7.5.2: Simple Names.
2718                 ///
2719                 ///   Local Variables and Parameters are handled at
2720                 ///   parse time, so they never occur as SimpleNames.
2721                 ///
2722                 ///   The `intermediate' flag is used by MemberAccess only
2723                 ///   and it is used to inform us that it is ok for us to
2724                 ///   avoid the static check, because MemberAccess might end
2725                 ///   up resolving the Name as a Type name and the access as
2726                 ///   a static type access.
2727                 ///
2728                 ///   ie: Type Type; .... { Type.GetType (""); }
2729                 ///
2730                 ///   Type is both an instance variable and a Type;  Type.GetType
2731                 ///   is the static method not an instance method of type.
2732                 /// </remarks>
2733                 Expression DoSimpleNameResolve (ResolveContext ec, Expression right_side, bool intermediate)
2734                 {
2735                         Expression e = null;
2736
2737                         //
2738                         // Stage 1: Performed by the parser (binding to locals or parameters).
2739                         //
2740                         Block current_block = ec.CurrentBlock;
2741                         if (current_block != null){
2742                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2743                                 if (vi != null){
2744                                         e = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2745
2746                                         if (right_side != null) {
2747                                                 e = e.ResolveLValue (ec, right_side);
2748                                         } else {
2749                                                 if (intermediate) {
2750                                                         using (ec.With (ResolveContext.Options.DoFlowAnalysis, false)) {
2751                                                                 e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2752                                                         }
2753                                                 } else {
2754                                                         e = e.Resolve (ec, ResolveFlags.VariableOrValue);
2755                                                 }
2756                                         }
2757
2758                                         if (targs != null && e != null)
2759                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2760
2761                                         return e;
2762                                 }
2763
2764                                 e = current_block.Toplevel.GetParameterReference (Name, loc);
2765                                 if (e != null) {
2766                                         if (right_side != null)
2767                                                 e = e.ResolveLValue (ec, right_side);
2768                                         else
2769                                                 e = e.Resolve (ec);
2770
2771                                         if (targs != null && e != null)
2772                                                 e.Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
2773
2774                                         return e;
2775                                 }
2776                         }
2777
2778                         //
2779                         // Stage 2: Lookup members
2780                         //
2781
2782                         Type almost_matched_type = null;
2783                         IList<MemberInfo> almost_matched = null;
2784                         for (Type lookup_ds = ec.CurrentType; lookup_ds != null; lookup_ds = lookup_ds.DeclaringType) {
2785                                 e = MemberLookup (ec.Compiler, ec.CurrentType, lookup_ds, Name, loc);
2786                                 if (e != null) {
2787                                         PropertyExpr pe = e as PropertyExpr;
2788                                         if (pe != null) {
2789                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2790
2791                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2792                                                 // it doesn't know which accessor to check permissions against
2793                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.CurrentType, right_side != null))
2794                                                         break;
2795                                         } else if (e is EventExpr) {
2796                                                 if (((EventExpr) e).IsAccessibleFrom (ec.CurrentType))
2797                                                         break;
2798                                         } else if (targs != null && e is TypeExpression) {
2799                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2800                                                 break;
2801                                         } else {
2802                                                 break;
2803                                         }
2804                                         e = null;
2805                                 }
2806
2807                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2808                                         almost_matched_type = lookup_ds;
2809                                         almost_matched = new List<MemberInfo>(almost_matched_members);
2810                                 }
2811                         }
2812
2813                         if (e == null) {
2814                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2815                                         almost_matched_type = ec.CurrentType;
2816                                         almost_matched = new List<MemberInfo> (almost_matched_members);
2817                                 }
2818                                 e = ResolveAsTypeStep (ec, true);
2819                         }
2820
2821                         if (e == null) {
2822                                 if (current_block != null) {
2823                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2824                                         if (ikv != null) {
2825                                                 LocalInfo li = ikv as LocalInfo;
2826                                                 // Supress CS0219 warning
2827                                                 if (li != null)
2828                                                         li.Used = true;
2829
2830                                                 Error_VariableIsUsedBeforeItIsDeclared (ec.Report, Name);
2831                                                 return null;
2832                                         }
2833                                 }
2834
2835                                 if (RootContext.EvalMode){
2836                                         FieldInfo fi = Evaluator.LookupField (Name);
2837                                         if (fi != null)
2838                                                 return new FieldExpr (fi, loc).Resolve (ec);
2839                                 }
2840
2841                                 if (almost_matched != null)
2842                                         almost_matched_members = almost_matched;
2843                                 if (almost_matched_type == null)
2844                                         almost_matched_type = ec.CurrentType;
2845
2846                                 string type_name = ec.MemberContext.CurrentType == null ? null : ec.MemberContext.CurrentType.Name;
2847                                 return Error_MemberLookupFailed (ec, ec.CurrentType, null, almost_matched_type, Name,
2848                                         type_name, AllMemberTypes, AllBindingFlags);
2849                         }
2850
2851                         if (e is MemberExpr) {
2852                                 MemberExpr me = (MemberExpr) e;
2853
2854                                 Expression left;
2855                                 if (me.IsInstance) {
2856                                         if (ec.IsStatic || ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer | ResolveContext.Options.ConstantScope)) {
2857                                                 //
2858                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2859                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2860                                                 // and each predicate is true if the MethodGroupExpr contains
2861                                                 // at least one of that kind of method.
2862                                                 //
2863
2864                                                 if (!me.IsStatic &&
2865                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2866                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2867                                                         return null;
2868                                                 }
2869
2870                                                 //
2871                                                 // Pass the buck to MemberAccess and Invocation.
2872                                                 //
2873                                                 left = EmptyExpression.Null;
2874                                         } else {
2875                                                 left = ec.GetThis (loc);
2876                                         }
2877                                 } else {
2878                                         left = new TypeExpression (ec.CurrentType, loc);
2879                                 }
2880
2881                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2882                                 if (me == null)
2883                                         return null;
2884
2885                                 if (targs != null) {
2886                                         if (!targs.Resolve (ec))
2887                                                 return null;
2888
2889                                         me.SetTypeArguments (ec, targs);
2890                                 }
2891
2892                                 if (!me.IsStatic && (me.InstanceExpression != null && me.InstanceExpression != EmptyExpression.Null) &&
2893                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2894                                     me.InstanceExpression.Type != me.DeclaringType &&
2895                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2896                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2897                                         ec.Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2898                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2899                                         return null;
2900                                 }
2901
2902                                 return (right_side != null)
2903                                         ? me.DoResolveLValue (ec, right_side)
2904                                         : me.Resolve (ec);
2905                         }
2906
2907                         return e;
2908                 }
2909         }
2910
2911         /// <summary>
2912         ///   Represents a namespace or a type.  The name of the class was inspired by
2913         ///   section 10.8.1 (Fully Qualified Names).
2914         /// </summary>
2915         public abstract class FullNamedExpression : Expression
2916         {
2917                 protected override void CloneTo (CloneContext clonectx, Expression target)
2918                 {
2919                         // Do nothing, most unresolved type expressions cannot be
2920                         // resolved to different type
2921                 }
2922
2923                 public override Expression CreateExpressionTree (ResolveContext ec)
2924                 {
2925                         throw new NotSupportedException ("ET");
2926                 }
2927
2928                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2929                 {
2930                         throw new NotSupportedException ();
2931                 }
2932
2933                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2934                 {
2935                         return this;
2936                 }
2937
2938                 public override void Emit (EmitContext ec)
2939                 {
2940                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2941                                 GetSignatureForError ());
2942                 }
2943         }
2944
2945         /// <summary>
2946         ///   Expression that evaluates to a type
2947         /// </summary>
2948         public abstract class TypeExpr : FullNamedExpression {
2949                 public override FullNamedExpression ResolveAsTypeStep (IMemberContext ec, bool silent)
2950                 {
2951                         TypeExpr t = DoResolveAsTypeStep (ec);
2952                         if (t == null)
2953                                 return null;
2954
2955                         eclass = ExprClass.Type;
2956                         return t;
2957                 }
2958
2959                 protected override Expression DoResolve (ResolveContext ec)
2960                 {
2961                         return ResolveAsTypeTerminal (ec, false);
2962                 }
2963
2964                 public virtual bool CheckAccessLevel (IMemberContext mc)
2965                 {
2966                         return mc.CurrentTypeDefinition.CheckAccessLevel (Type);
2967                 }
2968
2969                 public virtual bool IsClass {
2970                         get { return Type.IsClass; }
2971                 }
2972
2973                 public virtual bool IsValueType {
2974                         get { return TypeManager.IsStruct (Type); }
2975                 }
2976
2977                 public virtual bool IsInterface {
2978                         get { return Type.IsInterface; }
2979                 }
2980
2981                 public virtual bool IsSealed {
2982                         get { return Type.IsSealed; }
2983                 }
2984
2985                 public virtual bool CanInheritFrom ()
2986                 {
2987                         if (Type == TypeManager.enum_type ||
2988                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2989                             Type == TypeManager.multicast_delegate_type ||
2990                             Type == TypeManager.delegate_type ||
2991                             Type == TypeManager.array_type)
2992                                 return false;
2993
2994                         return true;
2995                 }
2996
2997                 protected abstract TypeExpr DoResolveAsTypeStep (IMemberContext ec);
2998
2999                 public override bool Equals (object obj)
3000                 {
3001                         TypeExpr tobj = obj as TypeExpr;
3002                         if (tobj == null)
3003                                 return false;
3004
3005                         return Type == tobj.Type;
3006                 }
3007
3008                 public override int GetHashCode ()
3009                 {
3010                         return Type.GetHashCode ();
3011                 }
3012
3013                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3014                 {
3015                         type = storey.MutateType (type);
3016                 }
3017         }
3018
3019         /// <summary>
3020         ///   Fully resolved Expression that already evaluated to a type
3021         /// </summary>
3022         public class TypeExpression : TypeExpr {
3023                 public TypeExpression (Type t, Location l)
3024                 {
3025                         Type = t;
3026                         eclass = ExprClass.Type;
3027                         loc = l;
3028                 }
3029
3030                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3031                 {
3032                         return this;
3033                 }
3034
3035                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3036                 {
3037                         return this;
3038                 }
3039         }
3040
3041         //
3042         // Used to create types from a fully qualified name.  These are just used
3043         // by the parser to setup the core types.
3044         //
3045         public sealed class TypeLookupExpression : TypeExpr {
3046                 readonly string ns_name;
3047                 readonly string name;
3048
3049                 public TypeLookupExpression (string ns, string name)
3050                 {
3051                         this.name = name;
3052                         this.ns_name = ns;
3053                         eclass = ExprClass.Type;
3054                 }
3055
3056                 public override TypeExpr ResolveAsTypeTerminal (IMemberContext ec, bool silent)
3057                 {
3058                         //
3059                         // It's null only during mscorlib bootstrap when DefineType
3060                         // nees to resolve base type of same type
3061                         //
3062                         // For instance struct Char : IComparable<char>
3063                         //
3064                         // TODO: it could be removed when Resolve starts to use
3065                         // DeclSpace instead of Type
3066                         //
3067                         if (type == null) {
3068                                 Namespace ns = GlobalRootNamespace.Instance.GetNamespace (ns_name, false);
3069                                 FullNamedExpression fne = ns.Lookup (ec.Compiler, name, loc);
3070                                 if (fne != null)
3071                                         type = fne.Type;
3072                         }
3073
3074                         return this;
3075                 }
3076
3077                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
3078                 {
3079                         return this;
3080                 }
3081
3082                 public override string GetSignatureForError ()
3083                 {
3084                         if (type == null)
3085                                 return TypeManager.CSharpName (ns_name + "." + name, null);
3086
3087                         return base.GetSignatureForError ();
3088                 }
3089         }
3090
3091         /// <summary>
3092         ///   This class denotes an expression which evaluates to a member
3093         ///   of a struct or a class.
3094         /// </summary>
3095         public abstract class MemberExpr : Expression
3096         {
3097                 protected bool is_base;
3098
3099                 /// <summary>
3100                 ///   The name of this member.
3101                 /// </summary>
3102                 public abstract string Name {
3103                         get;
3104                 }
3105
3106                 //
3107                 // When base.member is used
3108                 //
3109                 public bool IsBase {
3110                         get { return is_base; }
3111                         set { is_base = value; }
3112                 }
3113
3114                 /// <summary>
3115                 ///   Whether this is an instance member.
3116                 /// </summary>
3117                 public abstract bool IsInstance {
3118                         get;
3119                 }
3120
3121                 /// <summary>
3122                 ///   Whether this is a static member.
3123                 /// </summary>
3124                 public abstract bool IsStatic {
3125                         get;
3126                 }
3127
3128                 /// <summary>
3129                 ///   The type which declares this member.
3130                 /// </summary>
3131                 public abstract Type DeclaringType {
3132                         get;
3133                 }
3134
3135                 /// <summary>
3136                 ///   The instance expression associated with this member, if it's a
3137                 ///   non-static member.
3138                 /// </summary>
3139                 public Expression InstanceExpression;
3140
3141                 public static void error176 (ResolveContext ec, Location loc, string name)
3142                 {
3143                         ec.Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3144                                       "with an instance reference, qualify it with a type name instead", name);
3145                 }
3146
3147                 public static void Error_BaseAccessInExpressionTree (ResolveContext ec, Location loc)
3148                 {
3149                         ec.Report.Error (831, loc, "An expression tree may not contain a base access");
3150                 }
3151
3152                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3153                 {
3154                         if (InstanceExpression != null)
3155                                 InstanceExpression.MutateHoistedGenericType (storey);
3156                 }
3157
3158                 // TODO: possible optimalization
3159                 // Cache resolved constant result in FieldBuilder <-> expression map
3160                 public virtual MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3161                                                                SimpleName original)
3162                 {
3163                         //
3164                         // Precondition:
3165                         //   original == null || original.Resolve (...) ==> left
3166                         //
3167
3168                         if (left is TypeExpr) {
3169                                 left = left.ResolveAsBaseTerminal (ec, false);
3170                                 if (left == null)
3171                                         return null;
3172
3173                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3174                                 // always do all necessary checks
3175                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3176                                 if (oa != null && !ec.IsObsolete) {
3177                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc, ec.Report);
3178                                 }
3179
3180                                 GenericTypeExpr ct = left as GenericTypeExpr;
3181                                 if (ct != null && !ct.CheckConstraints (ec))
3182                                         return null;
3183                                 //
3184
3185                                 if (!IsStatic) {
3186                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3187                                         return null;
3188                                 }
3189
3190                                 return this;
3191                         }
3192
3193                         if (!IsInstance) {
3194                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3195                                         return this;
3196
3197                                 return ResolveExtensionMemberAccess (ec, left);
3198                         }
3199
3200                         InstanceExpression = left;
3201                         return this;
3202                 }
3203
3204                 protected virtual MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3205                 {
3206                         error176 (ec, loc, GetSignatureForError ());
3207                         return this;
3208                 }
3209
3210                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3211                 {
3212                         if (IsStatic)
3213                                 return;
3214
3215                         if (InstanceExpression == EmptyExpression.Null) {
3216                                 // FIXME: This should not be here at all
3217                                 SimpleName.Error_ObjectRefRequired (new ResolveContext (ec.MemberContext), loc, GetSignatureForError ());
3218                                 return;
3219                         }
3220
3221                         if (TypeManager.IsValueType (InstanceExpression.Type)) {
3222                                 if (InstanceExpression is IMemoryLocation) {
3223                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3224                                 } else {
3225                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3226                                         InstanceExpression.Emit (ec);
3227                                         t.Store (ec);
3228                                         t.AddressOf (ec, AddressOp.Store);
3229                                 }
3230                         } else
3231                                 InstanceExpression.Emit (ec);
3232
3233                         if (prepare_for_load)
3234                                 ec.ig.Emit (OpCodes.Dup);
3235                 }
3236
3237                 public virtual void SetTypeArguments (ResolveContext ec, TypeArguments ta)
3238                 {
3239                         // TODO: need to get correct member type
3240                         ec.Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3241                                 GetSignatureForError ());
3242                 }
3243         }
3244
3245         ///
3246         /// Represents group of extension methods
3247         ///
3248         public class ExtensionMethodGroupExpr : MethodGroupExpr
3249         {
3250                 readonly NamespaceEntry namespace_entry;
3251                 public Expression ExtensionExpression;
3252                 Argument extension_argument;
3253
3254                 public ExtensionMethodGroupExpr (List<MethodBase> list, NamespaceEntry n, Type extensionType, Location l)
3255                         : base (list, extensionType, l)
3256                 {
3257                         this.namespace_entry = n;
3258                 }
3259
3260                 public override bool IsStatic {
3261                         get { return true; }
3262                 }
3263
3264                 public bool IsTopLevel {
3265                         get { return namespace_entry == null; }
3266                 }
3267
3268                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3269                 {
3270                         extension_argument.Expr.MutateHoistedGenericType (storey);
3271                         base.MutateHoistedGenericType (storey);
3272                 }
3273
3274                 public override MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments arguments, bool may_fail, Location loc)
3275                 {
3276                         if (arguments == null)
3277                                 arguments = new Arguments (1);
3278
3279                         arguments.Insert (0, new Argument (ExtensionExpression));
3280                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, ref arguments, namespace_entry, loc);
3281
3282                         // Store resolved argument and restore original arguments
3283                         if (mg != null)
3284                                 ((ExtensionMethodGroupExpr)mg).extension_argument = arguments [0];
3285                         else
3286                                 arguments.RemoveAt (0); // Clean-up modified arguments for error reporting
3287
3288                         return mg;
3289                 }
3290
3291                 MethodGroupExpr ResolveOverloadExtensions (ResolveContext ec, ref Arguments arguments, NamespaceEntry ns, Location loc)
3292                 {
3293                         // Use normal resolve rules
3294                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3295                         if (mg != null)
3296                                 return mg;
3297
3298                         if (ns == null)
3299                                 return null;
3300
3301                         // Search continues
3302                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, Name, loc);
3303                         if (e == null)
3304                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3305
3306                         e.ExtensionExpression = ExtensionExpression;
3307                         e.SetTypeArguments (ec, type_arguments);
3308                         return e.ResolveOverloadExtensions (ec, ref arguments, e.namespace_entry, loc);
3309                 }
3310         }
3311
3312         /// <summary>
3313         ///   MethodGroupExpr represents a group of method candidates which
3314         ///   can be resolved to the best method overload
3315         /// </summary>
3316         public class MethodGroupExpr : MemberExpr
3317         {
3318                 public interface IErrorHandler
3319                 {
3320                         bool AmbiguousCall (ResolveContext ec, MethodBase ambiguous);
3321                         bool NoExactMatch (ResolveContext ec, MethodBase method);
3322                 }
3323
3324                 public IErrorHandler CustomErrorHandler;
3325                 public MethodBase [] Methods;
3326                 MethodBase best_candidate;
3327                 // TODO: make private
3328                 public TypeArguments type_arguments;
3329                 bool identical_type_name;
3330                 bool has_inaccessible_candidates_only;
3331                 Type delegate_type;
3332                 Type queried_type;
3333
3334                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3335                         : this (type, l)
3336                 {
3337                         Methods = new MethodBase [mi.Length];
3338                         mi.CopyTo (Methods, 0);
3339                 }
3340
3341                 public MethodGroupExpr (MemberInfo[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3342                         : this (mi, type, l)
3343                 {
3344                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3345                 }
3346
3347                 public MethodGroupExpr (List<MethodBase> list, Type type, Location l)
3348                         : this (type, l)
3349                 {
3350                         try {
3351                                 Methods = list.ToArray ();
3352                         } catch {
3353                                 foreach (MemberInfo m in list){
3354                                         if (!(m is MethodBase)){
3355                                                 Console.WriteLine ("Name " + m.Name);
3356                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3357                                         }
3358                                 }
3359                                 throw;
3360                         }
3361
3362
3363                 }
3364
3365                 protected MethodGroupExpr (Type type, Location loc)
3366                 {
3367                         this.loc = loc;
3368                         eclass = ExprClass.MethodGroup;
3369                         this.type = InternalType.MethodGroup;
3370                         queried_type = type;
3371                 }
3372
3373                 public override Type DeclaringType {
3374                         get {
3375                                 return queried_type;
3376                         }
3377                 }
3378
3379                 public Type DelegateType {
3380                         set {
3381                                 delegate_type = value;
3382                         }
3383                 }
3384
3385                 public bool IdenticalTypeName {
3386                         get {
3387                                 return identical_type_name;
3388                         }
3389                 }
3390
3391                 public override string GetSignatureForError ()
3392                 {
3393                         if (best_candidate != null)
3394                                 return TypeManager.CSharpSignature (best_candidate);
3395
3396                         return TypeManager.CSharpSignature (Methods [0]);
3397                 }
3398
3399                 public override string Name {
3400                         get {
3401                                 return Methods [0].Name;
3402                         }
3403                 }
3404
3405                 public override bool IsInstance {
3406                         get {
3407                                 if (best_candidate != null)
3408                                         return !best_candidate.IsStatic;
3409
3410                                 foreach (MethodBase mb in Methods)
3411                                         if (!mb.IsStatic)
3412                                                 return true;
3413
3414                                 return false;
3415                         }
3416                 }
3417
3418                 public override bool IsStatic {
3419                         get {
3420                                 if (best_candidate != null)
3421                                         return best_candidate.IsStatic;
3422
3423                                 foreach (MethodBase mb in Methods)
3424                                         if (mb.IsStatic)
3425                                                 return true;
3426
3427                                 return false;
3428                         }
3429                 }
3430
3431                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3432                 {
3433                         return (ConstructorInfo)mg.best_candidate;
3434                 }
3435
3436                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3437                 {
3438                         return (MethodInfo)mg.best_candidate;
3439                 }
3440
3441                 //
3442                 //  7.4.3.3  Better conversion from expression
3443                 //  Returns :   1    if a->p is better,
3444                 //              2    if a->q is better,
3445                 //              0 if neither is better
3446                 //
3447                 static int BetterExpressionConversion (ResolveContext ec, Argument a, Type p, Type q)
3448                 {
3449                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3450                         if (argument_type == InternalType.AnonymousMethod && RootContext.Version > LanguageVersion.ISO_2) {
3451                                 //
3452                                 // Uwrap delegate from Expression<T>
3453                                 //
3454                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3455                                         p = TypeManager.GetTypeArguments (p) [0];
3456                                 }
3457                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3458                                         q = TypeManager.GetTypeArguments (q) [0];
3459                                 }
3460
3461                                 p = Delegate.GetInvokeMethod (ec.Compiler, null, p).ReturnType;
3462                                 q = Delegate.GetInvokeMethod (ec.Compiler, null, q).ReturnType;
3463                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3464                                         return 2;
3465                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3466                                         return 1;
3467                         } else {
3468                                 if (argument_type == p)
3469                                         return 1;
3470
3471                                 if (argument_type == q)
3472                                         return 2;
3473                         }
3474
3475                         return BetterTypeConversion (ec, p, q);
3476                 }
3477
3478                 //
3479                 // 7.4.3.4  Better conversion from type
3480                 //
3481                 public static int BetterTypeConversion (ResolveContext ec, Type p, Type q)
3482                 {
3483                         if (p == null || q == null)
3484                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3485
3486                         if (p == TypeManager.int32_type) {
3487                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3488                                         return 1;
3489                         } else if (p == TypeManager.int64_type) {
3490                                 if (q == TypeManager.uint64_type)
3491                                         return 1;
3492                         } else if (p == TypeManager.sbyte_type) {
3493                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3494                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3495                                         return 1;
3496                         } else if (p == TypeManager.short_type) {
3497                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3498                                         q == TypeManager.uint64_type)
3499                                         return 1;
3500                         } else if (p == InternalType.Dynamic) {
3501                                 if (q == TypeManager.object_type)
3502                                         return 2;
3503                         }
3504
3505                         if (q == TypeManager.int32_type) {
3506                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3507                                         return 2;
3508                         } if (q == TypeManager.int64_type) {
3509                                 if (p == TypeManager.uint64_type)
3510                                         return 2;
3511                         } else if (q == TypeManager.sbyte_type) {
3512                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3513                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3514                                         return 2;
3515                         } if (q == TypeManager.short_type) {
3516                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3517                                         p == TypeManager.uint64_type)
3518                                         return 2;
3519                         } else if (q == InternalType.Dynamic) {
3520                                 if (p == TypeManager.object_type)
3521                                         return 1;
3522                         }
3523
3524                         // TODO: this is expensive
3525                         Expression p_tmp = new EmptyExpression (p);
3526                         Expression q_tmp = new EmptyExpression (q);
3527
3528                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3529                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3530
3531                         if (p_to_q && !q_to_p)
3532                                 return 1;
3533
3534                         if (q_to_p && !p_to_q)
3535                                 return 2;
3536
3537                         return 0;
3538                 }
3539
3540                 /// <summary>
3541                 ///   Determines "Better function" between candidate
3542                 ///   and the current best match
3543                 /// </summary>
3544                 /// <remarks>
3545                 ///    Returns a boolean indicating :
3546                 ///     false if candidate ain't better
3547                 ///     true  if candidate is better than the current best match
3548                 /// </remarks>
3549                 static bool BetterFunction (ResolveContext ec, Arguments args, int argument_count,
3550                         MethodBase candidate, bool candidate_params,
3551                         MethodBase best, bool best_params)
3552                 {
3553                         AParametersCollection candidate_pd = TypeManager.GetParameterData (candidate);
3554                         AParametersCollection best_pd = TypeManager.GetParameterData (best);
3555
3556                         bool better_at_least_one = false;
3557                         bool same = true;
3558                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3559                         {
3560                                 Argument a = args [j];
3561
3562                                 // Provided default argument value is never better
3563                                 if (a.IsDefaultArgument && candidate_params == best_params)
3564                                         return false;
3565
3566                                 Type ct = candidate_pd.Types [c_idx];
3567                                 Type bt = best_pd.Types [b_idx];
3568
3569                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3570                                 {
3571                                         ct = TypeManager.GetElementType (ct);
3572                                         --c_idx;
3573                                 }
3574
3575                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3576                                 {
3577                                         bt = TypeManager.GetElementType (bt);
3578                                         --b_idx;
3579                                 }
3580
3581                                 if (ct == bt)
3582                                         continue;
3583
3584                                 same = false;
3585                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3586
3587                                 // for each argument, the conversion to 'ct' should be no worse than
3588                                 // the conversion to 'bt'.
3589                                 if (result == 2)
3590                                         return false;
3591
3592                                 // for at least one argument, the conversion to 'ct' should be better than
3593                                 // the conversion to 'bt'.
3594                                 if (result != 0)
3595                                         better_at_least_one = true;
3596                         }
3597
3598                         if (better_at_least_one)
3599                                 return true;
3600
3601                         //
3602                         // This handles the case
3603                         //
3604                         //   Add (float f1, float f2, float f3);
3605                         //   Add (params decimal [] foo);
3606                         //
3607                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3608                         // first candidate would've chosen as better.
3609                         //
3610                         if (!same)
3611                                 return false;
3612
3613                         //
3614                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3615                         //
3616                         if (TypeManager.IsGenericMethod (best)) {
3617                                 if (!TypeManager.IsGenericMethod (candidate))
3618                                         return true;
3619                         } else if (TypeManager.IsGenericMethod (candidate)) {
3620                                 return false;
3621                         }
3622
3623                         //
3624                         // This handles the following cases:
3625                         //
3626                         //   Trim () is better than Trim (params char[] chars)
3627                         //   Concat (string s1, string s2, string s3) is better than
3628                         //     Concat (string s1, params string [] srest)
3629                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3630                         //
3631                         if (!candidate_params && best_params)
3632                                 return true;
3633                         if (candidate_params && !best_params)
3634                                 return false;
3635
3636                         int candidate_param_count = candidate_pd.Count;
3637                         int best_param_count = best_pd.Count;
3638
3639                         if (candidate_param_count != best_param_count)
3640                                 // can only happen if (candidate_params && best_params)
3641                                 return candidate_param_count > best_param_count && best_pd.HasParams;
3642
3643                         //
3644                         // now, both methods have the same number of parameters, and the parameters have the same types
3645                         // Pick the "more specific" signature
3646                         //
3647
3648                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3649                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3650
3651                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3652                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3653
3654                         bool specific_at_least_once = false;
3655                         for (int j = 0; j < candidate_param_count; ++j)
3656                         {
3657                                 Type ct = orig_candidate_pd.Types [j];
3658                                 Type bt = orig_best_pd.Types [j];
3659                                 if (ct.Equals (bt))
3660                                         continue;
3661                                 Type specific = MoreSpecific (ct, bt);
3662                                 if (specific == bt)
3663                                         return false;
3664                                 if (specific == ct)
3665                                         specific_at_least_once = true;
3666                         }
3667
3668                         if (specific_at_least_once)
3669                                 return true;
3670
3671                         // FIXME: handle lifted operators
3672                         // ...
3673
3674                         return false;
3675                 }
3676
3677                 protected override MemberExpr ResolveExtensionMemberAccess (ResolveContext ec, Expression left)
3678                 {
3679                         if (!IsStatic)
3680                                 return base.ResolveExtensionMemberAccess (ec, left);
3681
3682                         //
3683                         // When left side is an expression and at least one candidate method is
3684                         // static, it can be extension method
3685                         //
3686                         InstanceExpression = left;
3687                         return this;
3688                 }
3689
3690                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
3691                                                                 SimpleName original)
3692                 {
3693                         if (!(left is TypeExpr) &&
3694                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3695                                 identical_type_name = true;
3696
3697                         return base.ResolveMemberAccess (ec, left, loc, original);
3698                 }
3699
3700                 public override Expression CreateExpressionTree (ResolveContext ec)
3701                 {
3702                         if (best_candidate == null) {
3703                                 ec.Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3704                                 return null;
3705                         }
3706
3707                         IMethodData md = TypeManager.GetMethod (best_candidate);
3708                         if (md != null && md.IsExcluded ())
3709                                 ec.Report.Error (765, loc,
3710                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3711
3712                         return new TypeOfMethod (best_candidate, loc);
3713                 }
3714
3715                 protected override Expression DoResolve (ResolveContext ec)
3716                 {
3717                         this.eclass = ExprClass.MethodGroup;
3718
3719                         if (InstanceExpression != null) {
3720                                 InstanceExpression = InstanceExpression.Resolve (ec);
3721                                 if (InstanceExpression == null)
3722                                         return null;
3723                         }
3724
3725                         return this;
3726                 }
3727
3728                 public void ReportUsageError (ResolveContext ec)
3729                 {
3730                         ec.Report.Error (654, loc, "Method `" + DeclaringType + "." +
3731                                       Name + "()' is referenced without parentheses");
3732                 }
3733
3734                 override public void Emit (EmitContext ec)
3735                 {
3736                         throw new NotSupportedException ();
3737                         // ReportUsageError ();
3738                 }
3739
3740                 public void EmitCall (EmitContext ec, Arguments arguments)
3741                 {
3742                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3743                 }
3744
3745                 void Error_AmbiguousCall (ResolveContext ec, MethodBase ambiguous)
3746                 {
3747                         if (CustomErrorHandler != null && CustomErrorHandler.AmbiguousCall (ec, ambiguous))
3748                                 return;
3749
3750                         ec.Report.SymbolRelatedToPreviousError (best_candidate);
3751                         ec.Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
3752                                 TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
3753                 }
3754
3755                 protected virtual void Error_InvalidArguments (ResolveContext ec, Location loc, int idx, MethodBase method,
3756                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3757                 {
3758                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3759
3760                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3761                                 ec.Report.SymbolRelatedToPreviousError (method);
3762                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3763                                         ec.Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3764                                                 TypeManager.CSharpSignature (method));
3765                                         return;
3766                                 }
3767                                 ec.Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3768                                           TypeManager.CSharpSignature (method));
3769                         } else if (TypeManager.IsDelegateType (method.DeclaringType)) {
3770                                 ec.Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3771                                         TypeManager.CSharpName (method.DeclaringType));
3772                         } else {
3773                                 ec.Report.SymbolRelatedToPreviousError (method);
3774                                 if (emg != null) {
3775                                         ec.Report.Error (1928, loc,
3776                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3777                                                 emg.ExtensionExpression.GetSignatureForError (),
3778                                                 emg.Name, TypeManager.CSharpSignature (method));
3779                                 } else {
3780                                         ec.Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3781                                                 TypeManager.CSharpSignature (method));
3782                                 }
3783                         }
3784
3785                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3786
3787                         string index = (idx + 1).ToString ();
3788                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3789                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3790                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3791                                         ec.Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3792                                                 index, Parameter.GetModifierSignature (a.Modifier));
3793                                 else
3794                                         ec.Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3795                                                 index, Parameter.GetModifierSignature (mod));
3796                         } else {
3797                                 string p1 = a.GetSignatureForError ();
3798                                 string p2 = TypeManager.CSharpName (paramType);
3799
3800                                 if (p1 == p2) {
3801                                         ec.Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3802                                         ec.Report.SymbolRelatedToPreviousError (a.Expr.Type);
3803                                         ec.Report.SymbolRelatedToPreviousError (paramType);
3804                                 }
3805
3806                                 if (idx == 0 && emg != null) {
3807                                         ec.Report.Error (1929, loc,
3808                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3809                                 } else {
3810                                         ec.Report.Error (1503, loc,
3811                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3812                                 }
3813                         }
3814                 }
3815
3816                 public override void Error_ValueCannotBeConverted (ResolveContext ec, Location loc, Type target, bool expl)
3817                 {
3818                         ec.Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3819                                 Name, TypeManager.CSharpName (target));
3820                 }
3821
3822                 void Error_ArgumentCountWrong (ResolveContext ec, int arg_count)
3823                 {
3824                         ec.Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
3825                                       Name, arg_count.ToString ());
3826                 }
3827
3828                 protected virtual int GetApplicableParametersCount (MethodBase method, AParametersCollection parameters)
3829                 {
3830                         return parameters.Count;
3831                 }
3832
3833                 public static bool IsAncestralType (Type first_type, Type second_type)
3834                 {
3835                         return first_type != second_type &&
3836                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3837                                 TypeManager.ImplementsInterface (second_type, first_type));
3838                 }
3839
3840                 ///
3841                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3842                 /// to the given set of arguments
3843                 /// A return value rates candidate method compatibility,
3844                 /// 0 = the best, int.MaxValue = the worst
3845                 ///
3846                 public int IsApplicable (ResolveContext ec,
3847                                                 ref Arguments arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3848                 {
3849                         MethodBase candidate = method;
3850
3851                         AParametersCollection pd = TypeManager.GetParameterData (candidate);
3852                         int param_count = GetApplicableParametersCount (candidate, pd);
3853                         int optional_count = 0;
3854
3855                         if (arg_count != param_count) {
3856                                 for (int i = 0; i < pd.Count; ++i) {
3857                                         if (pd.FixedParameters [i].HasDefaultValue) {
3858                                                 optional_count = pd.Count - i;
3859                                                 break;
3860                                         }
3861                                 }
3862
3863                                 int args_gap = Math.Abs (arg_count - param_count);
3864                                 if (optional_count != 0) {
3865                                         if (args_gap > optional_count)
3866                                                 return int.MaxValue - 10000 + args_gap - optional_count;
3867
3868                                         // Readjust expected number when params used
3869                                         if (pd.HasParams) {
3870                                                 optional_count--;
3871                                                 if (arg_count < param_count)
3872                                                         param_count--;
3873                                         } else if (arg_count > param_count) {
3874                                                 return int.MaxValue - 10000 + args_gap;
3875                                         }
3876                                 } else if (arg_count != param_count) {
3877                                         if (!pd.HasParams)
3878                                                 return int.MaxValue - 10000 + args_gap;
3879                                         if (arg_count < param_count - 1)
3880                                                 return int.MaxValue - 10000 + args_gap;
3881                                 }
3882
3883                                 // Initialize expanded form of a method with 1 params parameter
3884                                 params_expanded_form = param_count == 1 && pd.HasParams;
3885
3886                                 // Resize to fit optional arguments
3887                                 if (optional_count != 0) {
3888                                         Arguments resized;
3889                                         if (arguments == null) {
3890                                                 resized = new Arguments (optional_count);
3891                                         } else {
3892                                                 resized = new Arguments (param_count);
3893                                                 resized.AddRange (arguments);
3894                                         }
3895
3896                                         for (int i = arg_count; i < param_count; ++i)
3897                                                 resized.Add (null);
3898                                         arguments = resized;
3899                                 }
3900                         }
3901
3902                         if (arg_count > 0) {
3903                                 //
3904                                 // Shuffle named arguments to the right positions if there are any
3905                                 //
3906                                 if (arguments [arg_count - 1] is NamedArgument) {
3907                                         arg_count = arguments.Count;
3908
3909                                         for (int i = 0; i < arg_count; ++i) {
3910                                                 bool arg_moved = false;
3911                                                 while (true) {
3912                                                         NamedArgument na = arguments[i] as NamedArgument;
3913                                                         if (na == null)
3914                                                                 break;
3915
3916                                                         int index = pd.GetParameterIndexByName (na.Name);
3917
3918                                                         // Named parameter not found or already reordered
3919                                                         if (index <= i)
3920                                                                 break;
3921
3922                                                         // When using parameters which should not be available to the user
3923                                                         if (index >= param_count)
3924                                                                 break;
3925
3926                                                         if (!arg_moved) {
3927                                                                 arguments.MarkReorderedArgument (na);
3928                                                                 arg_moved = true;
3929                                                         }
3930
3931                                                         Argument temp = arguments[index];
3932                                                         arguments[index] = arguments[i];
3933                                                         arguments[i] = temp;
3934
3935                                                         if (temp == null)
3936                                                                 break;
3937                                                 }
3938                                         }
3939                                 } else {
3940                                         arg_count = arguments.Count;
3941                                 }
3942                         } else if (arguments != null) {
3943                                 arg_count = arguments.Count;
3944                         }
3945
3946                         //
3947                         // 1. Handle generic method using type arguments when specified or type inference
3948                         //
3949                         if (TypeManager.IsGenericMethod (candidate)) {
3950                                 if (type_arguments != null) {
3951                                         Type [] g_args = candidate.GetGenericArguments ();
3952                                         if (g_args.Length != type_arguments.Count)
3953                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3954
3955                                         // TODO: Don't create new method, create Parameters only
3956                                         method = TypeManager.MakeGenericMethod ((MethodInfo) candidate, type_arguments.Arguments);
3957                                         candidate = method;
3958                                         pd = TypeManager.GetParameterData (candidate);
3959                                 } else {
3960                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3961                                         if (score != 0)
3962                                                 return score - 20000;
3963
3964                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3965                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3966                                                         TypeManager.CSharpSignature (candidate));
3967
3968                                         pd = TypeManager.GetParameterData (candidate);
3969                                 }
3970                         } else {
3971                                 if (type_arguments != null)
3972                                         return int.MaxValue - 15000;
3973                         }
3974
3975                         //
3976                         // 2. Each argument has to be implicitly convertible to method parameter
3977                         //
3978                         method = candidate;
3979                         Parameter.Modifier p_mod = 0;
3980                         Type pt = null;
3981                         for (int i = 0; i < arg_count; i++) {
3982                                 Argument a = arguments [i];
3983                                 if (a == null) {
3984                                         if (!pd.FixedParameters [i].HasDefaultValue)
3985                                                 throw new InternalErrorException ();
3986
3987                                         Expression e = pd.FixedParameters [i].DefaultValue as Constant;
3988                                         if (e == null)
3989                                                 e = new DefaultValueExpression (new TypeExpression (pd.Types [i], loc), loc).Resolve (ec);
3990
3991                                         arguments [i] = new Argument (e, Argument.AType.Default);
3992                                         continue;
3993                                 }
3994
3995                                 if (p_mod != Parameter.Modifier.PARAMS) {
3996                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3997                                         pt = pd.Types [i];
3998                                 } else {
3999                                         params_expanded_form = true;
4000                                 }
4001
4002                                 Parameter.Modifier a_mod = a.Modifier & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
4003                                 int score = 1;
4004                                 if (!params_expanded_form)
4005                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
4006
4007                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
4008                                         // It can be applicable in expanded form
4009                                         score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
4010                                         if (score == 0)
4011                                                 params_expanded_form = true;
4012                                 }
4013
4014                                 if (score != 0) {
4015                                         if (params_expanded_form)
4016                                                 ++score;
4017                                         return (arg_count - i) * 2 + score;
4018                                 }
4019                         }
4020
4021                         if (arg_count != param_count)
4022                                 params_expanded_form = true;
4023
4024                         return 0;
4025                 }
4026
4027                 int IsArgumentCompatible (ResolveContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
4028                 {
4029                         //
4030                         // Types have to be identical when ref or out modifer is used
4031                         //
4032                         if (arg_mod != 0 || param_mod != 0) {
4033                                 if (TypeManager.HasElementType (parameter))
4034                                         parameter = TypeManager.GetElementType (parameter);
4035
4036                                 Type a_type = argument.Type;
4037                                 if (TypeManager.HasElementType (a_type))
4038                                         a_type = TypeManager.GetElementType (a_type);
4039
4040                                 if (a_type != parameter) {
4041                                         if (TypeManager.IsDynamicType (a_type))
4042                                                 return 0;
4043
4044                                         return 2;
4045                                 }
4046                         } else {
4047                                 if (!Convert.ImplicitConversionExists (ec, argument.Expr, parameter)) {
4048                                         if (TypeManager.IsDynamicType (argument.Type))
4049                                                 return 0;
4050
4051                                         return 2;
4052                                 }
4053                         }
4054
4055                         if (arg_mod != param_mod)
4056                                 return 1;
4057
4058                         return 0;
4059                 }
4060
4061                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
4062                 {
4063                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
4064                                 return false;
4065
4066                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
4067                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
4068
4069                         if (cand_pd.Count != base_pd.Count)
4070                                 return false;
4071
4072                         for (int j = 0; j < cand_pd.Count; ++j)
4073                         {
4074                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
4075                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
4076                                 Type ct = cand_pd.Types [j];
4077                                 Type bt = base_pd.Types [j];
4078
4079                                 if (cm != bm || ct != bt)
4080                                         return false;
4081                         }
4082
4083                         return true;
4084                 }
4085
4086                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
4087                 {
4088                         if (mg1 == null) {
4089                                 if (mg2 == null)
4090                                         return null;
4091                                 return mg2;
4092                         }
4093
4094                         if (mg2 == null)
4095                                 return mg1;
4096
4097                         var all = new List<MethodBase> (mg1.Methods);
4098                         foreach (MethodBase m in mg2.Methods){
4099                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods, m, false))
4100                                         all.Add (m);
4101                         }
4102
4103                         return new MethodGroupExpr (all, null, loc);
4104                 }
4105
4106                 static Type MoreSpecific (Type p, Type q)
4107                 {
4108                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
4109                                 return q;
4110                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
4111                                 return p;
4112
4113                         if (TypeManager.HasElementType (p))
4114                         {
4115                                 Type pe = TypeManager.GetElementType (p);
4116                                 Type qe = TypeManager.GetElementType (q);
4117                                 Type specific = MoreSpecific (pe, qe);
4118                                 if (specific == pe)
4119                                         return p;
4120                                 if (specific == qe)
4121                                         return q;
4122                         }
4123                         else if (TypeManager.IsGenericType (p))
4124                         {
4125                                 Type[] pargs = TypeManager.GetTypeArguments (p);
4126                                 Type[] qargs = TypeManager.GetTypeArguments (q);
4127
4128                                 bool p_specific_at_least_once = false;
4129                                 bool q_specific_at_least_once = false;
4130
4131                                 for (int i = 0; i < pargs.Length; i++)
4132                                 {
4133                                         Type specific = MoreSpecific (TypeManager.TypeToCoreType (pargs [i]), TypeManager.TypeToCoreType (qargs [i]));
4134                                         if (specific == pargs [i])
4135                                                 p_specific_at_least_once = true;
4136                                         if (specific == qargs [i])
4137                                                 q_specific_at_least_once = true;
4138                                 }
4139
4140                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4141                                         return p;
4142                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4143                                         return q;
4144                         }
4145
4146                         return null;
4147                 }
4148
4149                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
4150                 {
4151                         base.MutateHoistedGenericType (storey);
4152
4153                         MethodInfo mi = best_candidate as MethodInfo;
4154                         if (mi != null) {
4155                                 best_candidate = storey.MutateGenericMethod (mi);
4156                                 return;
4157                         }
4158
4159                         best_candidate = storey.MutateConstructor ((ConstructorInfo) this);
4160                 }
4161
4162                 /// <summary>
4163                 ///   Find the Applicable Function Members (7.4.2.1)
4164                 ///
4165                 ///   me: Method Group expression with the members to select.
4166                 ///       it might contain constructors or methods (or anything
4167                 ///       that maps to a method).
4168                 ///
4169                 ///   Arguments: ArrayList containing resolved Argument objects.
4170                 ///
4171                 ///   loc: The location if we want an error to be reported, or a Null
4172                 ///        location for "probing" purposes.
4173                 ///
4174                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4175                 ///            that is the best match of me on Arguments.
4176                 ///
4177                 /// </summary>
4178                 public virtual MethodGroupExpr OverloadResolve (ResolveContext ec, ref Arguments Arguments,
4179                         bool may_fail, Location loc)
4180                 {
4181                         bool method_params = false;
4182                         Type applicable_type = null;
4183                         var candidates = new List<MethodBase> (2);
4184                         List<MethodBase> candidate_overrides = null;
4185
4186                         //
4187                         // Used to keep a map between the candidate
4188                         // and whether it is being considered in its
4189                         // normal or expanded form
4190                         //
4191                         // false is normal form, true is expanded form
4192                         //
4193                         Dictionary<MethodBase, MethodBase> candidate_to_form = null;
4194                         Dictionary<MethodBase, Arguments> candidates_expanded = null;
4195                         Arguments candidate_args = Arguments;
4196
4197                         int arg_count = Arguments != null ? Arguments.Count : 0;
4198
4199                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4200                                 if (!may_fail)
4201                                         ec.Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4202                                 return null;
4203                         }
4204
4205                         int nmethods = Methods.Length;
4206
4207                         if (!IsBase) {
4208                                 //
4209                                 // Methods marked 'override' don't take part in 'applicable_type'
4210                                 // computation, nor in the actual overload resolution.
4211                                 // However, they still need to be emitted instead of a base virtual method.
4212                                 // So, we salt them away into the 'candidate_overrides' array.
4213                                 //
4214                                 // In case of reflected methods, we replace each overriding method with
4215                                 // its corresponding base virtual method.  This is to improve compatibility
4216                                 // with non-C# libraries which change the visibility of overrides (#75636)
4217                                 //
4218                                 int j = 0;
4219                                 for (int i = 0; i < Methods.Length; ++i) {
4220                                         MethodBase m = Methods [i];
4221                                         if (TypeManager.IsOverride (m)) {
4222                                                 if (candidate_overrides == null)
4223                                                         candidate_overrides = new List<MethodBase> ();
4224                                                 candidate_overrides.Add (m);
4225                                                 m = TypeManager.TryGetBaseDefinition (m);
4226                                                 if (m != null && Array.Exists (Methods, l => l == m))
4227                                                         continue;
4228                                         }
4229                                         if (m != null)
4230                                                 Methods [j++] = m;
4231                                 }
4232                                 nmethods = j;
4233                         }
4234
4235                         //
4236                         // Enable message recording, it's used mainly by lambda expressions
4237                         //
4238                         SessionReportPrinter msg_recorder = new SessionReportPrinter ();
4239                         ReportPrinter prev_recorder = ec.Report.SetPrinter (msg_recorder);
4240
4241                         //
4242                         // First we construct the set of applicable methods
4243                         //
4244                         bool is_sorted = true;
4245                         int best_candidate_rate = int.MaxValue;
4246                         for (int i = 0; i < nmethods; i++) {
4247                                 Type decl_type = Methods [i].DeclaringType;
4248
4249                                 //
4250                                 // If we have already found an applicable method
4251                                 // we eliminate all base types (Section 14.5.5.1)
4252                                 //
4253                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4254                                         continue;
4255
4256                                 //
4257                                 // Check if candidate is applicable (section 14.4.2.1)
4258                                 //
4259                                 bool params_expanded_form = false;
4260                                 int candidate_rate = IsApplicable (ec, ref candidate_args, arg_count, ref Methods [i], ref params_expanded_form);
4261
4262                                 if (candidate_rate < best_candidate_rate) {
4263                                         best_candidate_rate = candidate_rate;
4264                                         best_candidate = Methods [i];
4265                                 }
4266
4267                                 if (params_expanded_form) {
4268                                         if (candidate_to_form == null)
4269                                                 candidate_to_form = new Dictionary<MethodBase, MethodBase> (4, ReferenceEquality<MethodBase>.Default);
4270                                         MethodBase candidate = Methods [i];
4271                                         candidate_to_form [candidate] = candidate;
4272                                 }
4273
4274                                 if (candidate_args != Arguments) {
4275                                         if (candidates_expanded == null)
4276                                                 candidates_expanded = new Dictionary<MethodBase, Arguments> (4, ReferenceEquality<MethodBase>.Default);
4277
4278                                         candidates_expanded.Add (Methods [i], candidate_args);
4279                                         candidate_args = Arguments;
4280                                 }
4281
4282                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4283                                         if (msg_recorder != null)
4284                                                 msg_recorder.EndSession ();
4285                                         continue;
4286                                 }
4287
4288                                 msg_recorder = null;
4289                                 candidates.Add (Methods [i]);
4290
4291                                 if (applicable_type == null)
4292                                         applicable_type = decl_type;
4293                                 else if (applicable_type != decl_type) {
4294                                         is_sorted = false;
4295                                         if (IsAncestralType (applicable_type, decl_type))
4296                                                 applicable_type = decl_type;
4297                                 }
4298                         }
4299
4300                         ec.Report.SetPrinter (prev_recorder);
4301                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4302                                 if (!may_fail)
4303                                         msg_recorder.Merge (prev_recorder);
4304
4305                                 return null;
4306                         }
4307
4308                         int candidate_top = candidates.Count;
4309
4310                         if (applicable_type == null) {
4311                                 //
4312                                 // When we found a top level method which does not match and it's
4313                                 // not an extension method. We start extension methods lookup from here
4314                                 //
4315                                 if (InstanceExpression != null) {
4316                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (type, Name, loc);
4317                                         if (ex_method_lookup != null) {
4318                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4319                                                 ex_method_lookup.SetTypeArguments (ec, type_arguments);
4320                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4321                                         }
4322                                 }
4323
4324                                 if (may_fail)
4325                                         return null;
4326
4327                                 //
4328                                 // Okay so we have failed to find exact match so we
4329                                 // return error info about the closest match
4330                                 //
4331                                 if (best_candidate != null) {
4332                                         if (CustomErrorHandler != null && !has_inaccessible_candidates_only && CustomErrorHandler.NoExactMatch (ec, best_candidate))
4333                                                 return null;
4334
4335                                         if (NoExactMatch (ec, ref Arguments, candidate_to_form))
4336                                                 return null;
4337                                 }
4338
4339                                 //
4340                                 // We failed to find any method with correct argument count
4341                                 //
4342                                 if (Name == ConstructorInfo.ConstructorName) {
4343                                         ec.Report.SymbolRelatedToPreviousError (queried_type);
4344                                         ec.Report.Error (1729, loc,
4345                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4346                                                 TypeManager.CSharpName (queried_type), arg_count);
4347                                 } else {
4348                                         Error_ArgumentCountWrong (ec, arg_count);
4349                                 }
4350
4351                                 return null;
4352                         }
4353
4354                         if (arg_count != 0 && Arguments.HasDynamic) {
4355                                 best_candidate = null;
4356                                 return this;
4357                         }
4358
4359                         if (!is_sorted) {
4360                                 //
4361                                 // At this point, applicable_type is _one_ of the most derived types
4362                                 // in the set of types containing the methods in this MethodGroup.
4363                                 // Filter the candidates so that they only contain methods from the
4364                                 // most derived types.
4365                                 //
4366
4367                                 int finalized = 0; // Number of finalized candidates
4368
4369                                 do {
4370                                         // Invariant: applicable_type is a most derived type
4371
4372                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4373                                         // eliminating all it's base types.  At the same time, we'll also move
4374                                         // every unrelated type to the end of the array, and pick the next
4375                                         // 'applicable_type'.
4376
4377                                         Type next_applicable_type = null;
4378                                         int j = finalized; // where to put the next finalized candidate
4379                                         int k = finalized; // where to put the next undiscarded candidate
4380                                         for (int i = finalized; i < candidate_top; ++i) {
4381                                                 MethodBase candidate = candidates [i];
4382                                                 Type decl_type = candidate.DeclaringType;
4383
4384                                                 if (decl_type == applicable_type) {
4385                                                         candidates [k++] = candidates [j];
4386                                                         candidates [j++] = candidates [i];
4387                                                         continue;
4388                                                 }
4389
4390                                                 if (IsAncestralType (decl_type, applicable_type))
4391                                                         continue;
4392
4393                                                 if (next_applicable_type != null &&
4394                                                         IsAncestralType (decl_type, next_applicable_type))
4395                                                         continue;
4396
4397                                                 candidates [k++] = candidates [i];
4398
4399                                                 if (next_applicable_type == null ||
4400                                                         IsAncestralType (next_applicable_type, decl_type))
4401                                                         next_applicable_type = decl_type;
4402                                         }
4403
4404                                         applicable_type = next_applicable_type;
4405                                         finalized = j;
4406                                         candidate_top = k;
4407                                 } while (applicable_type != null);
4408                         }
4409
4410                         //
4411                         // Now we actually find the best method
4412                         //
4413
4414                         best_candidate = candidates [0];
4415                         method_params = candidate_to_form != null && candidate_to_form.ContainsKey (best_candidate);
4416
4417                         //
4418                         // TODO: Broken inverse order of candidates logic does not work with optional
4419                         // parameters used for method overrides and I am not going to fix it for SRE
4420                         //
4421                         if (candidates_expanded != null && candidates_expanded.ContainsKey (best_candidate)) {
4422                                 candidate_args = candidates_expanded [best_candidate];
4423                                 arg_count = candidate_args.Count;
4424                         }
4425
4426                         for (int ix = 1; ix < candidate_top; ix++) {
4427                                 MethodBase candidate = (MethodBase) candidates [ix];
4428
4429                                 if (candidate == best_candidate)
4430                                         continue;
4431
4432                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (candidate);
4433
4434                                 if (BetterFunction (ec, candidate_args, arg_count,
4435                                         candidate, cand_params,
4436                                         best_candidate, method_params)) {
4437                                         best_candidate = candidate;
4438                                         method_params = cand_params;
4439                                 }
4440                         }
4441                         //
4442                         // Now check that there are no ambiguities i.e the selected method
4443                         // should be better than all the others
4444                         //
4445                         MethodBase ambiguous = null;
4446                         for (int ix = 1; ix < candidate_top; ix++) {
4447                                 MethodBase candidate = candidates [ix];
4448
4449                                 if (candidate == best_candidate)
4450                                         continue;
4451
4452                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (candidate);
4453                                 if (!BetterFunction (ec, candidate_args, arg_count,
4454                                         best_candidate, method_params,
4455                                         candidate, cand_params))
4456                                 {
4457                                         if (!may_fail)
4458                                                 ec.Report.SymbolRelatedToPreviousError (candidate);
4459                                         ambiguous = candidate;
4460                                 }
4461                         }
4462
4463                         if (ambiguous != null) {
4464                                 Error_AmbiguousCall (ec, ambiguous);
4465                                 return this;
4466                         }
4467
4468                         //
4469                         // If the method is a virtual function, pick an override closer to the LHS type.
4470                         //
4471                         if (!IsBase && best_candidate.IsVirtual) {
4472                                 if (TypeManager.IsOverride (best_candidate))
4473                                         throw new InternalErrorException (
4474                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4475
4476                                 if (candidate_overrides != null) {
4477                                         Type[] gen_args = null;
4478                                         bool gen_override = false;
4479                                         if (TypeManager.IsGenericMethod (best_candidate))
4480                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4481
4482                                         foreach (MethodBase candidate in candidate_overrides) {
4483                                                 if (TypeManager.IsGenericMethod (candidate)) {
4484                                                         if (gen_args == null)
4485                                                                 continue;
4486
4487                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4488                                                                 continue;
4489                                                 } else {
4490                                                         if (gen_args != null)
4491                                                                 continue;
4492                                                 }
4493
4494                                                 if (IsOverride (candidate, best_candidate)) {
4495                                                         gen_override = true;
4496                                                         best_candidate = candidate;
4497                                                 }
4498                                         }
4499
4500                                         if (gen_override && gen_args != null) {
4501                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4502                                         }
4503                                 }
4504                         }
4505
4506                         //
4507                         // And now check if the arguments are all
4508                         // compatible, perform conversions if
4509                         // necessary etc. and return if everything is
4510                         // all right
4511                         //
4512                         if (!VerifyArgumentsCompat (ec, ref candidate_args, arg_count, best_candidate,
4513                                 method_params, may_fail, loc))
4514                                 return null;
4515
4516                         if (best_candidate == null)
4517                                 return null;
4518
4519                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4520                         if (TypeManager.IsGenericMethodDefinition (the_method) &&
4521                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4522                                 return null;
4523
4524                         //
4525                         // Check ObsoleteAttribute on the best method
4526                         //
4527                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4528                         if (oa != null && !ec.IsObsolete)
4529                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
4530
4531                         IMethodData data = TypeManager.GetMethod (the_method);
4532                         if (data != null)
4533                                 data.SetMemberIsUsed ();
4534
4535                         Arguments = candidate_args;
4536                         return this;
4537                 }
4538
4539                 bool NoExactMatch (ResolveContext ec, ref Arguments Arguments, IDictionary<MethodBase, MethodBase> candidate_to_form)
4540                 {
4541                         AParametersCollection pd = TypeManager.GetParameterData (best_candidate);
4542                         int arg_count = Arguments == null ? 0 : Arguments.Count;
4543
4544                         if (arg_count == pd.Count || pd.HasParams) {
4545                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4546                                         if (type_arguments == null) {
4547                                                 ec.Report.Error (411, loc,
4548                                                         "The type arguments for method `{0}' cannot be inferred from " +
4549                                                         "the usage. Try specifying the type arguments explicitly",
4550                                                         TypeManager.CSharpSignature (best_candidate));
4551                                                 return true;
4552                                         }
4553
4554                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate);
4555                                         if (type_arguments.Count != g_args.Length) {
4556                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4557                                                 ec.Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4558                                                         TypeManager.CSharpSignature (best_candidate),
4559                                                         g_args.Length.ToString ());
4560                                                 return true;
4561                                         }
4562                                 } else {
4563                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4564                                                 Error_TypeArgumentsCannotBeUsed (ec.Report, loc);
4565                                                 return true;
4566                                         }
4567                                 }
4568
4569                                 if (has_inaccessible_candidates_only) {
4570                                         if (InstanceExpression != null && type != ec.CurrentType && TypeManager.IsNestedFamilyAccessible (ec.CurrentType, best_candidate.DeclaringType)) {
4571                                                 // Although a derived class can access protected members of
4572                                                 // its base class it cannot do so through an instance of the
4573                                                 // base class (CS1540).  If the qualifier_type is a base of the
4574                                                 // ec.CurrentType and the lookup succeeds with the latter one,
4575                                                 // then we are in this situation.
4576                                                 Error_CannotAccessProtected (ec, loc, best_candidate, queried_type, ec.CurrentType);
4577                                         } else {
4578                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4579                                                 ErrorIsInaccesible (loc, GetSignatureForError (), ec.Report);
4580                                         }
4581                                 }
4582
4583                                 bool cand_params = candidate_to_form != null && candidate_to_form.ContainsKey (best_candidate);
4584                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, false, loc))
4585                                         return true;
4586
4587                                 if (has_inaccessible_candidates_only)
4588                                         return true;
4589                         }
4590
4591                         return false;
4592                 }
4593
4594                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
4595                 {
4596                         type_arguments = ta;
4597                 }
4598
4599                 public bool VerifyArgumentsCompat (ResolveContext ec, ref Arguments arguments,
4600                                                           int arg_count, MethodBase method,
4601                                                           bool chose_params_expanded,
4602                                                           bool may_fail, Location loc)
4603                 {
4604                         AParametersCollection pd = TypeManager.GetParameterData (method);
4605                         int param_count = GetApplicableParametersCount (method, pd);
4606
4607                         int errors = ec.Report.Errors;
4608                         Parameter.Modifier p_mod = 0;
4609                         Type pt = null;
4610                         int a_idx = 0, a_pos = 0;
4611                         Argument a = null;
4612                         ArrayInitializer params_initializers = null;
4613                         bool has_unsafe_arg = method is MethodInfo ? ((MethodInfo) method).ReturnType.IsPointer : false;
4614
4615                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4616                                 a = arguments [a_idx];
4617                                 if (p_mod != Parameter.Modifier.PARAMS) {
4618                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4619                                         pt = pd.Types [a_idx];
4620                                         has_unsafe_arg |= pt.IsPointer;
4621
4622                                         if (p_mod == Parameter.Modifier.PARAMS) {
4623                                                 if (chose_params_expanded) {
4624                                                         params_initializers = new ArrayInitializer (arg_count - a_idx, a.Expr.Location);
4625                                                         pt = TypeManager.GetElementType (pt);
4626                                                 }
4627                                         }
4628                                 }
4629
4630                                 //
4631                                 // Types have to be identical when ref or out modifer is used
4632                                 //
4633                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4634                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4635                                                 break;
4636
4637                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4638                                                 break;
4639
4640                                         continue;
4641                                 } else {
4642                                         NamedArgument na = a as NamedArgument;
4643                                         if (na != null) {
4644                                                 int name_index = pd.GetParameterIndexByName (na.Name);
4645                                                 if (name_index < 0 || name_index >= param_count) {
4646                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType)) {
4647                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4648                                                                 ec.Report.Error (1746, na.Location,
4649                                                                         "The delegate `{0}' does not contain a parameter named `{1}'",
4650                                                                         TypeManager.CSharpName (DeclaringType), na.Name);
4651                                                         } else {
4652                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4653                                                                 ec.Report.Error (1739, na.Location,
4654                                                                         "The best overloaded method match for `{0}' does not contain a parameter named `{1}'",
4655                                                                         TypeManager.CSharpSignature (method), na.Name);
4656                                                         }
4657                                                 } else if (arguments[name_index] != a) {
4658                                                         if (DeclaringType != null && TypeManager.IsDelegateType (DeclaringType))
4659                                                                 ec.Report.SymbolRelatedToPreviousError (DeclaringType);
4660                                                         else
4661                                                                 ec.Report.SymbolRelatedToPreviousError (best_candidate);
4662
4663                                                         ec.Report.Error (1744, na.Location,
4664                                                                 "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
4665                                                                 na.Name);
4666                                                 }
4667                                         }
4668                                 }
4669
4670                                 if (TypeManager.IsDynamicType (a.Expr.Type))
4671                                         continue;
4672
4673                                 if (delegate_type != null && !Delegate.IsTypeCovariant (a.Expr, pt))
4674                                         break;
4675
4676                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4677                                 if (conv == null)
4678                                         break;
4679
4680                                 //
4681                                 // Convert params arguments to an array initializer
4682                                 //
4683                                 if (params_initializers != null) {
4684                                         // we choose to use 'a.Expr' rather than 'conv' so that
4685                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4686                                         params_initializers.Add (a.Expr);
4687                                         arguments.RemoveAt (a_idx--);
4688                                         --arg_count;
4689                                         continue;
4690                                 }
4691
4692                                 // Update the argument with the implicit conversion
4693                                 a.Expr = conv;
4694                         }
4695
4696                         if (a_idx != arg_count) {
4697                                 if (!may_fail && ec.Report.Errors == errors) {
4698                                         if (CustomErrorHandler != null)
4699                                                 CustomErrorHandler.NoExactMatch (ec, best_candidate);
4700                                         else
4701                                                 Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4702                                 }
4703                                 return false;
4704                         }
4705
4706                         //
4707                         // Fill not provided arguments required by params modifier
4708                         //
4709                         if (params_initializers == null && pd.HasParams && arg_count + 1 == param_count) {
4710                                 if (arguments == null)
4711                                         arguments = new Arguments (1);
4712
4713                                 pt = pd.Types [param_count - 1];
4714                                 pt = TypeManager.GetElementType (pt);
4715                                 has_unsafe_arg |= pt.IsPointer;
4716                                 params_initializers = new ArrayInitializer (0, loc);
4717                         }
4718
4719                         //
4720                         // Append an array argument with all params arguments
4721                         //
4722                         if (params_initializers != null) {
4723                                 arguments.Add (new Argument (
4724                                         new ArrayCreation (new TypeExpression (pt, loc), "[]", params_initializers, loc).Resolve (ec)));
4725                                 arg_count++;
4726                         }
4727
4728                         if (arg_count < param_count) {
4729                                 if (!may_fail)
4730                                         Error_ArgumentCountWrong (ec, arg_count);
4731                                 return false;
4732                         }
4733
4734                         if (has_unsafe_arg && !ec.IsUnsafe) {
4735                                 if (!may_fail)
4736                                         UnsafeError (ec, loc);
4737                                 return false;
4738                         }
4739
4740                         return true;
4741                 }
4742         }
4743
4744         public class ConstantExpr : MemberExpr
4745         {
4746                 FieldInfo constant;
4747
4748                 public ConstantExpr (FieldInfo constant, Location loc)
4749                 {
4750                         this.constant = constant;
4751                         this.loc = loc;
4752                 }
4753
4754                 public override string Name {
4755                         get { throw new NotImplementedException (); }
4756                 }
4757
4758                 public override bool IsInstance {
4759                         get { return !IsStatic; }
4760                 }
4761
4762                 public override bool IsStatic {
4763                         get { return constant.IsStatic; }
4764                 }
4765
4766                 public override Type DeclaringType {
4767                         get { return constant.DeclaringType; }
4768                 }
4769
4770                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc, SimpleName original)
4771                 {
4772                         constant = TypeManager.GetGenericFieldDefinition (constant);
4773
4774                         IConstant ic = TypeManager.GetConstant (constant);
4775                         if (ic == null) {
4776                                 if (constant.IsLiteral) {
4777                                         ic = new ExternalConstant (constant, ec.Compiler);
4778                                 } else {
4779                                         ic = ExternalConstant.CreateDecimal (constant, ec);
4780                                         // HACK: decimal field was not resolved as constant
4781                                         if (ic == null)
4782                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4783                                 }
4784                                 TypeManager.RegisterConstant (constant, ic);
4785                         }
4786
4787                         return base.ResolveMemberAccess (ec, left, loc, original);
4788                 }
4789
4790                 public override Expression CreateExpressionTree (ResolveContext ec)
4791                 {
4792                         throw new NotSupportedException ("ET");
4793                 }
4794
4795                 protected override Expression DoResolve (ResolveContext rc)
4796                 {
4797                         IConstant ic = TypeManager.GetConstant (constant);
4798                         if (ic.ResolveValue ()) {
4799                                 if (!rc.IsObsolete)
4800                                         ic.CheckObsoleteness (loc);
4801                         }
4802
4803                         return ic.CreateConstantReference (rc, loc);
4804                 }
4805
4806                 public override void Emit (EmitContext ec)
4807                 {
4808                         throw new NotSupportedException ();
4809                 }
4810
4811                 public override string GetSignatureForError ()
4812                 {
4813                         return TypeManager.GetFullNameSignature (constant);
4814                 }
4815         }
4816
4817         /// <summary>
4818         ///   Fully resolved expression that evaluates to a Field
4819         /// </summary>
4820         public class FieldExpr : MemberExpr, IDynamicAssign, IMemoryLocation, IVariableReference {
4821                 public FieldInfo FieldInfo;
4822                 readonly Type constructed_generic_type;
4823                 VariableInfo variable_info;
4824
4825                 LocalTemporary temp;
4826                 bool prepared;
4827
4828                 protected FieldExpr (Location l)
4829                 {
4830                         loc = l;
4831                 }
4832
4833                 public FieldExpr (FieldInfo fi, Location l)
4834                 {
4835                         FieldInfo = fi;
4836                         type = TypeManager.TypeToCoreType (fi.FieldType);
4837                         loc = l;
4838                 }
4839
4840                 public FieldExpr (FieldInfo fi, Type genericType, Location l)
4841                         : this (fi, l)
4842                 {
4843                         if (TypeManager.IsGenericTypeDefinition (genericType))
4844                                 return;
4845                         this.constructed_generic_type = genericType;
4846                 }
4847
4848                 public override string Name {
4849                         get {
4850                                 return FieldInfo.Name;
4851                         }
4852                 }
4853
4854                 public override bool IsInstance {
4855                         get {
4856                                 return !FieldInfo.IsStatic;
4857                         }
4858                 }
4859
4860                 public override bool IsStatic {
4861                         get {
4862                                 return FieldInfo.IsStatic;
4863                         }
4864                 }
4865
4866                 public override Type DeclaringType {
4867                         get {
4868                                 return FieldInfo.DeclaringType;
4869                         }
4870                 }
4871
4872                 public override string GetSignatureForError ()
4873                 {
4874                         return TypeManager.GetFullNameSignature (FieldInfo);
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 (FieldInfo);
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 (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 (!FieldInfo.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 (FieldInfo);
4971                                 if (f != null) {
4972                                         f.CheckObsoleteness (loc);
4973                                 } else {
4974                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4975                                         if (oa != null)
4976                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc, ec.Report);
4977                                 }
4978                         }
4979
4980                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
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 (FieldInfo);
4991                                         ec.Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4992                                                 TypeManager.GetFullNameSignature (FieldInfo));
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, FieldInfo.Name, loc))
5008                                 return null;
5009
5010                         variable_info = vi.GetSubStruct (FieldInfo.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, FieldInfo.Name);
5056
5057                         bool lvalue_instance = !FieldInfo.IsStatic && TypeManager.IsValueType (FieldInfo.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 (FieldInfo);
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 (FieldInfo.IsInitOnly) {
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, FieldInfo.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 FieldInfo.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 (FieldInfo != fe.FieldInfo)
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                         FieldBase f = TypeManager.GetField (FieldInfo);
5170                         if (f != null){
5171                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5172                                         is_volatile = true;
5173
5174                                 f.SetMemberIsUsed ();
5175                         }
5176
5177                         if (FieldInfo.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                                         IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
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 (!FieldInfo.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 (!FieldInfo.IsStatic) {
5225                                         temp = new LocalTemporary (this.Type);
5226                                         temp.Store (ec);
5227                                 }
5228                         }
5229
5230                         FieldBase f = TypeManager.GetField (FieldInfo);
5231                         if (f != null){
5232                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5233                                         ig.Emit (OpCodes.Volatile);
5234
5235                                 f.SetAssigned ();
5236                         }
5237
5238                         if (is_static)
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 (FieldInfo);
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 (FieldInfo);
5276                         if (f != null){
5277                                 if ((mode & AddressOp.Store) != 0)
5278                                         f.SetAssigned ();
5279                                 if ((mode & AddressOp.Load) != 0)
5280                                         f.SetMemberIsUsed ();
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 (FieldInfo.IsInitOnly){
5289                                 need_copy = true;
5290                                 if (ec.HasSet (EmitContext.Options.ConstructorScope)){
5291                                         if (FieldInfo.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 (FieldInfo.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 FieldInfo;
5323
5324                         return TypeBuilder.GetField (constructed_generic_type, FieldInfo);
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), FieldInfo);
5335                 }
5336
5337                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5338                 {
5339                         FieldInfo = storey.MutateField (FieldInfo);
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                 public readonly PropertyInfo PropertyInfo;
5355                 MethodInfo getter, setter;
5356                 bool is_static;
5357
5358                 TypeArguments targs;
5359
5360                 LocalTemporary temp;
5361                 bool prepared;
5362
5363                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5364                 {
5365                         PropertyInfo = pi;
5366                         is_static = false;
5367                         loc = l;
5368
5369                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5370
5371                         ResolveAccessors (container_type);
5372                 }
5373
5374                 public override string Name {
5375                         get {
5376                                 return PropertyInfo.Name;
5377                         }
5378                 }
5379
5380                 public override bool IsInstance {
5381                         get {
5382                                 return !is_static;
5383                         }
5384                 }
5385
5386                 public override bool IsStatic {
5387                         get {
5388                                 return is_static;
5389                         }
5390                 }
5391
5392                 public override Expression CreateExpressionTree (ResolveContext ec)
5393                 {
5394                         Arguments args;
5395                         if (IsSingleDimensionalArrayLength ()) {
5396                                 args = new Arguments (1);
5397                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5398                                 return CreateExpressionFactoryCall (ec, "ArrayLength", args);
5399                         }
5400
5401                         if (is_base) {
5402                                 Error_BaseAccessInExpressionTree (ec, loc);
5403                                 return null;
5404                         }
5405
5406                         args = new Arguments (2);
5407                         if (InstanceExpression == null)
5408                                 args.Add (new Argument (new NullLiteral (loc)));
5409                         else
5410                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5411                         args.Add (new Argument (new TypeOfMethod (getter, loc)));
5412                         return CreateExpressionFactoryCall (ec, "Property", args);
5413                 }
5414
5415                 public Expression CreateSetterTypeOfExpression ()
5416                 {
5417                         return new TypeOfMethod (setter, loc);
5418                 }
5419
5420                 public override Type DeclaringType {
5421                         get {
5422                                 return PropertyInfo.DeclaringType;
5423                         }
5424                 }
5425
5426                 public override string GetSignatureForError ()
5427                 {
5428                         return TypeManager.GetFullNameSignature (PropertyInfo);
5429                 }
5430
5431                 void FindAccessors (Type invocation_type)
5432                 {
5433                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5434                                 BindingFlags.Static | BindingFlags.Instance |
5435                                 BindingFlags.DeclaredOnly;
5436
5437                         Type current = PropertyInfo.DeclaringType;
5438                         for (; current != null; current = current.BaseType) {
5439                                 MemberInfo[] group = TypeManager.MemberLookup (
5440                                         invocation_type, invocation_type, current,
5441                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5442
5443                                 if (group == null)
5444                                         continue;
5445
5446                                 if (group.Length != 1)
5447                                         // Oooops, can this ever happen ?
5448                                         return;
5449
5450                                 PropertyInfo pi = (PropertyInfo) group [0];
5451
5452                                 if (getter == null)
5453                                         getter = pi.GetGetMethod (true);
5454
5455                                 if (setter == null)
5456                                         setter = pi.GetSetMethod (true);
5457
5458                                 MethodInfo accessor = getter != null ? getter : setter;
5459
5460                                 if (!accessor.IsVirtual)
5461                                         return;
5462                         }
5463                 }
5464
5465                 //
5466                 // We also perform the permission checking here, as the PropertyInfo does not
5467                 // hold the information for the accessibility of its setter/getter
5468                 //
5469                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5470                 void ResolveAccessors (Type container_type)
5471                 {
5472                         FindAccessors (container_type);
5473
5474                         if (getter != null) {
5475                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5476                                 IMethodData md = TypeManager.GetMethod (the_getter);
5477                                 if (md != null)
5478                                         md.SetMemberIsUsed ();
5479
5480                                 is_static = getter.IsStatic;
5481                         }
5482
5483                         if (setter != null) {
5484                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5485                                 IMethodData md = TypeManager.GetMethod (the_setter);
5486                                 if (md != null)
5487                                         md.SetMemberIsUsed ();
5488
5489                                 is_static = setter.IsStatic;
5490                         }
5491                 }
5492
5493                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
5494                 {
5495                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), setter);
5496                 }
5497
5498                 public override SLE.Expression MakeExpression (BuilderContext ctx)
5499                 {
5500                         return SLE.Expression.Property (InstanceExpression.MakeExpression (ctx), getter);
5501                 }
5502
5503                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5504                 {
5505                         if (InstanceExpression != null)
5506                                 InstanceExpression.MutateHoistedGenericType (storey);
5507
5508                         type = storey.MutateType (type);
5509                         if (getter != null)
5510                                 getter = storey.MutateGenericMethod (getter);
5511                         if (setter != null)
5512                                 setter = storey.MutateGenericMethod (setter);
5513                 }
5514
5515                 bool InstanceResolve (ResolveContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5516                 {
5517                         if (is_static) {
5518                                 InstanceExpression = null;
5519                                 return true;
5520                         }
5521
5522                         if (InstanceExpression == null) {
5523                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5524                                 return false;
5525                         }
5526
5527                         InstanceExpression = InstanceExpression.Resolve (ec);
5528                         if (lvalue_instance && InstanceExpression != null)
5529                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess);
5530
5531                         if (InstanceExpression == null)
5532                                 return false;
5533
5534                         InstanceExpression.CheckMarshalByRefAccess (ec);
5535
5536                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5537                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5538                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5539                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5540                                 ec.Report.SymbolRelatedToPreviousError (PropertyInfo);
5541                                 Error_CannotAccessProtected (ec, loc, PropertyInfo, InstanceExpression.Type, ec.CurrentType);
5542                                 return false;
5543                         }
5544
5545                         return true;
5546                 }
5547
5548                 void Error_PropertyNotFound (ResolveContext ec, MethodInfo mi, bool getter)
5549                 {
5550                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5551                         if (mi is MethodBuilder) {
5552                                 Error_TypeDoesNotContainDefinition (ec, loc, PropertyInfo.DeclaringType, Name);
5553                                 return;
5554                         }
5555
5556                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5557                         sig.Append ('.');
5558                         AParametersCollection iparams = TypeManager.GetParameterData (mi);
5559                         sig.Append (getter ? "get_" : "set_");
5560                         sig.Append (Name);
5561                         sig.Append (iparams.GetSignatureForError ());
5562
5563                         ec.Report.SymbolRelatedToPreviousError (mi);
5564                         ec.Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5565                                 Name, sig.ToString ());
5566                 }
5567
5568                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5569                 {
5570                         bool dummy;
5571                         MethodInfo accessor = lvalue ? setter : getter;
5572                         if (accessor == null && lvalue)
5573                                 accessor = getter;
5574                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5575                 }
5576
5577                 bool IsSingleDimensionalArrayLength ()
5578                 {
5579                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5580                                 return false;
5581
5582                         string t_name = InstanceExpression.Type.Name;
5583                         int t_name_len = t_name.Length;
5584                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5585                 }
5586
5587                 protected override Expression DoResolve (ResolveContext ec)
5588                 {
5589                         eclass = ExprClass.PropertyAccess;
5590
5591                         bool must_do_cs1540_check = false;
5592                         ec.Report.DisableReporting ();
5593                         bool res = ResolveGetter (ec, ref must_do_cs1540_check);
5594                         ec.Report.EnableReporting ();
5595
5596                         if (!res) {
5597                                 if (InstanceExpression != null) {
5598                                         Type expr_type = InstanceExpression.Type;
5599                                         ExtensionMethodGroupExpr ex_method_lookup = ec.LookupExtensionMethod (expr_type, Name, loc);
5600                                         if (ex_method_lookup != null) {
5601                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
5602                                                 ex_method_lookup.SetTypeArguments (ec, targs);
5603                                                 return ex_method_lookup.Resolve (ec);
5604                                         }
5605                                 }
5606
5607                                 ResolveGetter (ec, ref must_do_cs1540_check);
5608                                 return null;
5609                         }
5610
5611                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5612                                 return null;
5613
5614                         //
5615                         // Only base will allow this invocation to happen.
5616                         //
5617                         if (IsBase && getter.IsAbstract) {
5618                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (PropertyInfo));
5619                         }
5620
5621                         if (PropertyInfo.PropertyType.IsPointer && !ec.IsUnsafe){
5622                                 UnsafeError (ec, loc);
5623                         }
5624
5625                         if (!ec.IsObsolete) {
5626                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5627                                 if (pb != null) {
5628                                         pb.CheckObsoleteness (loc);
5629                                 } else {
5630                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5631                                         if (oa != null)
5632                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5633                                 }
5634                         }
5635
5636                         return this;
5637                 }
5638
5639                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5640                 {
5641                         eclass = ExprClass.PropertyAccess;
5642
5643                         if (right_side == EmptyExpression.OutAccess.Instance) {
5644                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5645                                         ec.Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5646                                             PropertyInfo.Name);
5647                                 } else {
5648                                         right_side.DoResolveLValue (ec, this);
5649                                 }
5650                                 return null;
5651                         }
5652
5653                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5654                                 Error_CannotModifyIntermediateExpressionValue (ec);
5655                         }
5656
5657                         if (setter == null){
5658                                 //
5659                                 // The following condition happens if the PropertyExpr was
5660                                 // created, but is invalid (ie, the property is inaccessible),
5661                                 // and we did not want to embed the knowledge about this in
5662                                 // the caller routine.  This only avoids double error reporting.
5663                                 //
5664                                 if (getter == null)
5665                                         return null;
5666
5667                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5668                                         ec.Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5669                                                 PropertyInfo.Name);
5670                                 } else {
5671                                         ec.Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5672                                                 GetSignatureForError ());
5673                                 }
5674                                 return null;
5675                         }
5676
5677                         if (targs != null) {
5678                                 base.SetTypeArguments (ec, targs);
5679                                 return null;
5680                         }
5681
5682                         if (TypeManager.GetParameterData (setter).Count != 1){
5683                                 Error_PropertyNotFound (ec, setter, false);
5684                                 return null;
5685                         }
5686
5687                         bool must_do_cs1540_check;
5688                         if (!IsAccessorAccessible (ec.CurrentType, setter, out must_do_cs1540_check)) {
5689                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5690                                 if (pm != null && pm.HasCustomAccessModifier) {
5691                                         ec.Report.SymbolRelatedToPreviousError (pm);
5692                                         ec.Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5693                                                 TypeManager.CSharpSignature (setter));
5694                                 }
5695                                 else {
5696                                         ec.Report.SymbolRelatedToPreviousError (setter);
5697                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter), ec.Report);
5698                                 }
5699                                 return null;
5700                         }
5701
5702                         if (!InstanceResolve (ec, TypeManager.IsStruct (PropertyInfo.DeclaringType), must_do_cs1540_check))
5703                                 return null;
5704
5705                         //
5706                         // Only base will allow this invocation to happen.
5707                         //
5708                         if (IsBase && setter.IsAbstract){
5709                                 Error_CannotCallAbstractBase (ec, TypeManager.GetFullNameSignature (PropertyInfo));
5710                         }
5711
5712                         if (PropertyInfo.PropertyType.IsPointer && !ec.IsUnsafe) {
5713                                 UnsafeError (ec, loc);
5714                         }
5715
5716                         if (!ec.IsObsolete) {
5717                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5718                                 if (pb != null) {
5719                                         pb.CheckObsoleteness (loc);
5720                                 } else {
5721                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5722                                         if (oa != null)
5723                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
5724                                 }
5725                         }
5726
5727                         return this;
5728                 }
5729
5730                 public override void Emit (EmitContext ec)
5731                 {
5732                         Emit (ec, false);
5733                 }
5734
5735                 public void Emit (EmitContext ec, bool leave_copy)
5736                 {
5737                         //
5738                         // Special case: length of single dimension array property is turned into ldlen
5739                         //
5740                         if (IsSingleDimensionalArrayLength ()) {
5741                                 if (!prepared)
5742                                         EmitInstance (ec, false);
5743                                 ec.ig.Emit (OpCodes.Ldlen);
5744                                 ec.ig.Emit (OpCodes.Conv_I4);
5745                                 return;
5746                         }
5747
5748                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5749
5750                         if (leave_copy) {
5751                                 ec.ig.Emit (OpCodes.Dup);
5752                                 if (!is_static) {
5753                                         temp = new LocalTemporary (this.Type);
5754                                         temp.Store (ec);
5755                                 }
5756                         }
5757                 }
5758
5759                 //
5760                 // Implements the IAssignMethod interface for assignments
5761                 //
5762                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5763                 {
5764                         Expression my_source = source;
5765
5766                         if (prepare_for_load) {
5767                                 prepared = true;
5768                                 source.Emit (ec);
5769
5770                                 if (leave_copy) {
5771                                         ec.ig.Emit (OpCodes.Dup);
5772                                         if (!is_static) {
5773                                                 temp = new LocalTemporary (this.Type);
5774                                                 temp.Store (ec);
5775                                         }
5776                                 }
5777                         } else if (leave_copy) {
5778                                 source.Emit (ec);
5779                                 temp = new LocalTemporary (this.Type);
5780                                 temp.Store (ec);
5781                                 my_source = temp;
5782                         }
5783
5784                         Arguments args = new Arguments (1);
5785                         args.Add (new Argument (my_source));
5786
5787                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5788
5789                         if (temp != null) {
5790                                 temp.Emit (ec);
5791                                 temp.Release (ec);
5792                         }
5793                 }
5794
5795                 bool ResolveGetter (ResolveContext ec, ref bool must_do_cs1540_check)
5796                 {
5797                         if (targs != null) {
5798                                 base.SetTypeArguments (ec, targs);
5799                                 return false;
5800                         }
5801
5802                         if (getter != null) {
5803                                 if (TypeManager.GetParameterData (getter).Count != 0) {
5804                                         Error_PropertyNotFound (ec, getter, true);
5805                                         return false;
5806                                 }
5807                         }
5808
5809                         if (getter == null) {
5810                                 //
5811                                 // The following condition happens if the PropertyExpr was
5812                                 // created, but is invalid (ie, the property is inaccessible),
5813                                 // and we did not want to embed the knowledge about this in
5814                                 // the caller routine.  This only avoids double error reporting.
5815                                 //
5816                                 if (setter == null)
5817                                         return false;
5818
5819                                 if (InstanceExpression != EmptyExpression.Null) {
5820                                         ec.Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5821                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5822                                         return false;
5823                                 }
5824                         }
5825
5826                         if (getter != null &&
5827                                 !IsAccessorAccessible (ec.CurrentType, getter, out must_do_cs1540_check)) {
5828                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5829                                 if (pm != null && pm.HasCustomAccessModifier) {
5830                                         ec.Report.SymbolRelatedToPreviousError (pm);
5831                                         ec.Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5832                                                 TypeManager.CSharpSignature (getter));
5833                                 } else {
5834                                         ec.Report.SymbolRelatedToPreviousError (getter);
5835                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter), ec.Report);
5836                                 }
5837
5838                                 return false;
5839                         }
5840
5841                         return true;
5842                 }
5843
5844                 public override void SetTypeArguments (ResolveContext ec, TypeArguments ta)
5845                 {
5846                         targs = ta;
5847                 }
5848         }
5849
5850         /// <summary>
5851         ///   Fully resolved expression that evaluates to an Event
5852         /// </summary>
5853         public class EventExpr : MemberExpr {
5854                 public readonly EventInfo EventInfo;
5855
5856                 bool is_static;
5857                 MethodInfo add_accessor, remove_accessor;
5858
5859                 public EventExpr (EventInfo ei, Location loc)
5860                 {
5861                         EventInfo = ei;
5862                         this.loc = loc;
5863
5864                         add_accessor = TypeManager.GetAddMethod (ei);
5865                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5866                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5867                                 is_static = true;
5868
5869                         if (EventInfo is MyEventBuilder){
5870                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5871                                 type = eb.EventType;
5872                                 eb.SetUsed ();
5873                         } else
5874                                 type = EventInfo.EventHandlerType;
5875                 }
5876
5877                 public override string Name {
5878                         get {
5879                                 return EventInfo.Name;
5880                         }
5881                 }
5882
5883                 public override bool IsInstance {
5884                         get {
5885                                 return !is_static;
5886                         }
5887                 }
5888
5889                 public override bool IsStatic {
5890                         get {
5891                                 return is_static;
5892                         }
5893                 }
5894
5895                 public override Type DeclaringType {
5896                         get {
5897                                 return EventInfo.DeclaringType;
5898                         }
5899                 }
5900
5901                 public void Error_AssignmentEventOnly (ResolveContext ec)
5902                 {
5903                         ec.Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5904                                 GetSignatureForError ());
5905                 }
5906
5907                 public override MemberExpr ResolveMemberAccess (ResolveContext ec, Expression left, Location loc,
5908                                                                 SimpleName original)
5909                 {
5910                         //
5911                         // If the event is local to this class, we transform ourselves into a FieldExpr
5912                         //
5913
5914                         if (EventInfo.DeclaringType == ec.CurrentType ||
5915                             TypeManager.IsNestedChildOf(ec.CurrentType, EventInfo.DeclaringType)) {
5916
5917                                 // TODO: Breaks dynamic binder as currect context fields are imported and not compiled
5918                                 EventField mi = TypeManager.GetEventField (EventInfo);
5919
5920                                 if (mi != null) {
5921                                         if (!ec.IsObsolete)
5922                                                 mi.CheckObsoleteness (loc);
5923
5924                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5925                                                 Error_AssignmentEventOnly (ec);
5926
5927                                         FieldExpr ml = new FieldExpr (mi.BackingField.FieldBuilder, loc);
5928
5929                                         InstanceExpression = null;
5930
5931                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5932                                 }
5933                         }
5934
5935                         if (left is This && !ec.HasSet (ResolveContext.Options.CompoundAssignmentScope))
5936                                 Error_AssignmentEventOnly (ec);
5937
5938                         return base.ResolveMemberAccess (ec, left, loc, original);
5939                 }
5940
5941                 bool InstanceResolve (ResolveContext ec, bool must_do_cs1540_check)
5942                 {
5943                         if (is_static) {
5944                                 InstanceExpression = null;
5945                                 return true;
5946                         }
5947
5948                         if (InstanceExpression == null) {
5949                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5950                                 return false;
5951                         }
5952
5953                         InstanceExpression = InstanceExpression.Resolve (ec);
5954                         if (InstanceExpression == null)
5955                                 return false;
5956
5957                         if (IsBase && add_accessor.IsAbstract) {
5958                                 Error_CannotCallAbstractBase (ec, TypeManager.CSharpSignature(add_accessor));
5959                                 return false;
5960                         }
5961
5962                         //
5963                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5964                         // However, in the Event case, we reported a CS0122 instead.
5965                         //
5966                         // TODO: Exact copy from PropertyExpr
5967                         //
5968                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5969                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.CurrentType) &&
5970                             !TypeManager.IsNestedChildOf (ec.CurrentType, InstanceExpression.Type) &&
5971                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.CurrentType)) {
5972                                 ec.Report.SymbolRelatedToPreviousError (EventInfo);
5973                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo), ec.Report);
5974                                 return false;
5975                         }
5976
5977                         return true;
5978                 }
5979
5980                 public bool IsAccessibleFrom (Type invocation_type)
5981                 {
5982                         bool dummy;
5983                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5984                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5985                 }
5986
5987                 public override Expression CreateExpressionTree (ResolveContext ec)
5988                 {
5989                         throw new NotSupportedException ("ET");
5990                 }
5991
5992                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
5993                 {
5994                         // contexts where an LValue is valid have already devolved to FieldExprs
5995                         Error_CannotAssign (ec);
5996                         return null;
5997                 }
5998
5999                 protected override Expression DoResolve (ResolveContext ec)
6000                 {
6001                         eclass = ExprClass.EventAccess;
6002
6003                         bool must_do_cs1540_check;
6004                         if (!(IsAccessorAccessible (ec.CurrentType, add_accessor, out must_do_cs1540_check) &&
6005                               IsAccessorAccessible (ec.CurrentType, remove_accessor, out must_do_cs1540_check))) {
6006                                 ec.Report.SymbolRelatedToPreviousError (EventInfo);
6007                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo), ec.Report);
6008                                 return null;
6009                         }
6010
6011                         if (!InstanceResolve (ec, must_do_cs1540_check))
6012                                 return null;
6013
6014                         if (!ec.HasSet (ResolveContext.Options.CompoundAssignmentScope)) {
6015                                 Error_CannotAssign (ec);
6016                                 return null;
6017                         }
6018
6019                         if (!ec.IsObsolete) {
6020                                 EventField ev = TypeManager.GetEventField (EventInfo);
6021                                 if (ev != null) {
6022                                         ev.CheckObsoleteness (loc);
6023                                 } else {
6024                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (EventInfo);
6025                                         if (oa != null)
6026                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, ec.Report);
6027                                 }
6028                         }
6029
6030                         return this;
6031                 }
6032
6033                 public override void Emit (EmitContext ec)
6034                 {
6035                         throw new NotSupportedException ();
6036                         //Error_CannotAssign ();
6037                 }
6038
6039                 public void Error_CannotAssign (ResolveContext ec)
6040                 {
6041                         ec.Report.Error (70, loc,
6042                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
6043                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
6044                 }
6045
6046                 public override string GetSignatureForError ()
6047                 {
6048                         return TypeManager.CSharpSignature (EventInfo);
6049                 }
6050
6051                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
6052                 {
6053                         Arguments args = new Arguments (1);
6054                         args.Add (new Argument (source));
6055                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
6056                 }
6057         }
6058
6059         public class TemporaryVariable : VariableReference
6060         {
6061                 LocalInfo li;
6062
6063                 public TemporaryVariable (Type type, Location loc)
6064                 {
6065                         this.type = type;
6066                         this.loc = loc;
6067                 }
6068
6069                 public override Expression CreateExpressionTree (ResolveContext ec)
6070                 {
6071                         throw new NotSupportedException ("ET");
6072                 }
6073
6074                 protected override Expression DoResolve (ResolveContext ec)
6075                 {
6076                         eclass = ExprClass.Variable;
6077
6078                         TypeExpr te = new TypeExpression (type, loc);
6079                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
6080                         if (!li.Resolve (ec))
6081                                 return null;
6082
6083                         //
6084                         // Don't capture temporary variables except when using
6085                         // iterator redirection
6086                         //
6087                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
6088                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
6089                                 storey.CaptureLocalVariable (ec, li);
6090                         }
6091
6092                         return this;
6093                 }
6094
6095                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
6096                 {
6097                         return Resolve (ec);
6098                 }
6099
6100                 public override void Emit (EmitContext ec)
6101                 {
6102                         Emit (ec, false);
6103                 }
6104
6105                 public void EmitAssign (EmitContext ec, Expression source)
6106                 {
6107                         EmitAssign (ec, source, false, false);
6108                 }
6109
6110                 public override HoistedVariable GetHoistedVariable (AnonymousExpression ae)
6111                 {
6112                         return li.HoistedVariant;
6113                 }
6114
6115                 public override bool IsFixed {
6116                         get { return true; }
6117                 }
6118
6119                 public override bool IsRef {
6120                         get { return false; }
6121                 }
6122
6123                 public override string Name {
6124                         get { throw new NotImplementedException (); }
6125                 }
6126
6127                 public override void SetHasAddressTaken ()
6128                 {
6129                         throw new NotImplementedException ();
6130                 }
6131
6132                 protected override ILocalVariable Variable {
6133                         get { return li; }
6134                 }
6135
6136                 public override VariableInfo VariableInfo {
6137                         get { throw new NotImplementedException (); }
6138                 }
6139         }
6140
6141         ///
6142         /// Handles `var' contextual keyword; var becomes a keyword only
6143         /// if no type called var exists in a variable scope
6144         ///
6145         class VarExpr : SimpleName
6146         {
6147                 // Used for error reporting only
6148                 int initializers_count;
6149
6150                 public VarExpr (Location loc)
6151                         : base ("var", loc)
6152                 {
6153                         initializers_count = 1;
6154                 }
6155
6156                 public int VariableInitializersCount {
6157                         set {
6158                                 this.initializers_count = value;
6159                         }
6160                 }
6161
6162                 public bool InferType (ResolveContext ec, Expression right_side)
6163                 {
6164                         if (type != null)
6165                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
6166
6167                         type = right_side.Type;
6168                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == InternalType.AnonymousMethod || type == InternalType.MethodGroup) {
6169                                 ec.Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
6170                                               right_side.GetSignatureForError ());
6171                                 return false;
6172                         }
6173
6174                         eclass = ExprClass.Variable;
6175                         return true;
6176                 }
6177
6178                 protected override void Error_TypeOrNamespaceNotFound (IMemberContext ec)
6179                 {
6180                         if (RootContext.Version < LanguageVersion.V_3)
6181                                 base.Error_TypeOrNamespaceNotFound (ec);
6182                         else
6183                                 ec.Compiler.Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
6184                 }
6185
6186                 public override TypeExpr ResolveAsContextualType (IMemberContext rc, bool silent)
6187                 {
6188                         TypeExpr te = base.ResolveAsContextualType (rc, true);
6189                         if (te != null)
6190                                 return te;
6191
6192                         if (RootContext.Version < LanguageVersion.V_3)
6193                                 rc.Compiler.Report.FeatureIsNotAvailable (loc, "implicitly typed local variable");
6194
6195                         if (initializers_count == 1)
6196                                 return null;
6197
6198                         if (initializers_count > 1) {
6199                                 rc.Compiler.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
6200                                 initializers_count = 1;
6201                                 return null;
6202                         }
6203
6204                         if (initializers_count == 0) {
6205                                 initializers_count = 1;
6206                                 rc.Compiler.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
6207                                 return null;
6208                         }
6209
6210                         return null;
6211                 }
6212         }
6213 }