mcs/mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001, 2002, 2003 Ximian, Inc.
   9 //
  10 //
  11
  12 namespace Mono.CSharp {
  13         using System;
  14         using System.Collections;
  15         using System.Diagnostics;
  16         using System.Reflection;
  17         using System.Reflection.Emit;
  18         using System.Text;
  19
  20         /// <remarks>
  21         ///   The ExprClass class contains the is used to pass the
  22         ///   classification of an expression (value, variable, namespace,
  23         ///   type, method group, property access, event access, indexer access,
  24         ///   nothing).
  25         /// </remarks>
  26         public enum ExprClass : byte {
  27                 Invalid,
  28
  29                 Value,
  30                 Variable,
  31                 Namespace,
  32                 Type,
  33                 MethodGroup,
  34                 PropertyAccess,
  35                 EventAccess,
  36                 IndexerAccess,
  37                 Nothing,
  38         }
  39
  40         /// <remarks>
  41         ///   This is used to tell Resolve in which types of expressions we're
  42         ///   interested.
  43         /// </remarks>
  44         [Flags]
  45         public enum ResolveFlags {
  46                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  47                 VariableOrValue         = 1,
  48
  49                 // Returns a type expression.
  50                 Type                    = 2,
  51
  52                 // Returns a method group.
  53                 MethodGroup             = 4,
  54
  55                 // Mask of all the expression class flags.
  56                 MaskExprClass           = 7,
  57
  58                 // Disable control flow analysis while resolving the expression.
  59                 // This is used when resolving the instance expression of a field expression.
  60                 DisableFlowAnalysis     = 8,
  61
  62                 // Set if this is resolving the first part of a MemberAccess.
  63                 Intermediate            = 16,
  64
  65                 // Disable control flow analysis _of struct_ while resolving the expression.
  66                 // This is used when resolving the instance expression of a field expression.
  67                 DisableStructFlowAnalysis       = 32,
  68
  69         }
  70
  71         //
  72         // This is just as a hint to AddressOf of what will be done with the
  73         // address.
  74         [Flags]
  75         public enum AddressOp {
  76                 Store = 1,
  77                 Load  = 2,
  78                 LoadStore = 3
  79         };
  80
  81         /// <summary>
  82         ///   This interface is implemented by variables
  83         /// </summary>
  84         public interface IMemoryLocation {
  85                 /// <summary>
  86                 ///   The AddressOf method should generate code that loads
  87                 ///   the address of the object and leaves it on the stack.
  88                 ///
  89                 ///   The `mode' argument is used to notify the expression
  90                 ///   of whether this will be used to read from the address or
  91                 ///   write to the address.
  92                 ///
  93                 ///   This is just a hint that can be used to provide good error
  94                 ///   reporting, and should have no other side effects.
  95                 /// </summary>
  96                 void AddressOf (EmitContext ec, AddressOp mode);
  97         }
  98
  99         /// <summary>
 100         ///   This interface is implemented by variables
 101         /// </summary>
 102         public interface IVariable {
 103                 VariableInfo VariableInfo {
 104                         get;
 105                 }
 106
 107                 bool VerifyFixed ();
 108         }
 109
 110         /// <remarks>
 111         ///   Base class for expressions
 112         /// </remarks>
 113         public abstract class Expression {
 114                 public ExprClass eclass;
 115                 protected Type type;
 116                 protected Location loc;
 117
 118                 public Type Type {
 119                         get { return type; }
 120                         set { type = value; }
 121                 }
 122
 123                 public virtual Location Location {
 124                         get { return loc; }
 125                 }
 126
 127                 /// <summary>
 128                 ///   Utility wrapper routine for Error, just to beautify the code
 129                 /// </summary>
 130                 public void Error (int error, string s)
 131                 {
 132                         Report.Error (error, loc, s);
 133                 }
 134
 135                 // Not nice but we have broken hierarchy.
 136                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 137                 {
 138                 }
 139
 140                 public virtual bool GetAttributableValue (Type value_type, out object value)
 141                 {
 142                         Attribute.Error_AttributeArgumentNotValid (loc);
 143                         value = null;
 144                         return false;
 145                 }
 146
 147                 public virtual string GetSignatureForError ()
 148                 {
 149                         return TypeManager.CSharpName (type);
 150                 }
 151
 152                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 153                 {
 154                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 155
 156                         must_do_cs1540_check = false; // by default we do not check for this
 157
 158                         if (ma == MethodAttributes.Public)
 159                                 return true;
 160
 161                         //
 162                         // If only accessible to the current class or children
 163                         //
 164                         if (ma == MethodAttributes.Private)
 165                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 166                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 167
 168                         if (mi.DeclaringType.Assembly == invocation_type.Assembly ||
 169                                         TypeManager.IsFriendAssembly (mi.DeclaringType.Assembly)) {
 170                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 171                                         return true;
 172                         } else {
 173                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 174                                         return false;
 175                         }
 176
 177                         // Family and FamANDAssem require that we derive.
 178                         // FamORAssem requires that we derive if in different assemblies.
 179                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 180                                 return false;
 181
 182                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 183                                 must_do_cs1540_check = true;
 184
 185                         return true;
 186                 }
 187
 188                 public virtual bool IsNull {
 189                         get {
 190                                 return false;
 191                         }
 192                 }
 193
 194                 /// <summary>
 195                 ///   Performs semantic analysis on the Expression
 196                 /// </summary>
 197                 ///
 198                 /// <remarks>
 199                 ///   The Resolve method is invoked to perform the semantic analysis
 200                 ///   on the node.
 201                 ///
 202                 ///   The return value is an expression (it can be the
 203                 ///   same expression in some cases) or a new
 204                 ///   expression that better represents this node.
 205                 ///
 206                 ///   For example, optimizations of Unary (LiteralInt)
 207                 ///   would return a new LiteralInt with a negated
 208                 ///   value.
 209                 ///
 210                 ///   If there is an error during semantic analysis,
 211                 ///   then an error should be reported (using Report)
 212                 ///   and a null value should be returned.
 213                 ///
 214                 ///   There are two side effects expected from calling
 215                 ///   Resolve(): the the field variable "eclass" should
 216                 ///   be set to any value of the enumeration
 217                 ///   `ExprClass' and the type variable should be set
 218                 ///   to a valid type (this is the type of the
 219                 ///   expression).
 220                 /// </remarks>
 221                 public abstract Expression DoResolve (EmitContext ec);
 222
 223                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 224                 {
 225                         return null;
 226                 }
 227
 228                 //
 229                 // This is used if the expression should be resolved as a type or namespace name.
 230                 // the default implementation fails.
 231                 //
 232                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext ec,  bool silent)
 233                 {
 234                         return null;
 235                 }
 236
 237                 //
 238                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 239                 // same name exists or as a keyword when no type was found
 240                 //
 241                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 242                 {
 243                         return ResolveAsTypeTerminal (rc, silent);
 244                 }
 245
 246                 //
 247                 // This is used to resolve the expression as a type, a null
 248                 // value will be returned if the expression is not a type
 249                 // reference
 250                 //
 251                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 252                 {
 253                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 254                         if (te == null)
 255                                 return null;
 256
 257                         if (!silent) { // && !(te is TypeParameterExpr)) {
 258                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 259                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 260                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 261                                 }
 262                         }
 263
 264                         // Constrains don't need to be checked for overrides
 265                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 266                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 267                                 te.loc = loc;
 268                                 return te;
 269                         }
 270
 271                         ConstructedType ct = te as ConstructedType;
 272                         if ((ct != null) && !ct.CheckConstraints (ec))
 273                                 return null;
 274
 275                         return te;
 276                 }
 277
 278                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 279                 {
 280                         int errors = Report.Errors;
 281
 282                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 283
 284                         if (fne == null)
 285                                 return null;
 286
 287                         if (fne.eclass != ExprClass.Type) {
 288                                 if (!silent && errors == Report.Errors)
 289                                         fne.Error_UnexpectedKind (null, "type", loc);
 290                                 return null;
 291                         }
 292
 293                         TypeExpr te = fne as TypeExpr;
 294
 295                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 296                                 Report.SymbolRelatedToPreviousError (te.Type);
 297                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 298                                 return null;
 299                         }
 300
 301                         te.loc = loc;
 302                         return te;
 303                 }
 304
 305                 public static void ErrorIsInaccesible (Location loc, string name)
 306                 {
 307                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 308                 }
 309
 310                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 311                 {
 312                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 313                                 + " The qualifier must be of type `{2}' or derived from it",
 314                                 TypeManager.GetFullNameSignature (m),
 315                                 TypeManager.CSharpName (qualifier),
 316                                 TypeManager.CSharpName (container));
 317
 318                 }
 319
 320                 public static void Error_InvalidExpressionStatement (Location loc)
 321                 {
 322                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 323                                        "expressions can be used as a statement");
 324                 }
 325
 326                 public void Error_InvalidExpressionStatement ()
 327                 {
 328                         Error_InvalidExpressionStatement (loc);
 329                 }
 330
 331                 protected void Error_CannotAssign (string to, string roContext)
 332                 {
 333                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 334                                 to, roContext);
 335                 }
 336
 337                 public static void Error_VoidInvalidInTheContext (Location loc)
 338                 {
 339                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 340                 }
 341
 342                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 343                 {
 344                         // The error was already reported as CS1660
 345                         if (type == TypeManager.anonymous_method_type)
 346                                 return;
 347
 348                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 349 #if GMCS_SOURCE
 350                                 string sig1 = Type.DeclaringMethod == null ?
 351                                         TypeManager.CSharpName (Type.DeclaringType) :
 352                                         TypeManager.CSharpSignature (Type.DeclaringMethod);
 353                                 string sig2 = target.DeclaringMethod == null ?
 354                                         TypeManager.CSharpName (target.DeclaringType) :
 355                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 356                                 Report.ExtraInformation (loc,
 357                                         String.Format (
 358                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 359                                                 Type.Name, sig1, sig2));
 360 #endif
 361                         } else if (Type.FullName == target.FullName){
 362                                 Report.ExtraInformation (loc,
 363                                         String.Format (
 364                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 365                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 366                         }
 367
 368                         if (expl) {
 369                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 370                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 371                                 return;
 372                         }
 373
 374                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 375                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 376
 377                         if (b ||
 378                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 379                             Convert.ExplicitUnsafe (e, target) != null ||
 380                             (ec != null && Convert.UserDefinedConversion (ec, this, target, Location.Null, true) != null))
 381                         {
 382                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 383                                               "An explicit conversion exists (are you missing a cast?)",
 384                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 385                                 return;
 386                         }
 387
 388                         if (Type != TypeManager.string_type && this is Constant && !(this is EmptyConstantCast)) {
 389                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 390                                         ((Constant)(this)).GetValue ().ToString (), TypeManager.CSharpName (target));
 391                                 return;
 392                         }
 393
 394                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 395                                 TypeManager.CSharpName (type),
 396                                 TypeManager.CSharpName (target));
 397                 }
 398
 399                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 400                 {
 401                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 402                                 name);
 403                 }
 404
 405                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 406                 {
 407                         Error_TypeDoesNotContainDefinition (loc, type, name);
 408                 }
 409
 410                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 411                 {
 412                         Report.SymbolRelatedToPreviousError (type);
 413                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 414                                 TypeManager.CSharpName (type), name);
 415                 }
 416
 417                 protected static void Error_ValueAssignment (Location loc)
 418                 {
 419                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 420                 }
 421
 422                 ResolveFlags ExprClassToResolveFlags
 423                 {
 424                         get {
 425                                 switch (eclass) {
 426                                         case ExprClass.Type:
 427                                         case ExprClass.Namespace:
 428                                                 return ResolveFlags.Type;
 429
 430                                         case ExprClass.MethodGroup:
 431                                                 return ResolveFlags.MethodGroup;
 432
 433                                         case ExprClass.Value:
 434                                         case ExprClass.Variable:
 435                                         case ExprClass.PropertyAccess:
 436                                         case ExprClass.EventAccess:
 437                                         case ExprClass.IndexerAccess:
 438                                                 return ResolveFlags.VariableOrValue;
 439
 440                                         default:
 441                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 442                                 }
 443                         }
 444                 }
 445
 446                 /// <summary>
 447                 ///   Resolves an expression and performs semantic analysis on it.
 448                 /// </summary>
 449                 ///
 450                 /// <remarks>
 451                 ///   Currently Resolve wraps DoResolve to perform sanity
 452                 ///   checking and assertion checking on what we expect from Resolve.
 453                 /// </remarks>
 454                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 455                 {
 456                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 457                                 return ResolveAsTypeStep (ec, false);
 458
 459                         bool do_flow_analysis = ec.DoFlowAnalysis;
 460                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 461                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 462                                 do_flow_analysis = false;
 463                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 464                                 omit_struct_analysis = true;
 465
 466                         Expression e;
 467                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 468                                 if (this is SimpleName) {
 469                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 470                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 471                                 } else {
 472                                         e = DoResolve (ec);
 473                                 }
 474                         }
 475
 476                         if (e == null)
 477                                 return null;
 478
 479                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 480                                 e.Error_UnexpectedKind (flags, loc);
 481                                 return null;
 482                         }
 483
 484                         if (e.type == null && !(e is Namespace)) {
 485                                 throw new Exception (
 486                                         "Expression " + e.GetType () +
 487                                         " did not set its type after Resolve\n" +
 488                                         "called from: " + this.GetType ());
 489                         }
 490
 491                         return e;
 492                 }
 493
 494                 /// <summary>
 495                 ///   Resolves an expression and performs semantic analysis on it.
 496                 /// </summary>
 497                 public Expression Resolve (EmitContext ec)
 498                 {
 499                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 500
 501                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 502                                 ((MethodGroupExpr) e).ReportUsageError ();
 503                                 return null;
 504                         }
 505                         return e;
 506                 }
 507
 508                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 509                 {
 510                         Expression e = Resolve (ec);
 511                         if (e == null)
 512                                 return null;
 513
 514                         Constant c = e as Constant;
 515                         if (c != null)
 516                                 return c;
 517
 518                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 519                         return null;
 520                 }
 521
 522                 /// <summary>
 523                 ///   Resolves an expression for LValue assignment
 524                 /// </summary>
 525                 ///
 526                 /// <remarks>
 527                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 528                 ///   checking and assertion checking on what we expect from Resolve
 529                 /// </remarks>
 530                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 531                 {
 532                         int errors = Report.Errors;
 533                         bool out_access = right_side == EmptyExpression.OutAccess;
 534
 535                         Expression e = DoResolveLValue (ec, right_side);
 536
 537                         if (e != null && out_access && !(e is IMemoryLocation)) {
 538                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 539                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 540
 541                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 542                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 543                                 e = null;
 544                         }
 545
 546                         if (e == null) {
 547                                 if (errors == Report.Errors) {
 548                                         if (out_access)
 549                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 550                                         else
 551                                                 Error_ValueAssignment (loc);
 552                                 }
 553                                 return null;
 554                         }
 555
 556                         if (e.eclass == ExprClass.Invalid)
 557                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 558
 559                         if (e.eclass == ExprClass.MethodGroup) {
 560                                 ((MethodGroupExpr) e).ReportUsageError ();
 561                                 return null;
 562                         }
 563
 564                         if ((e.type == null) && !(e is ConstructedType))
 565                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 566
 567                         return e;
 568                 }
 569
 570                 /// <summary>
 571                 ///   Emits the code for the expression
 572                 /// </summary>
 573                 ///
 574                 /// <remarks>
 575                 ///   The Emit method is invoked to generate the code
 576                 ///   for the expression.
 577                 /// </remarks>
 578                 public abstract void Emit (EmitContext ec);
 579
 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                 /// <summary>
 587                 ///   Protected constructor.  Only derivate types should
 588                 ///   be able to be created
 589                 /// </summary>
 590
 591                 protected Expression ()
 592                 {
 593                         eclass = ExprClass.Invalid;
 594                         type = null;
 595                 }
 596
 597                 /// <summary>
 598                 ///   Returns a fully formed expression after a MemberLookup
 599                 /// </summary>
 600                 ///
 601                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 602                 {
 603                         if (mi is EventInfo)
 604                                 return new EventExpr ((EventInfo) mi, loc);
 605                         else if (mi is FieldInfo) {
 606                                 FieldInfo fi = (FieldInfo) mi;
 607                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 608                                         return new ConstantExpr (fi, loc);
 609                                 return new FieldExpr (fi, loc);
 610                         } else if (mi is PropertyInfo)
 611                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 612                         else if (mi is Type) {
 613                                 return new TypeExpression ((System.Type) mi, loc);
 614                         }
 615
 616                         return null;
 617                 }
 618
 619                 protected static ArrayList almost_matched_members = new ArrayList (4);
 620
 621                 //
 622                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 623                 //
 624                 // This code could use some optimizations, but we need to do some
 625                 // measurements.  For example, we could use a delegate to `flag' when
 626                 // something can not any longer be a method-group (because it is something
 627                 // else).
 628                 //
 629                 // Return values:
 630                 //     If the return value is an Array, then it is an array of
 631                 //     MethodBases
 632                 //
 633                 //     If the return value is an MemberInfo, it is anything, but a Method
 634                 //
 635                 //     null on error.
 636                 //
 637                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 638                 // the arguments here and have MemberLookup return only the methods that
 639                 // match the argument count/type, unlike we are doing now (we delay this
 640                 // decision).
 641                 //
 642                 // This is so we can catch correctly attempts to invoke instance methods
 643                 // from a static body (scan for error 120 in ResolveSimpleName).
 644                 //
 645                 //
 646                 // FIXME: Potential optimization, have a static ArrayList
 647                 //
 648
 649                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 650                                                        MemberTypes mt, BindingFlags bf, Location loc)
 651                 {
 652                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 653                 }
 654
 655                 //
 656                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 657                 // `qualifier_type' or null to lookup members in the current class.
 658                 //
 659
 660                 public static Expression MemberLookup (Type container_type,
 661                                                        Type qualifier_type, Type queried_type,
 662                                                        string name, MemberTypes mt,
 663                                                        BindingFlags bf, Location loc)
 664                 {
 665                         almost_matched_members.Clear ();
 666
 667                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 668                                                                      queried_type, mt, bf, name, almost_matched_members);
 669
 670                         if (mi == null)
 671                                 return null;
 672
 673                         if (mi.Length > 1) {
 674                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 675                                 ArrayList methods = new ArrayList (2);
 676                                 ArrayList non_methods = null;
 677
 678                                 foreach (MemberInfo m in mi) {
 679                                         if (m is MethodBase) {
 680                                                 methods.Add (m);
 681                                                 continue;
 682                                         }
 683
 684                                         if (non_methods == null) {
 685                                                 non_methods = new ArrayList (2);
 686                                                 non_methods.Add (m);
 687                                                 continue;
 688                                         }
 689
 690                                         foreach (MemberInfo n_m in non_methods) {
 691                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 692                                                         continue;
 693
 694                                                 Report.SymbolRelatedToPreviousError (m);
 695                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 696                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 697                                                 return null;
 698                                         }
 699                                 }
 700
 701                                 if (methods.Count == 0)
 702                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 703
 704                                 if (non_methods != null) {
 705                                         MethodBase method = (MethodBase) methods [0];
 706                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 707                                         if (method.DeclaringType == non_method.DeclaringType) {
 708                                                 // Cannot happen with C# code, but is valid in IL
 709                                                 Report.SymbolRelatedToPreviousError (method);
 710                                                 Report.SymbolRelatedToPreviousError (non_method);
 711                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 712                                                               TypeManager.GetFullNameSignature (non_method),
 713                                                               TypeManager.CSharpSignature (method));
 714                                                 return null;
 715                                         }
 716
 717                                         if (is_interface) {
 718                                                 Report.SymbolRelatedToPreviousError (method);
 719                                                 Report.SymbolRelatedToPreviousError (non_method);
 720                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 721                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 722                                         }
 723                                 }
 724
 725                                 return new MethodGroupExpr (methods, queried_type, loc);
 726                         }
 727
 728                         if (mi [0] is MethodBase)
 729                                 return new MethodGroupExpr (mi, queried_type, loc);
 730
 731                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 732                 }
 733
 734                 public const MemberTypes AllMemberTypes =
 735                         MemberTypes.Constructor |
 736                         MemberTypes.Event       |
 737                         MemberTypes.Field       |
 738                         MemberTypes.Method      |
 739                         MemberTypes.NestedType  |
 740                         MemberTypes.Property;
 741
 742                 public const BindingFlags AllBindingFlags =
 743                         BindingFlags.Public |
 744                         BindingFlags.Static |
 745                         BindingFlags.Instance;
 746
 747                 public static Expression MemberLookup (Type container_type, Type queried_type,
 748                                                        string name, Location loc)
 749                 {
 750                         return MemberLookup (container_type, null, queried_type, name,
 751                                              AllMemberTypes, AllBindingFlags, loc);
 752                 }
 753
 754                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 755                                                        Type queried_type, string name, Location loc)
 756                 {
 757                         return MemberLookup (container_type, qualifier_type, queried_type,
 758                                              name, AllMemberTypes, AllBindingFlags, loc);
 759                 }
 760
 761                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 762                                                        string name, Location loc)
 763                 {
 764                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 765                                              MemberTypes.Method, AllBindingFlags, loc);
 766                 }
 767
 768                 /// <summary>
 769                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 770                 ///   to find a final definition.  If the final definition is not found, we
 771                 ///   look for private members and display a useful debugging message if we
 772                 ///   find it.
 773                 /// </summary>
 774                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 775                                                             Type queried_type, string name,
 776                                                             MemberTypes mt, BindingFlags bf,
 777                                                             Location loc)
 778                 {
 779                         Expression e;
 780
 781                         int errors = Report.Errors;
 782
 783                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 784
 785                         if (e != null || errors != Report.Errors)
 786                                 return e;
 787
 788                         // No errors were reported by MemberLookup, but there was an error.
 789                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 790                                         name, null, mt, bf);
 791                 }
 792
 793                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 794                                                        Type queried_type, string name, string class_name,
 795                                                            MemberTypes mt, BindingFlags bf)
 796                 {
 797                         if (almost_matched_members.Count != 0) {
 798                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 799                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 800                                         for (int j = 0; j < i; ++j) {
 801                                                 if (m == almost_matched_members [j]) {
 802                                                         m = null;
 803                                                         break;
 804                                                 }
 805                                         }
 806                                         if (m == null)
 807                                                 continue;
 808
 809                                         Type declaring_type = m.DeclaringType;
 810
 811                                         Report.SymbolRelatedToPreviousError (m);
 812                                         if (qualifier_type == null) {
 813                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 814                                                               TypeManager.CSharpName (m.DeclaringType),
 815                                                               TypeManager.CSharpName (container_type));
 816
 817                                         } else if (qualifier_type != container_type &&
 818                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 819                                                 // Although a derived class can access protected members of
 820                                                 // its base class it cannot do so through an instance of the
 821                                                 // base class (CS1540).  If the qualifier_type is a base of the
 822                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 823                                                 // then we are in this situation.
 824                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 825                                         } else {
 826                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 827                                         }
 828                                 }
 829                                 almost_matched_members.Clear ();
 830                                 return null;
 831                         }
 832
 833                         MemberInfo[] lookup = null;
 834                         if (queried_type == null) {
 835                                 class_name = "global::";
 836                         } else {
 837                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 838                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 839                                         name, null);
 840
 841                                 if (lookup != null) {
 842                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 843                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 844                                         return Error_MemberLookupFailed (lookup);
 845                                 }
 846
 847                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 848                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 849                                         name, null);
 850                         }
 851
 852                         if (lookup == null) {
 853                                 if (class_name != null) {
 854                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 855                                                 name);
 856                                 } else {
 857                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 858                                 }
 859                                 return null;
 860                         }
 861
 862                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 863                                                       AllMemberTypes, AllBindingFlags |
 864                                                       BindingFlags.NonPublic, name, null) == null) {
 865                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 866                                         Type t = (Type) lookup [0];
 867
 868                                         Report.Error (305, loc,
 869                                                       "Using the generic type `{0}' " +
 870                                                       "requires {1} type arguments",
 871                                                       TypeManager.CSharpName (t),
 872                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 873                                         return null;
 874                                 }
 875                         }
 876
 877                         return Error_MemberLookupFailed (lookup);
 878                 }
 879
 880                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 881                 {
 882                         for (int i = 0; i < members.Length; ++i) {
 883                                 if (!(members [i] is MethodBase))
 884                                         return null;
 885                         }
 886
 887                         // By default propagate the closest candidates upwards
 888                         return new MethodGroupExpr (members, type, loc);
 889                 }
 890
 891                 /// <summary>
 892                 ///   Returns an expression that can be used to invoke operator true
 893                 ///   on the expression if it exists.
 894                 /// </summary>
 895                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 896                 {
 897                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 898                 }
 899
 900                 /// <summary>
 901                 ///   Returns an expression that can be used to invoke operator false
 902                 ///   on the expression if it exists.
 903                 /// </summary>
 904                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 905                 {
 906                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 907                 }
 908
 909                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 910                 {
 911                         MethodGroupExpr operator_group;
 912
 913 #if GMCS_SOURCE
 914                         if (TypeManager.IsNullableType (e.Type))
 915                                 return new Nullable.OperatorTrueOrFalse (e, is_true, loc).Resolve (ec);
 916 #endif
 917
 918                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 919                         if (operator_group == null)
 920                                 return null;
 921
 922                         ArrayList arguments = new ArrayList (1);
 923                         arguments.Add (new Argument (e, Argument.AType.Expression));
 924                         operator_group = operator_group.OverloadResolve (
 925                                 ec, arguments, false, loc);
 926
 927                         if (operator_group == null)
 928                                 return null;
 929
 930                         return new StaticCallExpr ((MethodInfo) operator_group, arguments, loc);
 931                 }
 932
 933                 /// <summary>
 934                 ///   Resolves the expression `e' into a boolean expression: either through
 935                 ///   an implicit conversion, or through an `operator true' invocation
 936                 /// </summary>
 937                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 938                 {
 939                         e = e.Resolve (ec);
 940                         if (e == null)
 941                                 return null;
 942
 943                         if (e.Type == TypeManager.bool_type)
 944                                 return e;
 945
 946                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 947
 948                         if (converted != null)
 949                                 return converted;
 950
 951                         //
 952                         // If no implicit conversion to bool exists, try using `operator true'
 953                         //
 954                         converted = Expression.GetOperatorTrue (ec, e, loc);
 955                         if (converted == null){
 956                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 957                                 return null;
 958                         }
 959                         return converted;
 960                 }
 961
 962                 public virtual string ExprClassName
 963                 {
 964                         get {
 965                                 switch (eclass){
 966                                         case ExprClass.Invalid:
 967                                                 return "Invalid";
 968                                         case ExprClass.Value:
 969                                                 return "value";
 970                                         case ExprClass.Variable:
 971                                                 return "variable";
 972                                         case ExprClass.Namespace:
 973                                                 return "namespace";
 974                                         case ExprClass.Type:
 975                                                 return "type";
 976                                         case ExprClass.MethodGroup:
 977                                                 return "method group";
 978                                         case ExprClass.PropertyAccess:
 979                                                 return "property access";
 980                                         case ExprClass.EventAccess:
 981                                                 return "event access";
 982                                         case ExprClass.IndexerAccess:
 983                                                 return "indexer access";
 984                                         case ExprClass.Nothing:
 985                                                 return "null";
 986                                 }
 987                                 throw new Exception ("Should not happen");
 988                         }
 989                 }
 990
 991                 /// <summary>
 992                 ///   Reports that we were expecting `expr' to be of class `expected'
 993                 /// </summary>
 994                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
 995                 {
 996                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
 997                 }
 998
 999                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1000                 {
1001                         string name = GetSignatureForError ();
1002                         if (ds != null)
1003                                 name = ds.GetSignatureForError () + '.' + name;
1004
1005                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1006                               name, was, expected);
1007                 }
1008
1009                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1010                 {
1011                         string [] valid = new string [4];
1012                         int count = 0;
1013
1014                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1015                                 valid [count++] = "variable";
1016                                 valid [count++] = "value";
1017                         }
1018
1019                         if ((flags & ResolveFlags.Type) != 0)
1020                                 valid [count++] = "type";
1021
1022                         if ((flags & ResolveFlags.MethodGroup) != 0)
1023                                 valid [count++] = "method group";
1024
1025                         if (count == 0)
1026                                 valid [count++] = "unknown";
1027
1028                         StringBuilder sb = new StringBuilder (valid [0]);
1029                         for (int i = 1; i < count - 1; i++) {
1030                                 sb.Append ("', `");
1031                                 sb.Append (valid [i]);
1032                         }
1033                         if (count > 1) {
1034                                 sb.Append ("' or `");
1035                                 sb.Append (valid [count - 1]);
1036                         }
1037
1038                         Report.Error (119, loc,
1039                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1040                 }
1041
1042                 public static void UnsafeError (Location loc)
1043                 {
1044                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1045                 }
1046
1047                 //
1048                 // Load the object from the pointer.
1049                 //
1050                 public static void LoadFromPtr (ILGenerator ig, Type t)
1051                 {
1052                         if (t == TypeManager.int32_type)
1053                                 ig.Emit (OpCodes.Ldind_I4);
1054                         else if (t == TypeManager.uint32_type)
1055                                 ig.Emit (OpCodes.Ldind_U4);
1056                         else if (t == TypeManager.short_type)
1057                                 ig.Emit (OpCodes.Ldind_I2);
1058                         else if (t == TypeManager.ushort_type)
1059                                 ig.Emit (OpCodes.Ldind_U2);
1060                         else if (t == TypeManager.char_type)
1061                                 ig.Emit (OpCodes.Ldind_U2);
1062                         else if (t == TypeManager.byte_type)
1063                                 ig.Emit (OpCodes.Ldind_U1);
1064                         else if (t == TypeManager.sbyte_type)
1065                                 ig.Emit (OpCodes.Ldind_I1);
1066                         else if (t == TypeManager.uint64_type)
1067                                 ig.Emit (OpCodes.Ldind_I8);
1068                         else if (t == TypeManager.int64_type)
1069                                 ig.Emit (OpCodes.Ldind_I8);
1070                         else if (t == TypeManager.float_type)
1071                                 ig.Emit (OpCodes.Ldind_R4);
1072                         else if (t == TypeManager.double_type)
1073                                 ig.Emit (OpCodes.Ldind_R8);
1074                         else if (t == TypeManager.bool_type)
1075                                 ig.Emit (OpCodes.Ldind_I1);
1076                         else if (t == TypeManager.intptr_type)
1077                                 ig.Emit (OpCodes.Ldind_I);
1078                         else if (TypeManager.IsEnumType (t)) {
1079                                 if (t == TypeManager.enum_type)
1080                                         ig.Emit (OpCodes.Ldind_Ref);
1081                                 else
1082                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1083                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1084                                 ig.Emit (OpCodes.Ldobj, t);
1085                         else if (t.IsPointer)
1086                                 ig.Emit (OpCodes.Ldind_I);
1087                         else
1088                                 ig.Emit (OpCodes.Ldind_Ref);
1089                 }
1090
1091                 //
1092                 // The stack contains the pointer and the value of type `type'
1093                 //
1094                 public static void StoreFromPtr (ILGenerator ig, Type type)
1095                 {
1096                         if (TypeManager.IsEnumType (type))
1097                                 type = TypeManager.EnumToUnderlying (type);
1098                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1099                                 ig.Emit (OpCodes.Stind_I4);
1100                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1101                                 ig.Emit (OpCodes.Stind_I8);
1102                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1103                                  type == TypeManager.ushort_type)
1104                                 ig.Emit (OpCodes.Stind_I2);
1105                         else if (type == TypeManager.float_type)
1106                                 ig.Emit (OpCodes.Stind_R4);
1107                         else if (type == TypeManager.double_type)
1108                                 ig.Emit (OpCodes.Stind_R8);
1109                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1110                                  type == TypeManager.bool_type)
1111                                 ig.Emit (OpCodes.Stind_I1);
1112                         else if (type == TypeManager.intptr_type)
1113                                 ig.Emit (OpCodes.Stind_I);
1114                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1115                                 ig.Emit (OpCodes.Stobj, type);
1116                         else
1117                                 ig.Emit (OpCodes.Stind_Ref);
1118                 }
1119
1120                 //
1121                 // Returns the size of type `t' if known, otherwise, 0
1122                 //
1123                 public static int GetTypeSize (Type t)
1124                 {
1125                         t = TypeManager.TypeToCoreType (t);
1126                         if (t == TypeManager.int32_type ||
1127                             t == TypeManager.uint32_type ||
1128                             t == TypeManager.float_type)
1129                                 return 4;
1130                         else if (t == TypeManager.int64_type ||
1131                                  t == TypeManager.uint64_type ||
1132                                  t == TypeManager.double_type)
1133                                 return 8;
1134                         else if (t == TypeManager.byte_type ||
1135                                  t == TypeManager.sbyte_type ||
1136                                  t == TypeManager.bool_type)
1137                                 return 1;
1138                         else if (t == TypeManager.short_type ||
1139                                  t == TypeManager.char_type ||
1140                                  t == TypeManager.ushort_type)
1141                                 return 2;
1142                         else if (t == TypeManager.decimal_type)
1143                                 return 16;
1144                         else
1145                                 return 0;
1146                 }
1147
1148                 public static void Error_NegativeArrayIndex (Location loc)
1149                 {
1150                         Report.Error (248, loc, "Cannot create an array with a negative size");
1151                 }
1152
1153                 protected void Error_CannotCallAbstractBase (string name)
1154                 {
1155                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1156                 }
1157
1158                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1159                 {
1160                         Report.SymbolRelatedToPreviousError (type);
1161                         if (ec.CurrentInitializerVariable != null) {
1162                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1163                                         GetSignatureForError ());
1164                         } else {
1165                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1166                                         GetSignatureForError ());
1167                         }
1168                 }
1169
1170                 //
1171                 // Converts `source' to an int, uint, long or ulong.
1172                 //
1173                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1174                 {
1175                         Expression target;
1176
1177                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1178                                 target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1179                                 if (target == null)
1180                                         target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1181                                 if (target == null)
1182                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1183                                 if (target == null)
1184                                         target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1185
1186                                 if (target == null) {
1187                                         source.Error_ValueCannotBeConverted (ec, loc, TypeManager.int32_type, false);
1188                                         return null;
1189                                 }
1190                         }
1191
1192                         //
1193                         // Only positive constants are allowed at compile time
1194                         //
1195                         if (target is Constant){
1196                                 if (target is IntConstant){
1197                                         if (((IntConstant) target).Value < 0){
1198                                                 Error_NegativeArrayIndex (loc);
1199                                                 return null;
1200                                         }
1201                                 }
1202
1203                                 if (target is LongConstant){
1204                                         if (((LongConstant) target).Value < 0){
1205                                                 Error_NegativeArrayIndex (loc);
1206                                                 return null;
1207                                         }
1208                                 }
1209
1210                         }
1211
1212                         return target;
1213                 }
1214
1215                 //
1216                 // Derived classes implement this method by cloning the fields that
1217                 // could become altered during the Resolve stage
1218                 //
1219                 // Only expressions that are created for the parser need to implement
1220                 // this.
1221                 //
1222                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1223                 {
1224                         throw new NotImplementedException (
1225                                 String.Format (
1226                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1227                 }
1228
1229                 //
1230                 // Clones an expression created by the parser.
1231                 //
1232                 // We only support expressions created by the parser so far, not
1233                 // expressions that have been resolved (many more classes would need
1234                 // to implement CloneTo).
1235                 //
1236                 // This infrastructure is here merely for Lambda expressions which
1237                 // compile the same code using different type values for the same
1238                 // arguments to find the correct overload
1239                 //
1240                 public Expression Clone (CloneContext clonectx)
1241                 {
1242                         Expression cloned = (Expression) MemberwiseClone ();
1243                         CloneTo (clonectx, cloned);
1244
1245                         return cloned;
1246                 }
1247         }
1248
1249         /// <summary>
1250         ///   This is just a base class for expressions that can
1251         ///   appear on statements (invocations, object creation,
1252         ///   assignments, post/pre increment and decrement).  The idea
1253         ///   being that they would support an extra Emition interface that
1254         ///   does not leave a result on the stack.
1255         /// </summary>
1256         public abstract class ExpressionStatement : Expression {
1257
1258                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1259                 {
1260                         Expression e = Resolve (ec);
1261                         if (e == null)
1262                                 return null;
1263
1264                         ExpressionStatement es = e as ExpressionStatement;
1265                         if (es == null)
1266                                 Error_InvalidExpressionStatement ();
1267
1268                         return es;
1269                 }
1270
1271                 /// <summary>
1272                 ///   Requests the expression to be emitted in a `statement'
1273                 ///   context.  This means that no new value is left on the
1274                 ///   stack after invoking this method (constrasted with
1275                 ///   Emit that will always leave a value on the stack).
1276                 /// </summary>
1277                 public abstract void EmitStatement (EmitContext ec);
1278         }
1279
1280         /// <summary>
1281         ///   This kind of cast is used to encapsulate the child
1282         ///   whose type is child.Type into an expression that is
1283         ///   reported to return "return_type".  This is used to encapsulate
1284         ///   expressions which have compatible types, but need to be dealt
1285         ///   at higher levels with.
1286         ///
1287         ///   For example, a "byte" expression could be encapsulated in one
1288         ///   of these as an "unsigned int".  The type for the expression
1289         ///   would be "unsigned int".
1290         ///
1291         /// </summary>
1292         public class EmptyCast : Expression
1293         {
1294                 protected Expression child;
1295
1296                 protected EmptyCast (Expression child, Type return_type)
1297                 {
1298                         eclass = child.eclass;
1299                         loc = child.Location;
1300                         type = return_type;
1301                         this.child = child;
1302                 }
1303
1304                 public static Expression Create (Expression child, Type type)
1305                 {
1306                         Constant c = child as Constant;
1307                         if (c != null)
1308                                 return new EmptyConstantCast (c, type);
1309
1310                         return new EmptyCast (child, type);
1311                 }
1312
1313                 public override Expression DoResolve (EmitContext ec)
1314                 {
1315                         // This should never be invoked, we are born in fully
1316                         // initialized state.
1317
1318                         return this;
1319                 }
1320
1321                 public override void Emit (EmitContext ec)
1322                 {
1323                         child.Emit (ec);
1324                 }
1325
1326                 public override bool GetAttributableValue (Type value_type, out object value)
1327                 {
1328                         return child.GetAttributableValue (value_type, out value);
1329                 }
1330
1331                 protected override void CloneTo (CloneContext clonectx, Expression t)
1332                 {
1333                         EmptyCast target = (EmptyCast) t;
1334
1335                         target.child = child.Clone (clonectx);
1336                 }
1337         }
1338
1339         /// <summary>
1340         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1341         /// </summary>
1342         public class OperatorCast : EmptyCast {
1343                 MethodInfo conversion_operator;
1344                 bool find_explicit;
1345
1346                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1347
1348                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1349                         : base (child, target_type)
1350                 {
1351                         this.find_explicit = find_explicit;
1352                 }
1353
1354                 // Returns the implicit operator that converts from
1355                 // 'child.Type' to our target type (type)
1356                 MethodInfo GetConversionOperator (bool find_explicit)
1357                 {
1358                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1359
1360                         MemberInfo [] mi;
1361
1362                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1363                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1364
1365                         if (mi == null){
1366                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1367                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1368                         }
1369
1370                         foreach (MethodInfo oper in mi) {
1371                                 ParameterData pd = TypeManager.GetParameterData (oper);
1372
1373                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1374                                         return oper;
1375                         }
1376
1377                         return null;
1378
1379
1380                 }
1381                 public override void Emit (EmitContext ec)
1382                 {
1383                         ILGenerator ig = ec.ig;
1384
1385                         child.Emit (ec);
1386                         conversion_operator = GetConversionOperator (find_explicit);
1387
1388                         if (conversion_operator == null)
1389                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1390
1391                         ig.Emit (OpCodes.Call, conversion_operator);
1392                 }
1393
1394         }
1395
1396         /// <summary>
1397         ///     This is a numeric cast to a Decimal
1398         /// </summary>
1399         public class CastToDecimal : EmptyCast {
1400                 MethodInfo conversion_operator;
1401
1402                 public CastToDecimal (Expression child)
1403                         : this (child, false)
1404                 {
1405                 }
1406
1407                 public CastToDecimal (Expression child, bool find_explicit)
1408                         : base (child, TypeManager.decimal_type)
1409                 {
1410                         conversion_operator = GetConversionOperator (find_explicit);
1411
1412                         if (conversion_operator == null)
1413                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1414                 }
1415
1416                 // Returns the implicit operator that converts from
1417                 // 'child.Type' to System.Decimal.
1418                 MethodInfo GetConversionOperator (bool find_explicit)
1419                 {
1420                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1421
1422                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1423                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1424
1425                         foreach (MethodInfo oper in mi) {
1426                                 ParameterData pd = TypeManager.GetParameterData (oper);
1427
1428                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1429                                         return oper;
1430                         }
1431
1432                         return null;
1433                 }
1434                 public override void Emit (EmitContext ec)
1435                 {
1436                         ILGenerator ig = ec.ig;
1437                         child.Emit (ec);
1438
1439                         ig.Emit (OpCodes.Call, conversion_operator);
1440                 }
1441         }
1442
1443         /// <summary>
1444         ///     This is an explicit numeric cast from a Decimal
1445         /// </summary>
1446         public class CastFromDecimal : EmptyCast
1447         {
1448                 static IDictionary operators;
1449
1450                 public CastFromDecimal (Expression child, Type return_type)
1451                         : base (child, return_type)
1452                 {
1453                         if (child.Type != TypeManager.decimal_type)
1454                                 throw new InternalErrorException (
1455                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1456                 }
1457
1458                 // Returns the explicit operator that converts from an
1459                 // express of type System.Decimal to 'type'.
1460                 public Expression Resolve ()
1461                 {
1462                         if (operators == null) {
1463                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1464                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1465                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1466
1467                                 operators = new System.Collections.Specialized.HybridDictionary ();
1468                                 foreach (MethodInfo oper in all_oper) {
1469                                         ParameterData pd = TypeManager.GetParameterData (oper);
1470                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1471                                                 operators.Add (oper.ReturnType, oper);
1472                                 }
1473                         }
1474
1475                         return operators.Contains (type) ? this : null;
1476                 }
1477
1478                 public override void Emit (EmitContext ec)
1479                 {
1480                         ILGenerator ig = ec.ig;
1481                         child.Emit (ec);
1482
1483                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1484                 }
1485         }
1486
1487
1488         //
1489         // Constant specialization of EmptyCast.
1490         // We need to special case this since an empty cast of
1491         // a constant is still a constant.
1492         //
1493         public class EmptyConstantCast : Constant
1494         {
1495                 public readonly Constant child;
1496
1497                 public EmptyConstantCast(Constant child, Type type)
1498                         : base (child.Location)
1499                 {
1500                         eclass = child.eclass;
1501                         this.child = child;
1502                         this.type = type;
1503                 }
1504
1505                 public override string AsString ()
1506                 {
1507                         return child.AsString ();
1508                 }
1509
1510                 public override object GetValue ()
1511                 {
1512                         return child.GetValue ();
1513                 }
1514
1515                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1516                 {
1517                         // FIXME: check that 'type' can be converted to 'target_type' first
1518                         return child.ConvertExplicitly (in_checked_context, target_type);
1519                 }
1520
1521                 public override Constant Increment ()
1522                 {
1523                         return child.Increment ();
1524                 }
1525
1526                 public override bool IsDefaultValue {
1527                         get { return child.IsDefaultValue; }
1528                 }
1529
1530                 public override bool IsNegative {
1531                         get { return child.IsNegative; }
1532                 }
1533
1534                 public override bool IsNull {
1535                         get { return child.IsNull; }
1536                 }
1537
1538                 public override bool IsZeroInteger {
1539                         get { return child.IsZeroInteger; }
1540                 }
1541
1542                 public override void Emit (EmitContext ec)
1543                 {
1544                         child.Emit (ec);
1545                 }
1546
1547                 public override Constant ConvertImplicitly (Type target_type)
1548                 {
1549                         // FIXME: Do we need to check user conversions?
1550                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1551                                 return null;
1552                         return child.ConvertImplicitly (target_type);
1553                 }
1554         }
1555
1556
1557         /// <summary>
1558         ///  This class is used to wrap literals which belong inside Enums
1559         /// </summary>
1560         public class EnumConstant : Constant {
1561                 public Constant Child;
1562
1563                 public EnumConstant (Constant child, Type enum_type):
1564                         base (child.Location)
1565                 {
1566                         eclass = child.eclass;
1567                         this.Child = child;
1568                         type = enum_type;
1569                 }
1570
1571                 public override Expression DoResolve (EmitContext ec)
1572                 {
1573                         // This should never be invoked, we are born in fully
1574                         // initialized state.
1575
1576                         return this;
1577                 }
1578
1579                 public override void Emit (EmitContext ec)
1580                 {
1581                         Child.Emit (ec);
1582                 }
1583
1584                 public override bool GetAttributableValue (Type value_type, out object value)
1585                 {
1586                         value = GetTypedValue ();
1587                         return true;
1588                 }
1589
1590                 public override string GetSignatureForError()
1591                 {
1592                         return TypeManager.CSharpName (Type);
1593                 }
1594
1595                 public override object GetValue ()
1596                 {
1597                         return Child.GetValue ();
1598                 }
1599
1600                 public override object GetTypedValue ()
1601                 {
1602                         // FIXME: runtime is not ready to work with just emited enums
1603                         if (!RootContext.StdLib) {
1604                                 return Child.GetValue ();
1605                         }
1606
1607                         return System.Enum.ToObject (type, Child.GetValue ());
1608                 }
1609
1610                 public override string AsString ()
1611                 {
1612                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1613                 }
1614
1615                 public override Constant Increment()
1616                 {
1617                         return new EnumConstant (Child.Increment (), type);
1618                 }
1619
1620                 public override bool IsDefaultValue {
1621                         get {
1622                                 return Child.IsDefaultValue;
1623                         }
1624                 }
1625
1626                 public override bool IsZeroInteger {
1627                         get { return Child.IsZeroInteger; }
1628                 }
1629
1630                 public override bool IsNegative {
1631                         get {
1632                                 return Child.IsNegative;
1633                         }
1634                 }
1635
1636                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1637                 {
1638                         if (Child.Type == target_type)
1639                                 return Child;
1640
1641                         return Child.ConvertExplicitly (in_checked_context, target_type);
1642                 }
1643
1644                 public override Constant ConvertImplicitly (Type type)
1645                 {
1646                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1647                         type = TypeManager.DropGenericTypeArguments (type);
1648
1649                         if (this_type == type) {
1650                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1651                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1652                                         return this;
1653
1654                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1655                                 if (type.UnderlyingSystemType != child_type)
1656                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1657                                 return this;
1658                         }
1659
1660                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1661                                 return null;
1662                         }
1663
1664                         return Child.ConvertImplicitly(type);
1665                 }
1666
1667         }
1668
1669         /// <summary>
1670         ///   This kind of cast is used to encapsulate Value Types in objects.
1671         ///
1672         ///   The effect of it is to box the value type emitted by the previous
1673         ///   operation.
1674         /// </summary>
1675         public class BoxedCast : EmptyCast {
1676
1677                 public BoxedCast (Expression expr, Type target_type)
1678                         : base (expr, target_type)
1679                 {
1680                         eclass = ExprClass.Value;
1681                 }
1682
1683                 public override Expression DoResolve (EmitContext ec)
1684                 {
1685                         // This should never be invoked, we are born in fully
1686                         // initialized state.
1687
1688                         return this;
1689                 }
1690
1691                 public override void Emit (EmitContext ec)
1692                 {
1693                         base.Emit (ec);
1694
1695                         ec.ig.Emit (OpCodes.Box, child.Type);
1696                 }
1697         }
1698
1699         public class UnboxCast : EmptyCast {
1700                 public UnboxCast (Expression expr, Type return_type)
1701                         : base (expr, return_type)
1702                 {
1703                 }
1704
1705                 public override Expression DoResolve (EmitContext ec)
1706                 {
1707                         // This should never be invoked, we are born in fully
1708                         // initialized state.
1709
1710                         return this;
1711                 }
1712
1713                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1714                 {
1715                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1716                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1717                         return base.DoResolveLValue (ec, right_side);
1718                 }
1719
1720                 public override void Emit (EmitContext ec)
1721                 {
1722                         Type t = type;
1723                         ILGenerator ig = ec.ig;
1724
1725                         base.Emit (ec);
1726 #if GMCS_SOURCE
1727                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1728                                 ig.Emit (OpCodes.Unbox_Any, t);
1729                         else
1730 #endif
1731                         {
1732                                 ig.Emit (OpCodes.Unbox, t);
1733
1734                                 LoadFromPtr (ig, t);
1735                         }
1736                 }
1737         }
1738
1739         /// <summary>
1740         ///   This is used to perform explicit numeric conversions.
1741         ///
1742         ///   Explicit numeric conversions might trigger exceptions in a checked
1743         ///   context, so they should generate the conv.ovf opcodes instead of
1744         ///   conv opcodes.
1745         /// </summary>
1746         public class ConvCast : EmptyCast {
1747                 public enum Mode : byte {
1748                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1749                         U1_I1, U1_CH,
1750                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1751                         U2_I1, U2_U1, U2_I2, U2_CH,
1752                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1753                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1754                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1755                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1756                         CH_I1, CH_U1, CH_I2,
1757                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1758                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1759                 }
1760
1761                 Mode mode;
1762
1763                 public ConvCast (Expression child, Type return_type, Mode m)
1764                         : base (child, return_type)
1765                 {
1766                         mode = m;
1767                 }
1768
1769                 public override Expression DoResolve (EmitContext ec)
1770                 {
1771                         // This should never be invoked, we are born in fully
1772                         // initialized state.
1773
1774                         return this;
1775                 }
1776
1777                 public override string ToString ()
1778                 {
1779                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1780                 }
1781
1782                 public override void Emit (EmitContext ec)
1783                 {
1784                         ILGenerator ig = ec.ig;
1785
1786                         base.Emit (ec);
1787
1788                         if (ec.CheckState){
1789                                 switch (mode){
1790                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1791                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1792                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1793                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1794                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1795
1796                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1797                                 case Mode.U1_CH: /* nothing */ break;
1798
1799                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1800                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1801                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1802                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1803                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1804                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1805
1806                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1807                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1808                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1809                                 case Mode.U2_CH: /* nothing */ break;
1810
1811                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1812                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1813                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1814                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1815                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1816                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1817                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1818
1819                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1820                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1821                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1822                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1823                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1824                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1825
1826                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1827                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1828                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1829                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1830                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1831                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1832                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1833                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1834
1835                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1836                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1837                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1838                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1839                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1840                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1841                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1842                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1843
1844                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1845                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1846                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1847
1848                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1849                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1850                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1851                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1852                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1853                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1854                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1855                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1856                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1857
1858                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1859                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1860                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1861                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1862                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1863                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1864                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1865                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1866                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1867                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1868                                 }
1869                         } else {
1870                                 switch (mode){
1871                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1872                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1873                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1874                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1875                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1876
1877                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1878                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1879
1880                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1881                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1882                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1883                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1884                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1885                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1886
1887                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1888                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1889                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1890                                 case Mode.U2_CH: /* nothing */ break;
1891
1892                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1893                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1894                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1895                                 case Mode.I4_U4: /* nothing */ break;
1896                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1897                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1898                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1899
1900                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1901                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1902                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1903                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1904                                 case Mode.U4_I4: /* nothing */ break;
1905                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1906
1907                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1908                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1909                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1910                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1911                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1912                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1913                                 case Mode.I8_U8: /* nothing */ break;
1914                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1915
1916                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1917                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1918                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1919                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1920                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1921                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1922                                 case Mode.U8_I8: /* nothing */ break;
1923                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1924
1925                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1926                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1927                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1928
1929                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1930                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1931                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1932                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1933                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1934                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1935                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1936                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1937                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1938
1939                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1940                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1941                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1942                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1943                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1944                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1945                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1946                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1947                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1948                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1949                                 }
1950                         }
1951                 }
1952         }
1953
1954         public class OpcodeCast : EmptyCast {
1955                 OpCode op, op2;
1956                 bool second_valid;
1957
1958                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1959                         : base (child, return_type)
1960
1961                 {
1962                         this.op = op;
1963                         second_valid = false;
1964                 }
1965
1966                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1967                         : base (child, return_type)
1968
1969                 {
1970                         this.op = op;
1971                         this.op2 = op2;
1972                         second_valid = true;
1973                 }
1974
1975                 public override Expression DoResolve (EmitContext ec)
1976                 {
1977                         // This should never be invoked, we are born in fully
1978                         // initialized state.
1979
1980                         return this;
1981                 }
1982
1983                 public override void Emit (EmitContext ec)
1984                 {
1985                         base.Emit (ec);
1986                         ec.ig.Emit (op);
1987
1988                         if (second_valid)
1989                                 ec.ig.Emit (op2);
1990                 }
1991         }
1992
1993         /// <summary>
1994         ///   This kind of cast is used to encapsulate a child and cast it
1995         ///   to the class requested
1996         /// </summary>
1997         public class ClassCast : EmptyCast {
1998                 public ClassCast (Expression child, Type return_type)
1999                         : base (child, return_type)
2000
2001                 {
2002                 }
2003
2004                 public override Expression DoResolve (EmitContext ec)
2005                 {
2006                         // This should never be invoked, we are born in fully
2007                         // initialized state.
2008
2009                         return this;
2010                 }
2011
2012                 public override void Emit (EmitContext ec)
2013                 {
2014                         base.Emit (ec);
2015
2016                         if (TypeManager.IsGenericParameter (child.Type))
2017                                 ec.ig.Emit (OpCodes.Box, child.Type);
2018
2019 #if GMCS_SOURCE
2020                         if (type.IsGenericParameter)
2021                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2022                         else
2023 #endif
2024                                 ec.ig.Emit (OpCodes.Castclass, type);
2025                 }
2026         }
2027
2028         /// <summary>
2029         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2030         ///   of a dotted-name.
2031         /// </summary>
2032         public class SimpleName : Expression {
2033                 public readonly string Name;
2034                 public readonly TypeArguments Arguments;
2035                 bool in_transit;
2036
2037                 public SimpleName (string name, Location l)
2038                 {
2039                         Name = name;
2040                         loc = l;
2041                 }
2042
2043                 public SimpleName (string name, TypeArguments args, Location l)
2044                 {
2045                         Name = name;
2046                         Arguments = args;
2047                         loc = l;
2048                 }
2049
2050                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2051                 {
2052                         Name = name;
2053                         loc = l;
2054
2055                         Arguments = new TypeArguments (l);
2056                         foreach (TypeParameter type_param in type_params)
2057                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2058                 }
2059
2060                 public static string RemoveGenericArity (string name)
2061                 {
2062                         int start = 0;
2063                         StringBuilder sb = null;
2064                         do {
2065                                 int pos = name.IndexOf ('`', start);
2066                                 if (pos < 0) {
2067                                         if (start == 0)
2068                                                 return name;
2069
2070                                         sb.Append (name.Substring (start));
2071                                         break;
2072                                 }
2073
2074                                 if (sb == null)
2075                                         sb = new StringBuilder ();
2076                                 sb.Append (name.Substring (start, pos-start));
2077
2078                                 pos++;
2079                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2080                                         pos++;
2081
2082                                 start = pos;
2083                         } while (start < name.Length);
2084
2085                         return sb.ToString ();
2086                 }
2087
2088                 public SimpleName GetMethodGroup ()
2089                 {
2090                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2091                 }
2092
2093                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2094                 {
2095                         if (ec.IsInFieldInitializer)
2096                                 Report.Error (236, l,
2097                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2098                                         name);
2099                         else
2100                                 Report.Error (
2101                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2102                                         name);
2103                 }
2104
2105                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2106                 {
2107                         return resolved_to != null && resolved_to.Type != null &&
2108                                 resolved_to.Type.Name == Name &&
2109                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2110                 }
2111
2112                 public override Expression DoResolve (EmitContext ec)
2113                 {
2114                         return SimpleNameResolve (ec, null, false);
2115                 }
2116
2117                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2118                 {
2119                         return SimpleNameResolve (ec, right_side, false);
2120                 }
2121
2122
2123                 public Expression DoResolve (EmitContext ec, bool intermediate)
2124                 {
2125                         return SimpleNameResolve (ec, null, intermediate);
2126                 }
2127
2128                 private bool IsNestedChild (Type t, Type parent)
2129                 {
2130                         if (parent == null)
2131                                 return false;
2132
2133                         while (parent != null) {
2134                                 parent = TypeManager.DropGenericTypeArguments (parent);
2135                                 if (TypeManager.IsNestedChildOf (t, parent))
2136                                         return true;
2137
2138                                 parent = parent.BaseType;
2139                         }
2140
2141                         return false;
2142                 }
2143
2144                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2145                 {
2146                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2147                                 return null;
2148
2149                         DeclSpace ds = ec.DeclContainer;
2150                         while (ds != null) {
2151                                 if (IsNestedChild (t, ds.TypeBuilder))
2152                                         break;
2153
2154                                 ds = ds.Parent;
2155                         }
2156
2157                         if (ds == null)
2158                                 return null;
2159
2160                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2161
2162                         int arg_count = Arguments != null ? Arguments.Count : 0;
2163
2164                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2165                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2166                                         TypeArguments new_args = new TypeArguments (loc);
2167                                         foreach (TypeParameter param in ds.TypeParameters)
2168                                                 new_args.Add (new TypeParameterExpr (param, loc));
2169
2170                                         if (Arguments != null)
2171                                                 new_args.Add (Arguments);
2172
2173                                         return new ConstructedType (t, new_args, loc);
2174                                 }
2175                         }
2176
2177                         return null;
2178                 }
2179
2180                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2181                 {
2182                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2183                         if (fne != null)
2184                                 return fne.ResolveAsTypeStep (ec, silent);
2185
2186                         int errors = Report.Errors;
2187                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2188
2189                         if (fne != null) {
2190                                 if (fne.Type == null)
2191                                         return fne;
2192
2193                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2194                                 if (nested != null)
2195                                         return nested.ResolveAsTypeStep (ec, false);
2196
2197                                 if (Arguments != null) {
2198                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2199                                         return ct.ResolveAsTypeStep (ec, false);
2200                                 }
2201
2202                                 return fne;
2203                         }
2204
2205                         if (silent || errors != Report.Errors)
2206                                 return null;
2207
2208                         Error_TypeOrNamespaceNotFound (ec);
2209                         return null;
2210                 }
2211
2212                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2213                 {
2214                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2215                         if (mc != null) {
2216                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2217                                 return;
2218                         }
2219
2220                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2221                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2222                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2223                                 Type type = a.GetType (fullname);
2224                                 if (type != null) {
2225                                         Report.SymbolRelatedToPreviousError (type);
2226                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2227                                         return;
2228                                 }
2229                         }
2230
2231                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2232                         if (t != null) {
2233                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2234                                 return;
2235                         }
2236
2237                         if (Arguments != null) {
2238                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2239                                 if (retval != null) {
2240                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2241                                         return;
2242                                 }
2243                         }
2244
2245                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2246                 }
2247
2248                 // TODO: I am still not convinced about this. If someone else will need it
2249                 // implement this as virtual property in MemberCore hierarchy
2250                 public static string GetMemberType (MemberCore mc)
2251                 {
2252                         if (mc is Property)
2253                                 return "property";
2254                         if (mc is Indexer)
2255                                 return "indexer";
2256                         if (mc is FieldBase)
2257                                 return "field";
2258                         if (mc is MethodCore)
2259                                 return "method";
2260                         if (mc is EnumMember)
2261                                 return "enum";
2262                         if (mc is Event)
2263                                 return "event";
2264
2265                         return "type";
2266                 }
2267
2268                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2269                 {
2270                         if (in_transit)
2271                                 return null;
2272
2273                         in_transit = true;
2274                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2275                         in_transit = false;
2276
2277                         if (e == null)
2278                                 return null;
2279
2280                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2281                                 return e;
2282
2283                         return null;
2284                 }
2285
2286                 /// <remarks>
2287                 ///   7.5.2: Simple Names.
2288                 ///
2289                 ///   Local Variables and Parameters are handled at
2290                 ///   parse time, so they never occur as SimpleNames.
2291                 ///
2292                 ///   The `intermediate' flag is used by MemberAccess only
2293                 ///   and it is used to inform us that it is ok for us to
2294                 ///   avoid the static check, because MemberAccess might end
2295                 ///   up resolving the Name as a Type name and the access as
2296                 ///   a static type access.
2297                 ///
2298                 ///   ie: Type Type; .... { Type.GetType (""); }
2299                 ///
2300                 ///   Type is both an instance variable and a Type;  Type.GetType
2301                 ///   is the static method not an instance method of type.
2302                 /// </remarks>
2303                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2304                 {
2305                         Expression e = null;
2306
2307                         //
2308                         // Stage 1: Performed by the parser (binding to locals or parameters).
2309                         //
2310                         Block current_block = ec.CurrentBlock;
2311                         if (current_block != null){
2312                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2313                                 if (vi != null){
2314                                         if (Arguments != null) {
2315                                                 Report.Error (307, loc,
2316                                                               "The variable `{0}' cannot be used with type arguments",
2317                                                               Name);
2318                                                 return null;
2319                                         }
2320
2321                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2322                                         if (right_side != null) {
2323                                                 return var.ResolveLValue (ec, right_side, loc);
2324                                         } else {
2325                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2326                                                 if (intermediate)
2327                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2328                                                 return var.Resolve (ec, rf);
2329                                         }
2330                                 }
2331
2332                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2333                                 if (pref != null) {
2334                                         if (Arguments != null) {
2335                                                 Report.Error (307, loc,
2336                                                               "The variable `{0}' cannot be used with type arguments",
2337                                                               Name);
2338                                                 return null;
2339                                         }
2340
2341                                         if (right_side != null)
2342                                                 return pref.ResolveLValue (ec, right_side, loc);
2343                                         else
2344                                                 return pref.Resolve (ec);
2345                                 }
2346
2347                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2348                                 if (expr != null) {
2349                                         if (right_side != null)
2350                                                 return expr.ResolveLValue (ec, right_side, loc);
2351                                         return expr.Resolve (ec);
2352                                 }
2353                         }
2354
2355                         //
2356                         // Stage 2: Lookup members
2357                         //
2358
2359                         Type almost_matched_type = null;
2360                         ArrayList almost_matched = null;
2361                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2362                                 // either RootDeclSpace or GenericMethod
2363                                 if (lookup_ds.TypeBuilder == null)
2364                                         continue;
2365
2366                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2367                                 if (e != null) {
2368                                         if (e is PropertyExpr) {
2369                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2370                                                 // it doesn't know which accessor to check permissions against
2371                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2372                                                         break;
2373                                         } else if (e is EventExpr) {
2374                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2375                                                         break;
2376                                         } else {
2377                                                 break;
2378                                         }
2379                                         e = null;
2380                                 }
2381
2382                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2383                                         almost_matched_type = lookup_ds.TypeBuilder;
2384                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2385                                 }
2386                         }
2387
2388                         if (e == null) {
2389                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2390                                         almost_matched_type = ec.ContainerType;
2391                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2392                                 }
2393                                 e = ResolveAsTypeStep (ec, true);
2394                         }
2395
2396                         if (e == null) {
2397                                 if (current_block != null) {
2398                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2399                                         if (ikv != null) {
2400                                                 LocalInfo li = ikv as LocalInfo;
2401                                                 // Supress CS0219 warning
2402                                                 if (li != null)
2403                                                         li.Used = true;
2404
2405                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2406                                                 return null;
2407                                         }
2408                                 }
2409
2410                                 if (almost_matched != null)
2411                                         almost_matched_members = almost_matched;
2412                                 if (almost_matched_type == null)
2413                                         almost_matched_type = ec.ContainerType;
2414                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2415                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2416                                 return null;
2417                         }
2418
2419                         if (e is TypeExpr) {
2420                                 if (Arguments == null)
2421                                         return e;
2422
2423                                 ConstructedType ct = new ConstructedType (
2424                                         (FullNamedExpression) e, Arguments, loc);
2425                                 return ct.ResolveAsTypeStep (ec, false);
2426                         }
2427
2428                         if (e is MemberExpr) {
2429                                 MemberExpr me = (MemberExpr) e;
2430
2431                                 Expression left;
2432                                 if (me.IsInstance) {
2433                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2434                                                 //
2435                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2436                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2437                                                 // and each predicate is true if the MethodGroupExpr contains
2438                                                 // at least one of that kind of method.
2439                                                 //
2440
2441                                                 if (!me.IsStatic &&
2442                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2443                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2444                                                         return EmptyExpression.Null;
2445                                                 }
2446
2447                                                 //
2448                                                 // Pass the buck to MemberAccess and Invocation.
2449                                                 //
2450                                                 left = EmptyExpression.Null;
2451                                         } else {
2452                                                 left = ec.GetThis (loc);
2453                                         }
2454                                 } else {
2455                                         left = new TypeExpression (ec.ContainerType, loc);
2456                                 }
2457
2458                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2459                                 if (me == null)
2460                                         return null;
2461
2462                                 if (Arguments != null) {
2463                                         Arguments.Resolve (ec);
2464                                         me.SetTypeArguments (Arguments);
2465                                 }
2466
2467                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2468                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2469                                     me.InstanceExpression.Type != me.DeclaringType &&
2470                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2471                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2472                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2473                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2474                                         return null;
2475                                 }
2476
2477                                 return (right_side != null)
2478                                         ? me.DoResolveLValue (ec, right_side)
2479                                         : me.DoResolve (ec);
2480                         }
2481
2482                         return e;
2483                 }
2484
2485                 public override void Emit (EmitContext ec)
2486                 {
2487                         throw new InternalErrorException ("The resolve phase was not executed");
2488                 }
2489
2490                 public override string ToString ()
2491                 {
2492                         return Name;
2493                 }
2494
2495                 public override string GetSignatureForError ()
2496                 {
2497                         if (Arguments != null) {
2498                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2499                                         Arguments.GetSignatureForError () + ">";
2500                         }
2501
2502                         return Name;
2503                 }
2504
2505                 protected override void CloneTo (CloneContext clonectx, Expression target)
2506                 {
2507                         // CloneTo: Nothing, we do not keep any state on this expression
2508                 }
2509         }
2510
2511         /// <summary>
2512         ///   Represents a namespace or a type.  The name of the class was inspired by
2513         ///   section 10.8.1 (Fully Qualified Names).
2514         /// </summary>
2515         public abstract class FullNamedExpression : Expression {
2516                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2517                 {
2518                         return this;
2519                 }
2520
2521                 public abstract string FullName {
2522                         get;
2523                 }
2524         }
2525
2526         /// <summary>
2527         ///   Expression that evaluates to a type
2528         /// </summary>
2529         public abstract class TypeExpr : FullNamedExpression {
2530                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2531                 {
2532                         TypeExpr t = DoResolveAsTypeStep (ec);
2533                         if (t == null)
2534                                 return null;
2535
2536                         eclass = ExprClass.Type;
2537                         return t;
2538                 }
2539
2540                 override public Expression DoResolve (EmitContext ec)
2541                 {
2542                         return ResolveAsTypeTerminal (ec, false);
2543                 }
2544
2545                 override public void Emit (EmitContext ec)
2546                 {
2547                         throw new Exception ("Should never be called");
2548                 }
2549
2550                 public virtual bool CheckAccessLevel (DeclSpace ds)
2551                 {
2552                         return ds.CheckAccessLevel (Type);
2553                 }
2554
2555                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2556                 {
2557                         return ds.AsAccessible (Type, flags);
2558                 }
2559
2560                 public virtual bool IsClass {
2561                         get { return Type.IsClass; }
2562                 }
2563
2564                 public virtual bool IsValueType {
2565                         get { return Type.IsValueType; }
2566                 }
2567
2568                 public virtual bool IsInterface {
2569                         get { return Type.IsInterface; }
2570                 }
2571
2572                 public virtual bool IsSealed {
2573                         get { return Type.IsSealed; }
2574                 }
2575
2576                 public virtual bool CanInheritFrom ()
2577                 {
2578                         if (Type == TypeManager.enum_type ||
2579                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2580                             Type == TypeManager.multicast_delegate_type ||
2581                             Type == TypeManager.delegate_type ||
2582                             Type == TypeManager.array_type)
2583                                 return false;
2584
2585                         return true;
2586                 }
2587
2588                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2589
2590                 public abstract string Name {
2591                         get;
2592                 }
2593
2594                 public override bool Equals (object obj)
2595                 {
2596                         TypeExpr tobj = obj as TypeExpr;
2597                         if (tobj == null)
2598                                 return false;
2599
2600                         return Type == tobj.Type;
2601                 }
2602
2603                 public override int GetHashCode ()
2604                 {
2605                         return Type.GetHashCode ();
2606                 }
2607
2608                 public override string ToString ()
2609                 {
2610                         return Name;
2611                 }
2612         }
2613
2614         /// <summary>
2615         ///   Fully resolved Expression that already evaluated to a type
2616         /// </summary>
2617         public class TypeExpression : TypeExpr {
2618                 public TypeExpression (Type t, Location l)
2619                 {
2620                         Type = t;
2621                         eclass = ExprClass.Type;
2622                         loc = l;
2623                 }
2624
2625                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2626                 {
2627                         return this;
2628                 }
2629
2630                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2631                 {
2632                         return this;
2633                 }
2634
2635                 public override string Name {
2636                         get { return Type.ToString (); }
2637                 }
2638
2639                 public override string FullName {
2640                         get { return Type.FullName; }
2641                 }
2642         }
2643
2644         /// <summary>
2645         ///   Used to create types from a fully qualified name.  These are just used
2646         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2647         ///   classified as a type.
2648         /// </summary>
2649         public sealed class TypeLookupExpression : TypeExpr {
2650                 readonly string name;
2651
2652                 public TypeLookupExpression (string name)
2653                 {
2654                         this.name = name;
2655                         eclass = ExprClass.Type;
2656                 }
2657
2658                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2659                 {
2660                         // It's null for corlib compilation only
2661                         if (type == null)
2662                                 return DoResolveAsTypeStep (ec);
2663
2664                         return this;
2665                 }
2666
2667                 private class UnexpectedType
2668                 {
2669                 }
2670
2671                 // This performes recursive type lookup, providing support for generic types.
2672                 // For example, given the type:
2673                 //
2674                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2675                 //
2676                 // The types will be checked in the following order:
2677                 //                                                                             _
2678                 // System                                                                       |
2679                 // System.Collections                                                           |
2680                 // System.Collections.Generic                                                   |
2681                 //                        _                                                     |
2682                 //     System              | recursive call 1                                   |
2683                 //     System.Int32       _|                                                    | main method call
2684                 //                        _                                                     |
2685                 //     System              | recursive call 2                                   |
2686                 //     System.String      _|                                                    |
2687                 //                                                                              |
2688                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2689                 //
2690                 private Type TypeLookup (IResolveContext ec, string name)
2691                 {
2692                         int index = 0;
2693                         int dot = 0;
2694                         bool done = false;
2695                         FullNamedExpression resolved = null;
2696                         Type type = null;
2697                         Type recursive_type = null;
2698                         while (index < name.Length) {
2699                                 if (name[index] == '[') {
2700                                         int open = index;
2701                                         int braces = 1;
2702                                         do {
2703                                                 index++;
2704                                                 if (name[index] == '[')
2705                                                         braces++;
2706                                                 else if (name[index] == ']')
2707                                                         braces--;
2708                                         } while (braces > 0);
2709                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2710                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2711                                                 return recursive_type;
2712                                 }
2713                                 else {
2714                                         if (name[index] == ',')
2715                                                 done = true;
2716                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2717                                                 string substring = name.Substring(dot, index - dot);
2718
2719                                                 if (resolved == null)
2720                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2721                                                 else if (resolved is Namespace)
2722                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2723                                                 else if (type != null)
2724                                                         type = TypeManager.GetNestedType (type, substring);
2725                                                 else
2726                                                         return null;
2727
2728                                                 if (resolved == null)
2729                                                         return null;
2730                                                 else if (type == null && resolved is TypeExpr)
2731                                                         type = resolved.Type;
2732
2733                                                 dot = index + 1;
2734                                         }
2735                                 }
2736                                 index++;
2737                         }
2738                         if (name[0] != '[') {
2739                                 string substring = name.Substring(dot, index - dot);
2740
2741                                 if (type != null)
2742                                         return TypeManager.GetNestedType (type, substring);
2743
2744                                 if (resolved != null) {
2745                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2746                                         if (resolved is TypeExpr)
2747                                                 return resolved.Type;
2748
2749                                         if (resolved == null)
2750                                                 return null;
2751
2752                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2753                                         return typeof (UnexpectedType);
2754                                 }
2755                                 else
2756                                         return null;
2757                         }
2758                         else
2759                                 return recursive_type;
2760                         }
2761
2762                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2763                 {
2764                         Type t = TypeLookup (ec, name);
2765                         if (t == null) {
2766                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2767                                 return null;
2768                         }
2769                         if (t == typeof(UnexpectedType))
2770                                 return null;
2771                         type = t;
2772                         return this;
2773                 }
2774
2775                 public override string Name {
2776                         get { return name; }
2777                 }
2778
2779                 public override string FullName {
2780                         get { return name; }
2781                 }
2782
2783                 protected override void CloneTo (CloneContext clonectx, Expression target)
2784                 {
2785                         // CloneTo: Nothing, we do not keep any state on this expression
2786                 }
2787
2788                 public override string GetSignatureForError ()
2789                 {
2790                         if (type == null)
2791                                 return TypeManager.CSharpName (name);
2792
2793                         return base.GetSignatureForError ();
2794                 }
2795         }
2796
2797         /// <summary>
2798         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2799         ///   See 14.5.11.
2800         /// </summary>
2801         public class UnboundTypeExpression : TypeExpr
2802         {
2803                 MemberName name;
2804
2805                 public UnboundTypeExpression (MemberName name, Location l)
2806                 {
2807                         this.name = name;
2808                         loc = l;
2809                 }
2810
2811                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2812                 {
2813                         Expression expr;
2814                         if (name.Left != null) {
2815                                 Expression lexpr = name.Left.GetTypeExpression ();
2816                                 expr = new MemberAccess (lexpr, name.Basename);
2817                         } else {
2818                                 expr = new SimpleName (name.Basename, loc);
2819                         }
2820
2821                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2822                         if (fne == null)
2823                                 return null;
2824
2825                         type = fne.Type;
2826                         return new TypeExpression (type, loc);
2827                 }
2828
2829                 public override string Name {
2830                         get { return name.FullName; }
2831                 }
2832
2833                 public override string FullName {
2834                         get { return name.FullName; }
2835                 }
2836         }
2837
2838         public class TypeAliasExpression : TypeExpr {
2839                 FullNamedExpression alias;
2840                 TypeExpr texpr;
2841                 TypeArguments args;
2842                 string name;
2843
2844                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2845                 {
2846                         this.alias = alias;
2847                         this.args = args;
2848                         loc = l;
2849
2850                         eclass = ExprClass.Type;
2851                         if (args != null)
2852                                 name = alias.FullName + "<" + args.ToString () + ">";
2853                         else
2854                                 name = alias.FullName;
2855                 }
2856
2857                 public override string Name {
2858                         get { return alias.FullName; }
2859                 }
2860
2861                 public override string FullName {
2862                         get { return name; }
2863                 }
2864
2865                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2866                 {
2867                         texpr = alias.ResolveAsTypeTerminal (ec, false);
2868                         if (texpr == null)
2869                                 return null;
2870
2871                         Type type = texpr.Type;
2872                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2873
2874                         if (args != null) {
2875                                 if (num_args == 0) {
2876                                         Report.Error (308, loc,
2877                                                       "The non-generic type `{0}' cannot " +
2878                                                       "be used with type arguments.",
2879                                                       TypeManager.CSharpName (type));
2880                                         return null;
2881                                 }
2882
2883                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2884                                 return ctype.ResolveAsTypeTerminal (ec, false);
2885                         } else if (num_args > 0) {
2886                                 Report.Error (305, loc,
2887                                               "Using the generic type `{0}' " +
2888                                               "requires {1} type arguments",
2889                                               TypeManager.CSharpName (type), num_args.ToString ());
2890                                 return null;
2891                         }
2892
2893                         return texpr;
2894                 }
2895
2896                 public override bool CheckAccessLevel (DeclSpace ds)
2897                 {
2898                         return texpr.CheckAccessLevel (ds);
2899                 }
2900
2901                 public override bool AsAccessible (DeclSpace ds, int flags)
2902                 {
2903                         return texpr.AsAccessible (ds, flags);
2904                 }
2905
2906                 public override bool IsClass {
2907                         get { return texpr.IsClass; }
2908                 }
2909
2910                 public override bool IsValueType {
2911                         get { return texpr.IsValueType; }
2912                 }
2913
2914                 public override bool IsInterface {
2915                         get { return texpr.IsInterface; }
2916                 }
2917
2918                 public override bool IsSealed {
2919                         get { return texpr.IsSealed; }
2920                 }
2921         }
2922
2923         /// <summary>
2924         ///   This class denotes an expression which evaluates to a member
2925         ///   of a struct or a class.
2926         /// </summary>
2927         public abstract class MemberExpr : Expression
2928         {
2929                 protected bool is_base;
2930
2931                 /// <summary>
2932                 ///   The name of this member.
2933                 /// </summary>
2934                 public abstract string Name {
2935                         get;
2936                 }
2937
2938                 //
2939                 // When base.member is used
2940                 //
2941                 public bool IsBase {
2942                         get { return is_base; }
2943                         set { is_base = value; }
2944                 }
2945
2946                 /// <summary>
2947                 ///   Whether this is an instance member.
2948                 /// </summary>
2949                 public abstract bool IsInstance {
2950                         get;
2951                 }
2952
2953                 /// <summary>
2954                 ///   Whether this is a static member.
2955                 /// </summary>
2956                 public abstract bool IsStatic {
2957                         get;
2958                 }
2959
2960                 /// <summary>
2961                 ///   The type which declares this member.
2962                 /// </summary>
2963                 public abstract Type DeclaringType {
2964                         get;
2965                 }
2966
2967                 /// <summary>
2968                 ///   The instance expression associated with this member, if it's a
2969                 ///   non-static member.
2970                 /// </summary>
2971                 public Expression InstanceExpression;
2972
2973                 public static void error176 (Location loc, string name)
2974                 {
2975                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
2976                                       "with an instance reference, qualify it with a type name instead", name);
2977                 }
2978
2979                 // TODO: possible optimalization
2980                 // Cache resolved constant result in FieldBuilder <-> expression map
2981                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2982                                                                SimpleName original)
2983                 {
2984                         //
2985                         // Precondition:
2986                         //   original == null || original.Resolve (...) ==> left
2987                         //
2988
2989                         if (left is TypeExpr) {
2990                                 left = left.ResolveAsTypeTerminal (ec, true);
2991                                 if (left == null)
2992                                         return null;
2993
2994                                 if (!IsStatic) {
2995                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
2996                                         return null;
2997                                 }
2998
2999                                 return this;
3000                         }
3001
3002                         if (!IsInstance) {
3003                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3004                                         return this;
3005
3006                                 return ResolveExtensionMemberAccess (left);
3007                         }
3008
3009                         InstanceExpression = left;
3010                         return this;
3011                 }
3012
3013                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3014                 {
3015                         error176 (loc, GetSignatureForError ());
3016                         return this;
3017                 }
3018
3019                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3020                 {
3021                         if (IsStatic)
3022                                 return;
3023
3024                         if (InstanceExpression == EmptyExpression.Null) {
3025                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3026                                 return;
3027                         }
3028
3029                         if (InstanceExpression.Type.IsValueType) {
3030                                 if (InstanceExpression is IMemoryLocation) {
3031                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3032                                 } else {
3033                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3034                                         InstanceExpression.Emit (ec);
3035                                         t.Store (ec);
3036                                         t.AddressOf (ec, AddressOp.Store);
3037                                 }
3038                         } else
3039                                 InstanceExpression.Emit (ec);
3040
3041                         if (prepare_for_load)
3042                                 ec.ig.Emit (OpCodes.Dup);
3043                 }
3044
3045                 public virtual void SetTypeArguments (TypeArguments ta)
3046                 {
3047                         // TODO: need to get correct member type
3048                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3049                                 GetSignatureForError ());
3050                 }
3051         }
3052
3053         ///
3054         /// Represents group of extension methods
3055         ///
3056         public class ExtensionMethodGroupExpr : MethodGroupExpr
3057         {
3058                 readonly NamespaceEntry namespace_entry;
3059                 public Expression ExtensionExpression;
3060                 Argument extension_argument;
3061
3062                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3063                         : base (list, extensionType, l)
3064                 {
3065                         this.namespace_entry = n;
3066                 }
3067
3068                 public override bool IsStatic {
3069                         get { return true; }
3070                 }
3071
3072                 public bool IsTopLevel {
3073                         get { return namespace_entry == null; }
3074                 }
3075
3076                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3077                 {
3078                         if (arguments == null)
3079                                 arguments = new ArrayList (1);
3080                         arguments.Insert (0, extension_argument);
3081                         base.EmitArguments (ec, arguments);
3082                 }
3083
3084                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3085                 {
3086                         if (arguments == null)
3087                                 arguments = new ArrayList (1);
3088                         arguments.Insert (0, extension_argument);
3089                         base.EmitCall (ec, arguments);
3090                 }
3091
3092                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList arguments, bool may_fail, Location loc)
3093                 {
3094                         if ((ExtensionExpression.eclass & (ExprClass.Value | ExprClass.Variable)) == 0)
3095                                 return base.OverloadResolve (ec, arguments, may_fail, loc);
3096
3097                         if (arguments == null)
3098                                 arguments = new ArrayList (1);
3099
3100                         arguments.Insert (0, new Argument (ExtensionExpression));
3101                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3102
3103                         // Store resolved argument and restore original arguments
3104                         if (mg != null)
3105                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3106                         arguments.RemoveAt (0);
3107
3108                         return mg;
3109                 }
3110
3111                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3112                 {
3113                         // Use normal resolve rules
3114                         MethodGroupExpr mg = base.OverloadResolve (ec, arguments, ns != null, loc);
3115                         if (mg != null)
3116                                 return mg;
3117
3118                         if (ns == null)
3119                                 return null;
3120
3121                         // Search continues
3122                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name);
3123                         if (e == null)
3124                                 return base.OverloadResolve (ec, arguments, false, loc);
3125
3126                         e.ExtensionExpression = ExtensionExpression;
3127                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3128                 }
3129         }
3130
3131         /// <summary>
3132         ///   MethodGroupExpr represents a group of method candidates which
3133         ///   can be resolved to the best method overload
3134         /// </summary>
3135         public class MethodGroupExpr : MemberExpr
3136         {
3137                 public interface IErrorHandler
3138                 {
3139                         bool NoExactMatch (EmitContext ec, MethodBase method);
3140                 }
3141
3142                 public IErrorHandler CustomErrorHandler;
3143                 public MethodBase [] Methods;
3144                 MethodBase best_candidate;
3145                 // TODO: make private
3146                 public TypeArguments type_arguments;
3147                 bool identical_type_name;
3148                 Type delegate_type;
3149
3150                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3151                         : this (type, l)
3152                 {
3153                         Methods = new MethodBase [mi.Length];
3154                         mi.CopyTo (Methods, 0);
3155                 }
3156
3157                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3158                         : this (type, l)
3159                 {
3160                         try {
3161                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3162                         } catch {
3163                                 foreach (MemberInfo m in list){
3164                                         if (!(m is MethodBase)){
3165                                                 Console.WriteLine ("Name " + m.Name);
3166                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3167                                         }
3168                                 }
3169                                 throw;
3170                         }
3171
3172
3173                 }
3174
3175                 protected MethodGroupExpr (Type type, Location loc)
3176                 {
3177                         this.loc = loc;
3178                         eclass = ExprClass.MethodGroup;
3179                         this.type = type;
3180                 }
3181
3182                 public override Type DeclaringType {
3183                         get {
3184                                 //
3185                                 // We assume that the top-level type is in the end
3186                                 //
3187                                 return Methods [Methods.Length - 1].DeclaringType;
3188                                 //return Methods [0].DeclaringType;
3189                         }
3190                 }
3191
3192                 public Type DelegateType {
3193                         set {
3194                                 delegate_type = value;
3195                         }
3196                 }
3197
3198                 public bool IdenticalTypeName {
3199                         get {
3200                                 return identical_type_name;
3201                         }
3202
3203                         set {
3204                                 identical_type_name = value;
3205                         }
3206                 }
3207
3208                 public override string GetSignatureForError ()
3209                 {
3210                         if (best_candidate != null)
3211                                 return TypeManager.CSharpSignature (best_candidate);
3212
3213                         return TypeManager.CSharpSignature (Methods [0]);
3214                 }
3215
3216                 public override string Name {
3217                         get {
3218                                 return Methods [0].Name;
3219                         }
3220                 }
3221
3222                 public override bool IsInstance {
3223                         get {
3224                                 if (best_candidate != null)
3225                                         return !best_candidate.IsStatic;
3226
3227                                 foreach (MethodBase mb in Methods)
3228                                         if (!mb.IsStatic)
3229                                                 return true;
3230
3231                                 return false;
3232                         }
3233                 }
3234
3235                 public override bool IsStatic {
3236                         get {
3237                                 if (best_candidate != null)
3238                                         return best_candidate.IsStatic;
3239
3240                                 foreach (MethodBase mb in Methods)
3241                                         if (mb.IsStatic)
3242                                                 return true;
3243
3244                                 return false;
3245                         }
3246                 }
3247
3248                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3249                 {
3250                         return (ConstructorInfo)mg.best_candidate;
3251                 }
3252
3253                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3254                 {
3255                         return (MethodInfo)mg.best_candidate;
3256                 }
3257
3258                 /// <summary>
3259                 ///   Determines "better conversion" as specified in 14.4.2.3
3260                 ///
3261                 ///    Returns : p    if a->p is better,
3262                 ///              q    if a->q is better,
3263                 ///              null if neither is better
3264                 /// </summary>
3265                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q)
3266                 {
3267                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3268                         Expression argument_expr = a.Expr;
3269
3270                         if (argument_type == null)
3271                                 throw new Exception ("Expression of type " + a.Expr +
3272                                         " does not resolve its type");
3273
3274                         if (p == null || q == null)
3275                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
3276
3277                         if (p == q)
3278                                 return null;
3279
3280                         if (argument_expr is NullLiteral)
3281                         {
3282                                 //
3283                                 // If the argument is null and one of the types to compare is 'object' and
3284                                 // the other is a reference type, we prefer the other.
3285                                 //
3286                                 // This follows from the usual rules:
3287                                 //   * There is an implicit conversion from 'null' to type 'object'
3288                                 //   * There is an implicit conversion from 'null' to any reference type
3289                                 //   * There is an implicit conversion from any reference type to type 'object'
3290                                 //   * There is no implicit conversion from type 'object' to other reference types
3291                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
3292                                 //
3293                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
3294                                 //         null type. I think it used to be 'object' and thus needed a special
3295                                 //         case to avoid the immediately following two checks.
3296                                 //
3297                                 if (!p.IsValueType && q == TypeManager.object_type)
3298                                         return p;
3299                                 if (!q.IsValueType && p == TypeManager.object_type)
3300                                         return q;
3301                         }
3302
3303                         if (argument_type == p)
3304                                 return p;
3305
3306                         if (argument_type == q)
3307                                 return q;
3308
3309                         Expression p_tmp = new EmptyExpression (p);
3310                         Expression q_tmp = new EmptyExpression (q);
3311
3312                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3313                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3314
3315                         if (p_to_q && !q_to_p)
3316                                 return p;
3317
3318                         if (q_to_p && !p_to_q)
3319                                 return q;
3320
3321                         if (p == TypeManager.sbyte_type)
3322                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3323                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3324                                         return p;
3325                         if (q == TypeManager.sbyte_type)
3326                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3327                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3328                                         return q;
3329
3330                         if (p == TypeManager.short_type)
3331                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3332                                         q == TypeManager.uint64_type)
3333                                         return p;
3334                         if (q == TypeManager.short_type)
3335                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3336                                         p == TypeManager.uint64_type)
3337                                         return q;
3338
3339                         if (p == TypeManager.int32_type)
3340                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3341                                         return p;
3342                         if (q == TypeManager.int32_type)
3343                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3344                                         return q;
3345
3346                         if (p == TypeManager.int64_type)
3347                                 if (q == TypeManager.uint64_type)
3348                                         return p;
3349                         if (q == TypeManager.int64_type)
3350                                 if (p == TypeManager.uint64_type)
3351                                         return q;
3352
3353                         return null;
3354                 }
3355
3356                 /// <summary>
3357                 ///   Determines "Better function" between candidate
3358                 ///   and the current best match
3359                 /// </summary>
3360                 /// <remarks>
3361                 ///    Returns a boolean indicating :
3362                 ///     false if candidate ain't better
3363                 ///     true  if candidate is better than the current best match
3364                 /// </remarks>
3365                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3366                         MethodBase candidate, bool candidate_params,
3367                         MethodBase best, bool best_params)
3368                 {
3369                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3370                         ParameterData best_pd = TypeManager.GetParameterData (best);
3371
3372                         bool better_at_least_one = false;
3373                         bool same = true;
3374                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3375                         {
3376                                 Argument a = (Argument) args [j];
3377
3378                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3379                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3380
3381                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3382                                 {
3383                                         ct = TypeManager.GetElementType (ct);
3384                                         --c_idx;
3385                                 }
3386
3387                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3388                                 {
3389                                         bt = TypeManager.GetElementType (bt);
3390                                         --b_idx;
3391                                 }
3392
3393                                 if (ct.Equals (bt))
3394                                         continue;
3395
3396                                 same = false;
3397                                 Type better = BetterConversion (ec, a, ct, bt);
3398
3399                                 // for each argument, the conversion to 'ct' should be no worse than
3400                                 // the conversion to 'bt'.
3401                                 if (better == bt)
3402                                         return false;
3403
3404                                 // for at least one argument, the conversion to 'ct' should be better than
3405                                 // the conversion to 'bt'.
3406                                 if (better == ct)
3407                                         better_at_least_one = true;
3408                         }
3409
3410                         if (better_at_least_one)
3411                                 return true;
3412
3413                         //
3414                         // This handles the case
3415                         //
3416                         //   Add (float f1, float f2, float f3);
3417                         //   Add (params decimal [] foo);
3418                         //
3419                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3420                         // first candidate would've chosen as better.
3421                         //
3422                         if (!same)
3423                                 return false;
3424
3425                         //
3426                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3427                         //
3428                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3429                                 return true;
3430                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3431                                 return false;
3432
3433                         //
3434                         // This handles the following cases:
3435                         //
3436                         //   Trim () is better than Trim (params char[] chars)
3437                         //   Concat (string s1, string s2, string s3) is better than
3438                         //     Concat (string s1, params string [] srest)
3439                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3440                         //
3441                         if (!candidate_params && best_params)
3442                                 return true;
3443                         if (candidate_params && !best_params)
3444                                 return false;
3445
3446                         int candidate_param_count = candidate_pd.Count;
3447                         int best_param_count = best_pd.Count;
3448
3449                         if (candidate_param_count != best_param_count)
3450                                 // can only happen if (candidate_params && best_params)
3451                                 return candidate_param_count > best_param_count;
3452
3453                         //
3454                         // now, both methods have the same number of parameters, and the parameters have the same types
3455                         // Pick the "more specific" signature
3456                         //
3457
3458                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3459                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3460
3461                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3462                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3463
3464                         bool specific_at_least_once = false;
3465                         for (int j = 0; j < candidate_param_count; ++j)
3466                         {
3467                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3468                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3469                                 if (ct.Equals (bt))
3470                                         continue;
3471                                 Type specific = MoreSpecific (ct, bt);
3472                                 if (specific == bt)
3473                                         return false;
3474                                 if (specific == ct)
3475                                         specific_at_least_once = true;
3476                         }
3477
3478                         if (specific_at_least_once)
3479                                 return true;
3480
3481                         // FIXME: handle lifted operators
3482                         // ...
3483
3484                         return false;
3485                 }
3486
3487                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3488                 {
3489                         if (!IsStatic)
3490                                 return base.ResolveExtensionMemberAccess (left);
3491
3492                         //
3493                         // When left side is an expression and at least one candidate method is
3494                         // static, it can be extension method
3495                         //
3496                         InstanceExpression = left;
3497                         return this;
3498                 }
3499
3500                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3501                                                                 SimpleName original)
3502                 {
3503                         if (!(left is TypeExpr) &&
3504                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3505                                 IdenticalTypeName = true;
3506
3507                         return base.ResolveMemberAccess (ec, left, loc, original);
3508                 }
3509
3510                 override public Expression DoResolve (EmitContext ec)
3511                 {
3512                         if (InstanceExpression != null) {
3513                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3514                                 if (InstanceExpression == null)
3515                                         return null;
3516                         }
3517
3518                         return this;
3519                 }
3520
3521                 public void ReportUsageError ()
3522                 {
3523                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3524                                       Name + "()' is referenced without parentheses");
3525                 }
3526
3527                 override public void Emit (EmitContext ec)
3528                 {
3529                         ReportUsageError ();
3530                 }
3531
3532                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3533                 {
3534                         Invocation.EmitArguments (ec, best_candidate, arguments, false, null);
3535                 }
3536
3537                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3538                 {
3539                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3540                 }
3541
3542                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3543                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3544                 {
3545                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3546                                 Report.SymbolRelatedToPreviousError (method);
3547                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3548                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3549                                                 TypeManager.CSharpSignature (method));
3550                                         return;
3551                                 }
3552                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3553                                           TypeManager.CSharpSignature (method));
3554                         } else if (delegate_type == null) {
3555                                 Report.SymbolRelatedToPreviousError (method);
3556                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3557                                                   TypeManager.CSharpSignature (method));
3558                         } else
3559                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3560                                         TypeManager.CSharpName (delegate_type));
3561
3562                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3563
3564                         string index = (idx + 1).ToString ();
3565                         if ((mod & Parameter.Modifier.ISBYREF) != (a.Modifier & Parameter.Modifier.ISBYREF) ||
3566                                 (mod & Parameter.Modifier.ISBYREF) != 0) {
3567                                 if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) == 0)
3568                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3569                                                 index, Parameter.GetModifierSignature (a.Modifier));
3570                                 else
3571                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3572                                                 index, Parameter.GetModifierSignature (mod));
3573                         } else {
3574                                 string p1 = Argument.FullDesc (a);
3575                                 string p2 = TypeManager.CSharpName (paramType);
3576
3577                                 if (p1 == p2) {
3578                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3579                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3580                                         Report.SymbolRelatedToPreviousError (paramType);
3581                                 }
3582                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3583                         }
3584                 }
3585
3586                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3587                 {
3588                         return parameters.Count;
3589                 }
3590
3591                 public static bool IsAncestralType (Type first_type, Type second_type)
3592                 {
3593                         return first_type != second_type &&
3594                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3595                                 TypeManager.ImplementsInterface (second_type, first_type));
3596                 }
3597
3598                 ///
3599                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3600                 /// to the given set of arguments
3601                 /// A return value rates candidate method compatibility,
3602                 /// 0 = the best, int.MaxValue = the worst
3603                 ///
3604                 public int IsApplicable (EmitContext ec,
3605                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3606                 {
3607                         MethodBase candidate = method;
3608
3609                         ParameterData pd = TypeManager.GetParameterData (candidate);
3610                         int param_count = GetApplicableParametersCount (candidate, pd);
3611
3612                         if (arg_count != param_count) {
3613                                 if (!pd.HasParams)
3614                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3615                                 if (arg_count < param_count - 1)
3616                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3617                         }
3618
3619 #if GMCS_SOURCE
3620                         //
3621                         // 1. Handle generic method using type arguments when specified or type inference
3622                         //
3623                         if (TypeManager.IsGenericMethod (candidate)) {
3624                                 if (type_arguments != null) {
3625                                         Type [] g_args = candidate.GetGenericArguments ();
3626                                         if (g_args.Length != type_arguments.Count)
3627                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3628
3629                                         // TODO: Don't create new method, create Parameters only
3630                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3631                                         candidate = method;
3632                                         pd = TypeManager.GetParameterData (candidate);
3633                                 } else {
3634                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3635                                         if (score != 0)
3636                                                 return score - 20000;
3637
3638                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3639                                                 throw new InternalErrorException ("a generic method definition took part in overload resolution");
3640
3641                                         pd = TypeManager.GetParameterData (candidate);
3642                                 }
3643                         } else {
3644                                 if (type_arguments != null)
3645                                         return int.MaxValue - 15000;
3646                         }
3647 #endif
3648
3649                         //
3650                         // 2. Each argument has to be implicitly convertible to method parameter
3651                         //
3652                         Parameter.Modifier p_mod = 0;
3653                         Type pt = null;
3654                         for (int i = 0; i < arg_count; i++) {
3655                                 Argument a = (Argument) arguments [i];
3656                                 Parameter.Modifier a_mod = a.Modifier &
3657                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3658
3659                                 if (p_mod != Parameter.Modifier.PARAMS) {
3660                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3661
3662                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3663                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3664                                                         continue;
3665
3666                                                 p_mod = 0;
3667                                         }
3668
3669                                         pt = pd.ParameterType (i);
3670                                 } else {
3671                                         params_expanded_form = true;
3672                                 }
3673
3674                                 int score = 1;
3675                                 if (!params_expanded_form)
3676                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3677
3678                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3679                                         // It can be applicable in expanded form
3680                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3681                                         if (score == 0)
3682                                                 params_expanded_form = true;
3683                                 }
3684
3685                                 if (score != 0)
3686                                         return (arg_count - i) * 2 + score;
3687                         }
3688
3689                         if (arg_count != param_count)
3690                                 params_expanded_form = true;
3691
3692                         method = candidate;
3693                         return 0;
3694                 }
3695
3696                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3697                 {
3698                         //
3699                         // Types have to be identical when ref or out modifer is used
3700                         //
3701                         if (arg_mod != 0 || param_mod != 0) {
3702                                 if (TypeManager.HasElementType (parameter))
3703                                         parameter = parameter.GetElementType ();
3704
3705                                 Type a_type = argument.Type;
3706                                 if (TypeManager.HasElementType (a_type))
3707                                         a_type = a_type.GetElementType ();
3708
3709                                 if (a_type != parameter)
3710                                         return 2;
3711
3712                                 return 0;
3713                         }
3714
3715                         // FIXME: Kill this abomination (EmitContext.TempEc)
3716                         EmitContext prevec = EmitContext.TempEc;
3717                         EmitContext.TempEc = ec;
3718                         try {
3719                                 if (delegate_type != null ?
3720                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3721                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3722                                         return 2;
3723
3724                                 if (arg_mod != param_mod)
3725                                         return 1;
3726
3727                         } finally {
3728                                 EmitContext.TempEc = prevec;
3729                         }
3730
3731                         return 0;
3732                 }
3733
3734                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3735                 {
3736                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3737                                 return false;
3738
3739                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3740                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3741
3742                         if (cand_pd.Count != base_pd.Count)
3743                                 return false;
3744
3745                         for (int j = 0; j < cand_pd.Count; ++j)
3746                         {
3747                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3748                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3749                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3750                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3751
3752                                 if (cm != bm || ct != bt)
3753                                         return false;
3754                         }
3755
3756                         return true;
3757                 }
3758
3759                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3760                 {
3761                         MemberInfo [] miset;
3762                         MethodGroupExpr union;
3763
3764                         if (mg1 == null) {
3765                                 if (mg2 == null)
3766                                         return null;
3767                                 return (MethodGroupExpr) mg2;
3768                         } else {
3769                                 if (mg2 == null)
3770                                         return (MethodGroupExpr) mg1;
3771                         }
3772
3773                         MethodGroupExpr left_set = null, right_set = null;
3774                         int length1 = 0, length2 = 0;
3775
3776                         left_set = (MethodGroupExpr) mg1;
3777                         length1 = left_set.Methods.Length;
3778
3779                         right_set = (MethodGroupExpr) mg2;
3780                         length2 = right_set.Methods.Length;
3781
3782                         ArrayList common = new ArrayList ();
3783
3784                         foreach (MethodBase r in right_set.Methods){
3785                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3786                                         common.Add (r);
3787                         }
3788
3789                         miset = new MemberInfo [length1 + length2 - common.Count];
3790                         left_set.Methods.CopyTo (miset, 0);
3791
3792                         int k = length1;
3793
3794                         foreach (MethodBase r in right_set.Methods) {
3795                                 if (!common.Contains (r))
3796                                         miset [k++] = r;
3797                         }
3798
3799                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3800
3801                         return union;
3802                 }
3803
3804                 static Type MoreSpecific (Type p, Type q)
3805                 {
3806                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3807                                 return q;
3808                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3809                                 return p;
3810
3811                         if (TypeManager.HasElementType (p))
3812                         {
3813                                 Type pe = TypeManager.GetElementType (p);
3814                                 Type qe = TypeManager.GetElementType (q);
3815                                 Type specific = MoreSpecific (pe, qe);
3816                                 if (specific == pe)
3817                                         return p;
3818                                 if (specific == qe)
3819                                         return q;
3820                         }
3821                         else if (TypeManager.IsGenericType (p))
3822                         {
3823                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3824                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3825
3826                                 bool p_specific_at_least_once = false;
3827                                 bool q_specific_at_least_once = false;
3828
3829                                 for (int i = 0; i < pargs.Length; i++)
3830                                 {
3831                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3832                                         if (specific == pargs [i])
3833                                                 p_specific_at_least_once = true;
3834                                         if (specific == qargs [i])
3835                                                 q_specific_at_least_once = true;
3836                                 }
3837
3838                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3839                                         return p;
3840                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3841                                         return q;
3842                         }
3843
3844                         return null;
3845                 }
3846
3847                 /// <summary>
3848                 ///   Find the Applicable Function Members (7.4.2.1)
3849                 ///
3850                 ///   me: Method Group expression with the members to select.
3851                 ///       it might contain constructors or methods (or anything
3852                 ///       that maps to a method).
3853                 ///
3854                 ///   Arguments: ArrayList containing resolved Argument objects.
3855                 ///
3856                 ///   loc: The location if we want an error to be reported, or a Null
3857                 ///        location for "probing" purposes.
3858                 ///
3859                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3860                 ///            that is the best match of me on Arguments.
3861                 ///
3862                 /// </summary>
3863                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList Arguments,
3864                         bool may_fail, Location loc)
3865                 {
3866                         bool method_params = false;
3867                         Type applicable_type = null;
3868                         int arg_count = 0;
3869                         ArrayList candidates = new ArrayList (2);
3870                         ArrayList candidate_overrides = null;
3871
3872                         //
3873                         // Used to keep a map between the candidate
3874                         // and whether it is being considered in its
3875                         // normal or expanded form
3876                         //
3877                         // false is normal form, true is expanded form
3878                         //
3879                         Hashtable candidate_to_form = null;
3880
3881                         if (Arguments != null)
3882                                 arg_count = Arguments.Count;
3883
3884                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3885                                 if (!may_fail)
3886                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3887                                 return null;
3888                         }
3889
3890                         int nmethods = Methods.Length;
3891
3892                         if (!IsBase) {
3893                                 //
3894                                 // Methods marked 'override' don't take part in 'applicable_type'
3895                                 // computation, nor in the actual overload resolution.
3896                                 // However, they still need to be emitted instead of a base virtual method.
3897                                 // So, we salt them away into the 'candidate_overrides' array.
3898                                 //
3899                                 // In case of reflected methods, we replace each overriding method with
3900                                 // its corresponding base virtual method.  This is to improve compatibility
3901                                 // with non-C# libraries which change the visibility of overrides (#75636)
3902                                 //
3903                                 int j = 0;
3904                                 for (int i = 0; i < Methods.Length; ++i) {
3905                                         MethodBase m = Methods [i];
3906                                         if (TypeManager.IsOverride (m)) {
3907                                                 if (candidate_overrides == null)
3908                                                         candidate_overrides = new ArrayList ();
3909                                                 candidate_overrides.Add (m);
3910                                                 m = TypeManager.TryGetBaseDefinition (m);
3911                                         }
3912                                         if (m != null)
3913                                                 Methods [j++] = m;
3914                                 }
3915                                 nmethods = j;
3916                         }
3917
3918                         //
3919                         // Enable message recording, it's used mainly by lambda expressions
3920                         //
3921                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
3922                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
3923
3924                         //
3925                         // First we construct the set of applicable methods
3926                         //
3927                         bool is_sorted = true;
3928                         int best_candidate_rate = int.MaxValue;
3929                         for (int i = 0; i < nmethods; i++) {
3930                                 Type decl_type = Methods [i].DeclaringType;
3931
3932                                 //
3933                                 // If we have already found an applicable method
3934                                 // we eliminate all base types (Section 14.5.5.1)
3935                                 //
3936                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
3937                                         continue;
3938
3939                                 //
3940                                 // Check if candidate is applicable (section 14.4.2.1)
3941                                 //
3942                                 bool params_expanded_form = false;
3943                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
3944
3945                                 if (candidate_rate < best_candidate_rate) {
3946                                         best_candidate_rate = candidate_rate;
3947                                         best_candidate = Methods [i];
3948                                 }
3949
3950                                 if (params_expanded_form) {
3951                                         if (candidate_to_form == null)
3952                                                 candidate_to_form = new PtrHashtable ();
3953                                         MethodBase candidate = Methods [i];
3954                                         candidate_to_form [candidate] = candidate;
3955                                 }
3956
3957                                 if (candidate_rate != 0) {
3958                                         if (msg_recorder != null)
3959                                                 msg_recorder.EndSession ();
3960                                         continue;
3961                                 }
3962
3963                                 msg_recorder = null;
3964                                 candidates.Add (Methods [i]);
3965
3966                                 if (applicable_type == null)
3967                                         applicable_type = decl_type;
3968                                 else if (applicable_type != decl_type) {
3969                                         is_sorted = false;
3970                                         if (IsAncestralType (applicable_type, decl_type))
3971                                                 applicable_type = decl_type;
3972                                 }
3973                         }
3974
3975                         Report.SetMessageRecorder (prev_recorder);
3976                         if (msg_recorder != null && msg_recorder.PrintMessages ())
3977                                 return null;
3978
3979                         int candidate_top = candidates.Count;
3980
3981                         if (applicable_type == null) {
3982                                 //
3983                                 // When we found a top level method which does not match and it's
3984                                 // not an extension method. We start extension methods lookup from here
3985                                 //
3986                                 if (InstanceExpression != null) {
3987                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name);
3988                                         if (ex_method_lookup != null) {
3989                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
3990                                                 ex_method_lookup.SetTypeArguments (type_arguments);
3991                                                 return ex_method_lookup.OverloadResolve (ec, Arguments, may_fail, loc);
3992                                         }
3993                                 }
3994
3995                                 if (may_fail)
3996                                         return null;
3997
3998                                 //
3999                                 // Okay so we have failed to find exact match so we
4000                                 // return error info about the closest match
4001                                 //
4002                                 if (best_candidate != null) {
4003                                         if (CustomErrorHandler != null) {
4004                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4005                                                         return null;
4006                                         }
4007
4008                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4009                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4010                                         if (arg_count == pd.Count || pd.HasParams) {
4011                                                 if (TypeManager.IsGenericMethod (best_candidate)) {
4012                                                         if (type_arguments == null) {
4013                                                                 Report.Error (411, loc,
4014                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4015                                                                         "the usage. Try specifying the type arguments explicitly",
4016                                                                         TypeManager.CSharpSignature (best_candidate));
4017                                                                 return null;
4018                                                         }
4019
4020                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4021                                                         if (type_arguments.Count != g_args.Length) {
4022                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4023                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4024                                                                         TypeManager.CSharpSignature (best_candidate),
4025                                                                         g_args.Length.ToString ());
4026                                                                 return null;
4027                                                         }
4028                                                 } else {
4029                                                         if (type_arguments != null) {
4030                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4031                                                                 return null;
4032                                                         }
4033                                                 }
4034
4035                                                 if (VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4036                                                         throw new InternalErrorException ("Overload verification expected failure");
4037                                                 return null;
4038                                         }
4039                                 }
4040
4041                                 if (almost_matched_members.Count != 0) {
4042                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4043                                         null, MemberTypes.Constructor, AllBindingFlags);
4044                                         return null;
4045                                 }
4046
4047                                 //
4048                                 // We failed to find any method with correct argument count
4049                                 //
4050                                 if (Name == ConstructorInfo.ConstructorName) {
4051                                         Report.SymbolRelatedToPreviousError (type);
4052                                         Report.Error (1729, loc,
4053                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4054                                                 TypeManager.CSharpName (type), arg_count);
4055                                 } else {
4056                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4057                                                 Name, arg_count.ToString ());
4058                                 }
4059
4060                                 return null;
4061                         }
4062
4063                         if (!is_sorted) {
4064                                 //
4065                                 // At this point, applicable_type is _one_ of the most derived types
4066                                 // in the set of types containing the methods in this MethodGroup.
4067                                 // Filter the candidates so that they only contain methods from the
4068                                 // most derived types.
4069                                 //
4070
4071                                 int finalized = 0; // Number of finalized candidates
4072
4073                                 do {
4074                                         // Invariant: applicable_type is a most derived type
4075
4076                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4077                                         // eliminating all it's base types.  At the same time, we'll also move
4078                                         // every unrelated type to the end of the array, and pick the next
4079                                         // 'applicable_type'.
4080
4081                                         Type next_applicable_type = null;
4082                                         int j = finalized; // where to put the next finalized candidate
4083                                         int k = finalized; // where to put the next undiscarded candidate
4084                                         for (int i = finalized; i < candidate_top; ++i) {
4085                                                 MethodBase candidate = (MethodBase) candidates [i];
4086                                                 Type decl_type = candidate.DeclaringType;
4087
4088                                                 if (decl_type == applicable_type) {
4089                                                         candidates [k++] = candidates [j];
4090                                                         candidates [j++] = candidates [i];
4091                                                         continue;
4092                                                 }
4093
4094                                                 if (IsAncestralType (decl_type, applicable_type))
4095                                                         continue;
4096
4097                                                 if (next_applicable_type != null &&
4098                                                         IsAncestralType (decl_type, next_applicable_type))
4099                                                         continue;
4100
4101                                                 candidates [k++] = candidates [i];
4102
4103                                                 if (next_applicable_type == null ||
4104                                                         IsAncestralType (next_applicable_type, decl_type))
4105                                                         next_applicable_type = decl_type;
4106                                         }
4107
4108                                         applicable_type = next_applicable_type;
4109                                         finalized = j;
4110                                         candidate_top = k;
4111                                 } while (applicable_type != null);
4112                         }
4113
4114                         //
4115                         // Now we actually find the best method
4116                         //
4117
4118                         best_candidate = (MethodBase) candidates [0];
4119                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4120                         for (int ix = 1; ix < candidate_top; ix++) {
4121                                 MethodBase candidate = (MethodBase) candidates [ix];
4122
4123                                 if (candidate == best_candidate)
4124                                         continue;
4125
4126                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4127
4128                                 if (BetterFunction (ec, Arguments, arg_count,
4129                                         candidate, cand_params,
4130                                         best_candidate, method_params)) {
4131                                         best_candidate = candidate;
4132                                         method_params = cand_params;
4133                                 }
4134                         }
4135                         //
4136                         // Now check that there are no ambiguities i.e the selected method
4137                         // should be better than all the others
4138                         //
4139                         MethodBase ambiguous = null;
4140                         for (int ix = 0; ix < candidate_top; ix++) {
4141                                 MethodBase candidate = (MethodBase) candidates [ix];
4142
4143                                 if (candidate == best_candidate)
4144                                         continue;
4145
4146                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4147                                 if (!BetterFunction (ec, Arguments, arg_count,
4148                                         best_candidate, method_params,
4149                                         candidate, cand_params))
4150                                 {
4151                                         if (!may_fail)
4152                                                 Report.SymbolRelatedToPreviousError (candidate);
4153                                         ambiguous = candidate;
4154                                 }
4155                         }
4156
4157                         if (ambiguous != null) {
4158                                 Report.SymbolRelatedToPreviousError (best_candidate);
4159                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4160                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4161                                 return this;
4162                         }
4163
4164                         //
4165                         // If the method is a virtual function, pick an override closer to the LHS type.
4166                         //
4167                         if (!IsBase && best_candidate.IsVirtual) {
4168                                 if (TypeManager.IsOverride (best_candidate))
4169                                         throw new InternalErrorException (
4170                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4171
4172                                 if (candidate_overrides != null) {
4173                                         Type[] gen_args = null;
4174                                         bool gen_override = false;
4175                                         if (TypeManager.IsGenericMethod (best_candidate))
4176                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4177
4178                                         foreach (MethodBase candidate in candidate_overrides) {
4179                                                 if (TypeManager.IsGenericMethod (candidate)) {
4180                                                         if (gen_args == null)
4181                                                                 continue;
4182
4183                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4184                                                                 continue;
4185                                                 } else {
4186                                                         if (gen_args != null)
4187                                                                 continue;
4188                                                 }
4189
4190                                                 if (IsOverride (candidate, best_candidate)) {
4191                                                         gen_override = true;
4192                                                         best_candidate = candidate;
4193                                                 }
4194                                         }
4195
4196                                         if (gen_override && gen_args != null) {
4197 #if GMCS_SOURCE
4198                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4199 #endif
4200                                         }
4201                                 }
4202                         }
4203
4204                         //
4205                         // And now check if the arguments are all
4206                         // compatible, perform conversions if
4207                         // necessary etc. and return if everything is
4208                         // all right
4209                         //
4210                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate,
4211                                 method_params, may_fail, loc))
4212                                 return null;
4213
4214                         if (best_candidate == null)
4215                                 return null;
4216
4217                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4218 #if GMCS_SOURCE
4219                         if (the_method.IsGenericMethodDefinition &&
4220                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4221                                 return null;
4222 #endif
4223
4224                         IMethodData data = TypeManager.GetMethod (the_method);
4225                         if (data != null)
4226                                 data.SetMemberIsUsed ();
4227
4228                         return this;
4229                 }
4230
4231                 public override void SetTypeArguments (TypeArguments ta)
4232                 {
4233                         type_arguments = ta;
4234                 }
4235
4236                 public bool VerifyArgumentsCompat (EmitContext ec, ArrayList arguments,
4237                                                           int arg_count, MethodBase method,
4238                                                           bool chose_params_expanded,
4239                                                           bool may_fail, Location loc)
4240                 {
4241                         ParameterData pd = TypeManager.GetParameterData (method);
4242
4243                         int errors = Report.Errors;
4244                         Parameter.Modifier p_mod = 0;
4245                         Type pt = null;
4246                         int a_idx = 0;
4247                         Argument a = null;
4248                         for (; a_idx < arg_count; a_idx++) {
4249                                 a = (Argument) arguments [a_idx];
4250                                 if (p_mod != Parameter.Modifier.PARAMS) {
4251                                         p_mod = pd.ParameterModifier (a_idx);
4252                                         pt = pd.ParameterType (a_idx);
4253
4254                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4255                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4256                                                         break;
4257                                                 continue;
4258                                         }
4259
4260                                         if (pt.IsPointer && !ec.InUnsafe) {
4261                                                 if (may_fail)
4262                                                         return false;
4263
4264                                                 UnsafeError (loc);
4265                                         }
4266
4267                                         if (p_mod == Parameter.Modifier.PARAMS) {
4268                                                 if (chose_params_expanded)
4269                                                         pt = TypeManager.GetElementType (pt);
4270                                         } else if (p_mod != 0) {
4271                                                 pt = TypeManager.GetElementType (pt);
4272                                         }
4273                                 }
4274
4275                                 //
4276                                 // Types have to be identical when ref or out modifer is used
4277                                 //
4278                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4279                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4280                                                 break;
4281
4282                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4283                                                 break;
4284
4285                                         continue;
4286                                 }
4287
4288                                 if (TypeManager.IsEqual (a.Type, pt))
4289                                         continue;
4290
4291                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4292                                 if (conv == null)
4293                                         break;
4294
4295                                 if (!chose_params_expanded && (p_mod & Parameter.Modifier.PARAMS) != 0 && a.Type == TypeManager.null_type)
4296                                         conv.Type = pd.ParameterType (a_idx);
4297
4298                                 // Update the argument with the implicit conversion
4299                                 a.Expr = conv;
4300                         }
4301
4302                         if (a_idx == arg_count)
4303                                 return true;
4304
4305                         if (!may_fail && Report.Errors == errors)
4306                                 Error_InvalidArguments (ec, loc, a_idx, method, a, pd, pt);
4307                         return false;
4308                 }
4309         }
4310
4311         public class ConstantExpr : MemberExpr
4312         {
4313                 FieldInfo constant;
4314
4315                 public ConstantExpr (FieldInfo constant, Location loc)
4316                 {
4317                         this.constant = constant;
4318                         this.loc = loc;
4319                 }
4320
4321                 public override string Name {
4322                         get { throw new NotImplementedException (); }
4323                 }
4324
4325                 public override bool IsInstance {
4326                         get { return !IsStatic; }
4327                 }
4328
4329                 public override bool IsStatic {
4330                         get { return constant.IsStatic; }
4331                 }
4332
4333                 public override Type DeclaringType {
4334                         get { return constant.DeclaringType; }
4335                 }
4336
4337                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4338                 {
4339                         constant = TypeManager.GetGenericFieldDefinition (constant);
4340
4341                         IConstant ic = TypeManager.GetConstant (constant);
4342                         if (ic == null) {
4343                                 if (constant.IsLiteral) {
4344                                         ic = new ExternalConstant (constant);
4345                                 } else {
4346                                         ic = ExternalConstant.CreateDecimal (constant);
4347                                         // HACK: decimal field was not resolved as constant
4348                                         if (ic == null)
4349                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4350                                 }
4351                                 TypeManager.RegisterConstant (constant, ic);
4352                         }
4353
4354                         return base.ResolveMemberAccess (ec, left, loc, original);
4355                 }
4356
4357                 public override Expression DoResolve (EmitContext ec)
4358                 {
4359                         IConstant ic = TypeManager.GetConstant (constant);
4360                         if (ic.ResolveValue ()) {
4361                                 if (!ec.IsInObsoleteScope)
4362                                         ic.CheckObsoleteness (loc);
4363                         }
4364
4365                         return ic.CreateConstantReference (loc);
4366                 }
4367
4368                 public override void Emit (EmitContext ec)
4369                 {
4370                         throw new NotSupportedException ();
4371                 }
4372
4373                 public override string GetSignatureForError ()
4374                 {
4375                         return TypeManager.GetFullNameSignature (constant);
4376                 }
4377         }
4378
4379         /// <summary>
4380         ///   Fully resolved expression that evaluates to a Field
4381         /// </summary>
4382         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4383                 public readonly FieldInfo FieldInfo;
4384                 VariableInfo variable_info;
4385
4386                 LocalTemporary temp;
4387                 bool prepared;
4388                 bool in_initializer;
4389
4390                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4391                         this (fi, l)
4392                 {
4393                         this.in_initializer = in_initializer;
4394                 }
4395
4396                 public FieldExpr (FieldInfo fi, Location l)
4397                 {
4398                         FieldInfo = fi;
4399                         eclass = ExprClass.Variable;
4400                         type = TypeManager.TypeToCoreType (fi.FieldType);
4401                         loc = l;
4402                 }
4403
4404                 public override string Name {
4405                         get {
4406                                 return FieldInfo.Name;
4407                         }
4408                 }
4409
4410                 public override bool IsInstance {
4411                         get {
4412                                 return !FieldInfo.IsStatic;
4413                         }
4414                 }
4415
4416                 public override bool IsStatic {
4417                         get {
4418                                 return FieldInfo.IsStatic;
4419                         }
4420                 }
4421
4422                 public override Type DeclaringType {
4423                         get {
4424                                 return FieldInfo.DeclaringType;
4425                         }
4426                 }
4427
4428                 public override string GetSignatureForError ()
4429                 {
4430                         return TypeManager.GetFullNameSignature (FieldInfo);
4431                 }
4432
4433                 public VariableInfo VariableInfo {
4434                         get {
4435                                 return variable_info;
4436                         }
4437                 }
4438
4439                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4440                                                                 SimpleName original)
4441                 {
4442                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4443                         Type t = fi.FieldType;
4444
4445                         if (t.IsPointer && !ec.InUnsafe) {
4446                                 UnsafeError (loc);
4447                         }
4448
4449                         return base.ResolveMemberAccess (ec, left, loc, original);
4450                 }
4451
4452                 override public Expression DoResolve (EmitContext ec)
4453                 {
4454                         return DoResolve (ec, false, false);
4455                 }
4456
4457                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4458                 {
4459                         if (!FieldInfo.IsStatic){
4460                                 if (InstanceExpression == null){
4461                                         //
4462                                         // This can happen when referencing an instance field using
4463                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4464                                         //
4465                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4466                                         return null;
4467                                 }
4468
4469                                 // Resolve the field's instance expression while flow analysis is turned
4470                                 // off: when accessing a field "a.b", we must check whether the field
4471                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4472
4473                                 if (lvalue_instance) {
4474                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4475                                                 Expression right_side =
4476                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4477                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4478                                         }
4479                                 } else {
4480                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4481                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4482                                 }
4483
4484                                 if (InstanceExpression == null)
4485                                         return null;
4486
4487                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4488                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4489                                 }
4490                         }
4491
4492                         if (!in_initializer && !ec.IsInFieldInitializer) {
4493                                 ObsoleteAttribute oa;
4494                                 FieldBase f = TypeManager.GetField (FieldInfo);
4495                                 if (f != null) {
4496                                         if (!ec.IsInObsoleteScope)
4497                                                 f.CheckObsoleteness (loc);
4498
4499                                         // To be sure that type is external because we do not register generated fields
4500                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4501                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4502                                         if (oa != null)
4503                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4504                                 }
4505                         }
4506
4507                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4508                         if (am != null){
4509                                 if (!FieldInfo.IsStatic){
4510                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4511                                                 Report.Error (1673, loc,
4512                                                 "Anonymous methods inside structs cannot access instance members of `{0}'. Consider copying `{0}' to a local variable outside the anonymous method and using the local instead",
4513                                                         "this");
4514                                                 return null;
4515                                         }
4516                                 }
4517                         }
4518
4519                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4520                         if (fb != null) {
4521                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4522                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4523                                 }
4524
4525                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4526                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4527                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4528                                                 TypeManager.GetFullNameSignature (FieldInfo));
4529                                 }
4530
4531                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4532                         }
4533
4534                         // If the instance expression is a local variable or parameter.
4535                         IVariable var = InstanceExpression as IVariable;
4536                         if ((var == null) || (var.VariableInfo == null))
4537                                 return this;
4538
4539                         VariableInfo vi = var.VariableInfo;
4540                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4541                                 return null;
4542
4543                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4544                         return this;
4545                 }
4546
4547                 static readonly int [] codes = {
4548                         191,    // instance, write access
4549                         192,    // instance, out access
4550                         198,    // static, write access
4551                         199,    // static, out access
4552                         1648,   // member of value instance, write access
4553                         1649,   // member of value instance, out access
4554                         1650,   // member of value static, write access
4555                         1651    // member of value static, out access
4556                 };
4557
4558                 static readonly string [] msgs = {
4559                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4560                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4561                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4562                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4563                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4564                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4565                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4566                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4567                 };
4568
4569                 // The return value is always null.  Returning a value simplifies calling code.
4570                 Expression Report_AssignToReadonly (Expression right_side)
4571                 {
4572                         int i = 0;
4573                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4574                                 i += 1;
4575                         if (IsStatic)
4576                                 i += 2;
4577                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4578                                 i += 4;
4579                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4580
4581                         return null;
4582                 }
4583
4584                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4585                 {
4586                         IVariable var = InstanceExpression as IVariable;
4587                         if ((var != null) && (var.VariableInfo != null))
4588                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4589
4590                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4591                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4592
4593                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4594
4595                         if (e == null)
4596                                 return null;
4597
4598                         FieldBase fb = TypeManager.GetField (FieldInfo);
4599                         if (fb != null)
4600                                 fb.SetAssigned ();
4601
4602                         if (FieldInfo.IsInitOnly) {
4603                                 // InitOnly fields can only be assigned in constructors or initializers
4604                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4605                                         return Report_AssignToReadonly (right_side);
4606
4607                                 if (ec.IsConstructor) {
4608                                         Type ctype = ec.TypeContainer.CurrentType;
4609                                         if (ctype == null)
4610                                                 ctype = ec.ContainerType;
4611
4612                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4613                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4614                                                 return Report_AssignToReadonly (right_side);
4615                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4616                                         if (IsStatic && !ec.IsStatic)
4617                                                 return Report_AssignToReadonly (right_side);
4618                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4619                                         if (!IsStatic && !(InstanceExpression is This))
4620                                                 return Report_AssignToReadonly (right_side);
4621                                 }
4622                         }
4623
4624                         if (right_side == EmptyExpression.OutAccess &&
4625                             !IsStatic && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4626                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4627                                 Report.Warning (197, 1, loc,
4628                                                 "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",
4629                                                 GetSignatureForError ());
4630                         }
4631
4632                         return this;
4633                 }
4634
4635                 public override void CheckMarshalByRefAccess (EmitContext ec)
4636                 {
4637                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4638                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4639                                 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",
4640                                                 GetSignatureForError ());
4641                         }
4642                 }
4643
4644                 public bool VerifyFixed ()
4645                 {
4646                         IVariable variable = InstanceExpression as IVariable;
4647                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4648                         // We defer the InstanceExpression check after the variable check to avoid a
4649                         // separate null check on InstanceExpression.
4650                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4651                 }
4652
4653                 public override int GetHashCode ()
4654                 {
4655                         return FieldInfo.GetHashCode ();
4656                 }
4657
4658                 public override bool Equals (object obj)
4659                 {
4660                         FieldExpr fe = obj as FieldExpr;
4661                         if (fe == null)
4662                                 return false;
4663
4664                         if (FieldInfo != fe.FieldInfo)
4665                                 return false;
4666
4667                         if (InstanceExpression == null || fe.InstanceExpression == null)
4668                                 return true;
4669
4670                         return InstanceExpression.Equals (fe.InstanceExpression);
4671                 }
4672
4673                 public void Emit (EmitContext ec, bool leave_copy)
4674                 {
4675                         ILGenerator ig = ec.ig;
4676                         bool is_volatile = false;
4677
4678                         FieldBase f = TypeManager.GetField (FieldInfo);
4679                         if (f != null){
4680                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4681                                         is_volatile = true;
4682
4683                                 f.SetMemberIsUsed ();
4684                         }
4685
4686                         if (FieldInfo.IsStatic){
4687                                 if (is_volatile)
4688                                         ig.Emit (OpCodes.Volatile);
4689
4690                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4691                         } else {
4692                                 if (!prepared)
4693                                         EmitInstance (ec, false);
4694
4695                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4696                                 if (ff != null) {
4697                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4698                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4699                                 } else {
4700                                         if (is_volatile)
4701                                                 ig.Emit (OpCodes.Volatile);
4702
4703                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4704                                 }
4705                         }
4706
4707                         if (leave_copy) {
4708                                 ec.ig.Emit (OpCodes.Dup);
4709                                 if (!FieldInfo.IsStatic) {
4710                                         temp = new LocalTemporary (this.Type);
4711                                         temp.Store (ec);
4712                                 }
4713                         }
4714                 }
4715
4716                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4717                 {
4718                         FieldAttributes fa = FieldInfo.Attributes;
4719                         bool is_static = (fa & FieldAttributes.Static) != 0;
4720                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4721                         ILGenerator ig = ec.ig;
4722
4723                         if (is_readonly && !ec.IsConstructor){
4724                                 Report_AssignToReadonly (source);
4725                                 return;
4726                         }
4727
4728                         //
4729                         // String concatenation creates a new string instance
4730                         //
4731                         prepared = prepare_for_load && !(source is StringConcat);
4732                         EmitInstance (ec, prepared);
4733
4734                         source.Emit (ec);
4735                         if (leave_copy) {
4736                                 ec.ig.Emit (OpCodes.Dup);
4737                                 if (!FieldInfo.IsStatic) {
4738                                         temp = new LocalTemporary (this.Type);
4739                                         temp.Store (ec);
4740                                 }
4741                         }
4742
4743                         FieldBase f = TypeManager.GetField (FieldInfo);
4744                         if (f != null){
4745                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4746                                         ig.Emit (OpCodes.Volatile);
4747
4748                                 f.SetAssigned ();
4749                         }
4750
4751                         if (is_static)
4752                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4753                         else
4754                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4755
4756                         if (temp != null) {
4757                                 temp.Emit (ec);
4758                                 temp.Release (ec);
4759                         }
4760                 }
4761
4762                 public override void Emit (EmitContext ec)
4763                 {
4764                         Emit (ec, false);
4765                 }
4766
4767                 public void AddressOf (EmitContext ec, AddressOp mode)
4768                 {
4769                         ILGenerator ig = ec.ig;
4770
4771                         FieldBase f = TypeManager.GetField (FieldInfo);
4772                         if (f != null){
4773                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4774                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4775                                                         f.GetSignatureForError ());
4776                                 }
4777
4778                                 if ((mode & AddressOp.Store) != 0)
4779                                         f.SetAssigned ();
4780                                 if ((mode & AddressOp.Load) != 0)
4781                                         f.SetMemberIsUsed ();
4782                         }
4783
4784                         //
4785                         // Handle initonly fields specially: make a copy and then
4786                         // get the address of the copy.
4787                         //
4788                         bool need_copy;
4789                         if (FieldInfo.IsInitOnly){
4790                                 need_copy = true;
4791                                 if (ec.IsConstructor){
4792                                         if (FieldInfo.IsStatic){
4793                                                 if (ec.IsStatic)
4794                                                         need_copy = false;
4795                                         } else
4796                                                 need_copy = false;
4797                                 }
4798                         } else
4799                                 need_copy = false;
4800
4801                         if (need_copy){
4802                                 LocalBuilder local;
4803                                 Emit (ec);
4804                                 local = ig.DeclareLocal (type);
4805                                 ig.Emit (OpCodes.Stloc, local);
4806                                 ig.Emit (OpCodes.Ldloca, local);
4807                                 return;
4808                         }
4809
4810
4811                         if (FieldInfo.IsStatic){
4812                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
4813                         } else {
4814                                 if (!prepared)
4815                                         EmitInstance (ec, false);
4816                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
4817                         }
4818                 }
4819         }
4820
4821
4822         /// <summary>
4823         ///   Expression that evaluates to a Property.  The Assign class
4824         ///   might set the `Value' expression if we are in an assignment.
4825         ///
4826         ///   This is not an LValue because we need to re-write the expression, we
4827         ///   can not take data from the stack and store it.
4828         /// </summary>
4829         public class PropertyExpr : MemberExpr, IAssignMethod {
4830                 public readonly PropertyInfo PropertyInfo;
4831                 MethodInfo getter, setter;
4832                 bool is_static;
4833
4834                 bool resolved;
4835
4836                 LocalTemporary temp;
4837                 bool prepared;
4838
4839                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
4840                 {
4841                         PropertyInfo = pi;
4842                         eclass = ExprClass.PropertyAccess;
4843                         is_static = false;
4844                         loc = l;
4845
4846                         type = TypeManager.TypeToCoreType (pi.PropertyType);
4847
4848                         ResolveAccessors (container_type);
4849                 }
4850
4851                 public override string Name {
4852                         get {
4853                                 return PropertyInfo.Name;
4854                         }
4855                 }
4856
4857                 public override bool IsInstance {
4858                         get {
4859                                 return !is_static;
4860                         }
4861                 }
4862
4863                 public override bool IsStatic {
4864                         get {
4865                                 return is_static;
4866                         }
4867                 }
4868
4869                 public override Type DeclaringType {
4870                         get {
4871                                 return PropertyInfo.DeclaringType;
4872                         }
4873                 }
4874
4875                 public override string GetSignatureForError ()
4876                 {
4877                         return TypeManager.GetFullNameSignature (PropertyInfo);
4878                 }
4879
4880                 void FindAccessors (Type invocation_type)
4881                 {
4882                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
4883                                 BindingFlags.Static | BindingFlags.Instance |
4884                                 BindingFlags.DeclaredOnly;
4885
4886                         Type current = PropertyInfo.DeclaringType;
4887                         for (; current != null; current = current.BaseType) {
4888                                 MemberInfo[] group = TypeManager.MemberLookup (
4889                                         invocation_type, invocation_type, current,
4890                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
4891
4892                                 if (group == null)
4893                                         continue;
4894
4895                                 if (group.Length != 1)
4896                                         // Oooops, can this ever happen ?
4897                                         return;
4898
4899                                 PropertyInfo pi = (PropertyInfo) group [0];
4900
4901                                 if (getter == null)
4902                                         getter = pi.GetGetMethod (true);
4903
4904                                 if (setter == null)
4905                                         setter = pi.GetSetMethod (true);
4906
4907                                 MethodInfo accessor = getter != null ? getter : setter;
4908
4909                                 if (!accessor.IsVirtual)
4910                                         return;
4911                         }
4912                 }
4913
4914                 //
4915                 // We also perform the permission checking here, as the PropertyInfo does not
4916                 // hold the information for the accessibility of its setter/getter
4917                 //
4918                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
4919                 void ResolveAccessors (Type container_type)
4920                 {
4921                         FindAccessors (container_type);
4922
4923                         if (getter != null) {
4924                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
4925                                 IMethodData md = TypeManager.GetMethod (the_getter);
4926                                 if (md != null)
4927                                         md.SetMemberIsUsed ();
4928
4929                                 is_static = getter.IsStatic;
4930                         }
4931
4932                         if (setter != null) {
4933                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
4934                                 IMethodData md = TypeManager.GetMethod (the_setter);
4935                                 if (md != null)
4936                                         md.SetMemberIsUsed ();
4937
4938                                 is_static = setter.IsStatic;
4939                         }
4940                 }
4941
4942                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
4943                 {
4944                         if (is_static) {
4945                                 InstanceExpression = null;
4946                                 return true;
4947                         }
4948
4949                         if (InstanceExpression == null) {
4950                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4951                                 return false;
4952                         }
4953
4954                         InstanceExpression = InstanceExpression.DoResolve (ec);
4955                         if (lvalue_instance && InstanceExpression != null)
4956                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
4957
4958                         if (InstanceExpression == null)
4959                                 return false;
4960
4961                         InstanceExpression.CheckMarshalByRefAccess (ec);
4962
4963                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
4964                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
4965                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
4966                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
4967                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
4968                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
4969                                 return false;
4970                         }
4971
4972                         return true;
4973                 }
4974
4975                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
4976                 {
4977                         // TODO: correctly we should compare arguments but it will lead to bigger changes
4978                         if (mi is MethodBuilder) {
4979                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
4980                                 return;
4981                         }
4982
4983                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
4984                         sig.Append ('.');
4985                         ParameterData iparams = TypeManager.GetParameterData (mi);
4986                         sig.Append (getter ? "get_" : "set_");
4987                         sig.Append (Name);
4988                         sig.Append (iparams.GetSignatureForError ());
4989
4990                         Report.SymbolRelatedToPreviousError (mi);
4991                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
4992                                 Name, sig.ToString ());
4993                 }
4994
4995                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
4996                 {
4997                         bool dummy;
4998                         MethodInfo accessor = lvalue ? setter : getter;
4999                         if (accessor == null && lvalue)
5000                                 accessor = getter;
5001                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5002                 }
5003
5004                 override public Expression DoResolve (EmitContext ec)
5005                 {
5006                         if (resolved)
5007                                 return this;
5008
5009                         if (getter != null){
5010                                 if (TypeManager.GetParameterData (getter).Count != 0){
5011                                         Error_PropertyNotFound (getter, true);
5012                                         return null;
5013                                 }
5014                         }
5015
5016                         if (getter == null){
5017                                 //
5018                                 // The following condition happens if the PropertyExpr was
5019                                 // created, but is invalid (ie, the property is inaccessible),
5020                                 // and we did not want to embed the knowledge about this in
5021                                 // the caller routine.  This only avoids double error reporting.
5022                                 //
5023                                 if (setter == null)
5024                                         return null;
5025
5026                                 if (InstanceExpression != EmptyExpression.Null) {
5027                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5028                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5029                                         return null;
5030                                 }
5031                         }
5032
5033                         bool must_do_cs1540_check = false;
5034                         if (getter != null &&
5035                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5036                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5037                                 if (pm != null && pm.HasCustomAccessModifier) {
5038                                         Report.SymbolRelatedToPreviousError (pm);
5039                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5040                                                 TypeManager.CSharpSignature (getter));
5041                                 }
5042                                 else {
5043                                         Report.SymbolRelatedToPreviousError (getter);
5044                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5045                                 }
5046                                 return null;
5047                         }
5048
5049                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5050                                 return null;
5051
5052                         //
5053                         // Only base will allow this invocation to happen.
5054                         //
5055                         if (IsBase && getter.IsAbstract) {
5056                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5057                                 return null;
5058                         }
5059
5060                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5061                                 UnsafeError (loc);
5062                                 return null;
5063                         }
5064
5065                         resolved = true;
5066
5067                         return this;
5068                 }
5069
5070                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5071                 {
5072                         if (right_side == EmptyExpression.OutAccess) {
5073                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5074                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5075                                             PropertyInfo.Name);
5076                                 } else {
5077                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5078                                               GetSignatureForError ());
5079                                 }
5080                                 return null;
5081                         }
5082
5083                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5084                                 Error_CannotModifyIntermediateExpressionValue (ec);
5085                         }
5086
5087                         if (setter == null){
5088                                 //
5089                                 // The following condition happens if the PropertyExpr was
5090                                 // created, but is invalid (ie, the property is inaccessible),
5091                                 // and we did not want to embed the knowledge about this in
5092                                 // the caller routine.  This only avoids double error reporting.
5093                                 //
5094                                 if (getter == null)
5095                                         return null;
5096                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5097                                               GetSignatureForError ());
5098                                 return null;
5099                         }
5100
5101                         if (TypeManager.GetParameterData (setter).Count != 1){
5102                                 Error_PropertyNotFound (setter, false);
5103                                 return null;
5104                         }
5105
5106                         bool must_do_cs1540_check;
5107                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5108                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5109                                 if (pm != null && pm.HasCustomAccessModifier) {
5110                                         Report.SymbolRelatedToPreviousError (pm);
5111                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5112                                                 TypeManager.CSharpSignature (setter));
5113                                 }
5114                                 else {
5115                                         Report.SymbolRelatedToPreviousError (setter);
5116                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5117                                 }
5118                                 return null;
5119                         }
5120
5121                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5122                                 return null;
5123
5124                         //
5125                         // Only base will allow this invocation to happen.
5126                         //
5127                         if (IsBase && setter.IsAbstract){
5128                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5129                                 return null;
5130                         }
5131
5132                         return this;
5133                 }
5134
5135                 public override void Emit (EmitContext ec)
5136                 {
5137                         Emit (ec, false);
5138                 }
5139
5140                 public void Emit (EmitContext ec, bool leave_copy)
5141                 {
5142                         //
5143                         // Special case: length of single dimension array property is turned into ldlen
5144                         //
5145                         if ((getter == TypeManager.system_int_array_get_length) ||
5146                             (getter == TypeManager.int_array_get_length)){
5147                                 Type iet = InstanceExpression.Type;
5148
5149                                 //
5150                                 // System.Array.Length can be called, but the Type does not
5151                                 // support invoking GetArrayRank, so test for that case first
5152                                 //
5153                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
5154                                         if (!prepared)
5155                                                 EmitInstance (ec, false);
5156                                         ec.ig.Emit (OpCodes.Ldlen);
5157                                         ec.ig.Emit (OpCodes.Conv_I4);
5158                                         return;
5159                                 }
5160                         }
5161
5162                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5163
5164                         if (leave_copy) {
5165                                 ec.ig.Emit (OpCodes.Dup);
5166                                 if (!is_static) {
5167                                         temp = new LocalTemporary (this.Type);
5168                                         temp.Store (ec);
5169                                 }
5170                         }
5171                 }
5172
5173                 //
5174                 // Implements the IAssignMethod interface for assignments
5175                 //
5176                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5177                 {
5178                         Expression my_source = source;
5179
5180                         if (prepare_for_load) {
5181                                 if (source is StringConcat)
5182                                         EmitInstance (ec, false);
5183                                 else
5184                                         prepared = true;
5185
5186                                 source.Emit (ec);
5187
5188                                 prepared = true;
5189                                 if (leave_copy) {
5190                                         ec.ig.Emit (OpCodes.Dup);
5191                                         if (!is_static) {
5192                                                 temp = new LocalTemporary (this.Type);
5193                                                 temp.Store (ec);
5194                                         }
5195                                 }
5196                         } else if (leave_copy) {
5197                                 source.Emit (ec);
5198                                 temp = new LocalTemporary (this.Type);
5199                                 temp.Store (ec);
5200                                 my_source = temp;
5201                         }
5202
5203                         ArrayList args = new ArrayList (1);
5204                         args.Add (new Argument (my_source, Argument.AType.Expression));
5205
5206                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5207
5208                         if (temp != null) {
5209                                 temp.Emit (ec);
5210                                 temp.Release (ec);
5211                         }
5212                 }
5213         }
5214
5215         /// <summary>
5216         ///   Fully resolved expression that evaluates to an Event
5217         /// </summary>
5218         public class EventExpr : MemberExpr {
5219                 public readonly EventInfo EventInfo;
5220
5221                 bool is_static;
5222                 MethodInfo add_accessor, remove_accessor;
5223
5224                 public EventExpr (EventInfo ei, Location loc)
5225                 {
5226                         EventInfo = ei;
5227                         this.loc = loc;
5228                         eclass = ExprClass.EventAccess;
5229
5230                         add_accessor = TypeManager.GetAddMethod (ei);
5231                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5232                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5233                                 is_static = true;
5234
5235                         if (EventInfo is MyEventBuilder){
5236                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5237                                 type = eb.EventType;
5238                                 eb.SetUsed ();
5239                         } else
5240                                 type = EventInfo.EventHandlerType;
5241                 }
5242
5243                 public override string Name {
5244                         get {
5245                                 return EventInfo.Name;
5246                         }
5247                 }
5248
5249                 public override bool IsInstance {
5250                         get {
5251                                 return !is_static;
5252                         }
5253                 }
5254
5255                 public override bool IsStatic {
5256                         get {
5257                                 return is_static;
5258                         }
5259                 }
5260
5261                 public override Type DeclaringType {
5262                         get {
5263                                 return EventInfo.DeclaringType;
5264                         }
5265                 }
5266
5267                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5268                                                                 SimpleName original)
5269                 {
5270                         //
5271                         // If the event is local to this class, we transform ourselves into a FieldExpr
5272                         //
5273
5274                         if (EventInfo.DeclaringType == ec.ContainerType ||
5275                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5276                                 EventField mi = TypeManager.GetEventField (EventInfo);
5277
5278                                 if (mi != null) {
5279                                         if (!ec.IsInObsoleteScope)
5280                                                 mi.CheckObsoleteness (loc);
5281
5282                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5283
5284                                         InstanceExpression = null;
5285
5286                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5287                                 }
5288                         }
5289
5290                         return base.ResolveMemberAccess (ec, left, loc, original);
5291                 }
5292
5293
5294                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5295                 {
5296                         if (is_static) {
5297                                 InstanceExpression = null;
5298                                 return true;
5299                         }
5300
5301                         if (InstanceExpression == null) {
5302                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5303                                 return false;
5304                         }
5305
5306                         InstanceExpression = InstanceExpression.DoResolve (ec);
5307                         if (InstanceExpression == null)
5308                                 return false;
5309
5310                         if (IsBase && add_accessor.IsAbstract) {
5311                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5312                                 return false;
5313                         }
5314
5315                         //
5316                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5317                         // However, in the Event case, we reported a CS0122 instead.
5318                         //
5319                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5320                             InstanceExpression.Type != ec.ContainerType &&
5321                             ec.ContainerType.IsSubclassOf (InstanceExpression.Type)) {
5322                                 Report.SymbolRelatedToPreviousError (EventInfo);
5323                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5324                                 return false;
5325                         }
5326
5327                         return true;
5328                 }
5329
5330                 public bool IsAccessibleFrom (Type invocation_type)
5331                 {
5332                         bool dummy;
5333                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5334                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5335                 }
5336
5337                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5338                 {
5339                         return DoResolve (ec);
5340                 }
5341
5342                 public override Expression DoResolve (EmitContext ec)
5343                 {
5344                         bool must_do_cs1540_check;
5345                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5346                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5347                                 Report.SymbolRelatedToPreviousError (EventInfo);
5348                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5349                                 return null;
5350                         }
5351
5352                         if (!InstanceResolve (ec, must_do_cs1540_check))
5353                                 return null;
5354
5355                         return this;
5356                 }
5357
5358                 public override void Emit (EmitContext ec)
5359                 {
5360                         if (InstanceExpression is This)
5361                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=", GetSignatureForError ());
5362                         else
5363                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5364                                               "(except on the defining type)", Name);
5365                 }
5366
5367                 public override string GetSignatureForError ()
5368                 {
5369                         return TypeManager.CSharpSignature (EventInfo);
5370                 }
5371
5372                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5373                 {
5374                         BinaryDelegate source_del = source as BinaryDelegate;
5375                         if (source_del == null) {
5376                                 Emit (ec);
5377                                 return;
5378                         }
5379                         Expression handler = source_del.Right;
5380
5381                         Argument arg = new Argument (handler, Argument.AType.Expression);
5382                         ArrayList args = new ArrayList ();
5383
5384                         args.Add (arg);
5385
5386                         if (source_del.IsAddition)
5387                                 Invocation.EmitCall (
5388                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5389                         else
5390                                 Invocation.EmitCall (
5391                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5392                 }
5393         }
5394
5395         public class TemporaryVariable : Expression, IMemoryLocation
5396         {
5397                 LocalInfo li;
5398                 Variable var;
5399
5400                 public TemporaryVariable (Type type, Location loc)
5401                 {
5402                         this.type = type;
5403                         this.loc = loc;
5404                         eclass = ExprClass.Value;
5405                 }
5406
5407                 public override Expression DoResolve (EmitContext ec)
5408                 {
5409                         if (li != null)
5410                                 return this;
5411
5412                         TypeExpr te = new TypeExpression (type, loc);
5413                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5414                         if (!li.Resolve (ec))
5415                                 return null;
5416
5417                         if (ec.MustCaptureVariable (li)) {
5418                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5419                                 var = scope.AddLocal (li);
5420                                 type = var.Type;
5421                         }
5422
5423                         return this;
5424                 }
5425
5426                 public Variable Variable {
5427                         get { return var != null ? var : li.Variable; }
5428                 }
5429
5430                 public override void Emit (EmitContext ec)
5431                 {
5432                         Variable.EmitInstance (ec);
5433                         Variable.Emit (ec);
5434                 }
5435
5436                 public void EmitLoadAddress (EmitContext ec)
5437                 {
5438                         Variable.EmitInstance (ec);
5439                         Variable.EmitAddressOf (ec);
5440                 }
5441
5442                 public void Store (EmitContext ec, Expression right_side)
5443                 {
5444                         Variable.EmitInstance (ec);
5445                         right_side.Emit (ec);
5446                         Variable.EmitAssign (ec);
5447                 }
5448
5449                 public void EmitThis (EmitContext ec)
5450                 {
5451                         Variable.EmitInstance (ec);
5452                 }
5453
5454                 public void EmitStore (EmitContext ec)
5455                 {
5456                         Variable.EmitAssign (ec);
5457                 }
5458
5459                 public void AddressOf (EmitContext ec, AddressOp mode)
5460                 {
5461                         EmitLoadAddress (ec);
5462                 }
5463         }
5464
5465         ///
5466         /// Handles `var' contextual keyword; var becomes a keyword only
5467         /// if no type called var exists in a variable scope
5468         ///
5469         public class VarExpr : SimpleName
5470         {
5471                 // Used for error reporting only
5472                 ArrayList initializer;
5473
5474                 public VarExpr (Location loc)
5475                         : base ("var", loc)
5476                 {
5477                 }
5478
5479                 public ArrayList VariableInitializer {
5480                         set {
5481                                 this.initializer = value;
5482                         }
5483                 }
5484
5485                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5486                 {
5487                         if (type != null)
5488                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5489
5490                         type = right_side.Type;
5491                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5492                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5493                                               right_side.GetSignatureForError ());
5494                                 return null;
5495                         }
5496
5497                         eclass = ExprClass.Variable;
5498                         return this;
5499                 }
5500
5501                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5502                 {
5503                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5504                 }
5505
5506                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5507                 {
5508                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5509                         if (te != null)
5510                                 return te;
5511
5512                         if (initializer == null)
5513                                 return null;
5514
5515                         if (initializer.Count > 1) {
5516                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5517                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5518                                 initializer = null;
5519                                 return null;
5520                         }
5521
5522                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5523                         if (variable_initializer == null) {
5524                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5525                                 return null;
5526                         }
5527
5528                         return null;
5529                 }
5530         }
5531 }