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                 protected virtual void Error_NegativeArrayIndex (Location loc)
 892                 {
 893                         throw new NotImplementedException ();
 894                 }
 895
 896                 /// <summary>
 897                 ///   Returns an expression that can be used to invoke operator true
 898                 ///   on the expression if it exists.
 899                 /// </summary>
 900                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 901                 {
 902                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 903                 }
 904
 905                 /// <summary>
 906                 ///   Returns an expression that can be used to invoke operator false
 907                 ///   on the expression if it exists.
 908                 /// </summary>
 909                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 910                 {
 911                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 912                 }
 913
 914                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 915                 {
 916                         MethodGroupExpr operator_group;
 917
 918 #if GMCS_SOURCE
 919                         if (TypeManager.IsNullableType (e.Type))
 920                                 return new Nullable.OperatorTrueOrFalse (e, is_true, loc).Resolve (ec);
 921 #endif
 922
 923                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 924                         if (operator_group == null)
 925                                 return null;
 926
 927                         ArrayList arguments = new ArrayList (1);
 928                         arguments.Add (new Argument (e, Argument.AType.Expression));
 929                         operator_group = operator_group.OverloadResolve (
 930                                 ec, arguments, false, loc);
 931
 932                         if (operator_group == null)
 933                                 return null;
 934
 935                         return new StaticCallExpr ((MethodInfo) operator_group, arguments, loc);
 936                 }
 937
 938                 /// <summary>
 939                 ///   Resolves the expression `e' into a boolean expression: either through
 940                 ///   an implicit conversion, or through an `operator true' invocation
 941                 /// </summary>
 942                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 943                 {
 944                         e = e.Resolve (ec);
 945                         if (e == null)
 946                                 return null;
 947
 948                         if (e.Type == TypeManager.bool_type)
 949                                 return e;
 950
 951                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 952
 953                         if (converted != null)
 954                                 return converted;
 955
 956                         //
 957                         // If no implicit conversion to bool exists, try using `operator true'
 958                         //
 959                         converted = Expression.GetOperatorTrue (ec, e, loc);
 960                         if (converted == null){
 961                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 962                                 return null;
 963                         }
 964                         return converted;
 965                 }
 966
 967                 public virtual string ExprClassName
 968                 {
 969                         get {
 970                                 switch (eclass){
 971                                         case ExprClass.Invalid:
 972                                                 return "Invalid";
 973                                         case ExprClass.Value:
 974                                                 return "value";
 975                                         case ExprClass.Variable:
 976                                                 return "variable";
 977                                         case ExprClass.Namespace:
 978                                                 return "namespace";
 979                                         case ExprClass.Type:
 980                                                 return "type";
 981                                         case ExprClass.MethodGroup:
 982                                                 return "method group";
 983                                         case ExprClass.PropertyAccess:
 984                                                 return "property access";
 985                                         case ExprClass.EventAccess:
 986                                                 return "event access";
 987                                         case ExprClass.IndexerAccess:
 988                                                 return "indexer access";
 989                                         case ExprClass.Nothing:
 990                                                 return "null";
 991                                 }
 992                                 throw new Exception ("Should not happen");
 993                         }
 994                 }
 995
 996                 /// <summary>
 997                 ///   Reports that we were expecting `expr' to be of class `expected'
 998                 /// </summary>
 999                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1000                 {
1001                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1002                 }
1003
1004                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1005                 {
1006                         string name = GetSignatureForError ();
1007                         if (ds != null)
1008                                 name = ds.GetSignatureForError () + '.' + name;
1009
1010                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1011                               name, was, expected);
1012                 }
1013
1014                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1015                 {
1016                         string [] valid = new string [4];
1017                         int count = 0;
1018
1019                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1020                                 valid [count++] = "variable";
1021                                 valid [count++] = "value";
1022                         }
1023
1024                         if ((flags & ResolveFlags.Type) != 0)
1025                                 valid [count++] = "type";
1026
1027                         if ((flags & ResolveFlags.MethodGroup) != 0)
1028                                 valid [count++] = "method group";
1029
1030                         if (count == 0)
1031                                 valid [count++] = "unknown";
1032
1033                         StringBuilder sb = new StringBuilder (valid [0]);
1034                         for (int i = 1; i < count - 1; i++) {
1035                                 sb.Append ("', `");
1036                                 sb.Append (valid [i]);
1037                         }
1038                         if (count > 1) {
1039                                 sb.Append ("' or `");
1040                                 sb.Append (valid [count - 1]);
1041                         }
1042
1043                         Report.Error (119, loc,
1044                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1045                 }
1046
1047                 public static void UnsafeError (Location loc)
1048                 {
1049                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1050                 }
1051
1052                 //
1053                 // Load the object from the pointer.
1054                 //
1055                 public static void LoadFromPtr (ILGenerator ig, Type t)
1056                 {
1057                         if (t == TypeManager.int32_type)
1058                                 ig.Emit (OpCodes.Ldind_I4);
1059                         else if (t == TypeManager.uint32_type)
1060                                 ig.Emit (OpCodes.Ldind_U4);
1061                         else if (t == TypeManager.short_type)
1062                                 ig.Emit (OpCodes.Ldind_I2);
1063                         else if (t == TypeManager.ushort_type)
1064                                 ig.Emit (OpCodes.Ldind_U2);
1065                         else if (t == TypeManager.char_type)
1066                                 ig.Emit (OpCodes.Ldind_U2);
1067                         else if (t == TypeManager.byte_type)
1068                                 ig.Emit (OpCodes.Ldind_U1);
1069                         else if (t == TypeManager.sbyte_type)
1070                                 ig.Emit (OpCodes.Ldind_I1);
1071                         else if (t == TypeManager.uint64_type)
1072                                 ig.Emit (OpCodes.Ldind_I8);
1073                         else if (t == TypeManager.int64_type)
1074                                 ig.Emit (OpCodes.Ldind_I8);
1075                         else if (t == TypeManager.float_type)
1076                                 ig.Emit (OpCodes.Ldind_R4);
1077                         else if (t == TypeManager.double_type)
1078                                 ig.Emit (OpCodes.Ldind_R8);
1079                         else if (t == TypeManager.bool_type)
1080                                 ig.Emit (OpCodes.Ldind_I1);
1081                         else if (t == TypeManager.intptr_type)
1082                                 ig.Emit (OpCodes.Ldind_I);
1083                         else if (TypeManager.IsEnumType (t)) {
1084                                 if (t == TypeManager.enum_type)
1085                                         ig.Emit (OpCodes.Ldind_Ref);
1086                                 else
1087                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1088                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1089                                 ig.Emit (OpCodes.Ldobj, t);
1090                         else if (t.IsPointer)
1091                                 ig.Emit (OpCodes.Ldind_I);
1092                         else
1093                                 ig.Emit (OpCodes.Ldind_Ref);
1094                 }
1095
1096                 //
1097                 // The stack contains the pointer and the value of type `type'
1098                 //
1099                 public static void StoreFromPtr (ILGenerator ig, Type type)
1100                 {
1101                         if (TypeManager.IsEnumType (type))
1102                                 type = TypeManager.EnumToUnderlying (type);
1103                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1104                                 ig.Emit (OpCodes.Stind_I4);
1105                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1106                                 ig.Emit (OpCodes.Stind_I8);
1107                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1108                                  type == TypeManager.ushort_type)
1109                                 ig.Emit (OpCodes.Stind_I2);
1110                         else if (type == TypeManager.float_type)
1111                                 ig.Emit (OpCodes.Stind_R4);
1112                         else if (type == TypeManager.double_type)
1113                                 ig.Emit (OpCodes.Stind_R8);
1114                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1115                                  type == TypeManager.bool_type)
1116                                 ig.Emit (OpCodes.Stind_I1);
1117                         else if (type == TypeManager.intptr_type)
1118                                 ig.Emit (OpCodes.Stind_I);
1119                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1120                                 ig.Emit (OpCodes.Stobj, type);
1121                         else
1122                                 ig.Emit (OpCodes.Stind_Ref);
1123                 }
1124
1125                 //
1126                 // Returns the size of type `t' if known, otherwise, 0
1127                 //
1128                 public static int GetTypeSize (Type t)
1129                 {
1130                         t = TypeManager.TypeToCoreType (t);
1131                         if (t == TypeManager.int32_type ||
1132                             t == TypeManager.uint32_type ||
1133                             t == TypeManager.float_type)
1134                                 return 4;
1135                         else if (t == TypeManager.int64_type ||
1136                                  t == TypeManager.uint64_type ||
1137                                  t == TypeManager.double_type)
1138                                 return 8;
1139                         else if (t == TypeManager.byte_type ||
1140                                  t == TypeManager.sbyte_type ||
1141                                  t == TypeManager.bool_type)
1142                                 return 1;
1143                         else if (t == TypeManager.short_type ||
1144                                  t == TypeManager.char_type ||
1145                                  t == TypeManager.ushort_type)
1146                                 return 2;
1147                         else if (t == TypeManager.decimal_type)
1148                                 return 16;
1149                         else
1150                                 return 0;
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 ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1174                 {
1175                         Expression converted;
1176
1177                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1178                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1179                                 if (converted == null)
1180                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1181                                 if (converted == null)
1182                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1183                                 if (converted == null)
1184                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1185
1186                                 if (converted == null) {
1187                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1188                                         return null;
1189                                 }
1190                         }
1191
1192                         //
1193                         // Only positive constants are allowed at compile time
1194                         //
1195                         Constant c = converted as Constant;
1196                         if (c != null) {
1197                                 if (c.IsNegative) {
1198                                         Error_NegativeArrayIndex (source.loc);
1199                                 }
1200                                 return c;
1201                         }
1202
1203                         return new ArrayIndexCast (converted).Resolve (ec);
1204                 }
1205
1206                 //
1207                 // Derived classes implement this method by cloning the fields that
1208                 // could become altered during the Resolve stage
1209                 //
1210                 // Only expressions that are created for the parser need to implement
1211                 // this.
1212                 //
1213                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1214                 {
1215                         throw new NotImplementedException (
1216                                 String.Format (
1217                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1218                 }
1219
1220                 //
1221                 // Clones an expression created by the parser.
1222                 //
1223                 // We only support expressions created by the parser so far, not
1224                 // expressions that have been resolved (many more classes would need
1225                 // to implement CloneTo).
1226                 //
1227                 // This infrastructure is here merely for Lambda expressions which
1228                 // compile the same code using different type values for the same
1229                 // arguments to find the correct overload
1230                 //
1231                 public Expression Clone (CloneContext clonectx)
1232                 {
1233                         Expression cloned = (Expression) MemberwiseClone ();
1234                         CloneTo (clonectx, cloned);
1235
1236                         return cloned;
1237                 }
1238
1239                 public virtual Expression CreateExpressionTree (EmitContext ec)
1240                 {
1241                         throw new NotImplementedException (
1242                                 "Expression tree conversion not implemented for " + GetType ());
1243                 }
1244
1245                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1246                 {
1247                         return CreateExpressionFactoryCall (name, null, args, loc);
1248                 }
1249
1250                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1251                 {
1252                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1253                 }
1254
1255                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1256                 {
1257                         return new Invocation (
1258                                 new MemberAccess (ExpressionTreeManager.Type, name, typeArguments, loc),
1259                                 args);
1260                 }
1261         }
1262
1263         /// <summary>
1264         ///   This is just a base class for expressions that can
1265         ///   appear on statements (invocations, object creation,
1266         ///   assignments, post/pre increment and decrement).  The idea
1267         ///   being that they would support an extra Emition interface that
1268         ///   does not leave a result on the stack.
1269         /// </summary>
1270         public abstract class ExpressionStatement : Expression {
1271
1272                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1273                 {
1274                         Expression e = Resolve (ec);
1275                         if (e == null)
1276                                 return null;
1277
1278                         ExpressionStatement es = e as ExpressionStatement;
1279                         if (es == null)
1280                                 Error_InvalidExpressionStatement ();
1281
1282                         return es;
1283                 }
1284
1285                 /// <summary>
1286                 ///   Requests the expression to be emitted in a `statement'
1287                 ///   context.  This means that no new value is left on the
1288                 ///   stack after invoking this method (constrasted with
1289                 ///   Emit that will always leave a value on the stack).
1290                 /// </summary>
1291                 public abstract void EmitStatement (EmitContext ec);
1292         }
1293
1294         /// <summary>
1295         ///   This kind of cast is used to encapsulate the child
1296         ///   whose type is child.Type into an expression that is
1297         ///   reported to return "return_type".  This is used to encapsulate
1298         ///   expressions which have compatible types, but need to be dealt
1299         ///   at higher levels with.
1300         ///
1301         ///   For example, a "byte" expression could be encapsulated in one
1302         ///   of these as an "unsigned int".  The type for the expression
1303         ///   would be "unsigned int".
1304         ///
1305         /// </summary>
1306         public class EmptyCast : Expression
1307         {
1308                 protected Expression child;
1309
1310                 protected EmptyCast (Expression child, Type return_type)
1311                 {
1312                         eclass = child.eclass;
1313                         loc = child.Location;
1314                         type = return_type;
1315                         this.child = child;
1316                 }
1317
1318                 public static Expression Create (Expression child, Type type)
1319                 {
1320                         Constant c = child as Constant;
1321                         if (c != null)
1322                                 return new EmptyConstantCast (c, type);
1323
1324                         return new EmptyCast (child, type);
1325                 }
1326
1327                 public override Expression DoResolve (EmitContext ec)
1328                 {
1329                         // This should never be invoked, we are born in fully
1330                         // initialized state.
1331
1332                         return this;
1333                 }
1334
1335                 public override void Emit (EmitContext ec)
1336                 {
1337                         child.Emit (ec);
1338                 }
1339
1340                 public override bool GetAttributableValue (Type value_type, out object value)
1341                 {
1342                         return child.GetAttributableValue (value_type, out value);
1343                 }
1344
1345                 protected override void CloneTo (CloneContext clonectx, Expression t)
1346                 {
1347                         EmptyCast target = (EmptyCast) t;
1348
1349                         target.child = child.Clone (clonectx);
1350                 }
1351         }
1352
1353         /// <summary>
1354         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1355         /// </summary>
1356         public class OperatorCast : EmptyCast {
1357                 MethodInfo conversion_operator;
1358                 bool find_explicit;
1359
1360                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1361
1362                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1363                         : base (child, target_type)
1364                 {
1365                         this.find_explicit = find_explicit;
1366                 }
1367
1368                 // Returns the implicit operator that converts from
1369                 // 'child.Type' to our target type (type)
1370                 MethodInfo GetConversionOperator (bool find_explicit)
1371                 {
1372                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1373
1374                         MemberInfo [] mi;
1375
1376                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1377                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1378
1379                         if (mi == null){
1380                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1381                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1382                         }
1383
1384                         foreach (MethodInfo oper in mi) {
1385                                 ParameterData pd = TypeManager.GetParameterData (oper);
1386
1387                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1388                                         return oper;
1389                         }
1390
1391                         return null;
1392
1393
1394                 }
1395                 public override void Emit (EmitContext ec)
1396                 {
1397                         ILGenerator ig = ec.ig;
1398
1399                         child.Emit (ec);
1400                         conversion_operator = GetConversionOperator (find_explicit);
1401
1402                         if (conversion_operator == null)
1403                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1404
1405                         ig.Emit (OpCodes.Call, conversion_operator);
1406                 }
1407
1408         }
1409
1410         /// <summary>
1411         ///     This is a numeric cast to a Decimal
1412         /// </summary>
1413         public class CastToDecimal : EmptyCast {
1414                 MethodInfo conversion_operator;
1415
1416                 public CastToDecimal (Expression child)
1417                         : this (child, false)
1418                 {
1419                 }
1420
1421                 public CastToDecimal (Expression child, bool find_explicit)
1422                         : base (child, TypeManager.decimal_type)
1423                 {
1424                         conversion_operator = GetConversionOperator (find_explicit);
1425
1426                         if (conversion_operator == null)
1427                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1428                 }
1429
1430                 // Returns the implicit operator that converts from
1431                 // 'child.Type' to System.Decimal.
1432                 MethodInfo GetConversionOperator (bool find_explicit)
1433                 {
1434                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1435
1436                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1437                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1438
1439                         foreach (MethodInfo oper in mi) {
1440                                 ParameterData pd = TypeManager.GetParameterData (oper);
1441
1442                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1443                                         return oper;
1444                         }
1445
1446                         return null;
1447                 }
1448                 public override void Emit (EmitContext ec)
1449                 {
1450                         ILGenerator ig = ec.ig;
1451                         child.Emit (ec);
1452
1453                         ig.Emit (OpCodes.Call, conversion_operator);
1454                 }
1455         }
1456
1457         /// <summary>
1458         ///     This is an explicit numeric cast from a Decimal
1459         /// </summary>
1460         public class CastFromDecimal : EmptyCast
1461         {
1462                 static IDictionary operators;
1463
1464                 public CastFromDecimal (Expression child, Type return_type)
1465                         : base (child, return_type)
1466                 {
1467                         if (child.Type != TypeManager.decimal_type)
1468                                 throw new InternalErrorException (
1469                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1470                 }
1471
1472                 // Returns the explicit operator that converts from an
1473                 // express of type System.Decimal to 'type'.
1474                 public Expression Resolve ()
1475                 {
1476                         if (operators == null) {
1477                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1478                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1479                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1480
1481                                 operators = new System.Collections.Specialized.HybridDictionary ();
1482                                 foreach (MethodInfo oper in all_oper) {
1483                                         ParameterData pd = TypeManager.GetParameterData (oper);
1484                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1485                                                 operators.Add (oper.ReturnType, oper);
1486                                 }
1487                         }
1488
1489                         return operators.Contains (type) ? this : null;
1490                 }
1491
1492                 public override void Emit (EmitContext ec)
1493                 {
1494                         ILGenerator ig = ec.ig;
1495                         child.Emit (ec);
1496
1497                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1498                 }
1499         }
1500
1501
1502         //
1503         // Constant specialization of EmptyCast.
1504         // We need to special case this since an empty cast of
1505         // a constant is still a constant.
1506         //
1507         public class EmptyConstantCast : Constant
1508         {
1509                 public readonly Constant child;
1510
1511                 public EmptyConstantCast(Constant child, Type type)
1512                         : base (child.Location)
1513                 {
1514                         eclass = child.eclass;
1515                         this.child = child;
1516                         this.type = type;
1517                 }
1518
1519                 public override string AsString ()
1520                 {
1521                         return child.AsString ();
1522                 }
1523
1524                 public override object GetValue ()
1525                 {
1526                         return child.GetValue ();
1527                 }
1528
1529                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1530                 {
1531                         // FIXME: check that 'type' can be converted to 'target_type' first
1532                         return child.ConvertExplicitly (in_checked_context, target_type);
1533                 }
1534
1535                 public override Constant Increment ()
1536                 {
1537                         return child.Increment ();
1538                 }
1539
1540                 public override bool IsDefaultValue {
1541                         get { return child.IsDefaultValue; }
1542                 }
1543
1544                 public override bool IsNegative {
1545                         get { return child.IsNegative; }
1546                 }
1547
1548                 public override bool IsNull {
1549                         get { return child.IsNull; }
1550                 }
1551
1552                 public override bool IsZeroInteger {
1553                         get { return child.IsZeroInteger; }
1554                 }
1555
1556                 public override void Emit (EmitContext ec)
1557                 {
1558                         child.Emit (ec);
1559                 }
1560
1561                 public override Constant ConvertImplicitly (Type target_type)
1562                 {
1563                         // FIXME: Do we need to check user conversions?
1564                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1565                                 return null;
1566                         return child.ConvertImplicitly (target_type);
1567                 }
1568         }
1569
1570
1571         /// <summary>
1572         ///  This class is used to wrap literals which belong inside Enums
1573         /// </summary>
1574         public class EnumConstant : Constant {
1575                 public Constant Child;
1576
1577                 public EnumConstant (Constant child, Type enum_type):
1578                         base (child.Location)
1579                 {
1580                         eclass = child.eclass;
1581                         this.Child = child;
1582                         type = enum_type;
1583                 }
1584
1585                 public override Expression DoResolve (EmitContext ec)
1586                 {
1587                         // This should never be invoked, we are born in fully
1588                         // initialized state.
1589
1590                         return this;
1591                 }
1592
1593                 public override void Emit (EmitContext ec)
1594                 {
1595                         Child.Emit (ec);
1596                 }
1597
1598                 public override bool GetAttributableValue (Type value_type, out object value)
1599                 {
1600                         value = GetTypedValue ();
1601                         return true;
1602                 }
1603
1604                 public override string GetSignatureForError()
1605                 {
1606                         return TypeManager.CSharpName (Type);
1607                 }
1608
1609                 public override object GetValue ()
1610                 {
1611                         return Child.GetValue ();
1612                 }
1613
1614                 public override object GetTypedValue ()
1615                 {
1616                         // FIXME: runtime is not ready to work with just emited enums
1617                         if (!RootContext.StdLib) {
1618                                 return Child.GetValue ();
1619                         }
1620
1621                         return System.Enum.ToObject (type, Child.GetValue ());
1622                 }
1623
1624                 public override string AsString ()
1625                 {
1626                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1627                 }
1628
1629                 public override Constant Increment()
1630                 {
1631                         return new EnumConstant (Child.Increment (), type);
1632                 }
1633
1634                 public override bool IsDefaultValue {
1635                         get {
1636                                 return Child.IsDefaultValue;
1637                         }
1638                 }
1639
1640                 public override bool IsZeroInteger {
1641                         get { return Child.IsZeroInteger; }
1642                 }
1643
1644                 public override bool IsNegative {
1645                         get {
1646                                 return Child.IsNegative;
1647                         }
1648                 }
1649
1650                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1651                 {
1652                         if (Child.Type == target_type)
1653                                 return Child;
1654
1655                         return Child.ConvertExplicitly (in_checked_context, target_type);
1656                 }
1657
1658                 public override Constant ConvertImplicitly (Type type)
1659                 {
1660                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1661                         type = TypeManager.DropGenericTypeArguments (type);
1662
1663                         if (this_type == type) {
1664                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1665                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1666                                         return this;
1667
1668                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1669                                 if (type.UnderlyingSystemType != child_type)
1670                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1671                                 return this;
1672                         }
1673
1674                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1675                                 return null;
1676                         }
1677
1678                         return Child.ConvertImplicitly(type);
1679                 }
1680
1681         }
1682
1683         /// <summary>
1684         ///   This kind of cast is used to encapsulate Value Types in objects.
1685         ///
1686         ///   The effect of it is to box the value type emitted by the previous
1687         ///   operation.
1688         /// </summary>
1689         public class BoxedCast : EmptyCast {
1690
1691                 public BoxedCast (Expression expr, Type target_type)
1692                         : base (expr, target_type)
1693                 {
1694                         eclass = ExprClass.Value;
1695                 }
1696
1697                 public override Expression DoResolve (EmitContext ec)
1698                 {
1699                         // This should never be invoked, we are born in fully
1700                         // initialized state.
1701
1702                         return this;
1703                 }
1704
1705                 public override void Emit (EmitContext ec)
1706                 {
1707                         base.Emit (ec);
1708
1709                         ec.ig.Emit (OpCodes.Box, child.Type);
1710                 }
1711         }
1712
1713         public class UnboxCast : EmptyCast {
1714                 public UnboxCast (Expression expr, Type return_type)
1715                         : base (expr, return_type)
1716                 {
1717                 }
1718
1719                 public override Expression DoResolve (EmitContext ec)
1720                 {
1721                         // This should never be invoked, we are born in fully
1722                         // initialized state.
1723
1724                         return this;
1725                 }
1726
1727                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1728                 {
1729                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1730                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1731                         return base.DoResolveLValue (ec, right_side);
1732                 }
1733
1734                 public override void Emit (EmitContext ec)
1735                 {
1736                         Type t = type;
1737                         ILGenerator ig = ec.ig;
1738
1739                         base.Emit (ec);
1740 #if GMCS_SOURCE
1741                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1742                                 ig.Emit (OpCodes.Unbox_Any, t);
1743                         else
1744 #endif
1745                         {
1746                                 ig.Emit (OpCodes.Unbox, t);
1747
1748                                 LoadFromPtr (ig, t);
1749                         }
1750                 }
1751         }
1752
1753         /// <summary>
1754         ///   This is used to perform explicit numeric conversions.
1755         ///
1756         ///   Explicit numeric conversions might trigger exceptions in a checked
1757         ///   context, so they should generate the conv.ovf opcodes instead of
1758         ///   conv opcodes.
1759         /// </summary>
1760         public class ConvCast : EmptyCast {
1761                 public enum Mode : byte {
1762                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1763                         U1_I1, U1_CH,
1764                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1765                         U2_I1, U2_U1, U2_I2, U2_CH,
1766                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1767                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1768                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1769                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1770                         CH_I1, CH_U1, CH_I2,
1771                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1772                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1773                 }
1774
1775                 Mode mode;
1776
1777                 public ConvCast (Expression child, Type return_type, Mode m)
1778                         : base (child, return_type)
1779                 {
1780                         mode = m;
1781                 }
1782
1783                 public override Expression DoResolve (EmitContext ec)
1784                 {
1785                         // This should never be invoked, we are born in fully
1786                         // initialized state.
1787
1788                         return this;
1789                 }
1790
1791                 public override string ToString ()
1792                 {
1793                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1794                 }
1795
1796                 public override void Emit (EmitContext ec)
1797                 {
1798                         ILGenerator ig = ec.ig;
1799
1800                         base.Emit (ec);
1801
1802                         if (ec.CheckState){
1803                                 switch (mode){
1804                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1805                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1806                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1807                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1808                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1809
1810                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1811                                 case Mode.U1_CH: /* nothing */ break;
1812
1813                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1814                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1815                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1816                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1817                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1818                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1819
1820                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1821                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1822                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1823                                 case Mode.U2_CH: /* nothing */ break;
1824
1825                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1826                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1827                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1828                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1829                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1830                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1831                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1832
1833                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1834                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1835                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1836                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1837                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1838                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1839
1840                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1841                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1842                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1843                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1844                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1845                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1846                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1847                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1848
1849                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1850                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1851                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1852                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1853                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1854                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1855                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1856                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1857
1858                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1859                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1860                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1861
1862                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1863                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1864                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1865                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1866                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1867                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1868                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1869                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1870                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1871
1872                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1873                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1874                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1875                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1876                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1877                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1878                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1879                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1880                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1881                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1882                                 }
1883                         } else {
1884                                 switch (mode){
1885                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1886                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1887                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1888                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1889                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1890
1891                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1892                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1893
1894                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1895                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1896                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1897                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1898                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1899                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1900
1901                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1902                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1903                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1904                                 case Mode.U2_CH: /* nothing */ break;
1905
1906                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1907                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1908                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1909                                 case Mode.I4_U4: /* nothing */ break;
1910                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1911                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1912                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1913
1914                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1915                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1916                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1917                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1918                                 case Mode.U4_I4: /* nothing */ break;
1919                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1920
1921                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1922                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1923                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1924                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1925                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1926                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1927                                 case Mode.I8_U8: /* nothing */ break;
1928                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1929
1930                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1931                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1932                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1933                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1934                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1935                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1936                                 case Mode.U8_I8: /* nothing */ break;
1937                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1938
1939                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1940                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1941                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1942
1943                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1944                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1945                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1946                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1947                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1948                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1949                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1950                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1951                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1952
1953                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1954                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1955                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1956                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1957                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1958                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1959                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1960                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1961                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1962                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1963                                 }
1964                         }
1965                 }
1966         }
1967
1968         public class OpcodeCast : EmptyCast {
1969                 OpCode op, op2;
1970                 bool second_valid;
1971
1972                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1973                         : base (child, return_type)
1974
1975                 {
1976                         this.op = op;
1977                         second_valid = false;
1978                 }
1979
1980                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1981                         : base (child, return_type)
1982
1983                 {
1984                         this.op = op;
1985                         this.op2 = op2;
1986                         second_valid = true;
1987                 }
1988
1989                 public override Expression DoResolve (EmitContext ec)
1990                 {
1991                         // This should never be invoked, we are born in fully
1992                         // initialized state.
1993
1994                         return this;
1995                 }
1996
1997                 public override void Emit (EmitContext ec)
1998                 {
1999                         base.Emit (ec);
2000                         ec.ig.Emit (op);
2001
2002                         if (second_valid)
2003                                 ec.ig.Emit (op2);
2004                 }
2005         }
2006
2007         /// <summary>
2008         ///   This kind of cast is used to encapsulate a child and cast it
2009         ///   to the class requested
2010         /// </summary>
2011         public class ClassCast : EmptyCast {
2012                 public ClassCast (Expression child, Type return_type)
2013                         : base (child, return_type)
2014
2015                 {
2016                 }
2017
2018                 public override Expression DoResolve (EmitContext ec)
2019                 {
2020                         // This should never be invoked, we are born in fully
2021                         // initialized state.
2022
2023                         return this;
2024                 }
2025
2026                 public override void Emit (EmitContext ec)
2027                 {
2028                         base.Emit (ec);
2029
2030                         if (TypeManager.IsGenericParameter (child.Type))
2031                                 ec.ig.Emit (OpCodes.Box, child.Type);
2032
2033 #if GMCS_SOURCE
2034                         if (type.IsGenericParameter)
2035                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2036                         else
2037 #endif
2038                                 ec.ig.Emit (OpCodes.Castclass, type);
2039                 }
2040         }
2041
2042         /// <summary>
2043         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2044         ///   of a dotted-name.
2045         /// </summary>
2046         public class SimpleName : Expression {
2047                 public readonly string Name;
2048                 public readonly TypeArguments Arguments;
2049                 bool in_transit;
2050
2051                 public SimpleName (string name, Location l)
2052                 {
2053                         Name = name;
2054                         loc = l;
2055                 }
2056
2057                 public SimpleName (string name, TypeArguments args, Location l)
2058                 {
2059                         Name = name;
2060                         Arguments = args;
2061                         loc = l;
2062                 }
2063
2064                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2065                 {
2066                         Name = name;
2067                         loc = l;
2068
2069                         Arguments = new TypeArguments (l);
2070                         foreach (TypeParameter type_param in type_params)
2071                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2072                 }
2073
2074                 public static string RemoveGenericArity (string name)
2075                 {
2076                         int start = 0;
2077                         StringBuilder sb = null;
2078                         do {
2079                                 int pos = name.IndexOf ('`', start);
2080                                 if (pos < 0) {
2081                                         if (start == 0)
2082                                                 return name;
2083
2084                                         sb.Append (name.Substring (start));
2085                                         break;
2086                                 }
2087
2088                                 if (sb == null)
2089                                         sb = new StringBuilder ();
2090                                 sb.Append (name.Substring (start, pos-start));
2091
2092                                 pos++;
2093                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2094                                         pos++;
2095
2096                                 start = pos;
2097                         } while (start < name.Length);
2098
2099                         return sb.ToString ();
2100                 }
2101
2102                 public SimpleName GetMethodGroup ()
2103                 {
2104                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2105                 }
2106
2107                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2108                 {
2109                         if (ec.IsInFieldInitializer)
2110                                 Report.Error (236, l,
2111                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2112                                         name);
2113                         else
2114                                 Report.Error (
2115                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2116                                         name);
2117                 }
2118
2119                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2120                 {
2121                         return resolved_to != null && resolved_to.Type != null &&
2122                                 resolved_to.Type.Name == Name &&
2123                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2124                 }
2125
2126                 public override Expression DoResolve (EmitContext ec)
2127                 {
2128                         return SimpleNameResolve (ec, null, false);
2129                 }
2130
2131                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2132                 {
2133                         return SimpleNameResolve (ec, right_side, false);
2134                 }
2135
2136
2137                 public Expression DoResolve (EmitContext ec, bool intermediate)
2138                 {
2139                         return SimpleNameResolve (ec, null, intermediate);
2140                 }
2141
2142                 static bool IsNestedChild (Type t, Type parent)
2143                 {
2144                         while (parent != null) {
2145                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2146                                         return true;
2147
2148                                 parent = parent.BaseType;
2149                         }
2150
2151                         return false;
2152                 }
2153
2154                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2155                 {
2156                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2157                                 return null;
2158
2159                         DeclSpace ds = ec.DeclContainer;
2160                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2161                                 ds = ds.Parent;
2162
2163                         if (ds == null)
2164                                 return null;
2165
2166                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2167
2168                         int arg_count = Arguments != null ? Arguments.Count : 0;
2169
2170                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2171                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2172                                         TypeArguments new_args = new TypeArguments (loc);
2173                                         foreach (TypeParameter param in ds.TypeParameters)
2174                                                 new_args.Add (new TypeParameterExpr (param, loc));
2175
2176                                         if (Arguments != null)
2177                                                 new_args.Add (Arguments);
2178
2179                                         return new ConstructedType (t, new_args, loc);
2180                                 }
2181                         }
2182
2183                         return null;
2184                 }
2185
2186                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2187                 {
2188                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2189                         if (fne != null)
2190                                 return fne.ResolveAsTypeStep (ec, silent);
2191
2192                         int errors = Report.Errors;
2193                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2194
2195                         if (fne != null) {
2196                                 if (fne.Type == null)
2197                                         return fne;
2198
2199                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2200                                 if (nested != null)
2201                                         return nested.ResolveAsTypeStep (ec, false);
2202
2203                                 if (Arguments != null) {
2204                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2205                                         return ct.ResolveAsTypeStep (ec, false);
2206                                 }
2207
2208                                 return fne;
2209                         }
2210
2211                         if (silent || errors != Report.Errors)
2212                                 return null;
2213
2214                         Error_TypeOrNamespaceNotFound (ec);
2215                         return null;
2216                 }
2217
2218                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2219                 {
2220                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2221                         if (mc != null) {
2222                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2223                                 return;
2224                         }
2225
2226                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2227                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2228                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2229                                 Type type = a.GetType (fullname);
2230                                 if (type != null) {
2231                                         Report.SymbolRelatedToPreviousError (type);
2232                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2233                                         return;
2234                                 }
2235                         }
2236
2237                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2238                         if (t != null) {
2239                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2240                                 return;
2241                         }
2242
2243                         if (Arguments != null) {
2244                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2245                                 if (retval != null) {
2246                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2247                                         return;
2248                                 }
2249                         }
2250
2251                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2252                 }
2253
2254                 // TODO: I am still not convinced about this. If someone else will need it
2255                 // implement this as virtual property in MemberCore hierarchy
2256                 public static string GetMemberType (MemberCore mc)
2257                 {
2258                         if (mc is Property)
2259                                 return "property";
2260                         if (mc is Indexer)
2261                                 return "indexer";
2262                         if (mc is FieldBase)
2263                                 return "field";
2264                         if (mc is MethodCore)
2265                                 return "method";
2266                         if (mc is EnumMember)
2267                                 return "enum";
2268                         if (mc is Event)
2269                                 return "event";
2270
2271                         return "type";
2272                 }
2273
2274                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2275                 {
2276                         if (in_transit)
2277                                 return null;
2278
2279                         in_transit = true;
2280                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2281                         in_transit = false;
2282
2283                         if (e == null)
2284                                 return null;
2285
2286                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2287                                 return e;
2288
2289                         return null;
2290                 }
2291
2292                 /// <remarks>
2293                 ///   7.5.2: Simple Names.
2294                 ///
2295                 ///   Local Variables and Parameters are handled at
2296                 ///   parse time, so they never occur as SimpleNames.
2297                 ///
2298                 ///   The `intermediate' flag is used by MemberAccess only
2299                 ///   and it is used to inform us that it is ok for us to
2300                 ///   avoid the static check, because MemberAccess might end
2301                 ///   up resolving the Name as a Type name and the access as
2302                 ///   a static type access.
2303                 ///
2304                 ///   ie: Type Type; .... { Type.GetType (""); }
2305                 ///
2306                 ///   Type is both an instance variable and a Type;  Type.GetType
2307                 ///   is the static method not an instance method of type.
2308                 /// </remarks>
2309                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2310                 {
2311                         Expression e = null;
2312
2313                         //
2314                         // Stage 1: Performed by the parser (binding to locals or parameters).
2315                         //
2316                         Block current_block = ec.CurrentBlock;
2317                         if (current_block != null){
2318                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2319                                 if (vi != null){
2320                                         if (Arguments != null) {
2321                                                 Report.Error (307, loc,
2322                                                               "The variable `{0}' cannot be used with type arguments",
2323                                                               Name);
2324                                                 return null;
2325                                         }
2326
2327                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2328                                         if (right_side != null) {
2329                                                 return var.ResolveLValue (ec, right_side, loc);
2330                                         } else {
2331                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2332                                                 if (intermediate)
2333                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2334                                                 return var.Resolve (ec, rf);
2335                                         }
2336                                 }
2337
2338                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2339                                 if (pref != null) {
2340                                         if (Arguments != null) {
2341                                                 Report.Error (307, loc,
2342                                                               "The variable `{0}' cannot be used with type arguments",
2343                                                               Name);
2344                                                 return null;
2345                                         }
2346
2347                                         if (right_side != null)
2348                                                 return pref.ResolveLValue (ec, right_side, loc);
2349                                         else
2350                                                 return pref.Resolve (ec);
2351                                 }
2352
2353                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2354                                 if (expr != null) {
2355                                         if (right_side != null)
2356                                                 return expr.ResolveLValue (ec, right_side, loc);
2357                                         return expr.Resolve (ec);
2358                                 }
2359                         }
2360
2361                         //
2362                         // Stage 2: Lookup members
2363                         //
2364
2365                         Type almost_matched_type = null;
2366                         ArrayList almost_matched = null;
2367                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2368                                 // either RootDeclSpace or GenericMethod
2369                                 if (lookup_ds.TypeBuilder == null)
2370                                         continue;
2371
2372                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2373                                 if (e != null) {
2374                                         if (e is PropertyExpr) {
2375                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2376                                                 // it doesn't know which accessor to check permissions against
2377                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2378                                                         break;
2379                                         } else if (e is EventExpr) {
2380                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2381                                                         break;
2382                                         } else {
2383                                                 break;
2384                                         }
2385                                         e = null;
2386                                 }
2387
2388                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2389                                         almost_matched_type = lookup_ds.TypeBuilder;
2390                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2391                                 }
2392                         }
2393
2394                         if (e == null) {
2395                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2396                                         almost_matched_type = ec.ContainerType;
2397                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2398                                 }
2399                                 e = ResolveAsTypeStep (ec, true);
2400                         }
2401
2402                         if (e == null) {
2403                                 if (current_block != null) {
2404                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2405                                         if (ikv != null) {
2406                                                 LocalInfo li = ikv as LocalInfo;
2407                                                 // Supress CS0219 warning
2408                                                 if (li != null)
2409                                                         li.Used = true;
2410
2411                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2412                                                 return null;
2413                                         }
2414                                 }
2415
2416                                 if (almost_matched != null)
2417                                         almost_matched_members = almost_matched;
2418                                 if (almost_matched_type == null)
2419                                         almost_matched_type = ec.ContainerType;
2420                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2421                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2422                                 return null;
2423                         }
2424
2425                         if (e is TypeExpr) {
2426                                 if (Arguments == null)
2427                                         return e;
2428
2429                                 ConstructedType ct = new ConstructedType (
2430                                         (FullNamedExpression) e, Arguments, loc);
2431                                 return ct.ResolveAsTypeStep (ec, false);
2432                         }
2433
2434                         if (e is MemberExpr) {
2435                                 MemberExpr me = (MemberExpr) e;
2436
2437                                 Expression left;
2438                                 if (me.IsInstance) {
2439                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2440                                                 //
2441                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2442                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2443                                                 // and each predicate is true if the MethodGroupExpr contains
2444                                                 // at least one of that kind of method.
2445                                                 //
2446
2447                                                 if (!me.IsStatic &&
2448                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2449                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2450                                                         return EmptyExpression.Null;
2451                                                 }
2452
2453                                                 //
2454                                                 // Pass the buck to MemberAccess and Invocation.
2455                                                 //
2456                                                 left = EmptyExpression.Null;
2457                                         } else {
2458                                                 left = ec.GetThis (loc);
2459                                         }
2460                                 } else {
2461                                         left = new TypeExpression (ec.ContainerType, loc);
2462                                 }
2463
2464                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2465                                 if (me == null)
2466                                         return null;
2467
2468                                 if (Arguments != null) {
2469                                         Arguments.Resolve (ec);
2470                                         me.SetTypeArguments (Arguments);
2471                                 }
2472
2473                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2474                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2475                                     me.InstanceExpression.Type != me.DeclaringType &&
2476                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2477                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2478                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2479                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2480                                         return null;
2481                                 }
2482
2483                                 return (right_side != null)
2484                                         ? me.DoResolveLValue (ec, right_side)
2485                                         : me.DoResolve (ec);
2486                         }
2487
2488                         return e;
2489                 }
2490
2491                 public override void Emit (EmitContext ec)
2492                 {
2493                         throw new InternalErrorException ("The resolve phase was not executed");
2494                 }
2495
2496                 public override string ToString ()
2497                 {
2498                         return Name;
2499                 }
2500
2501                 public override string GetSignatureForError ()
2502                 {
2503                         if (Arguments != null) {
2504                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2505                                         Arguments.GetSignatureForError () + ">";
2506                         }
2507
2508                         return Name;
2509                 }
2510
2511                 protected override void CloneTo (CloneContext clonectx, Expression target)
2512                 {
2513                         // CloneTo: Nothing, we do not keep any state on this expression
2514                 }
2515         }
2516
2517         /// <summary>
2518         ///   Represents a namespace or a type.  The name of the class was inspired by
2519         ///   section 10.8.1 (Fully Qualified Names).
2520         /// </summary>
2521         public abstract class FullNamedExpression : Expression {
2522                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2523                 {
2524                         return this;
2525                 }
2526
2527                 public abstract string FullName {
2528                         get;
2529                 }
2530         }
2531
2532         /// <summary>
2533         ///   Expression that evaluates to a type
2534         /// </summary>
2535         public abstract class TypeExpr : FullNamedExpression {
2536                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2537                 {
2538                         TypeExpr t = DoResolveAsTypeStep (ec);
2539                         if (t == null)
2540                                 return null;
2541
2542                         eclass = ExprClass.Type;
2543                         return t;
2544                 }
2545
2546                 override public Expression DoResolve (EmitContext ec)
2547                 {
2548                         return ResolveAsTypeTerminal (ec, false);
2549                 }
2550
2551                 override public void Emit (EmitContext ec)
2552                 {
2553                         throw new Exception ("Should never be called");
2554                 }
2555
2556                 public virtual bool CheckAccessLevel (DeclSpace ds)
2557                 {
2558                         return ds.CheckAccessLevel (Type);
2559                 }
2560
2561                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2562                 {
2563                         return ds.AsAccessible (Type, flags);
2564                 }
2565
2566                 public virtual bool IsClass {
2567                         get { return Type.IsClass; }
2568                 }
2569
2570                 public virtual bool IsValueType {
2571                         get { return Type.IsValueType; }
2572                 }
2573
2574                 public virtual bool IsInterface {
2575                         get { return Type.IsInterface; }
2576                 }
2577
2578                 public virtual bool IsSealed {
2579                         get { return Type.IsSealed; }
2580                 }
2581
2582                 public virtual bool CanInheritFrom ()
2583                 {
2584                         if (Type == TypeManager.enum_type ||
2585                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2586                             Type == TypeManager.multicast_delegate_type ||
2587                             Type == TypeManager.delegate_type ||
2588                             Type == TypeManager.array_type)
2589                                 return false;
2590
2591                         return true;
2592                 }
2593
2594                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2595
2596                 public abstract string Name {
2597                         get;
2598                 }
2599
2600                 public override bool Equals (object obj)
2601                 {
2602                         TypeExpr tobj = obj as TypeExpr;
2603                         if (tobj == null)
2604                                 return false;
2605
2606                         return Type == tobj.Type;
2607                 }
2608
2609                 public override int GetHashCode ()
2610                 {
2611                         return Type.GetHashCode ();
2612                 }
2613
2614                 public override string ToString ()
2615                 {
2616                         return Name;
2617                 }
2618         }
2619
2620         /// <summary>
2621         ///   Fully resolved Expression that already evaluated to a type
2622         /// </summary>
2623         public class TypeExpression : TypeExpr {
2624                 public TypeExpression (Type t, Location l)
2625                 {
2626                         Type = t;
2627                         eclass = ExprClass.Type;
2628                         loc = l;
2629                 }
2630
2631                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2632                 {
2633                         return this;
2634                 }
2635
2636                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2637                 {
2638                         return this;
2639                 }
2640
2641                 public override string Name {
2642                         get { return Type.ToString (); }
2643                 }
2644
2645                 public override string FullName {
2646                         get { return Type.FullName; }
2647                 }
2648         }
2649
2650         /// <summary>
2651         ///   Used to create types from a fully qualified name.  These are just used
2652         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2653         ///   classified as a type.
2654         /// </summary>
2655         public sealed class TypeLookupExpression : TypeExpr {
2656                 readonly string name;
2657
2658                 public TypeLookupExpression (string name)
2659                 {
2660                         this.name = name;
2661                         eclass = ExprClass.Type;
2662                 }
2663
2664                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2665                 {
2666                         // It's null for corlib compilation only
2667                         if (type == null)
2668                                 return DoResolveAsTypeStep (ec);
2669
2670                         return this;
2671                 }
2672
2673                 private class UnexpectedType
2674                 {
2675                 }
2676
2677                 // This performes recursive type lookup, providing support for generic types.
2678                 // For example, given the type:
2679                 //
2680                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2681                 //
2682                 // The types will be checked in the following order:
2683                 //                                                                             _
2684                 // System                                                                       |
2685                 // System.Collections                                                           |
2686                 // System.Collections.Generic                                                   |
2687                 //                        _                                                     |
2688                 //     System              | recursive call 1                                   |
2689                 //     System.Int32       _|                                                    | main method call
2690                 //                        _                                                     |
2691                 //     System              | recursive call 2                                   |
2692                 //     System.String      _|                                                    |
2693                 //                                                                              |
2694                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2695                 //
2696                 private Type TypeLookup (IResolveContext ec, string name)
2697                 {
2698                         int index = 0;
2699                         int dot = 0;
2700                         bool done = false;
2701                         FullNamedExpression resolved = null;
2702                         Type type = null;
2703                         Type recursive_type = null;
2704                         while (index < name.Length) {
2705                                 if (name[index] == '[') {
2706                                         int open = index;
2707                                         int braces = 1;
2708                                         do {
2709                                                 index++;
2710                                                 if (name[index] == '[')
2711                                                         braces++;
2712                                                 else if (name[index] == ']')
2713                                                         braces--;
2714                                         } while (braces > 0);
2715                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2716                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2717                                                 return recursive_type;
2718                                 }
2719                                 else {
2720                                         if (name[index] == ',')
2721                                                 done = true;
2722                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2723                                                 string substring = name.Substring(dot, index - dot);
2724
2725                                                 if (resolved == null)
2726                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2727                                                 else if (resolved is Namespace)
2728                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2729                                                 else if (type != null)
2730                                                         type = TypeManager.GetNestedType (type, substring);
2731                                                 else
2732                                                         return null;
2733
2734                                                 if (resolved == null)
2735                                                         return null;
2736                                                 else if (type == null && resolved is TypeExpr)
2737                                                         type = resolved.Type;
2738
2739                                                 dot = index + 1;
2740                                         }
2741                                 }
2742                                 index++;
2743                         }
2744                         if (name[0] != '[') {
2745                                 string substring = name.Substring(dot, index - dot);
2746
2747                                 if (type != null)
2748                                         return TypeManager.GetNestedType (type, substring);
2749
2750                                 if (resolved != null) {
2751                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2752                                         if (resolved is TypeExpr)
2753                                                 return resolved.Type;
2754
2755                                         if (resolved == null)
2756                                                 return null;
2757
2758                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2759                                         return typeof (UnexpectedType);
2760                                 }
2761                                 else
2762                                         return null;
2763                         }
2764                         else
2765                                 return recursive_type;
2766                         }
2767
2768                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2769                 {
2770                         Type t = TypeLookup (ec, name);
2771                         if (t == null) {
2772                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2773                                 return null;
2774                         }
2775                         if (t == typeof(UnexpectedType))
2776                                 return null;
2777                         type = t;
2778                         return this;
2779                 }
2780
2781                 public override string Name {
2782                         get { return name; }
2783                 }
2784
2785                 public override string FullName {
2786                         get { return name; }
2787                 }
2788
2789                 protected override void CloneTo (CloneContext clonectx, Expression target)
2790                 {
2791                         // CloneTo: Nothing, we do not keep any state on this expression
2792                 }
2793
2794                 public override string GetSignatureForError ()
2795                 {
2796                         if (type == null)
2797                                 return TypeManager.CSharpName (name);
2798
2799                         return base.GetSignatureForError ();
2800                 }
2801         }
2802
2803         /// <summary>
2804         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2805         ///   See 14.5.11.
2806         /// </summary>
2807         public class UnboundTypeExpression : TypeExpr
2808         {
2809                 MemberName name;
2810
2811                 public UnboundTypeExpression (MemberName name, Location l)
2812                 {
2813                         this.name = name;
2814                         loc = l;
2815                 }
2816
2817                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2818                 {
2819                         Expression expr;
2820                         if (name.Left != null) {
2821                                 Expression lexpr = name.Left.GetTypeExpression ();
2822                                 expr = new MemberAccess (lexpr, name.Basename);
2823                         } else {
2824                                 expr = new SimpleName (name.Basename, loc);
2825                         }
2826
2827                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2828                         if (fne == null)
2829                                 return null;
2830
2831                         type = fne.Type;
2832                         return new TypeExpression (type, loc);
2833                 }
2834
2835                 public override string Name {
2836                         get { return name.FullName; }
2837                 }
2838
2839                 public override string FullName {
2840                         get { return name.FullName; }
2841                 }
2842         }
2843
2844         public class TypeAliasExpression : TypeExpr {
2845                 FullNamedExpression alias;
2846                 TypeExpr texpr;
2847                 TypeArguments args;
2848                 string name;
2849
2850                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2851                 {
2852                         this.alias = alias;
2853                         this.args = args;
2854                         loc = l;
2855
2856                         eclass = ExprClass.Type;
2857                         if (args != null)
2858                                 name = alias.FullName + "<" + args.ToString () + ">";
2859                         else
2860                                 name = alias.FullName;
2861                 }
2862
2863                 public override string Name {
2864                         get { return alias.FullName; }
2865                 }
2866
2867                 public override string FullName {
2868                         get { return name; }
2869                 }
2870
2871                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2872                 {
2873                         texpr = alias.ResolveAsTypeTerminal (ec, false);
2874                         if (texpr == null)
2875                                 return null;
2876
2877                         Type type = texpr.Type;
2878                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2879
2880                         if (args != null) {
2881                                 if (num_args == 0) {
2882                                         Report.Error (308, loc,
2883                                                       "The non-generic type `{0}' cannot " +
2884                                                       "be used with type arguments.",
2885                                                       TypeManager.CSharpName (type));
2886                                         return null;
2887                                 }
2888
2889                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2890                                 return ctype.ResolveAsTypeTerminal (ec, false);
2891                         } else if (num_args > 0) {
2892                                 Report.Error (305, loc,
2893                                               "Using the generic type `{0}' " +
2894                                               "requires {1} type arguments",
2895                                               TypeManager.CSharpName (type), num_args.ToString ());
2896                                 return null;
2897                         }
2898
2899                         return texpr;
2900                 }
2901
2902                 public override bool CheckAccessLevel (DeclSpace ds)
2903                 {
2904                         return texpr.CheckAccessLevel (ds);
2905                 }
2906
2907                 public override bool AsAccessible (DeclSpace ds, int flags)
2908                 {
2909                         return texpr.AsAccessible (ds, flags);
2910                 }
2911
2912                 public override bool IsClass {
2913                         get { return texpr.IsClass; }
2914                 }
2915
2916                 public override bool IsValueType {
2917                         get { return texpr.IsValueType; }
2918                 }
2919
2920                 public override bool IsInterface {
2921                         get { return texpr.IsInterface; }
2922                 }
2923
2924                 public override bool IsSealed {
2925                         get { return texpr.IsSealed; }
2926                 }
2927         }
2928
2929         /// <summary>
2930         ///   This class denotes an expression which evaluates to a member
2931         ///   of a struct or a class.
2932         /// </summary>
2933         public abstract class MemberExpr : Expression
2934         {
2935                 protected bool is_base;
2936
2937                 /// <summary>
2938                 ///   The name of this member.
2939                 /// </summary>
2940                 public abstract string Name {
2941                         get;
2942                 }
2943
2944                 //
2945                 // When base.member is used
2946                 //
2947                 public bool IsBase {
2948                         get { return is_base; }
2949                         set { is_base = value; }
2950                 }
2951
2952                 /// <summary>
2953                 ///   Whether this is an instance member.
2954                 /// </summary>
2955                 public abstract bool IsInstance {
2956                         get;
2957                 }
2958
2959                 /// <summary>
2960                 ///   Whether this is a static member.
2961                 /// </summary>
2962                 public abstract bool IsStatic {
2963                         get;
2964                 }
2965
2966                 /// <summary>
2967                 ///   The type which declares this member.
2968                 /// </summary>
2969                 public abstract Type DeclaringType {
2970                         get;
2971                 }
2972
2973                 /// <summary>
2974                 ///   The instance expression associated with this member, if it's a
2975                 ///   non-static member.
2976                 /// </summary>
2977                 public Expression InstanceExpression;
2978
2979                 public static void error176 (Location loc, string name)
2980                 {
2981                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
2982                                       "with an instance reference, qualify it with a type name instead", name);
2983                 }
2984
2985                 // TODO: possible optimalization
2986                 // Cache resolved constant result in FieldBuilder <-> expression map
2987                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2988                                                                SimpleName original)
2989                 {
2990                         //
2991                         // Precondition:
2992                         //   original == null || original.Resolve (...) ==> left
2993                         //
2994
2995                         if (left is TypeExpr) {
2996                                 left = left.ResolveAsTypeTerminal (ec, true);
2997                                 if (left == null)
2998                                         return null;
2999
3000                                 if (!IsStatic) {
3001                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3002                                         return null;
3003                                 }
3004
3005                                 return this;
3006                         }
3007
3008                         if (!IsInstance) {
3009                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3010                                         return this;
3011
3012                                 return ResolveExtensionMemberAccess (left);
3013                         }
3014
3015                         InstanceExpression = left;
3016                         return this;
3017                 }
3018
3019                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3020                 {
3021                         error176 (loc, GetSignatureForError ());
3022                         return this;
3023                 }
3024
3025                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3026                 {
3027                         if (IsStatic)
3028                                 return;
3029
3030                         if (InstanceExpression == EmptyExpression.Null) {
3031                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3032                                 return;
3033                         }
3034
3035                         if (InstanceExpression.Type.IsValueType) {
3036                                 if (InstanceExpression is IMemoryLocation) {
3037                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3038                                 } else {
3039                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3040                                         InstanceExpression.Emit (ec);
3041                                         t.Store (ec);
3042                                         t.AddressOf (ec, AddressOp.Store);
3043                                 }
3044                         } else
3045                                 InstanceExpression.Emit (ec);
3046
3047                         if (prepare_for_load)
3048                                 ec.ig.Emit (OpCodes.Dup);
3049                 }
3050
3051                 public virtual void SetTypeArguments (TypeArguments ta)
3052                 {
3053                         // TODO: need to get correct member type
3054                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3055                                 GetSignatureForError ());
3056                 }
3057         }
3058
3059         ///
3060         /// Represents group of extension methods
3061         ///
3062         public class ExtensionMethodGroupExpr : MethodGroupExpr
3063         {
3064                 readonly NamespaceEntry namespace_entry;
3065                 public Expression ExtensionExpression;
3066                 Argument extension_argument;
3067
3068                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3069                         : base (list, extensionType, l)
3070                 {
3071                         this.namespace_entry = n;
3072                 }
3073
3074                 public override bool IsStatic {
3075                         get { return true; }
3076                 }
3077
3078                 public bool IsTopLevel {
3079                         get { return namespace_entry == null; }
3080                 }
3081
3082                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3083                 {
3084                         if (arguments == null)
3085                                 arguments = new ArrayList (1);
3086                         arguments.Insert (0, extension_argument);
3087                         base.EmitArguments (ec, arguments);
3088                 }
3089
3090                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3091                 {
3092                         if (arguments == null)
3093                                 arguments = new ArrayList (1);
3094                         arguments.Insert (0, extension_argument);
3095                         base.EmitCall (ec, arguments);
3096                 }
3097
3098                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList arguments, bool may_fail, Location loc)
3099                 {
3100                         if ((ExtensionExpression.eclass & (ExprClass.Value | ExprClass.Variable)) == 0)
3101                                 return base.OverloadResolve (ec, arguments, may_fail, loc);
3102
3103                         if (arguments == null)
3104                                 arguments = new ArrayList (1);
3105
3106                         arguments.Insert (0, new Argument (ExtensionExpression));
3107                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3108
3109                         // Store resolved argument and restore original arguments
3110                         if (mg != null)
3111                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3112                         arguments.RemoveAt (0);
3113
3114                         return mg;
3115                 }
3116
3117                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3118                 {
3119                         // Use normal resolve rules
3120                         MethodGroupExpr mg = base.OverloadResolve (ec, arguments, ns != null, loc);
3121                         if (mg != null)
3122                                 return mg;
3123
3124                         if (ns == null)
3125                                 return null;
3126
3127                         // Search continues
3128                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name);
3129                         if (e == null)
3130                                 return base.OverloadResolve (ec, arguments, false, loc);
3131
3132                         e.ExtensionExpression = ExtensionExpression;
3133                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3134                 }
3135         }
3136
3137         /// <summary>
3138         ///   MethodGroupExpr represents a group of method candidates which
3139         ///   can be resolved to the best method overload
3140         /// </summary>
3141         public class MethodGroupExpr : MemberExpr
3142         {
3143                 public interface IErrorHandler
3144                 {
3145                         bool NoExactMatch (EmitContext ec, MethodBase method);
3146                 }
3147
3148                 public IErrorHandler CustomErrorHandler;
3149                 public MethodBase [] Methods;
3150                 MethodBase best_candidate;
3151                 // TODO: make private
3152                 public TypeArguments type_arguments;
3153                 bool identical_type_name;
3154                 Type delegate_type;
3155
3156                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3157                         : this (type, l)
3158                 {
3159                         Methods = new MethodBase [mi.Length];
3160                         mi.CopyTo (Methods, 0);
3161                 }
3162
3163                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3164                         : this (type, l)
3165                 {
3166                         try {
3167                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3168                         } catch {
3169                                 foreach (MemberInfo m in list){
3170                                         if (!(m is MethodBase)){
3171                                                 Console.WriteLine ("Name " + m.Name);
3172                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3173                                         }
3174                                 }
3175                                 throw;
3176                         }
3177
3178
3179                 }
3180
3181                 protected MethodGroupExpr (Type type, Location loc)
3182                 {
3183                         this.loc = loc;
3184                         eclass = ExprClass.MethodGroup;
3185                         this.type = type;
3186                 }
3187
3188                 public override Type DeclaringType {
3189                         get {
3190                                 //
3191                                 // We assume that the top-level type is in the end
3192                                 //
3193                                 return Methods [Methods.Length - 1].DeclaringType;
3194                                 //return Methods [0].DeclaringType;
3195                         }
3196                 }
3197
3198                 public Type DelegateType {
3199                         set {
3200                                 delegate_type = value;
3201                         }
3202                 }
3203
3204                 public bool IdenticalTypeName {
3205                         get {
3206                                 return identical_type_name;
3207                         }
3208
3209                         set {
3210                                 identical_type_name = value;
3211                         }
3212                 }
3213
3214                 public override string GetSignatureForError ()
3215                 {
3216                         if (best_candidate != null)
3217                                 return TypeManager.CSharpSignature (best_candidate);
3218
3219                         return TypeManager.CSharpSignature (Methods [0]);
3220                 }
3221
3222                 public override string Name {
3223                         get {
3224                                 return Methods [0].Name;
3225                         }
3226                 }
3227
3228                 public override bool IsInstance {
3229                         get {
3230                                 if (best_candidate != null)
3231                                         return !best_candidate.IsStatic;
3232
3233                                 foreach (MethodBase mb in Methods)
3234                                         if (!mb.IsStatic)
3235                                                 return true;
3236
3237                                 return false;
3238                         }
3239                 }
3240
3241                 public override bool IsStatic {
3242                         get {
3243                                 if (best_candidate != null)
3244                                         return best_candidate.IsStatic;
3245
3246                                 foreach (MethodBase mb in Methods)
3247                                         if (mb.IsStatic)
3248                                                 return true;
3249
3250                                 return false;
3251                         }
3252                 }
3253
3254                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3255                 {
3256                         return (ConstructorInfo)mg.best_candidate;
3257                 }
3258
3259                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3260                 {
3261                         return (MethodInfo)mg.best_candidate;
3262                 }
3263
3264                 /// <summary>
3265                 ///   Determines "better conversion" as specified in 14.4.2.3
3266                 ///
3267                 ///    Returns : p    if a->p is better,
3268                 ///              q    if a->q is better,
3269                 ///              null if neither is better
3270                 /// </summary>
3271                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q)
3272                 {
3273                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3274                         Expression argument_expr = a.Expr;
3275
3276                         if (argument_type == null)
3277                                 throw new Exception ("Expression of type " + a.Expr +
3278                                         " does not resolve its type");
3279
3280                         if (p == null || q == null)
3281                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
3282
3283                         if (p == q)
3284                                 return null;
3285
3286                         if (argument_expr is NullLiteral)
3287                         {
3288                                 //
3289                                 // If the argument is null and one of the types to compare is 'object' and
3290                                 // the other is a reference type, we prefer the other.
3291                                 //
3292                                 // This follows from the usual rules:
3293                                 //   * There is an implicit conversion from 'null' to type 'object'
3294                                 //   * There is an implicit conversion from 'null' to any reference type
3295                                 //   * There is an implicit conversion from any reference type to type 'object'
3296                                 //   * There is no implicit conversion from type 'object' to other reference types
3297                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
3298                                 //
3299                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
3300                                 //         null type. I think it used to be 'object' and thus needed a special
3301                                 //         case to avoid the immediately following two checks.
3302                                 //
3303                                 if (!p.IsValueType && q == TypeManager.object_type)
3304                                         return p;
3305                                 if (!q.IsValueType && p == TypeManager.object_type)
3306                                         return q;
3307                         }
3308
3309                         if (argument_type == p)
3310                                 return p;
3311
3312                         if (argument_type == q)
3313                                 return q;
3314
3315                         Expression p_tmp = new EmptyExpression (p);
3316                         Expression q_tmp = new EmptyExpression (q);
3317
3318                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3319                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3320
3321                         if (p_to_q && !q_to_p)
3322                                 return p;
3323
3324                         if (q_to_p && !p_to_q)
3325                                 return q;
3326
3327                         if (p == TypeManager.sbyte_type)
3328                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3329                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3330                                         return p;
3331                         if (q == TypeManager.sbyte_type)
3332                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3333                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3334                                         return q;
3335
3336                         if (p == TypeManager.short_type)
3337                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3338                                         q == TypeManager.uint64_type)
3339                                         return p;
3340                         if (q == TypeManager.short_type)
3341                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3342                                         p == TypeManager.uint64_type)
3343                                         return q;
3344
3345                         if (p == TypeManager.int32_type)
3346                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3347                                         return p;
3348                         if (q == TypeManager.int32_type)
3349                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3350                                         return q;
3351
3352                         if (p == TypeManager.int64_type)
3353                                 if (q == TypeManager.uint64_type)
3354                                         return p;
3355                         if (q == TypeManager.int64_type)
3356                                 if (p == TypeManager.uint64_type)
3357                                         return q;
3358
3359                         return null;
3360                 }
3361
3362                 /// <summary>
3363                 ///   Determines "Better function" between candidate
3364                 ///   and the current best match
3365                 /// </summary>
3366                 /// <remarks>
3367                 ///    Returns a boolean indicating :
3368                 ///     false if candidate ain't better
3369                 ///     true  if candidate is better than the current best match
3370                 /// </remarks>
3371                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3372                         MethodBase candidate, bool candidate_params,
3373                         MethodBase best, bool best_params)
3374                 {
3375                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3376                         ParameterData best_pd = TypeManager.GetParameterData (best);
3377
3378                         bool better_at_least_one = false;
3379                         bool same = true;
3380                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3381                         {
3382                                 Argument a = (Argument) args [j];
3383
3384                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3385                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3386
3387                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3388                                 {
3389                                         ct = TypeManager.GetElementType (ct);
3390                                         --c_idx;
3391                                 }
3392
3393                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3394                                 {
3395                                         bt = TypeManager.GetElementType (bt);
3396                                         --b_idx;
3397                                 }
3398
3399                                 if (ct.Equals (bt))
3400                                         continue;
3401
3402                                 same = false;
3403                                 Type better = BetterConversion (ec, a, ct, bt);
3404
3405                                 // for each argument, the conversion to 'ct' should be no worse than
3406                                 // the conversion to 'bt'.
3407                                 if (better == bt)
3408                                         return false;
3409
3410                                 // for at least one argument, the conversion to 'ct' should be better than
3411                                 // the conversion to 'bt'.
3412                                 if (better == ct)
3413                                         better_at_least_one = true;
3414                         }
3415
3416                         if (better_at_least_one)
3417                                 return true;
3418
3419                         //
3420                         // This handles the case
3421                         //
3422                         //   Add (float f1, float f2, float f3);
3423                         //   Add (params decimal [] foo);
3424                         //
3425                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3426                         // first candidate would've chosen as better.
3427                         //
3428                         if (!same)
3429                                 return false;
3430
3431                         //
3432                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3433                         //
3434                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3435                                 return true;
3436                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3437                                 return false;
3438
3439                         //
3440                         // This handles the following cases:
3441                         //
3442                         //   Trim () is better than Trim (params char[] chars)
3443                         //   Concat (string s1, string s2, string s3) is better than
3444                         //     Concat (string s1, params string [] srest)
3445                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3446                         //
3447                         if (!candidate_params && best_params)
3448                                 return true;
3449                         if (candidate_params && !best_params)
3450                                 return false;
3451
3452                         int candidate_param_count = candidate_pd.Count;
3453                         int best_param_count = best_pd.Count;
3454
3455                         if (candidate_param_count != best_param_count)
3456                                 // can only happen if (candidate_params && best_params)
3457                                 return candidate_param_count > best_param_count;
3458
3459                         //
3460                         // now, both methods have the same number of parameters, and the parameters have the same types
3461                         // Pick the "more specific" signature
3462                         //
3463
3464                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3465                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3466
3467                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3468                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3469
3470                         bool specific_at_least_once = false;
3471                         for (int j = 0; j < candidate_param_count; ++j)
3472                         {
3473                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3474                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3475                                 if (ct.Equals (bt))
3476                                         continue;
3477                                 Type specific = MoreSpecific (ct, bt);
3478                                 if (specific == bt)
3479                                         return false;
3480                                 if (specific == ct)
3481                                         specific_at_least_once = true;
3482                         }
3483
3484                         if (specific_at_least_once)
3485                                 return true;
3486
3487                         // FIXME: handle lifted operators
3488                         // ...
3489
3490                         return false;
3491                 }
3492
3493                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3494                 {
3495                         if (!IsStatic)
3496                                 return base.ResolveExtensionMemberAccess (left);
3497
3498                         //
3499                         // When left side is an expression and at least one candidate method is
3500                         // static, it can be extension method
3501                         //
3502                         InstanceExpression = left;
3503                         return this;
3504                 }
3505
3506                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3507                                                                 SimpleName original)
3508                 {
3509                         if (!(left is TypeExpr) &&
3510                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3511                                 IdenticalTypeName = true;
3512
3513                         return base.ResolveMemberAccess (ec, left, loc, original);
3514                 }
3515
3516                 override public Expression DoResolve (EmitContext ec)
3517                 {
3518                         if (InstanceExpression != null) {
3519                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3520                                 if (InstanceExpression == null)
3521                                         return null;
3522                         }
3523
3524                         return this;
3525                 }
3526
3527                 public void ReportUsageError ()
3528                 {
3529                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3530                                       Name + "()' is referenced without parentheses");
3531                 }
3532
3533                 override public void Emit (EmitContext ec)
3534                 {
3535                         ReportUsageError ();
3536                 }
3537
3538                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3539                 {
3540                         Invocation.EmitArguments (ec, best_candidate, arguments, false, null);
3541                 }
3542
3543                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3544                 {
3545                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3546                 }
3547
3548                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3549                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3550                 {
3551                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3552                                 Report.SymbolRelatedToPreviousError (method);
3553                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3554                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3555                                                 TypeManager.CSharpSignature (method));
3556                                         return;
3557                                 }
3558                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3559                                           TypeManager.CSharpSignature (method));
3560                         } else if (delegate_type == null) {
3561                                 Report.SymbolRelatedToPreviousError (method);
3562                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3563                                                   TypeManager.CSharpSignature (method));
3564                         } else
3565                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3566                                         TypeManager.CSharpName (delegate_type));
3567
3568                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3569
3570                         string index = (idx + 1).ToString ();
3571                         if ((mod & Parameter.Modifier.ISBYREF) != (a.Modifier & Parameter.Modifier.ISBYREF) ||
3572                                 (mod & Parameter.Modifier.ISBYREF) != 0) {
3573                                 if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) == 0)
3574                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3575                                                 index, Parameter.GetModifierSignature (a.Modifier));
3576                                 else
3577                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3578                                                 index, Parameter.GetModifierSignature (mod));
3579                         } else {
3580                                 string p1 = Argument.FullDesc (a);
3581                                 string p2 = TypeManager.CSharpName (paramType);
3582
3583                                 if (p1 == p2) {
3584                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3585                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3586                                         Report.SymbolRelatedToPreviousError (paramType);
3587                                 }
3588                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3589                         }
3590                 }
3591
3592                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3593                 {
3594                         return parameters.Count;
3595                 }
3596
3597                 public static bool IsAncestralType (Type first_type, Type second_type)
3598                 {
3599                         return first_type != second_type &&
3600                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3601                                 TypeManager.ImplementsInterface (second_type, first_type));
3602                 }
3603
3604                 ///
3605                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3606                 /// to the given set of arguments
3607                 /// A return value rates candidate method compatibility,
3608                 /// 0 = the best, int.MaxValue = the worst
3609                 ///
3610                 public int IsApplicable (EmitContext ec,
3611                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3612                 {
3613                         MethodBase candidate = method;
3614
3615                         ParameterData pd = TypeManager.GetParameterData (candidate);
3616                         int param_count = GetApplicableParametersCount (candidate, pd);
3617
3618                         if (arg_count != param_count) {
3619                                 if (!pd.HasParams)
3620                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3621                                 if (arg_count < param_count - 1)
3622                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3623                         }
3624
3625 #if GMCS_SOURCE
3626                         //
3627                         // 1. Handle generic method using type arguments when specified or type inference
3628                         //
3629                         if (TypeManager.IsGenericMethod (candidate)) {
3630                                 if (type_arguments != null) {
3631                                         Type [] g_args = candidate.GetGenericArguments ();
3632                                         if (g_args.Length != type_arguments.Count)
3633                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3634
3635                                         // TODO: Don't create new method, create Parameters only
3636                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3637                                         candidate = method;
3638                                         pd = TypeManager.GetParameterData (candidate);
3639                                 } else {
3640                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3641                                         if (score != 0)
3642                                                 return score - 20000;
3643
3644                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3645                                                 throw new InternalErrorException ("a generic method definition took part in overload resolution");
3646
3647                                         pd = TypeManager.GetParameterData (candidate);
3648                                 }
3649                         } else {
3650                                 if (type_arguments != null)
3651                                         return int.MaxValue - 15000;
3652                         }
3653 #endif
3654
3655                         //
3656                         // 2. Each argument has to be implicitly convertible to method parameter
3657                         //
3658                         Parameter.Modifier p_mod = 0;
3659                         Type pt = null;
3660                         for (int i = 0; i < arg_count; i++) {
3661                                 Argument a = (Argument) arguments [i];
3662                                 Parameter.Modifier a_mod = a.Modifier &
3663                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3664
3665                                 if (p_mod != Parameter.Modifier.PARAMS) {
3666                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3667
3668                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3669                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3670                                                         continue;
3671
3672                                                 p_mod = 0;
3673                                         }
3674
3675                                         pt = pd.ParameterType (i);
3676                                 } else {
3677                                         params_expanded_form = true;
3678                                 }
3679
3680                                 int score = 1;
3681                                 if (!params_expanded_form)
3682                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3683
3684                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3685                                         // It can be applicable in expanded form
3686                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3687                                         if (score == 0)
3688                                                 params_expanded_form = true;
3689                                 }
3690
3691                                 if (score != 0)
3692                                         return (arg_count - i) * 2 + score;
3693                         }
3694
3695                         if (arg_count != param_count)
3696                                 params_expanded_form = true;
3697
3698                         method = candidate;
3699                         return 0;
3700                 }
3701
3702                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3703                 {
3704                         //
3705                         // Types have to be identical when ref or out modifer is used
3706                         //
3707                         if (arg_mod != 0 || param_mod != 0) {
3708                                 if (TypeManager.HasElementType (parameter))
3709                                         parameter = parameter.GetElementType ();
3710
3711                                 Type a_type = argument.Type;
3712                                 if (TypeManager.HasElementType (a_type))
3713                                         a_type = a_type.GetElementType ();
3714
3715                                 if (a_type != parameter)
3716                                         return 2;
3717
3718                                 return 0;
3719                         }
3720
3721                         // FIXME: Kill this abomination (EmitContext.TempEc)
3722                         EmitContext prevec = EmitContext.TempEc;
3723                         EmitContext.TempEc = ec;
3724                         try {
3725                                 if (delegate_type != null ?
3726                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3727                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3728                                         return 2;
3729
3730                                 if (arg_mod != param_mod)
3731                                         return 1;
3732
3733                         } finally {
3734                                 EmitContext.TempEc = prevec;
3735                         }
3736
3737                         return 0;
3738                 }
3739
3740                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3741                 {
3742                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3743                                 return false;
3744
3745                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3746                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3747
3748                         if (cand_pd.Count != base_pd.Count)
3749                                 return false;
3750
3751                         for (int j = 0; j < cand_pd.Count; ++j)
3752                         {
3753                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3754                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3755                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3756                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3757
3758                                 if (cm != bm || ct != bt)
3759                                         return false;
3760                         }
3761
3762                         return true;
3763                 }
3764
3765                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3766                 {
3767                         MemberInfo [] miset;
3768                         MethodGroupExpr union;
3769
3770                         if (mg1 == null) {
3771                                 if (mg2 == null)
3772                                         return null;
3773                                 return (MethodGroupExpr) mg2;
3774                         } else {
3775                                 if (mg2 == null)
3776                                         return (MethodGroupExpr) mg1;
3777                         }
3778
3779                         MethodGroupExpr left_set = null, right_set = null;
3780                         int length1 = 0, length2 = 0;
3781
3782                         left_set = (MethodGroupExpr) mg1;
3783                         length1 = left_set.Methods.Length;
3784
3785                         right_set = (MethodGroupExpr) mg2;
3786                         length2 = right_set.Methods.Length;
3787
3788                         ArrayList common = new ArrayList ();
3789
3790                         foreach (MethodBase r in right_set.Methods){
3791                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3792                                         common.Add (r);
3793                         }
3794
3795                         miset = new MemberInfo [length1 + length2 - common.Count];
3796                         left_set.Methods.CopyTo (miset, 0);
3797
3798                         int k = length1;
3799
3800                         foreach (MethodBase r in right_set.Methods) {
3801                                 if (!common.Contains (r))
3802                                         miset [k++] = r;
3803                         }
3804
3805                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3806
3807                         return union;
3808                 }
3809
3810                 static Type MoreSpecific (Type p, Type q)
3811                 {
3812                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3813                                 return q;
3814                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3815                                 return p;
3816
3817                         if (TypeManager.HasElementType (p))
3818                         {
3819                                 Type pe = TypeManager.GetElementType (p);
3820                                 Type qe = TypeManager.GetElementType (q);
3821                                 Type specific = MoreSpecific (pe, qe);
3822                                 if (specific == pe)
3823                                         return p;
3824                                 if (specific == qe)
3825                                         return q;
3826                         }
3827                         else if (TypeManager.IsGenericType (p))
3828                         {
3829                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3830                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3831
3832                                 bool p_specific_at_least_once = false;
3833                                 bool q_specific_at_least_once = false;
3834
3835                                 for (int i = 0; i < pargs.Length; i++)
3836                                 {
3837                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3838                                         if (specific == pargs [i])
3839                                                 p_specific_at_least_once = true;
3840                                         if (specific == qargs [i])
3841                                                 q_specific_at_least_once = true;
3842                                 }
3843
3844                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3845                                         return p;
3846                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3847                                         return q;
3848                         }
3849
3850                         return null;
3851                 }
3852
3853                 /// <summary>
3854                 ///   Find the Applicable Function Members (7.4.2.1)
3855                 ///
3856                 ///   me: Method Group expression with the members to select.
3857                 ///       it might contain constructors or methods (or anything
3858                 ///       that maps to a method).
3859                 ///
3860                 ///   Arguments: ArrayList containing resolved Argument objects.
3861                 ///
3862                 ///   loc: The location if we want an error to be reported, or a Null
3863                 ///        location for "probing" purposes.
3864                 ///
3865                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3866                 ///            that is the best match of me on Arguments.
3867                 ///
3868                 /// </summary>
3869                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList Arguments,
3870                         bool may_fail, Location loc)
3871                 {
3872                         bool method_params = false;
3873                         Type applicable_type = null;
3874                         int arg_count = 0;
3875                         ArrayList candidates = new ArrayList (2);
3876                         ArrayList candidate_overrides = null;
3877
3878                         //
3879                         // Used to keep a map between the candidate
3880                         // and whether it is being considered in its
3881                         // normal or expanded form
3882                         //
3883                         // false is normal form, true is expanded form
3884                         //
3885                         Hashtable candidate_to_form = null;
3886
3887                         if (Arguments != null)
3888                                 arg_count = Arguments.Count;
3889
3890                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3891                                 if (!may_fail)
3892                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3893                                 return null;
3894                         }
3895
3896                         int nmethods = Methods.Length;
3897
3898                         if (!IsBase) {
3899                                 //
3900                                 // Methods marked 'override' don't take part in 'applicable_type'
3901                                 // computation, nor in the actual overload resolution.
3902                                 // However, they still need to be emitted instead of a base virtual method.
3903                                 // So, we salt them away into the 'candidate_overrides' array.
3904                                 //
3905                                 // In case of reflected methods, we replace each overriding method with
3906                                 // its corresponding base virtual method.  This is to improve compatibility
3907                                 // with non-C# libraries which change the visibility of overrides (#75636)
3908                                 //
3909                                 int j = 0;
3910                                 for (int i = 0; i < Methods.Length; ++i) {
3911                                         MethodBase m = Methods [i];
3912                                         if (TypeManager.IsOverride (m)) {
3913                                                 if (candidate_overrides == null)
3914                                                         candidate_overrides = new ArrayList ();
3915                                                 candidate_overrides.Add (m);
3916                                                 m = TypeManager.TryGetBaseDefinition (m);
3917                                         }
3918                                         if (m != null)
3919                                                 Methods [j++] = m;
3920                                 }
3921                                 nmethods = j;
3922                         }
3923
3924                         //
3925                         // Enable message recording, it's used mainly by lambda expressions
3926                         //
3927                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
3928                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
3929
3930                         //
3931                         // First we construct the set of applicable methods
3932                         //
3933                         bool is_sorted = true;
3934                         int best_candidate_rate = int.MaxValue;
3935                         for (int i = 0; i < nmethods; i++) {
3936                                 Type decl_type = Methods [i].DeclaringType;
3937
3938                                 //
3939                                 // If we have already found an applicable method
3940                                 // we eliminate all base types (Section 14.5.5.1)
3941                                 //
3942                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
3943                                         continue;
3944
3945                                 //
3946                                 // Check if candidate is applicable (section 14.4.2.1)
3947                                 //
3948                                 bool params_expanded_form = false;
3949                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
3950
3951                                 if (candidate_rate < best_candidate_rate) {
3952                                         best_candidate_rate = candidate_rate;
3953                                         best_candidate = Methods [i];
3954                                 }
3955
3956                                 if (params_expanded_form) {
3957                                         if (candidate_to_form == null)
3958                                                 candidate_to_form = new PtrHashtable ();
3959                                         MethodBase candidate = Methods [i];
3960                                         candidate_to_form [candidate] = candidate;
3961                                 }
3962
3963                                 if (candidate_rate != 0) {
3964                                         if (msg_recorder != null)
3965                                                 msg_recorder.EndSession ();
3966                                         continue;
3967                                 }
3968
3969                                 msg_recorder = null;
3970                                 candidates.Add (Methods [i]);
3971
3972                                 if (applicable_type == null)
3973                                         applicable_type = decl_type;
3974                                 else if (applicable_type != decl_type) {
3975                                         is_sorted = false;
3976                                         if (IsAncestralType (applicable_type, decl_type))
3977                                                 applicable_type = decl_type;
3978                                 }
3979                         }
3980
3981                         Report.SetMessageRecorder (prev_recorder);
3982                         if (msg_recorder != null && msg_recorder.PrintMessages ())
3983                                 return null;
3984
3985                         int candidate_top = candidates.Count;
3986
3987                         if (applicable_type == null) {
3988                                 //
3989                                 // When we found a top level method which does not match and it's
3990                                 // not an extension method. We start extension methods lookup from here
3991                                 //
3992                                 if (InstanceExpression != null) {
3993                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name);
3994                                         if (ex_method_lookup != null) {
3995                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
3996                                                 ex_method_lookup.SetTypeArguments (type_arguments);
3997                                                 return ex_method_lookup.OverloadResolve (ec, Arguments, may_fail, loc);
3998                                         }
3999                                 }
4000
4001                                 if (may_fail)
4002                                         return null;
4003
4004                                 //
4005                                 // Okay so we have failed to find exact match so we
4006                                 // return error info about the closest match
4007                                 //
4008                                 if (best_candidate != null) {
4009                                         if (CustomErrorHandler != null) {
4010                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4011                                                         return null;
4012                                         }
4013
4014                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4015                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4016                                         if (arg_count == pd.Count || pd.HasParams) {
4017                                                 if (TypeManager.IsGenericMethod (best_candidate)) {
4018                                                         if (type_arguments == null) {
4019                                                                 Report.Error (411, loc,
4020                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4021                                                                         "the usage. Try specifying the type arguments explicitly",
4022                                                                         TypeManager.CSharpSignature (best_candidate));
4023                                                                 return null;
4024                                                         }
4025
4026                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4027                                                         if (type_arguments.Count != g_args.Length) {
4028                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4029                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4030                                                                         TypeManager.CSharpSignature (best_candidate),
4031                                                                         g_args.Length.ToString ());
4032                                                                 return null;
4033                                                         }
4034                                                 } else {
4035                                                         if (type_arguments != null) {
4036                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4037                                                                 return null;
4038                                                         }
4039                                                 }
4040
4041                                                 if (VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4042                                                         throw new InternalErrorException ("Overload verification expected failure");
4043                                                 return null;
4044                                         }
4045                                 }
4046
4047                                 if (almost_matched_members.Count != 0) {
4048                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4049                                         null, MemberTypes.Constructor, AllBindingFlags);
4050                                         return null;
4051                                 }
4052
4053                                 //
4054                                 // We failed to find any method with correct argument count
4055                                 //
4056                                 if (Name == ConstructorInfo.ConstructorName) {
4057                                         Report.SymbolRelatedToPreviousError (type);
4058                                         Report.Error (1729, loc,
4059                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4060                                                 TypeManager.CSharpName (type), arg_count);
4061                                 } else {
4062                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4063                                                 Name, arg_count.ToString ());
4064                                 }
4065
4066                                 return null;
4067                         }
4068
4069                         if (!is_sorted) {
4070                                 //
4071                                 // At this point, applicable_type is _one_ of the most derived types
4072                                 // in the set of types containing the methods in this MethodGroup.
4073                                 // Filter the candidates so that they only contain methods from the
4074                                 // most derived types.
4075                                 //
4076
4077                                 int finalized = 0; // Number of finalized candidates
4078
4079                                 do {
4080                                         // Invariant: applicable_type is a most derived type
4081
4082                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4083                                         // eliminating all it's base types.  At the same time, we'll also move
4084                                         // every unrelated type to the end of the array, and pick the next
4085                                         // 'applicable_type'.
4086
4087                                         Type next_applicable_type = null;
4088                                         int j = finalized; // where to put the next finalized candidate
4089                                         int k = finalized; // where to put the next undiscarded candidate
4090                                         for (int i = finalized; i < candidate_top; ++i) {
4091                                                 MethodBase candidate = (MethodBase) candidates [i];
4092                                                 Type decl_type = candidate.DeclaringType;
4093
4094                                                 if (decl_type == applicable_type) {
4095                                                         candidates [k++] = candidates [j];
4096                                                         candidates [j++] = candidates [i];
4097                                                         continue;
4098                                                 }
4099
4100                                                 if (IsAncestralType (decl_type, applicable_type))
4101                                                         continue;
4102
4103                                                 if (next_applicable_type != null &&
4104                                                         IsAncestralType (decl_type, next_applicable_type))
4105                                                         continue;
4106
4107                                                 candidates [k++] = candidates [i];
4108
4109                                                 if (next_applicable_type == null ||
4110                                                         IsAncestralType (next_applicable_type, decl_type))
4111                                                         next_applicable_type = decl_type;
4112                                         }
4113
4114                                         applicable_type = next_applicable_type;
4115                                         finalized = j;
4116                                         candidate_top = k;
4117                                 } while (applicable_type != null);
4118                         }
4119
4120                         //
4121                         // Now we actually find the best method
4122                         //
4123
4124                         best_candidate = (MethodBase) candidates [0];
4125                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4126                         for (int ix = 1; ix < candidate_top; ix++) {
4127                                 MethodBase candidate = (MethodBase) candidates [ix];
4128
4129                                 if (candidate == best_candidate)
4130                                         continue;
4131
4132                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4133
4134                                 if (BetterFunction (ec, Arguments, arg_count,
4135                                         candidate, cand_params,
4136                                         best_candidate, method_params)) {
4137                                         best_candidate = candidate;
4138                                         method_params = cand_params;
4139                                 }
4140                         }
4141                         //
4142                         // Now check that there are no ambiguities i.e the selected method
4143                         // should be better than all the others
4144                         //
4145                         MethodBase ambiguous = null;
4146                         for (int ix = 0; ix < candidate_top; ix++) {
4147                                 MethodBase candidate = (MethodBase) candidates [ix];
4148
4149                                 if (candidate == best_candidate)
4150                                         continue;
4151
4152                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4153                                 if (!BetterFunction (ec, Arguments, arg_count,
4154                                         best_candidate, method_params,
4155                                         candidate, cand_params))
4156                                 {
4157                                         if (!may_fail)
4158                                                 Report.SymbolRelatedToPreviousError (candidate);
4159                                         ambiguous = candidate;
4160                                 }
4161                         }
4162
4163                         if (ambiguous != null) {
4164                                 Report.SymbolRelatedToPreviousError (best_candidate);
4165                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4166                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4167                                 return this;
4168                         }
4169
4170                         //
4171                         // If the method is a virtual function, pick an override closer to the LHS type.
4172                         //
4173                         if (!IsBase && best_candidate.IsVirtual) {
4174                                 if (TypeManager.IsOverride (best_candidate))
4175                                         throw new InternalErrorException (
4176                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4177
4178                                 if (candidate_overrides != null) {
4179                                         Type[] gen_args = null;
4180                                         bool gen_override = false;
4181                                         if (TypeManager.IsGenericMethod (best_candidate))
4182                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4183
4184                                         foreach (MethodBase candidate in candidate_overrides) {
4185                                                 if (TypeManager.IsGenericMethod (candidate)) {
4186                                                         if (gen_args == null)
4187                                                                 continue;
4188
4189                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4190                                                                 continue;
4191                                                 } else {
4192                                                         if (gen_args != null)
4193                                                                 continue;
4194                                                 }
4195
4196                                                 if (IsOverride (candidate, best_candidate)) {
4197                                                         gen_override = true;
4198                                                         best_candidate = candidate;
4199                                                 }
4200                                         }
4201
4202                                         if (gen_override && gen_args != null) {
4203 #if GMCS_SOURCE
4204                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4205 #endif
4206                                         }
4207                                 }
4208                         }
4209
4210                         //
4211                         // And now check if the arguments are all
4212                         // compatible, perform conversions if
4213                         // necessary etc. and return if everything is
4214                         // all right
4215                         //
4216                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate,
4217                                 method_params, may_fail, loc))
4218                                 return null;
4219
4220                         if (best_candidate == null)
4221                                 return null;
4222
4223                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4224 #if GMCS_SOURCE
4225                         if (the_method.IsGenericMethodDefinition &&
4226                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4227                                 return null;
4228 #endif
4229
4230                         IMethodData data = TypeManager.GetMethod (the_method);
4231                         if (data != null)
4232                                 data.SetMemberIsUsed ();
4233
4234                         return this;
4235                 }
4236
4237                 public override void SetTypeArguments (TypeArguments ta)
4238                 {
4239                         type_arguments = ta;
4240                 }
4241
4242                 public bool VerifyArgumentsCompat (EmitContext ec, ArrayList arguments,
4243                                                           int arg_count, MethodBase method,
4244                                                           bool chose_params_expanded,
4245                                                           bool may_fail, Location loc)
4246                 {
4247                         ParameterData pd = TypeManager.GetParameterData (method);
4248
4249                         int errors = Report.Errors;
4250                         Parameter.Modifier p_mod = 0;
4251                         Type pt = null;
4252                         int a_idx = 0;
4253                         Argument a = null;
4254                         for (; a_idx < arg_count; a_idx++) {
4255                                 a = (Argument) arguments [a_idx];
4256                                 if (p_mod != Parameter.Modifier.PARAMS) {
4257                                         p_mod = pd.ParameterModifier (a_idx);
4258                                         pt = pd.ParameterType (a_idx);
4259
4260                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4261                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4262                                                         break;
4263                                                 continue;
4264                                         }
4265
4266                                         if (pt.IsPointer && !ec.InUnsafe) {
4267                                                 if (may_fail)
4268                                                         return false;
4269
4270                                                 UnsafeError (loc);
4271                                         }
4272
4273                                         if (p_mod == Parameter.Modifier.PARAMS) {
4274                                                 if (chose_params_expanded)
4275                                                         pt = TypeManager.GetElementType (pt);
4276                                         } else if (p_mod != 0) {
4277                                                 pt = TypeManager.GetElementType (pt);
4278                                         }
4279                                 }
4280
4281                                 //
4282                                 // Types have to be identical when ref or out modifer is used
4283                                 //
4284                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4285                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4286                                                 break;
4287
4288                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4289                                                 break;
4290
4291                                         continue;
4292                                 }
4293
4294                                 if (TypeManager.IsEqual (a.Type, pt))
4295                                         continue;
4296
4297                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4298                                 if (conv == null)
4299                                         break;
4300
4301                                 if (!chose_params_expanded && (p_mod & Parameter.Modifier.PARAMS) != 0 && a.Type == TypeManager.null_type)
4302                                         conv.Type = pd.ParameterType (a_idx);
4303
4304                                 // Update the argument with the implicit conversion
4305                                 a.Expr = conv;
4306                         }
4307
4308                         if (a_idx == arg_count)
4309                                 return true;
4310
4311                         if (!may_fail && Report.Errors == errors)
4312                                 Error_InvalidArguments (ec, loc, a_idx, method, a, pd, pt);
4313                         return false;
4314                 }
4315         }
4316
4317         public class ConstantExpr : MemberExpr
4318         {
4319                 FieldInfo constant;
4320
4321                 public ConstantExpr (FieldInfo constant, Location loc)
4322                 {
4323                         this.constant = constant;
4324                         this.loc = loc;
4325                 }
4326
4327                 public override string Name {
4328                         get { throw new NotImplementedException (); }
4329                 }
4330
4331                 public override bool IsInstance {
4332                         get { return !IsStatic; }
4333                 }
4334
4335                 public override bool IsStatic {
4336                         get { return constant.IsStatic; }
4337                 }
4338
4339                 public override Type DeclaringType {
4340                         get { return constant.DeclaringType; }
4341                 }
4342
4343                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4344                 {
4345                         constant = TypeManager.GetGenericFieldDefinition (constant);
4346
4347                         IConstant ic = TypeManager.GetConstant (constant);
4348                         if (ic == null) {
4349                                 if (constant.IsLiteral) {
4350                                         ic = new ExternalConstant (constant);
4351                                 } else {
4352                                         ic = ExternalConstant.CreateDecimal (constant);
4353                                         // HACK: decimal field was not resolved as constant
4354                                         if (ic == null)
4355                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4356                                 }
4357                                 TypeManager.RegisterConstant (constant, ic);
4358                         }
4359
4360                         return base.ResolveMemberAccess (ec, left, loc, original);
4361                 }
4362
4363                 public override Expression DoResolve (EmitContext ec)
4364                 {
4365                         IConstant ic = TypeManager.GetConstant (constant);
4366                         if (ic.ResolveValue ()) {
4367                                 if (!ec.IsInObsoleteScope)
4368                                         ic.CheckObsoleteness (loc);
4369                         }
4370
4371                         return ic.CreateConstantReference (loc);
4372                 }
4373
4374                 public override void Emit (EmitContext ec)
4375                 {
4376                         throw new NotSupportedException ();
4377                 }
4378
4379                 public override string GetSignatureForError ()
4380                 {
4381                         return TypeManager.GetFullNameSignature (constant);
4382                 }
4383         }
4384
4385         /// <summary>
4386         ///   Fully resolved expression that evaluates to a Field
4387         /// </summary>
4388         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4389                 public readonly FieldInfo FieldInfo;
4390                 VariableInfo variable_info;
4391
4392                 LocalTemporary temp;
4393                 bool prepared;
4394                 bool in_initializer;
4395
4396                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4397                         this (fi, l)
4398                 {
4399                         this.in_initializer = in_initializer;
4400                 }
4401
4402                 public FieldExpr (FieldInfo fi, Location l)
4403                 {
4404                         FieldInfo = fi;
4405                         eclass = ExprClass.Variable;
4406                         type = TypeManager.TypeToCoreType (fi.FieldType);
4407                         loc = l;
4408                 }
4409
4410                 public override string Name {
4411                         get {
4412                                 return FieldInfo.Name;
4413                         }
4414                 }
4415
4416                 public override bool IsInstance {
4417                         get {
4418                                 return !FieldInfo.IsStatic;
4419                         }
4420                 }
4421
4422                 public override bool IsStatic {
4423                         get {
4424                                 return FieldInfo.IsStatic;
4425                         }
4426                 }
4427
4428                 public override Type DeclaringType {
4429                         get {
4430                                 return FieldInfo.DeclaringType;
4431                         }
4432                 }
4433
4434                 public override string GetSignatureForError ()
4435                 {
4436                         return TypeManager.GetFullNameSignature (FieldInfo);
4437                 }
4438
4439                 public VariableInfo VariableInfo {
4440                         get {
4441                                 return variable_info;
4442                         }
4443                 }
4444
4445                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4446                                                                 SimpleName original)
4447                 {
4448                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4449                         Type t = fi.FieldType;
4450
4451                         if (t.IsPointer && !ec.InUnsafe) {
4452                                 UnsafeError (loc);
4453                         }
4454
4455                         return base.ResolveMemberAccess (ec, left, loc, original);
4456                 }
4457
4458                 override public Expression DoResolve (EmitContext ec)
4459                 {
4460                         return DoResolve (ec, false, false);
4461                 }
4462
4463                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4464                 {
4465                         if (!FieldInfo.IsStatic){
4466                                 if (InstanceExpression == null){
4467                                         //
4468                                         // This can happen when referencing an instance field using
4469                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4470                                         //
4471                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4472                                         return null;
4473                                 }
4474
4475                                 // Resolve the field's instance expression while flow analysis is turned
4476                                 // off: when accessing a field "a.b", we must check whether the field
4477                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4478
4479                                 if (lvalue_instance) {
4480                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4481                                                 Expression right_side =
4482                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4483                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4484                                         }
4485                                 } else {
4486                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4487                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4488                                 }
4489
4490                                 if (InstanceExpression == null)
4491                                         return null;
4492
4493                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4494                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4495                                 }
4496                         }
4497
4498                         if (!in_initializer && !ec.IsInFieldInitializer) {
4499                                 ObsoleteAttribute oa;
4500                                 FieldBase f = TypeManager.GetField (FieldInfo);
4501                                 if (f != null) {
4502                                         if (!ec.IsInObsoleteScope)
4503                                                 f.CheckObsoleteness (loc);
4504
4505                                         // To be sure that type is external because we do not register generated fields
4506                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4507                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4508                                         if (oa != null)
4509                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4510                                 }
4511                         }
4512
4513                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4514                         if (am != null){
4515                                 if (!FieldInfo.IsStatic){
4516                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4517                                                 Report.Error (1673, loc,
4518                                                 "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",
4519                                                         "this");
4520                                                 return null;
4521                                         }
4522                                 }
4523                         }
4524
4525                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4526                         if (fb != null) {
4527                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4528                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4529                                 }
4530
4531                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4532                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4533                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4534                                                 TypeManager.GetFullNameSignature (FieldInfo));
4535                                 }
4536
4537                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4538                         }
4539
4540                         // If the instance expression is a local variable or parameter.
4541                         IVariable var = InstanceExpression as IVariable;
4542                         if ((var == null) || (var.VariableInfo == null))
4543                                 return this;
4544
4545                         VariableInfo vi = var.VariableInfo;
4546                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4547                                 return null;
4548
4549                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4550                         return this;
4551                 }
4552
4553                 static readonly int [] codes = {
4554                         191,    // instance, write access
4555                         192,    // instance, out access
4556                         198,    // static, write access
4557                         199,    // static, out access
4558                         1648,   // member of value instance, write access
4559                         1649,   // member of value instance, out access
4560                         1650,   // member of value static, write access
4561                         1651    // member of value static, out access
4562                 };
4563
4564                 static readonly string [] msgs = {
4565                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4566                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4567                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4568                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4569                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4570                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4571                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4572                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4573                 };
4574
4575                 // The return value is always null.  Returning a value simplifies calling code.
4576                 Expression Report_AssignToReadonly (Expression right_side)
4577                 {
4578                         int i = 0;
4579                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4580                                 i += 1;
4581                         if (IsStatic)
4582                                 i += 2;
4583                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4584                                 i += 4;
4585                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4586
4587                         return null;
4588                 }
4589
4590                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4591                 {
4592                         IVariable var = InstanceExpression as IVariable;
4593                         if ((var != null) && (var.VariableInfo != null))
4594                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4595
4596                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4597                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4598
4599                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4600
4601                         if (e == null)
4602                                 return null;
4603
4604                         FieldBase fb = TypeManager.GetField (FieldInfo);
4605                         if (fb != null)
4606                                 fb.SetAssigned ();
4607
4608                         if (FieldInfo.IsInitOnly) {
4609                                 // InitOnly fields can only be assigned in constructors or initializers
4610                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4611                                         return Report_AssignToReadonly (right_side);
4612
4613                                 if (ec.IsConstructor) {
4614                                         Type ctype = ec.TypeContainer.CurrentType;
4615                                         if (ctype == null)
4616                                                 ctype = ec.ContainerType;
4617
4618                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4619                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4620                                                 return Report_AssignToReadonly (right_side);
4621                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4622                                         if (IsStatic && !ec.IsStatic)
4623                                                 return Report_AssignToReadonly (right_side);
4624                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4625                                         if (!IsStatic && !(InstanceExpression is This))
4626                                                 return Report_AssignToReadonly (right_side);
4627                                 }
4628                         }
4629
4630                         if (right_side == EmptyExpression.OutAccess &&
4631                             !IsStatic && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4632                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4633                                 Report.Warning (197, 1, loc,
4634                                                 "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",
4635                                                 GetSignatureForError ());
4636                         }
4637
4638                         return this;
4639                 }
4640
4641                 public override void CheckMarshalByRefAccess (EmitContext ec)
4642                 {
4643                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4644                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4645                                 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",
4646                                                 GetSignatureForError ());
4647                         }
4648                 }
4649
4650                 public bool VerifyFixed ()
4651                 {
4652                         IVariable variable = InstanceExpression as IVariable;
4653                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4654                         // We defer the InstanceExpression check after the variable check to avoid a
4655                         // separate null check on InstanceExpression.
4656                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4657                 }
4658
4659                 public override int GetHashCode ()
4660                 {
4661                         return FieldInfo.GetHashCode ();
4662                 }
4663
4664                 public override bool Equals (object obj)
4665                 {
4666                         FieldExpr fe = obj as FieldExpr;
4667                         if (fe == null)
4668                                 return false;
4669
4670                         if (FieldInfo != fe.FieldInfo)
4671                                 return false;
4672
4673                         if (InstanceExpression == null || fe.InstanceExpression == null)
4674                                 return true;
4675
4676                         return InstanceExpression.Equals (fe.InstanceExpression);
4677                 }
4678
4679                 public void Emit (EmitContext ec, bool leave_copy)
4680                 {
4681                         ILGenerator ig = ec.ig;
4682                         bool is_volatile = false;
4683
4684                         FieldBase f = TypeManager.GetField (FieldInfo);
4685                         if (f != null){
4686                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4687                                         is_volatile = true;
4688
4689                                 f.SetMemberIsUsed ();
4690                         }
4691
4692                         if (FieldInfo.IsStatic){
4693                                 if (is_volatile)
4694                                         ig.Emit (OpCodes.Volatile);
4695
4696                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4697                         } else {
4698                                 if (!prepared)
4699                                         EmitInstance (ec, false);
4700
4701                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4702                                 if (ff != null) {
4703                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4704                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4705                                 } else {
4706                                         if (is_volatile)
4707                                                 ig.Emit (OpCodes.Volatile);
4708
4709                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4710                                 }
4711                         }
4712
4713                         if (leave_copy) {
4714                                 ec.ig.Emit (OpCodes.Dup);
4715                                 if (!FieldInfo.IsStatic) {
4716                                         temp = new LocalTemporary (this.Type);
4717                                         temp.Store (ec);
4718                                 }
4719                         }
4720                 }
4721
4722                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4723                 {
4724                         FieldAttributes fa = FieldInfo.Attributes;
4725                         bool is_static = (fa & FieldAttributes.Static) != 0;
4726                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4727                         ILGenerator ig = ec.ig;
4728
4729                         if (is_readonly && !ec.IsConstructor){
4730                                 Report_AssignToReadonly (source);
4731                                 return;
4732                         }
4733
4734                         //
4735                         // String concatenation creates a new string instance
4736                         //
4737                         prepared = prepare_for_load && !(source is StringConcat);
4738                         EmitInstance (ec, prepared);
4739
4740                         source.Emit (ec);
4741                         if (leave_copy) {
4742                                 ec.ig.Emit (OpCodes.Dup);
4743                                 if (!FieldInfo.IsStatic) {
4744                                         temp = new LocalTemporary (this.Type);
4745                                         temp.Store (ec);
4746                                 }
4747                         }
4748
4749                         FieldBase f = TypeManager.GetField (FieldInfo);
4750                         if (f != null){
4751                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4752                                         ig.Emit (OpCodes.Volatile);
4753
4754                                 f.SetAssigned ();
4755                         }
4756
4757                         if (is_static)
4758                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4759                         else
4760                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4761
4762                         if (temp != null) {
4763                                 temp.Emit (ec);
4764                                 temp.Release (ec);
4765                         }
4766                 }
4767
4768                 public override void Emit (EmitContext ec)
4769                 {
4770                         Emit (ec, false);
4771                 }
4772
4773                 public void AddressOf (EmitContext ec, AddressOp mode)
4774                 {
4775                         ILGenerator ig = ec.ig;
4776
4777                         FieldBase f = TypeManager.GetField (FieldInfo);
4778                         if (f != null){
4779                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4780                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4781                                                         f.GetSignatureForError ());
4782                                 }
4783
4784                                 if ((mode & AddressOp.Store) != 0)
4785                                         f.SetAssigned ();
4786                                 if ((mode & AddressOp.Load) != 0)
4787                                         f.SetMemberIsUsed ();
4788                         }
4789
4790                         //
4791                         // Handle initonly fields specially: make a copy and then
4792                         // get the address of the copy.
4793                         //
4794                         bool need_copy;
4795                         if (FieldInfo.IsInitOnly){
4796                                 need_copy = true;
4797                                 if (ec.IsConstructor){
4798                                         if (FieldInfo.IsStatic){
4799                                                 if (ec.IsStatic)
4800                                                         need_copy = false;
4801                                         } else
4802                                                 need_copy = false;
4803                                 }
4804                         } else
4805                                 need_copy = false;
4806
4807                         if (need_copy){
4808                                 LocalBuilder local;
4809                                 Emit (ec);
4810                                 local = ig.DeclareLocal (type);
4811                                 ig.Emit (OpCodes.Stloc, local);
4812                                 ig.Emit (OpCodes.Ldloca, local);
4813                                 return;
4814                         }
4815
4816
4817                         if (FieldInfo.IsStatic){
4818                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
4819                         } else {
4820                                 if (!prepared)
4821                                         EmitInstance (ec, false);
4822                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
4823                         }
4824                 }
4825         }
4826
4827
4828         /// <summary>
4829         ///   Expression that evaluates to a Property.  The Assign class
4830         ///   might set the `Value' expression if we are in an assignment.
4831         ///
4832         ///   This is not an LValue because we need to re-write the expression, we
4833         ///   can not take data from the stack and store it.
4834         /// </summary>
4835         public class PropertyExpr : MemberExpr, IAssignMethod {
4836                 public readonly PropertyInfo PropertyInfo;
4837                 MethodInfo getter, setter;
4838                 bool is_static;
4839
4840                 bool resolved;
4841
4842                 LocalTemporary temp;
4843                 bool prepared;
4844
4845                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
4846                 {
4847                         PropertyInfo = pi;
4848                         eclass = ExprClass.PropertyAccess;
4849                         is_static = false;
4850                         loc = l;
4851
4852                         type = TypeManager.TypeToCoreType (pi.PropertyType);
4853
4854                         ResolveAccessors (container_type);
4855                 }
4856
4857                 public override string Name {
4858                         get {
4859                                 return PropertyInfo.Name;
4860                         }
4861                 }
4862
4863                 public override bool IsInstance {
4864                         get {
4865                                 return !is_static;
4866                         }
4867                 }
4868
4869                 public override bool IsStatic {
4870                         get {
4871                                 return is_static;
4872                         }
4873                 }
4874
4875                 public override Type DeclaringType {
4876                         get {
4877                                 return PropertyInfo.DeclaringType;
4878                         }
4879                 }
4880
4881                 public override string GetSignatureForError ()
4882                 {
4883                         return TypeManager.GetFullNameSignature (PropertyInfo);
4884                 }
4885
4886                 void FindAccessors (Type invocation_type)
4887                 {
4888                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
4889                                 BindingFlags.Static | BindingFlags.Instance |
4890                                 BindingFlags.DeclaredOnly;
4891
4892                         Type current = PropertyInfo.DeclaringType;
4893                         for (; current != null; current = current.BaseType) {
4894                                 MemberInfo[] group = TypeManager.MemberLookup (
4895                                         invocation_type, invocation_type, current,
4896                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
4897
4898                                 if (group == null)
4899                                         continue;
4900
4901                                 if (group.Length != 1)
4902                                         // Oooops, can this ever happen ?
4903                                         return;
4904
4905                                 PropertyInfo pi = (PropertyInfo) group [0];
4906
4907                                 if (getter == null)
4908                                         getter = pi.GetGetMethod (true);
4909
4910                                 if (setter == null)
4911                                         setter = pi.GetSetMethod (true);
4912
4913                                 MethodInfo accessor = getter != null ? getter : setter;
4914
4915                                 if (!accessor.IsVirtual)
4916                                         return;
4917                         }
4918                 }
4919
4920                 //
4921                 // We also perform the permission checking here, as the PropertyInfo does not
4922                 // hold the information for the accessibility of its setter/getter
4923                 //
4924                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
4925                 void ResolveAccessors (Type container_type)
4926                 {
4927                         FindAccessors (container_type);
4928
4929                         if (getter != null) {
4930                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
4931                                 IMethodData md = TypeManager.GetMethod (the_getter);
4932                                 if (md != null)
4933                                         md.SetMemberIsUsed ();
4934
4935                                 is_static = getter.IsStatic;
4936                         }
4937
4938                         if (setter != null) {
4939                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
4940                                 IMethodData md = TypeManager.GetMethod (the_setter);
4941                                 if (md != null)
4942                                         md.SetMemberIsUsed ();
4943
4944                                 is_static = setter.IsStatic;
4945                         }
4946                 }
4947
4948                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
4949                 {
4950                         if (is_static) {
4951                                 InstanceExpression = null;
4952                                 return true;
4953                         }
4954
4955                         if (InstanceExpression == null) {
4956                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4957                                 return false;
4958                         }
4959
4960                         InstanceExpression = InstanceExpression.DoResolve (ec);
4961                         if (lvalue_instance && InstanceExpression != null)
4962                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
4963
4964                         if (InstanceExpression == null)
4965                                 return false;
4966
4967                         InstanceExpression.CheckMarshalByRefAccess (ec);
4968
4969                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
4970                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
4971                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
4972                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
4973                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
4974                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
4975                                 return false;
4976                         }
4977
4978                         return true;
4979                 }
4980
4981                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
4982                 {
4983                         // TODO: correctly we should compare arguments but it will lead to bigger changes
4984                         if (mi is MethodBuilder) {
4985                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
4986                                 return;
4987                         }
4988
4989                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
4990                         sig.Append ('.');
4991                         ParameterData iparams = TypeManager.GetParameterData (mi);
4992                         sig.Append (getter ? "get_" : "set_");
4993                         sig.Append (Name);
4994                         sig.Append (iparams.GetSignatureForError ());
4995
4996                         Report.SymbolRelatedToPreviousError (mi);
4997                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
4998                                 Name, sig.ToString ());
4999                 }
5000
5001                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5002                 {
5003                         bool dummy;
5004                         MethodInfo accessor = lvalue ? setter : getter;
5005                         if (accessor == null && lvalue)
5006                                 accessor = getter;
5007                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5008                 }
5009
5010                 override public Expression DoResolve (EmitContext ec)
5011                 {
5012                         if (resolved)
5013                                 return this;
5014
5015                         if (getter != null){
5016                                 if (TypeManager.GetParameterData (getter).Count != 0){
5017                                         Error_PropertyNotFound (getter, true);
5018                                         return null;
5019                                 }
5020                         }
5021
5022                         if (getter == null){
5023                                 //
5024                                 // The following condition happens if the PropertyExpr was
5025                                 // created, but is invalid (ie, the property is inaccessible),
5026                                 // and we did not want to embed the knowledge about this in
5027                                 // the caller routine.  This only avoids double error reporting.
5028                                 //
5029                                 if (setter == null)
5030                                         return null;
5031
5032                                 if (InstanceExpression != EmptyExpression.Null) {
5033                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5034                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5035                                         return null;
5036                                 }
5037                         }
5038
5039                         bool must_do_cs1540_check = false;
5040                         if (getter != null &&
5041                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5042                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5043                                 if (pm != null && pm.HasCustomAccessModifier) {
5044                                         Report.SymbolRelatedToPreviousError (pm);
5045                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5046                                                 TypeManager.CSharpSignature (getter));
5047                                 }
5048                                 else {
5049                                         Report.SymbolRelatedToPreviousError (getter);
5050                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5051                                 }
5052                                 return null;
5053                         }
5054
5055                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5056                                 return null;
5057
5058                         //
5059                         // Only base will allow this invocation to happen.
5060                         //
5061                         if (IsBase && getter.IsAbstract) {
5062                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5063                                 return null;
5064                         }
5065
5066                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5067                                 UnsafeError (loc);
5068                                 return null;
5069                         }
5070
5071                         resolved = true;
5072
5073                         return this;
5074                 }
5075
5076                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5077                 {
5078                         if (right_side == EmptyExpression.OutAccess) {
5079                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5080                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5081                                             PropertyInfo.Name);
5082                                 } else {
5083                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5084                                               GetSignatureForError ());
5085                                 }
5086                                 return null;
5087                         }
5088
5089                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5090                                 Error_CannotModifyIntermediateExpressionValue (ec);
5091                         }
5092
5093                         if (setter == null){
5094                                 //
5095                                 // The following condition happens if the PropertyExpr was
5096                                 // created, but is invalid (ie, the property is inaccessible),
5097                                 // and we did not want to embed the knowledge about this in
5098                                 // the caller routine.  This only avoids double error reporting.
5099                                 //
5100                                 if (getter == null)
5101                                         return null;
5102                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5103                                               GetSignatureForError ());
5104                                 return null;
5105                         }
5106
5107                         if (TypeManager.GetParameterData (setter).Count != 1){
5108                                 Error_PropertyNotFound (setter, false);
5109                                 return null;
5110                         }
5111
5112                         bool must_do_cs1540_check;
5113                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5114                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5115                                 if (pm != null && pm.HasCustomAccessModifier) {
5116                                         Report.SymbolRelatedToPreviousError (pm);
5117                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5118                                                 TypeManager.CSharpSignature (setter));
5119                                 }
5120                                 else {
5121                                         Report.SymbolRelatedToPreviousError (setter);
5122                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5123                                 }
5124                                 return null;
5125                         }
5126
5127                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5128                                 return null;
5129
5130                         //
5131                         // Only base will allow this invocation to happen.
5132                         //
5133                         if (IsBase && setter.IsAbstract){
5134                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5135                                 return null;
5136                         }
5137
5138                         return this;
5139                 }
5140
5141                 public override void Emit (EmitContext ec)
5142                 {
5143                         Emit (ec, false);
5144                 }
5145
5146                 public void Emit (EmitContext ec, bool leave_copy)
5147                 {
5148                         //
5149                         // Special case: length of single dimension array property is turned into ldlen
5150                         //
5151                         if ((getter == TypeManager.system_int_array_get_length) ||
5152                             (getter == TypeManager.int_array_get_length)){
5153                                 Type iet = InstanceExpression.Type;
5154
5155                                 //
5156                                 // System.Array.Length can be called, but the Type does not
5157                                 // support invoking GetArrayRank, so test for that case first
5158                                 //
5159                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
5160                                         if (!prepared)
5161                                                 EmitInstance (ec, false);
5162                                         ec.ig.Emit (OpCodes.Ldlen);
5163                                         ec.ig.Emit (OpCodes.Conv_I4);
5164                                         return;
5165                                 }
5166                         }
5167
5168                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5169
5170                         if (leave_copy) {
5171                                 ec.ig.Emit (OpCodes.Dup);
5172                                 if (!is_static) {
5173                                         temp = new LocalTemporary (this.Type);
5174                                         temp.Store (ec);
5175                                 }
5176                         }
5177                 }
5178
5179                 //
5180                 // Implements the IAssignMethod interface for assignments
5181                 //
5182                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5183                 {
5184                         Expression my_source = source;
5185
5186                         if (prepare_for_load) {
5187                                 if (source is StringConcat)
5188                                         EmitInstance (ec, false);
5189                                 else
5190                                         prepared = true;
5191
5192                                 source.Emit (ec);
5193
5194                                 prepared = true;
5195                                 if (leave_copy) {
5196                                         ec.ig.Emit (OpCodes.Dup);
5197                                         if (!is_static) {
5198                                                 temp = new LocalTemporary (this.Type);
5199                                                 temp.Store (ec);
5200                                         }
5201                                 }
5202                         } else if (leave_copy) {
5203                                 source.Emit (ec);
5204                                 temp = new LocalTemporary (this.Type);
5205                                 temp.Store (ec);
5206                                 my_source = temp;
5207                         }
5208
5209                         ArrayList args = new ArrayList (1);
5210                         args.Add (new Argument (my_source, Argument.AType.Expression));
5211
5212                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5213
5214                         if (temp != null) {
5215                                 temp.Emit (ec);
5216                                 temp.Release (ec);
5217                         }
5218                 }
5219         }
5220
5221         /// <summary>
5222         ///   Fully resolved expression that evaluates to an Event
5223         /// </summary>
5224         public class EventExpr : MemberExpr {
5225                 public readonly EventInfo EventInfo;
5226
5227                 bool is_static;
5228                 MethodInfo add_accessor, remove_accessor;
5229
5230                 public EventExpr (EventInfo ei, Location loc)
5231                 {
5232                         EventInfo = ei;
5233                         this.loc = loc;
5234                         eclass = ExprClass.EventAccess;
5235
5236                         add_accessor = TypeManager.GetAddMethod (ei);
5237                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5238                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5239                                 is_static = true;
5240
5241                         if (EventInfo is MyEventBuilder){
5242                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5243                                 type = eb.EventType;
5244                                 eb.SetUsed ();
5245                         } else
5246                                 type = EventInfo.EventHandlerType;
5247                 }
5248
5249                 public override string Name {
5250                         get {
5251                                 return EventInfo.Name;
5252                         }
5253                 }
5254
5255                 public override bool IsInstance {
5256                         get {
5257                                 return !is_static;
5258                         }
5259                 }
5260
5261                 public override bool IsStatic {
5262                         get {
5263                                 return is_static;
5264                         }
5265                 }
5266
5267                 public override Type DeclaringType {
5268                         get {
5269                                 return EventInfo.DeclaringType;
5270                         }
5271                 }
5272
5273                 void Error_AssignmentEventOnly ()
5274                 {
5275                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5276                                 GetSignatureForError ());
5277                 }
5278
5279                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5280                                                                 SimpleName original)
5281                 {
5282                         //
5283                         // If the event is local to this class, we transform ourselves into a FieldExpr
5284                         //
5285
5286                         if (EventInfo.DeclaringType == ec.ContainerType ||
5287                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5288                                 EventField mi = TypeManager.GetEventField (EventInfo);
5289
5290                                 if (mi != null) {
5291                                         if (!ec.IsInObsoleteScope)
5292                                                 mi.CheckObsoleteness (loc);
5293
5294                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5295                                                 Error_AssignmentEventOnly ();
5296
5297                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5298
5299                                         InstanceExpression = null;
5300
5301                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5302                                 }
5303                         }
5304
5305                         if (left is This && !ec.IsInCompoundAssignment)
5306                                 Error_AssignmentEventOnly ();
5307
5308                         return base.ResolveMemberAccess (ec, left, loc, original);
5309                 }
5310
5311
5312                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5313                 {
5314                         if (is_static) {
5315                                 InstanceExpression = null;
5316                                 return true;
5317                         }
5318
5319                         if (InstanceExpression == null) {
5320                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5321                                 return false;
5322                         }
5323
5324                         InstanceExpression = InstanceExpression.DoResolve (ec);
5325                         if (InstanceExpression == null)
5326                                 return false;
5327
5328                         if (IsBase && add_accessor.IsAbstract) {
5329                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5330                                 return false;
5331                         }
5332
5333                         //
5334                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5335                         // However, in the Event case, we reported a CS0122 instead.
5336                         //
5337                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5338                             InstanceExpression.Type != ec.ContainerType &&
5339                             ec.ContainerType.IsSubclassOf (InstanceExpression.Type)) {
5340                                 Report.SymbolRelatedToPreviousError (EventInfo);
5341                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5342                                 return false;
5343                         }
5344
5345                         return true;
5346                 }
5347
5348                 public bool IsAccessibleFrom (Type invocation_type)
5349                 {
5350                         bool dummy;
5351                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5352                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5353                 }
5354
5355                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5356                 {
5357                         return DoResolve (ec);
5358                 }
5359
5360                 public override Expression DoResolve (EmitContext ec)
5361                 {
5362                         bool must_do_cs1540_check;
5363                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5364                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5365                                 Report.SymbolRelatedToPreviousError (EventInfo);
5366                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5367                                 return null;
5368                         }
5369
5370                         if (!InstanceResolve (ec, must_do_cs1540_check))
5371                                 return null;
5372
5373                         return this;
5374                 }
5375
5376                 public override void Emit (EmitContext ec)
5377                 {
5378                         Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5379                                       "(except on the defining type)", GetSignatureForError ());
5380                 }
5381
5382                 public override string GetSignatureForError ()
5383                 {
5384                         return TypeManager.CSharpSignature (EventInfo);
5385                 }
5386
5387                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5388                 {
5389                         BinaryDelegate source_del = source as BinaryDelegate;
5390                         if (source_del == null) {
5391                                 Emit (ec);
5392                                 return;
5393                         }
5394                         Expression handler = source_del.Right;
5395
5396                         Argument arg = new Argument (handler, Argument.AType.Expression);
5397                         ArrayList args = new ArrayList ();
5398
5399                         args.Add (arg);
5400
5401                         if (source_del.IsAddition)
5402                                 Invocation.EmitCall (
5403                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5404                         else
5405                                 Invocation.EmitCall (
5406                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5407                 }
5408         }
5409
5410         public class TemporaryVariable : Expression, IMemoryLocation
5411         {
5412                 LocalInfo li;
5413                 Variable var;
5414
5415                 public TemporaryVariable (Type type, Location loc)
5416                 {
5417                         this.type = type;
5418                         this.loc = loc;
5419                         eclass = ExprClass.Value;
5420                 }
5421
5422                 public override Expression DoResolve (EmitContext ec)
5423                 {
5424                         if (li != null)
5425                                 return this;
5426
5427                         TypeExpr te = new TypeExpression (type, loc);
5428                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5429                         if (!li.Resolve (ec))
5430                                 return null;
5431
5432                         if (ec.MustCaptureVariable (li)) {
5433                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5434                                 var = scope.AddLocal (li);
5435                                 type = var.Type;
5436                         }
5437
5438                         return this;
5439                 }
5440
5441                 public Variable Variable {
5442                         get { return var != null ? var : li.Variable; }
5443                 }
5444
5445                 public override void Emit (EmitContext ec)
5446                 {
5447                         Variable.EmitInstance (ec);
5448                         Variable.Emit (ec);
5449                 }
5450
5451                 public void EmitLoadAddress (EmitContext ec)
5452                 {
5453                         Variable.EmitInstance (ec);
5454                         Variable.EmitAddressOf (ec);
5455                 }
5456
5457                 public void Store (EmitContext ec, Expression right_side)
5458                 {
5459                         Variable.EmitInstance (ec);
5460                         right_side.Emit (ec);
5461                         Variable.EmitAssign (ec);
5462                 }
5463
5464                 public void EmitThis (EmitContext ec)
5465                 {
5466                         Variable.EmitInstance (ec);
5467                 }
5468
5469                 public void EmitStore (EmitContext ec)
5470                 {
5471                         Variable.EmitAssign (ec);
5472                 }
5473
5474                 public void AddressOf (EmitContext ec, AddressOp mode)
5475                 {
5476                         EmitLoadAddress (ec);
5477                 }
5478         }
5479
5480         ///
5481         /// Handles `var' contextual keyword; var becomes a keyword only
5482         /// if no type called var exists in a variable scope
5483         ///
5484         public class VarExpr : SimpleName
5485         {
5486                 // Used for error reporting only
5487                 ArrayList initializer;
5488
5489                 public VarExpr (Location loc)
5490                         : base ("var", loc)
5491                 {
5492                 }
5493
5494                 public ArrayList VariableInitializer {
5495                         set {
5496                                 this.initializer = value;
5497                         }
5498                 }
5499
5500                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5501                 {
5502                         if (type != null)
5503                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5504
5505                         type = right_side.Type;
5506                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5507                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5508                                               right_side.GetSignatureForError ());
5509                                 return null;
5510                         }
5511
5512                         eclass = ExprClass.Variable;
5513                         return this;
5514                 }
5515
5516                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5517                 {
5518                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5519                 }
5520
5521                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5522                 {
5523                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5524                         if (te != null)
5525                                 return te;
5526
5527                         if (initializer == null)
5528                                 return null;
5529
5530                         if (initializer.Count > 1) {
5531                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5532                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5533                                 initializer = null;
5534                                 return null;
5535                         }
5536
5537                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5538                         if (variable_initializer == null) {
5539                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5540                                 return null;
5541                         }
5542
5543                         return null;
5544                 }
5545         }
5546 }