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                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 918                         if (operator_group == null)
 919                                 return null;
 920
 921                         ArrayList arguments = new ArrayList (1);
 922                         arguments.Add (new Argument (e, Argument.AType.Expression));
 923                         operator_group = operator_group.OverloadResolve (
 924                                 ec, ref arguments, false, loc);
 925
 926                         if (operator_group == null)
 927                                 return null;
 928
 929                         return new UserOperatorCall (operator_group, arguments, null, loc);
 930                 }
 931
 932                 /// <summary>
 933                 ///   Resolves the expression `e' into a boolean expression: either through
 934                 ///   an implicit conversion, or through an `operator true' invocation
 935                 /// </summary>
 936                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 937                 {
 938                         e = e.Resolve (ec);
 939                         if (e == null)
 940                                 return null;
 941
 942                         if (e.Type == TypeManager.bool_type)
 943                                 return e;
 944
 945                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 946
 947                         if (converted != null)
 948                                 return converted;
 949
 950                         //
 951                         // If no implicit conversion to bool exists, try using `operator true'
 952                         //
 953                         converted = Expression.GetOperatorTrue (ec, e, loc);
 954                         if (converted == null){
 955                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 956                                 return null;
 957                         }
 958                         return converted;
 959                 }
 960
 961                 public virtual string ExprClassName
 962                 {
 963                         get {
 964                                 switch (eclass){
 965                                         case ExprClass.Invalid:
 966                                                 return "Invalid";
 967                                         case ExprClass.Value:
 968                                                 return "value";
 969                                         case ExprClass.Variable:
 970                                                 return "variable";
 971                                         case ExprClass.Namespace:
 972                                                 return "namespace";
 973                                         case ExprClass.Type:
 974                                                 return "type";
 975                                         case ExprClass.MethodGroup:
 976                                                 return "method group";
 977                                         case ExprClass.PropertyAccess:
 978                                                 return "property access";
 979                                         case ExprClass.EventAccess:
 980                                                 return "event access";
 981                                         case ExprClass.IndexerAccess:
 982                                                 return "indexer access";
 983                                         case ExprClass.Nothing:
 984                                                 return "null";
 985                                 }
 986                                 throw new Exception ("Should not happen");
 987                         }
 988                 }
 989
 990                 /// <summary>
 991                 ///   Reports that we were expecting `expr' to be of class `expected'
 992                 /// </summary>
 993                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
 994                 {
 995                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
 996                 }
 997
 998                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
 999                 {
1000                         string name = GetSignatureForError ();
1001                         if (ds != null)
1002                                 name = ds.GetSignatureForError () + '.' + name;
1003
1004                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1005                               name, was, expected);
1006                 }
1007
1008                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1009                 {
1010                         string [] valid = new string [4];
1011                         int count = 0;
1012
1013                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1014                                 valid [count++] = "variable";
1015                                 valid [count++] = "value";
1016                         }
1017
1018                         if ((flags & ResolveFlags.Type) != 0)
1019                                 valid [count++] = "type";
1020
1021                         if ((flags & ResolveFlags.MethodGroup) != 0)
1022                                 valid [count++] = "method group";
1023
1024                         if (count == 0)
1025                                 valid [count++] = "unknown";
1026
1027                         StringBuilder sb = new StringBuilder (valid [0]);
1028                         for (int i = 1; i < count - 1; i++) {
1029                                 sb.Append ("', `");
1030                                 sb.Append (valid [i]);
1031                         }
1032                         if (count > 1) {
1033                                 sb.Append ("' or `");
1034                                 sb.Append (valid [count - 1]);
1035                         }
1036
1037                         Report.Error (119, loc,
1038                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1039                 }
1040
1041                 public static void UnsafeError (Location loc)
1042                 {
1043                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1044                 }
1045
1046                 //
1047                 // Load the object from the pointer.
1048                 //
1049                 public static void LoadFromPtr (ILGenerator ig, Type t)
1050                 {
1051                         if (t == TypeManager.int32_type)
1052                                 ig.Emit (OpCodes.Ldind_I4);
1053                         else if (t == TypeManager.uint32_type)
1054                                 ig.Emit (OpCodes.Ldind_U4);
1055                         else if (t == TypeManager.short_type)
1056                                 ig.Emit (OpCodes.Ldind_I2);
1057                         else if (t == TypeManager.ushort_type)
1058                                 ig.Emit (OpCodes.Ldind_U2);
1059                         else if (t == TypeManager.char_type)
1060                                 ig.Emit (OpCodes.Ldind_U2);
1061                         else if (t == TypeManager.byte_type)
1062                                 ig.Emit (OpCodes.Ldind_U1);
1063                         else if (t == TypeManager.sbyte_type)
1064                                 ig.Emit (OpCodes.Ldind_I1);
1065                         else if (t == TypeManager.uint64_type)
1066                                 ig.Emit (OpCodes.Ldind_I8);
1067                         else if (t == TypeManager.int64_type)
1068                                 ig.Emit (OpCodes.Ldind_I8);
1069                         else if (t == TypeManager.float_type)
1070                                 ig.Emit (OpCodes.Ldind_R4);
1071                         else if (t == TypeManager.double_type)
1072                                 ig.Emit (OpCodes.Ldind_R8);
1073                         else if (t == TypeManager.bool_type)
1074                                 ig.Emit (OpCodes.Ldind_I1);
1075                         else if (t == TypeManager.intptr_type)
1076                                 ig.Emit (OpCodes.Ldind_I);
1077                         else if (TypeManager.IsEnumType (t)) {
1078                                 if (t == TypeManager.enum_type)
1079                                         ig.Emit (OpCodes.Ldind_Ref);
1080                                 else
1081                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1082                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1083                                 ig.Emit (OpCodes.Ldobj, t);
1084                         else if (t.IsPointer)
1085                                 ig.Emit (OpCodes.Ldind_I);
1086                         else
1087                                 ig.Emit (OpCodes.Ldind_Ref);
1088                 }
1089
1090                 //
1091                 // The stack contains the pointer and the value of type `type'
1092                 //
1093                 public static void StoreFromPtr (ILGenerator ig, Type type)
1094                 {
1095                         if (TypeManager.IsEnumType (type))
1096                                 type = TypeManager.EnumToUnderlying (type);
1097                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1098                                 ig.Emit (OpCodes.Stind_I4);
1099                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1100                                 ig.Emit (OpCodes.Stind_I8);
1101                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1102                                  type == TypeManager.ushort_type)
1103                                 ig.Emit (OpCodes.Stind_I2);
1104                         else if (type == TypeManager.float_type)
1105                                 ig.Emit (OpCodes.Stind_R4);
1106                         else if (type == TypeManager.double_type)
1107                                 ig.Emit (OpCodes.Stind_R8);
1108                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1109                                  type == TypeManager.bool_type)
1110                                 ig.Emit (OpCodes.Stind_I1);
1111                         else if (type == TypeManager.intptr_type)
1112                                 ig.Emit (OpCodes.Stind_I);
1113                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1114                                 ig.Emit (OpCodes.Stobj, type);
1115                         else
1116                                 ig.Emit (OpCodes.Stind_Ref);
1117                 }
1118
1119                 //
1120                 // Returns the size of type `t' if known, otherwise, 0
1121                 //
1122                 public static int GetTypeSize (Type t)
1123                 {
1124                         t = TypeManager.TypeToCoreType (t);
1125                         if (t == TypeManager.int32_type ||
1126                             t == TypeManager.uint32_type ||
1127                             t == TypeManager.float_type)
1128                                 return 4;
1129                         else if (t == TypeManager.int64_type ||
1130                                  t == TypeManager.uint64_type ||
1131                                  t == TypeManager.double_type)
1132                                 return 8;
1133                         else if (t == TypeManager.byte_type ||
1134                                  t == TypeManager.sbyte_type ||
1135                                  t == TypeManager.bool_type)
1136                                 return 1;
1137                         else if (t == TypeManager.short_type ||
1138                                  t == TypeManager.char_type ||
1139                                  t == TypeManager.ushort_type)
1140                                 return 2;
1141                         else if (t == TypeManager.decimal_type)
1142                                 return 16;
1143                         else
1144                                 return 0;
1145                 }
1146
1147                 protected void Error_CannotCallAbstractBase (string name)
1148                 {
1149                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1150                 }
1151
1152                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1153                 {
1154                         Report.SymbolRelatedToPreviousError (type);
1155                         if (ec.CurrentInitializerVariable != null) {
1156                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1157                                         GetSignatureForError ());
1158                         } else {
1159                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1160                                         GetSignatureForError ());
1161                         }
1162                 }
1163
1164                 //
1165                 // Converts `source' to an int, uint, long or ulong.
1166                 //
1167                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1168                 {
1169                         Expression converted;
1170
1171                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1172                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1173                                 if (converted == null)
1174                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1175                                 if (converted == null)
1176                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1177                                 if (converted == null)
1178                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1179
1180                                 if (converted == null) {
1181                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1182                                         return null;
1183                                 }
1184                         }
1185
1186                         //
1187                         // Only positive constants are allowed at compile time
1188                         //
1189                         Constant c = converted as Constant;
1190                         if (c != null) {
1191                                 if (c.IsNegative) {
1192                                         Error_NegativeArrayIndex (source.loc);
1193                                 }
1194                                 return c;
1195                         }
1196
1197                         return new ArrayIndexCast (converted).Resolve (ec);
1198                 }
1199
1200                 //
1201                 // Derived classes implement this method by cloning the fields that
1202                 // could become altered during the Resolve stage
1203                 //
1204                 // Only expressions that are created for the parser need to implement
1205                 // this.
1206                 //
1207                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1208                 {
1209                         throw new NotImplementedException (
1210                                 String.Format (
1211                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1212                 }
1213
1214                 //
1215                 // Clones an expression created by the parser.
1216                 //
1217                 // We only support expressions created by the parser so far, not
1218                 // expressions that have been resolved (many more classes would need
1219                 // to implement CloneTo).
1220                 //
1221                 // This infrastructure is here merely for Lambda expressions which
1222                 // compile the same code using different type values for the same
1223                 // arguments to find the correct overload
1224                 //
1225                 public Expression Clone (CloneContext clonectx)
1226                 {
1227                         Expression cloned = (Expression) MemberwiseClone ();
1228                         CloneTo (clonectx, cloned);
1229
1230                         return cloned;
1231                 }
1232
1233                 public virtual Expression CreateExpressionTree (EmitContext ec)
1234                 {
1235                         throw new NotImplementedException (
1236                                 "Expression tree conversion not implemented for " + GetType ());
1237                 }
1238
1239                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1240                 {
1241                         return CreateExpressionFactoryCall (name, null, args, loc);
1242                 }
1243
1244                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1245                 {
1246                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1247                 }
1248
1249                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1250                 {
1251                         TypeExpression texpr = new TypeExpression (LinqExpression.expression_type, loc);
1252                         return new Invocation (new MemberAccess (texpr, name, typeArguments, loc), args);
1253                 }
1254         }
1255
1256         /// <summary>
1257         ///   This is just a base class for expressions that can
1258         ///   appear on statements (invocations, object creation,
1259         ///   assignments, post/pre increment and decrement).  The idea
1260         ///   being that they would support an extra Emition interface that
1261         ///   does not leave a result on the stack.
1262         /// </summary>
1263         public abstract class ExpressionStatement : Expression {
1264
1265                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1266                 {
1267                         Expression e = Resolve (ec);
1268                         if (e == null)
1269                                 return null;
1270
1271                         ExpressionStatement es = e as ExpressionStatement;
1272                         if (es == null)
1273                                 Error_InvalidExpressionStatement ();
1274
1275                         return es;
1276                 }
1277
1278                 /// <summary>
1279                 ///   Requests the expression to be emitted in a `statement'
1280                 ///   context.  This means that no new value is left on the
1281                 ///   stack after invoking this method (constrasted with
1282                 ///   Emit that will always leave a value on the stack).
1283                 /// </summary>
1284                 public abstract void EmitStatement (EmitContext ec);
1285         }
1286
1287         /// <summary>
1288         ///   This kind of cast is used to encapsulate the child
1289         ///   whose type is child.Type into an expression that is
1290         ///   reported to return "return_type".  This is used to encapsulate
1291         ///   expressions which have compatible types, but need to be dealt
1292         ///   at higher levels with.
1293         ///
1294         ///   For example, a "byte" expression could be encapsulated in one
1295         ///   of these as an "unsigned int".  The type for the expression
1296         ///   would be "unsigned int".
1297         ///
1298         /// </summary>
1299         public class EmptyCast : Expression
1300         {
1301                 protected Expression child;
1302
1303                 protected EmptyCast (Expression child, Type return_type)
1304                 {
1305                         eclass = child.eclass;
1306                         loc = child.Location;
1307                         type = return_type;
1308                         this.child = child;
1309                 }
1310
1311                 public static Expression Create (Expression child, Type type)
1312                 {
1313                         Constant c = child as Constant;
1314                         if (c != null)
1315                                 return new EmptyConstantCast (c, type);
1316
1317                         return new EmptyCast (child, type);
1318                 }
1319
1320                 public override Expression CreateExpressionTree (EmitContext ec)
1321                 {
1322                         ArrayList args = new ArrayList (2);
1323                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1324                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1325                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1326                 }
1327
1328                 public override Expression DoResolve (EmitContext ec)
1329                 {
1330                         // This should never be invoked, we are born in fully
1331                         // initialized state.
1332
1333                         return this;
1334                 }
1335
1336                 public override void Emit (EmitContext ec)
1337                 {
1338                         child.Emit (ec);
1339                 }
1340
1341                 public override bool GetAttributableValue (Type value_type, out object value)
1342                 {
1343                         return child.GetAttributableValue (value_type, out value);
1344                 }
1345
1346                 protected override void CloneTo (CloneContext clonectx, Expression t)
1347                 {
1348                         EmptyCast target = (EmptyCast) t;
1349
1350                         target.child = child.Clone (clonectx);
1351                 }
1352         }
1353
1354         /// <summary>
1355         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1356         /// </summary>
1357         public class OperatorCast : EmptyCast {
1358                 MethodInfo conversion_operator;
1359                 bool find_explicit;
1360
1361                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1362
1363                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1364                         : base (child, target_type)
1365                 {
1366                         this.find_explicit = find_explicit;
1367                 }
1368
1369                 // Returns the implicit operator that converts from
1370                 // 'child.Type' to our target type (type)
1371                 MethodInfo GetConversionOperator (bool find_explicit)
1372                 {
1373                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1374
1375                         MemberInfo [] mi;
1376
1377                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1378                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1379
1380                         if (mi == null){
1381                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1382                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1383                         }
1384
1385                         foreach (MethodInfo oper in mi) {
1386                                 ParameterData pd = TypeManager.GetParameterData (oper);
1387
1388                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1389                                         return oper;
1390                         }
1391
1392                         return null;
1393
1394
1395                 }
1396                 public override void Emit (EmitContext ec)
1397                 {
1398                         ILGenerator ig = ec.ig;
1399
1400                         child.Emit (ec);
1401                         conversion_operator = GetConversionOperator (find_explicit);
1402
1403                         if (conversion_operator == null)
1404                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1405
1406                         ig.Emit (OpCodes.Call, conversion_operator);
1407                 }
1408
1409         }
1410
1411         /// <summary>
1412         ///     This is a numeric cast to a Decimal
1413         /// </summary>
1414         public class CastToDecimal : EmptyCast {
1415                 MethodInfo conversion_operator;
1416
1417                 public CastToDecimal (Expression child)
1418                         : this (child, false)
1419                 {
1420                 }
1421
1422                 public CastToDecimal (Expression child, bool find_explicit)
1423                         : base (child, TypeManager.decimal_type)
1424                 {
1425                         conversion_operator = GetConversionOperator (find_explicit);
1426
1427                         if (conversion_operator == null)
1428                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1429                 }
1430
1431                 // Returns the implicit operator that converts from
1432                 // 'child.Type' to System.Decimal.
1433                 MethodInfo GetConversionOperator (bool find_explicit)
1434                 {
1435                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1436
1437                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1438                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1439
1440                         foreach (MethodInfo oper in mi) {
1441                                 ParameterData pd = TypeManager.GetParameterData (oper);
1442
1443                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1444                                         return oper;
1445                         }
1446
1447                         return null;
1448                 }
1449                 public override void Emit (EmitContext ec)
1450                 {
1451                         ILGenerator ig = ec.ig;
1452                         child.Emit (ec);
1453
1454                         ig.Emit (OpCodes.Call, conversion_operator);
1455                 }
1456         }
1457
1458         /// <summary>
1459         ///     This is an explicit numeric cast from a Decimal
1460         /// </summary>
1461         public class CastFromDecimal : EmptyCast
1462         {
1463                 static IDictionary operators;
1464
1465                 public CastFromDecimal (Expression child, Type return_type)
1466                         : base (child, return_type)
1467                 {
1468                         if (child.Type != TypeManager.decimal_type)
1469                                 throw new InternalErrorException (
1470                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1471                 }
1472
1473                 // Returns the explicit operator that converts from an
1474                 // express of type System.Decimal to 'type'.
1475                 public Expression Resolve ()
1476                 {
1477                         if (operators == null) {
1478                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1479                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1480                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1481
1482                                 operators = new System.Collections.Specialized.HybridDictionary ();
1483                                 foreach (MethodInfo oper in all_oper) {
1484                                         ParameterData pd = TypeManager.GetParameterData (oper);
1485                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1486                                                 operators.Add (oper.ReturnType, oper);
1487                                 }
1488                         }
1489
1490                         return operators.Contains (type) ? this : null;
1491                 }
1492
1493                 public override void Emit (EmitContext ec)
1494                 {
1495                         ILGenerator ig = ec.ig;
1496                         child.Emit (ec);
1497
1498                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1499                 }
1500         }
1501
1502
1503         //
1504         // Constant specialization of EmptyCast.
1505         // We need to special case this since an empty cast of
1506         // a constant is still a constant.
1507         //
1508         public class EmptyConstantCast : Constant
1509         {
1510                 public readonly Constant child;
1511
1512                 public EmptyConstantCast(Constant child, Type type)
1513                         : base (child.Location)
1514                 {
1515                         eclass = child.eclass;
1516                         this.child = child;
1517                         this.type = type;
1518                 }
1519
1520                 public override string AsString ()
1521                 {
1522                         return child.AsString ();
1523                 }
1524
1525                 public override object GetValue ()
1526                 {
1527                         return child.GetValue ();
1528                 }
1529
1530                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1531                 {
1532                         // FIXME: check that 'type' can be converted to 'target_type' first
1533                         return child.ConvertExplicitly (in_checked_context, target_type);
1534                 }
1535
1536                 public override Constant Increment ()
1537                 {
1538                         return child.Increment ();
1539                 }
1540
1541                 public override bool IsDefaultValue {
1542                         get { return child.IsDefaultValue; }
1543                 }
1544
1545                 public override bool IsNegative {
1546                         get { return child.IsNegative; }
1547                 }
1548
1549                 public override bool IsNull {
1550                         get { return child.IsNull; }
1551                 }
1552
1553                 public override bool IsZeroInteger {
1554                         get { return child.IsZeroInteger; }
1555                 }
1556
1557                 public override void Emit (EmitContext ec)
1558                 {
1559                         child.Emit (ec);
1560                 }
1561
1562                 public override Constant ConvertImplicitly (Type target_type)
1563                 {
1564                         // FIXME: Do we need to check user conversions?
1565                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1566                                 return null;
1567                         return child.ConvertImplicitly (target_type);
1568                 }
1569         }
1570
1571
1572         /// <summary>
1573         ///  This class is used to wrap literals which belong inside Enums
1574         /// </summary>
1575         public class EnumConstant : Constant {
1576                 public Constant Child;
1577
1578                 public EnumConstant (Constant child, Type enum_type):
1579                         base (child.Location)
1580                 {
1581                         eclass = child.eclass;
1582                         this.Child = child;
1583                         type = enum_type;
1584                 }
1585
1586                 public override Expression DoResolve (EmitContext ec)
1587                 {
1588                         // This should never be invoked, we are born in fully
1589                         // initialized state.
1590
1591                         return this;
1592                 }
1593
1594                 public override void Emit (EmitContext ec)
1595                 {
1596                         Child.Emit (ec);
1597                 }
1598
1599                 public override bool GetAttributableValue (Type value_type, out object value)
1600                 {
1601                         value = GetTypedValue ();
1602                         return true;
1603                 }
1604
1605                 public override string GetSignatureForError()
1606                 {
1607                         return TypeManager.CSharpName (Type);
1608                 }
1609
1610                 public override object GetValue ()
1611                 {
1612                         return Child.GetValue ();
1613                 }
1614
1615                 public override object GetTypedValue ()
1616                 {
1617                         // FIXME: runtime is not ready to work with just emited enums
1618                         if (!RootContext.StdLib) {
1619                                 return Child.GetValue ();
1620                         }
1621
1622                         return System.Enum.ToObject (type, Child.GetValue ());
1623                 }
1624
1625                 public override string AsString ()
1626                 {
1627                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1628                 }
1629
1630                 public override Constant Increment()
1631                 {
1632                         return new EnumConstant (Child.Increment (), type);
1633                 }
1634
1635                 public override bool IsDefaultValue {
1636                         get {
1637                                 return Child.IsDefaultValue;
1638                         }
1639                 }
1640
1641                 public override bool IsZeroInteger {
1642                         get { return Child.IsZeroInteger; }
1643                 }
1644
1645                 public override bool IsNegative {
1646                         get {
1647                                 return Child.IsNegative;
1648                         }
1649                 }
1650
1651                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1652                 {
1653                         if (Child.Type == target_type)
1654                                 return Child;
1655
1656                         return Child.ConvertExplicitly (in_checked_context, target_type);
1657                 }
1658
1659                 public override Constant ConvertImplicitly (Type type)
1660                 {
1661                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1662                         type = TypeManager.DropGenericTypeArguments (type);
1663
1664                         if (this_type == type) {
1665                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1666                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1667                                         return this;
1668
1669                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1670                                 if (type.UnderlyingSystemType != child_type)
1671                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1672                                 return this;
1673                         }
1674
1675                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1676                                 return null;
1677                         }
1678
1679                         return Child.ConvertImplicitly(type);
1680                 }
1681
1682         }
1683
1684         /// <summary>
1685         ///   This kind of cast is used to encapsulate Value Types in objects.
1686         ///
1687         ///   The effect of it is to box the value type emitted by the previous
1688         ///   operation.
1689         /// </summary>
1690         public class BoxedCast : EmptyCast {
1691
1692                 public BoxedCast (Expression expr, Type target_type)
1693                         : base (expr, target_type)
1694                 {
1695                         eclass = ExprClass.Value;
1696                 }
1697
1698                 public override Expression DoResolve (EmitContext ec)
1699                 {
1700                         // This should never be invoked, we are born in fully
1701                         // initialized state.
1702
1703                         return this;
1704                 }
1705
1706                 public override void Emit (EmitContext ec)
1707                 {
1708                         base.Emit (ec);
1709
1710                         ec.ig.Emit (OpCodes.Box, child.Type);
1711                 }
1712         }
1713
1714         public class UnboxCast : EmptyCast {
1715                 public UnboxCast (Expression expr, Type return_type)
1716                         : base (expr, return_type)
1717                 {
1718                 }
1719
1720                 public override Expression DoResolve (EmitContext ec)
1721                 {
1722                         // This should never be invoked, we are born in fully
1723                         // initialized state.
1724
1725                         return this;
1726                 }
1727
1728                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1729                 {
1730                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1731                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1732                         return base.DoResolveLValue (ec, right_side);
1733                 }
1734
1735                 public override void Emit (EmitContext ec)
1736                 {
1737                         Type t = type;
1738                         ILGenerator ig = ec.ig;
1739
1740                         base.Emit (ec);
1741 #if GMCS_SOURCE
1742                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1743                                 ig.Emit (OpCodes.Unbox_Any, t);
1744                         else
1745 #endif
1746                         {
1747                                 ig.Emit (OpCodes.Unbox, t);
1748
1749                                 LoadFromPtr (ig, t);
1750                         }
1751                 }
1752         }
1753
1754         /// <summary>
1755         ///   This is used to perform explicit numeric conversions.
1756         ///
1757         ///   Explicit numeric conversions might trigger exceptions in a checked
1758         ///   context, so they should generate the conv.ovf opcodes instead of
1759         ///   conv opcodes.
1760         /// </summary>
1761         public class ConvCast : EmptyCast {
1762                 public enum Mode : byte {
1763                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1764                         U1_I1, U1_CH,
1765                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1766                         U2_I1, U2_U1, U2_I2, U2_CH,
1767                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1768                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1769                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1770                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1771                         CH_I1, CH_U1, CH_I2,
1772                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1773                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1774                 }
1775
1776                 Mode mode;
1777
1778                 public ConvCast (Expression child, Type return_type, Mode m)
1779                         : base (child, return_type)
1780                 {
1781                         mode = m;
1782                 }
1783
1784                 public override Expression DoResolve (EmitContext ec)
1785                 {
1786                         // This should never be invoked, we are born in fully
1787                         // initialized state.
1788
1789                         return this;
1790                 }
1791
1792                 public override string ToString ()
1793                 {
1794                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1795                 }
1796
1797                 public override void Emit (EmitContext ec)
1798                 {
1799                         ILGenerator ig = ec.ig;
1800
1801                         base.Emit (ec);
1802
1803                         if (ec.CheckState){
1804                                 switch (mode){
1805                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1806                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1807                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1808                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1809                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1810
1811                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1812                                 case Mode.U1_CH: /* nothing */ break;
1813
1814                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1815                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1816                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1817                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1818                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1819                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1820
1821                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1822                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1823                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1824                                 case Mode.U2_CH: /* nothing */ break;
1825
1826                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1827                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1828                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1829                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1830                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1831                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1832                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1833
1834                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1835                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1836                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1837                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1838                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1839                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1840
1841                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1842                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1843                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1844                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1845                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1846                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1847                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1848                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1849
1850                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1851                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1852                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1853                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1854                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1855                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1856                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1857                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1858
1859                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1860                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1861                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1862
1863                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1864                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1865                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1866                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1867                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1868                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1869                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1870                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1871                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1872
1873                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1874                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1875                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1876                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1877                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1878                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1879                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1880                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1881                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1882                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1883                                 }
1884                         } else {
1885                                 switch (mode){
1886                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1887                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1888                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1889                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1890                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1891
1892                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1893                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1894
1895                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1896                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1897                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1898                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1899                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1900                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1901
1902                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1903                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1904                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1905                                 case Mode.U2_CH: /* nothing */ break;
1906
1907                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1908                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1909                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1910                                 case Mode.I4_U4: /* nothing */ break;
1911                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1912                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1913                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1914
1915                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1916                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1917                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1918                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1919                                 case Mode.U4_I4: /* nothing */ break;
1920                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1921
1922                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1923                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1924                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1925                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1926                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1927                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1928                                 case Mode.I8_U8: /* nothing */ break;
1929                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1930
1931                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1932                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1933                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1934                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1935                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1936                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1937                                 case Mode.U8_I8: /* nothing */ break;
1938                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1939
1940                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1941                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1942                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1943
1944                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1945                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1946                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1947                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1948                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1949                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1950                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1951                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1952                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1953
1954                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1955                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1956                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1957                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1958                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1959                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1960                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1961                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1962                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1963                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1964                                 }
1965                         }
1966                 }
1967         }
1968
1969         public class OpcodeCast : EmptyCast {
1970                 OpCode op, op2;
1971                 bool second_valid;
1972
1973                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1974                         : base (child, return_type)
1975
1976                 {
1977                         this.op = op;
1978                         second_valid = false;
1979                 }
1980
1981                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1982                         : base (child, return_type)
1983
1984                 {
1985                         this.op = op;
1986                         this.op2 = op2;
1987                         second_valid = true;
1988                 }
1989
1990                 public override Expression CreateExpressionTree (EmitContext ec)
1991                 {
1992                         // This has no expresion tree representation
1993                         return this;
1994                 }
1995
1996                 public override Expression DoResolve (EmitContext ec)
1997                 {
1998                         // This should never be invoked, we are born in fully
1999                         // initialized state.
2000
2001                         return this;
2002                 }
2003
2004                 public override void Emit (EmitContext ec)
2005                 {
2006                         base.Emit (ec);
2007                         ec.ig.Emit (op);
2008
2009                         if (second_valid)
2010                                 ec.ig.Emit (op2);
2011                 }
2012
2013                 public Type UnderlyingType {
2014                         get { return child.Type; }
2015                 }
2016         }
2017
2018         /// <summary>
2019         ///   This kind of cast is used to encapsulate a child and cast it
2020         ///   to the class requested
2021         /// </summary>
2022         public class ClassCast : EmptyCast {
2023                 public ClassCast (Expression child, Type return_type)
2024                         : base (child, return_type)
2025
2026                 {
2027                 }
2028
2029                 public override Expression DoResolve (EmitContext ec)
2030                 {
2031                         // This should never be invoked, we are born in fully
2032                         // initialized state.
2033
2034                         return this;
2035                 }
2036
2037                 public override void Emit (EmitContext ec)
2038                 {
2039                         base.Emit (ec);
2040
2041                         if (TypeManager.IsGenericParameter (child.Type))
2042                                 ec.ig.Emit (OpCodes.Box, child.Type);
2043
2044 #if GMCS_SOURCE
2045                         if (type.IsGenericParameter)
2046                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2047                         else
2048 #endif
2049                                 ec.ig.Emit (OpCodes.Castclass, type);
2050                 }
2051         }
2052
2053         /// <summary>
2054         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2055         ///   of a dotted-name.
2056         /// </summary>
2057         public class SimpleName : Expression {
2058                 public readonly string Name;
2059                 public readonly TypeArguments Arguments;
2060                 bool in_transit;
2061
2062                 public SimpleName (string name, Location l)
2063                 {
2064                         Name = name;
2065                         loc = l;
2066                 }
2067
2068                 public SimpleName (string name, TypeArguments args, Location l)
2069                 {
2070                         Name = name;
2071                         Arguments = args;
2072                         loc = l;
2073                 }
2074
2075                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2076                 {
2077                         Name = name;
2078                         loc = l;
2079
2080                         Arguments = new TypeArguments (l);
2081                         foreach (TypeParameter type_param in type_params)
2082                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2083                 }
2084
2085                 public static string RemoveGenericArity (string name)
2086                 {
2087                         int start = 0;
2088                         StringBuilder sb = null;
2089                         do {
2090                                 int pos = name.IndexOf ('`', start);
2091                                 if (pos < 0) {
2092                                         if (start == 0)
2093                                                 return name;
2094
2095                                         sb.Append (name.Substring (start));
2096                                         break;
2097                                 }
2098
2099                                 if (sb == null)
2100                                         sb = new StringBuilder ();
2101                                 sb.Append (name.Substring (start, pos-start));
2102
2103                                 pos++;
2104                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2105                                         pos++;
2106
2107                                 start = pos;
2108                         } while (start < name.Length);
2109
2110                         return sb.ToString ();
2111                 }
2112
2113                 public SimpleName GetMethodGroup ()
2114                 {
2115                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2116                 }
2117
2118                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2119                 {
2120                         if (ec.IsInFieldInitializer)
2121                                 Report.Error (236, l,
2122                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2123                                         name);
2124                         else
2125                                 Report.Error (
2126                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2127                                         name);
2128                 }
2129
2130                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2131                 {
2132                         return resolved_to != null && resolved_to.Type != null &&
2133                                 resolved_to.Type.Name == Name &&
2134                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2135                 }
2136
2137                 public override Expression DoResolve (EmitContext ec)
2138                 {
2139                         return SimpleNameResolve (ec, null, false);
2140                 }
2141
2142                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2143                 {
2144                         return SimpleNameResolve (ec, right_side, false);
2145                 }
2146
2147
2148                 public Expression DoResolve (EmitContext ec, bool intermediate)
2149                 {
2150                         return SimpleNameResolve (ec, null, intermediate);
2151                 }
2152
2153                 static bool IsNestedChild (Type t, Type parent)
2154                 {
2155                         while (parent != null) {
2156                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2157                                         return true;
2158
2159                                 parent = parent.BaseType;
2160                         }
2161
2162                         return false;
2163                 }
2164
2165                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2166                 {
2167                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2168                                 return null;
2169
2170                         DeclSpace ds = ec.DeclContainer;
2171                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2172                                 ds = ds.Parent;
2173
2174                         if (ds == null)
2175                                 return null;
2176
2177                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2178
2179                         int arg_count = Arguments != null ? Arguments.Count : 0;
2180
2181                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2182                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2183                                         TypeArguments new_args = new TypeArguments (loc);
2184                                         foreach (TypeParameter param in ds.TypeParameters)
2185                                                 new_args.Add (new TypeParameterExpr (param, loc));
2186
2187                                         if (Arguments != null)
2188                                                 new_args.Add (Arguments);
2189
2190                                         return new ConstructedType (t, new_args, loc);
2191                                 }
2192                         }
2193
2194                         return null;
2195                 }
2196
2197                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2198                 {
2199                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2200                         if (fne != null)
2201                                 return fne.ResolveAsTypeStep (ec, silent);
2202
2203                         int errors = Report.Errors;
2204                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2205
2206                         if (fne != null) {
2207                                 if (fne.Type == null)
2208                                         return fne;
2209
2210                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2211                                 if (nested != null)
2212                                         return nested.ResolveAsTypeStep (ec, false);
2213
2214                                 if (Arguments != null) {
2215                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2216                                         return ct.ResolveAsTypeStep (ec, false);
2217                                 }
2218
2219                                 return fne;
2220                         }
2221
2222                         if (silent || errors != Report.Errors)
2223                                 return null;
2224
2225                         Error_TypeOrNamespaceNotFound (ec);
2226                         return null;
2227                 }
2228
2229                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2230                 {
2231                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2232                         if (mc != null) {
2233                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2234                                 return;
2235                         }
2236
2237                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2238                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2239                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2240                                 Type type = a.GetType (fullname);
2241                                 if (type != null) {
2242                                         Report.SymbolRelatedToPreviousError (type);
2243                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2244                                         return;
2245                                 }
2246                         }
2247
2248                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2249                         if (t != null) {
2250                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2251                                 return;
2252                         }
2253
2254                         if (Arguments != null) {
2255                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2256                                 if (retval != null) {
2257                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2258                                         return;
2259                                 }
2260                         }
2261
2262                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2263                 }
2264
2265                 // TODO: I am still not convinced about this. If someone else will need it
2266                 // implement this as virtual property in MemberCore hierarchy
2267                 public static string GetMemberType (MemberCore mc)
2268                 {
2269                         if (mc is Property)
2270                                 return "property";
2271                         if (mc is Indexer)
2272                                 return "indexer";
2273                         if (mc is FieldBase)
2274                                 return "field";
2275                         if (mc is MethodCore)
2276                                 return "method";
2277                         if (mc is EnumMember)
2278                                 return "enum";
2279                         if (mc is Event)
2280                                 return "event";
2281
2282                         return "type";
2283                 }
2284
2285                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2286                 {
2287                         if (in_transit)
2288                                 return null;
2289
2290                         in_transit = true;
2291                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2292                         in_transit = false;
2293
2294                         if (e == null)
2295                                 return null;
2296
2297                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2298                                 return e;
2299
2300                         return null;
2301                 }
2302
2303                 /// <remarks>
2304                 ///   7.5.2: Simple Names.
2305                 ///
2306                 ///   Local Variables and Parameters are handled at
2307                 ///   parse time, so they never occur as SimpleNames.
2308                 ///
2309                 ///   The `intermediate' flag is used by MemberAccess only
2310                 ///   and it is used to inform us that it is ok for us to
2311                 ///   avoid the static check, because MemberAccess might end
2312                 ///   up resolving the Name as a Type name and the access as
2313                 ///   a static type access.
2314                 ///
2315                 ///   ie: Type Type; .... { Type.GetType (""); }
2316                 ///
2317                 ///   Type is both an instance variable and a Type;  Type.GetType
2318                 ///   is the static method not an instance method of type.
2319                 /// </remarks>
2320                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2321                 {
2322                         Expression e = null;
2323
2324                         //
2325                         // Stage 1: Performed by the parser (binding to locals or parameters).
2326                         //
2327                         Block current_block = ec.CurrentBlock;
2328                         if (current_block != null){
2329                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2330                                 if (vi != null){
2331                                         if (Arguments != null) {
2332                                                 Report.Error (307, loc,
2333                                                               "The variable `{0}' cannot be used with type arguments",
2334                                                               Name);
2335                                                 return null;
2336                                         }
2337
2338                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2339                                         if (right_side != null) {
2340                                                 return var.ResolveLValue (ec, right_side, loc);
2341                                         } else {
2342                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2343                                                 if (intermediate)
2344                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2345                                                 return var.Resolve (ec, rf);
2346                                         }
2347                                 }
2348
2349                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2350                                 if (pref != null) {
2351                                         if (Arguments != null) {
2352                                                 Report.Error (307, loc,
2353                                                               "The variable `{0}' cannot be used with type arguments",
2354                                                               Name);
2355                                                 return null;
2356                                         }
2357
2358                                         if (right_side != null)
2359                                                 return pref.ResolveLValue (ec, right_side, loc);
2360                                         else
2361                                                 return pref.Resolve (ec);
2362                                 }
2363
2364                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2365                                 if (expr != null) {
2366                                         if (right_side != null)
2367                                                 return expr.ResolveLValue (ec, right_side, loc);
2368                                         return expr.Resolve (ec);
2369                                 }
2370                         }
2371
2372                         //
2373                         // Stage 2: Lookup members
2374                         //
2375
2376                         Type almost_matched_type = null;
2377                         ArrayList almost_matched = null;
2378                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2379                                 // either RootDeclSpace or GenericMethod
2380                                 if (lookup_ds.TypeBuilder == null)
2381                                         continue;
2382
2383                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2384                                 if (e != null) {
2385                                         if (e is PropertyExpr) {
2386                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2387                                                 // it doesn't know which accessor to check permissions against
2388                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2389                                                         break;
2390                                         } else if (e is EventExpr) {
2391                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2392                                                         break;
2393                                         } else {
2394                                                 break;
2395                                         }
2396                                         e = null;
2397                                 }
2398
2399                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2400                                         almost_matched_type = lookup_ds.TypeBuilder;
2401                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2402                                 }
2403                         }
2404
2405                         if (e == null) {
2406                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2407                                         almost_matched_type = ec.ContainerType;
2408                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2409                                 }
2410                                 e = ResolveAsTypeStep (ec, true);
2411                         }
2412
2413                         if (e == null) {
2414                                 if (current_block != null) {
2415                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2416                                         if (ikv != null) {
2417                                                 LocalInfo li = ikv as LocalInfo;
2418                                                 // Supress CS0219 warning
2419                                                 if (li != null)
2420                                                         li.Used = true;
2421
2422                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2423                                                 return null;
2424                                         }
2425                                 }
2426
2427                                 if (almost_matched != null)
2428                                         almost_matched_members = almost_matched;
2429                                 if (almost_matched_type == null)
2430                                         almost_matched_type = ec.ContainerType;
2431                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2432                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2433                                 return null;
2434                         }
2435
2436                         if (e is TypeExpr) {
2437                                 if (Arguments == null)
2438                                         return e;
2439
2440                                 ConstructedType ct = new ConstructedType (
2441                                         (FullNamedExpression) e, Arguments, loc);
2442                                 return ct.ResolveAsTypeStep (ec, false);
2443                         }
2444
2445                         if (e is MemberExpr) {
2446                                 MemberExpr me = (MemberExpr) e;
2447
2448                                 Expression left;
2449                                 if (me.IsInstance) {
2450                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2451                                                 //
2452                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2453                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2454                                                 // and each predicate is true if the MethodGroupExpr contains
2455                                                 // at least one of that kind of method.
2456                                                 //
2457
2458                                                 if (!me.IsStatic &&
2459                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2460                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2461                                                         return null;
2462                                                 }
2463
2464                                                 //
2465                                                 // Pass the buck to MemberAccess and Invocation.
2466                                                 //
2467                                                 left = EmptyExpression.Null;
2468                                         } else {
2469                                                 left = ec.GetThis (loc);
2470                                         }
2471                                 } else {
2472                                         left = new TypeExpression (ec.ContainerType, loc);
2473                                 }
2474
2475                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2476                                 if (me == null)
2477                                         return null;
2478
2479                                 if (Arguments != null) {
2480                                         Arguments.Resolve (ec);
2481                                         me.SetTypeArguments (Arguments);
2482                                 }
2483
2484                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2485                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2486                                     me.InstanceExpression.Type != me.DeclaringType &&
2487                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2488                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2489                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2490                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2491                                         return null;
2492                                 }
2493
2494                                 return (right_side != null)
2495                                         ? me.DoResolveLValue (ec, right_side)
2496                                         : me.DoResolve (ec);
2497                         }
2498
2499                         return e;
2500                 }
2501
2502                 public override void Emit (EmitContext ec)
2503                 {
2504                         throw new InternalErrorException ("The resolve phase was not executed");
2505                 }
2506
2507                 public override string ToString ()
2508                 {
2509                         return Name;
2510                 }
2511
2512                 public override string GetSignatureForError ()
2513                 {
2514                         if (Arguments != null) {
2515                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2516                                         Arguments.GetSignatureForError () + ">";
2517                         }
2518
2519                         return Name;
2520                 }
2521
2522                 protected override void CloneTo (CloneContext clonectx, Expression target)
2523                 {
2524                         // CloneTo: Nothing, we do not keep any state on this expression
2525                 }
2526         }
2527
2528         /// <summary>
2529         ///   Represents a namespace or a type.  The name of the class was inspired by
2530         ///   section 10.8.1 (Fully Qualified Names).
2531         /// </summary>
2532         public abstract class FullNamedExpression : Expression {
2533                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2534                 {
2535                         return this;
2536                 }
2537
2538                 public abstract string FullName {
2539                         get;
2540                 }
2541         }
2542
2543         /// <summary>
2544         ///   Expression that evaluates to a type
2545         /// </summary>
2546         public abstract class TypeExpr : FullNamedExpression {
2547                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2548                 {
2549                         TypeExpr t = DoResolveAsTypeStep (ec);
2550                         if (t == null)
2551                                 return null;
2552
2553                         eclass = ExprClass.Type;
2554                         return t;
2555                 }
2556
2557                 override public Expression DoResolve (EmitContext ec)
2558                 {
2559                         return ResolveAsTypeTerminal (ec, false);
2560                 }
2561
2562                 override public void Emit (EmitContext ec)
2563                 {
2564                         throw new Exception ("Should never be called");
2565                 }
2566
2567                 public virtual bool CheckAccessLevel (DeclSpace ds)
2568                 {
2569                         return ds.CheckAccessLevel (Type);
2570                 }
2571
2572                 public virtual bool AsAccessible (DeclSpace ds)
2573                 {
2574                         return ds.IsAccessibleAs (Type);
2575                 }
2576
2577                 public virtual bool IsClass {
2578                         get { return Type.IsClass; }
2579                 }
2580
2581                 public virtual bool IsValueType {
2582                         get { return Type.IsValueType; }
2583                 }
2584
2585                 public virtual bool IsInterface {
2586                         get { return Type.IsInterface; }
2587                 }
2588
2589                 public virtual bool IsSealed {
2590                         get { return Type.IsSealed; }
2591                 }
2592
2593                 public virtual bool CanInheritFrom ()
2594                 {
2595                         if (Type == TypeManager.enum_type ||
2596                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2597                             Type == TypeManager.multicast_delegate_type ||
2598                             Type == TypeManager.delegate_type ||
2599                             Type == TypeManager.array_type)
2600                                 return false;
2601
2602                         return true;
2603                 }
2604
2605                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2606
2607                 public abstract string Name {
2608                         get;
2609                 }
2610
2611                 public override bool Equals (object obj)
2612                 {
2613                         TypeExpr tobj = obj as TypeExpr;
2614                         if (tobj == null)
2615                                 return false;
2616
2617                         return Type == tobj.Type;
2618                 }
2619
2620                 public override int GetHashCode ()
2621                 {
2622                         return Type.GetHashCode ();
2623                 }
2624
2625                 public override string ToString ()
2626                 {
2627                         return Name;
2628                 }
2629         }
2630
2631         /// <summary>
2632         ///   Fully resolved Expression that already evaluated to a type
2633         /// </summary>
2634         public class TypeExpression : TypeExpr {
2635                 public TypeExpression (Type t, Location l)
2636                 {
2637                         Type = t;
2638                         eclass = ExprClass.Type;
2639                         loc = l;
2640                 }
2641
2642                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2643                 {
2644                         return this;
2645                 }
2646
2647                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2648                 {
2649                         return this;
2650                 }
2651
2652                 public override string Name {
2653                         get { return Type.ToString (); }
2654                 }
2655
2656                 public override string FullName {
2657                         get { return Type.FullName; }
2658                 }
2659         }
2660
2661         /// <summary>
2662         ///   Used to create types from a fully qualified name.  These are just used
2663         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2664         ///   classified as a type.
2665         /// </summary>
2666         public sealed class TypeLookupExpression : TypeExpr {
2667                 readonly string name;
2668
2669                 public TypeLookupExpression (string name)
2670                 {
2671                         this.name = name;
2672                         eclass = ExprClass.Type;
2673                 }
2674
2675                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2676                 {
2677                         // It's null for corlib compilation only
2678                         if (type == null)
2679                                 return DoResolveAsTypeStep (ec);
2680
2681                         return this;
2682                 }
2683
2684                 private class UnexpectedType
2685                 {
2686                 }
2687
2688                 // This performes recursive type lookup, providing support for generic types.
2689                 // For example, given the type:
2690                 //
2691                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2692                 //
2693                 // The types will be checked in the following order:
2694                 //                                                                             _
2695                 // System                                                                       |
2696                 // System.Collections                                                           |
2697                 // System.Collections.Generic                                                   |
2698                 //                        _                                                     |
2699                 //     System              | recursive call 1                                   |
2700                 //     System.Int32       _|                                                    | main method call
2701                 //                        _                                                     |
2702                 //     System              | recursive call 2                                   |
2703                 //     System.String      _|                                                    |
2704                 //                                                                              |
2705                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2706                 //
2707                 private Type TypeLookup (IResolveContext ec, string name)
2708                 {
2709                         int index = 0;
2710                         int dot = 0;
2711                         bool done = false;
2712                         FullNamedExpression resolved = null;
2713                         Type type = null;
2714                         Type recursive_type = null;
2715                         while (index < name.Length) {
2716                                 if (name[index] == '[') {
2717                                         int open = index;
2718                                         int braces = 1;
2719                                         do {
2720                                                 index++;
2721                                                 if (name[index] == '[')
2722                                                         braces++;
2723                                                 else if (name[index] == ']')
2724                                                         braces--;
2725                                         } while (braces > 0);
2726                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2727                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2728                                                 return recursive_type;
2729                                 }
2730                                 else {
2731                                         if (name[index] == ',')
2732                                                 done = true;
2733                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2734                                                 string substring = name.Substring(dot, index - dot);
2735
2736                                                 if (resolved == null)
2737                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2738                                                 else if (resolved is Namespace)
2739                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2740                                                 else if (type != null)
2741                                                         type = TypeManager.GetNestedType (type, substring);
2742                                                 else
2743                                                         return null;
2744
2745                                                 if (resolved == null)
2746                                                         return null;
2747                                                 else if (type == null && resolved is TypeExpr)
2748                                                         type = resolved.Type;
2749
2750                                                 dot = index + 1;
2751                                         }
2752                                 }
2753                                 index++;
2754                         }
2755                         if (name[0] != '[') {
2756                                 string substring = name.Substring(dot, index - dot);
2757
2758                                 if (type != null)
2759                                         return TypeManager.GetNestedType (type, substring);
2760
2761                                 if (resolved != null) {
2762                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2763                                         if (resolved is TypeExpr)
2764                                                 return resolved.Type;
2765
2766                                         if (resolved == null)
2767                                                 return null;
2768
2769                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2770                                         return typeof (UnexpectedType);
2771                                 }
2772                                 else
2773                                         return null;
2774                         }
2775                         else
2776                                 return recursive_type;
2777                         }
2778
2779                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2780                 {
2781                         Type t = TypeLookup (ec, name);
2782                         if (t == null) {
2783                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2784                                 return null;
2785                         }
2786                         if (t == typeof(UnexpectedType))
2787                                 return null;
2788                         type = t;
2789                         return this;
2790                 }
2791
2792                 public override string Name {
2793                         get { return name; }
2794                 }
2795
2796                 public override string FullName {
2797                         get { return name; }
2798                 }
2799
2800                 protected override void CloneTo (CloneContext clonectx, Expression target)
2801                 {
2802                         // CloneTo: Nothing, we do not keep any state on this expression
2803                 }
2804
2805                 public override string GetSignatureForError ()
2806                 {
2807                         if (type == null)
2808                                 return TypeManager.CSharpName (name);
2809
2810                         return base.GetSignatureForError ();
2811                 }
2812         }
2813
2814         /// <summary>
2815         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2816         ///   See 14.5.11.
2817         /// </summary>
2818         public class UnboundTypeExpression : TypeExpr
2819         {
2820                 MemberName name;
2821
2822                 public UnboundTypeExpression (MemberName name, Location l)
2823                 {
2824                         this.name = name;
2825                         loc = l;
2826                 }
2827
2828                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2829                 {
2830                         Expression expr;
2831                         if (name.Left != null) {
2832                                 Expression lexpr = name.Left.GetTypeExpression ();
2833                                 expr = new MemberAccess (lexpr, name.Basename);
2834                         } else {
2835                                 expr = new SimpleName (name.Basename, loc);
2836                         }
2837
2838                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2839                         if (fne == null)
2840                                 return null;
2841
2842                         type = fne.Type;
2843                         return new TypeExpression (type, loc);
2844                 }
2845
2846                 public override string Name {
2847                         get { return name.FullName; }
2848                 }
2849
2850                 public override string FullName {
2851                         get { return name.FullName; }
2852                 }
2853         }
2854
2855         public class TypeAliasExpression : TypeExpr {
2856                 FullNamedExpression alias;
2857                 TypeExpr texpr;
2858                 TypeArguments args;
2859                 string name;
2860
2861                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2862                 {
2863                         this.alias = alias;
2864                         this.args = args;
2865                         loc = l;
2866
2867                         eclass = ExprClass.Type;
2868                         if (args != null)
2869                                 name = alias.FullName + "<" + args.ToString () + ">";
2870                         else
2871                                 name = alias.FullName;
2872                 }
2873
2874                 public override string Name {
2875                         get { return alias.FullName; }
2876                 }
2877
2878                 public override string FullName {
2879                         get { return name; }
2880                 }
2881
2882                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2883                 {
2884                         texpr = alias.ResolveAsTypeTerminal (ec, false);
2885                         if (texpr == null)
2886                                 return null;
2887
2888                         Type type = texpr.Type;
2889                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2890
2891                         if (args != null) {
2892                                 if (num_args == 0) {
2893                                         Report.Error (308, loc,
2894                                                       "The non-generic type `{0}' cannot " +
2895                                                       "be used with type arguments.",
2896                                                       TypeManager.CSharpName (type));
2897                                         return null;
2898                                 }
2899
2900                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2901                                 return ctype.ResolveAsTypeTerminal (ec, false);
2902                         } else if (num_args > 0) {
2903                                 Report.Error (305, loc,
2904                                               "Using the generic type `{0}' " +
2905                                               "requires {1} type arguments",
2906                                               TypeManager.CSharpName (type), num_args.ToString ());
2907                                 return null;
2908                         }
2909
2910                         return texpr;
2911                 }
2912
2913                 public override bool CheckAccessLevel (DeclSpace ds)
2914                 {
2915                         return texpr.CheckAccessLevel (ds);
2916                 }
2917
2918                 public override bool AsAccessible (DeclSpace ds)
2919                 {
2920                         return texpr.AsAccessible (ds);
2921                 }
2922
2923                 public override bool IsClass {
2924                         get { return texpr.IsClass; }
2925                 }
2926
2927                 public override bool IsValueType {
2928                         get { return texpr.IsValueType; }
2929                 }
2930
2931                 public override bool IsInterface {
2932                         get { return texpr.IsInterface; }
2933                 }
2934
2935                 public override bool IsSealed {
2936                         get { return texpr.IsSealed; }
2937                 }
2938         }
2939
2940         /// <summary>
2941         ///   This class denotes an expression which evaluates to a member
2942         ///   of a struct or a class.
2943         /// </summary>
2944         public abstract class MemberExpr : Expression
2945         {
2946                 protected bool is_base;
2947
2948                 /// <summary>
2949                 ///   The name of this member.
2950                 /// </summary>
2951                 public abstract string Name {
2952                         get;
2953                 }
2954
2955                 //
2956                 // When base.member is used
2957                 //
2958                 public bool IsBase {
2959                         get { return is_base; }
2960                         set { is_base = value; }
2961                 }
2962
2963                 /// <summary>
2964                 ///   Whether this is an instance member.
2965                 /// </summary>
2966                 public abstract bool IsInstance {
2967                         get;
2968                 }
2969
2970                 /// <summary>
2971                 ///   Whether this is a static member.
2972                 /// </summary>
2973                 public abstract bool IsStatic {
2974                         get;
2975                 }
2976
2977                 /// <summary>
2978                 ///   The type which declares this member.
2979                 /// </summary>
2980                 public abstract Type DeclaringType {
2981                         get;
2982                 }
2983
2984                 /// <summary>
2985                 ///   The instance expression associated with this member, if it's a
2986                 ///   non-static member.
2987                 /// </summary>
2988                 public Expression InstanceExpression;
2989
2990                 public static void error176 (Location loc, string name)
2991                 {
2992                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
2993                                       "with an instance reference, qualify it with a type name instead", name);
2994                 }
2995
2996                 // TODO: possible optimalization
2997                 // Cache resolved constant result in FieldBuilder <-> expression map
2998                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2999                                                                SimpleName original)
3000                 {
3001                         //
3002                         // Precondition:
3003                         //   original == null || original.Resolve (...) ==> left
3004                         //
3005
3006                         if (left is TypeExpr) {
3007                                 left = left.ResolveAsTypeTerminal (ec, true);
3008                                 if (left == null)
3009                                         return null;
3010
3011                                 if (!IsStatic) {
3012                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3013                                         return null;
3014                                 }
3015
3016                                 return this;
3017                         }
3018
3019                         if (!IsInstance) {
3020                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3021                                         return this;
3022
3023                                 return ResolveExtensionMemberAccess (left);
3024                         }
3025
3026                         InstanceExpression = left;
3027                         return this;
3028                 }
3029
3030                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3031                 {
3032                         error176 (loc, GetSignatureForError ());
3033                         return this;
3034                 }
3035
3036                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3037                 {
3038                         if (IsStatic)
3039                                 return;
3040
3041                         if (InstanceExpression == EmptyExpression.Null) {
3042                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3043                                 return;
3044                         }
3045
3046                         if (InstanceExpression.Type.IsValueType) {
3047                                 if (InstanceExpression is IMemoryLocation) {
3048                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3049                                 } else {
3050                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3051                                         InstanceExpression.Emit (ec);
3052                                         t.Store (ec);
3053                                         t.AddressOf (ec, AddressOp.Store);
3054                                 }
3055                         } else
3056                                 InstanceExpression.Emit (ec);
3057
3058                         if (prepare_for_load)
3059                                 ec.ig.Emit (OpCodes.Dup);
3060                 }
3061
3062                 public virtual void SetTypeArguments (TypeArguments ta)
3063                 {
3064                         // TODO: need to get correct member type
3065                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3066                                 GetSignatureForError ());
3067                 }
3068         }
3069
3070         ///
3071         /// Represents group of extension methods
3072         ///
3073         public class ExtensionMethodGroupExpr : MethodGroupExpr
3074         {
3075                 readonly NamespaceEntry namespace_entry;
3076                 public Expression ExtensionExpression;
3077                 Argument extension_argument;
3078
3079                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3080                         : base (list, extensionType, l)
3081                 {
3082                         this.namespace_entry = n;
3083                 }
3084
3085                 public override bool IsStatic {
3086                         get { return true; }
3087                 }
3088
3089                 public bool IsTopLevel {
3090                         get { return namespace_entry == null; }
3091                 }
3092
3093                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3094                 {
3095                         if (arguments == null)
3096                                 arguments = new ArrayList (1);
3097                         arguments.Insert (0, extension_argument);
3098                         base.EmitArguments (ec, arguments);
3099                 }
3100
3101                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3102                 {
3103                         if (arguments == null)
3104                                 arguments = new ArrayList (1);
3105                         arguments.Insert (0, extension_argument);
3106                         base.EmitCall (ec, arguments);
3107                 }
3108
3109                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3110                 {
3111                         if (arguments == null)
3112                                 arguments = new ArrayList (1);
3113
3114                         arguments.Insert (0, new Argument (ExtensionExpression));
3115                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3116
3117                         // Store resolved argument and restore original arguments
3118                         if (mg != null)
3119                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3120                         arguments.RemoveAt (0);
3121
3122                         return mg;
3123                 }
3124
3125                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3126                 {
3127                         // Use normal resolve rules
3128                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3129                         if (mg != null)
3130                                 return mg;
3131
3132                         if (ns == null)
3133                                 return null;
3134
3135                         // Search continues
3136                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name);
3137                         if (e == null)
3138                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3139
3140                         e.ExtensionExpression = ExtensionExpression;
3141                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3142                 }
3143         }
3144
3145         /// <summary>
3146         ///   MethodGroupExpr represents a group of method candidates which
3147         ///   can be resolved to the best method overload
3148         /// </summary>
3149         public class MethodGroupExpr : MemberExpr
3150         {
3151                 public interface IErrorHandler
3152                 {
3153                         bool NoExactMatch (EmitContext ec, MethodBase method);
3154                 }
3155
3156                 public IErrorHandler CustomErrorHandler;
3157                 public MethodBase [] Methods;
3158                 MethodBase best_candidate;
3159                 // TODO: make private
3160                 public TypeArguments type_arguments;
3161                 bool identical_type_name;
3162                 Type delegate_type;
3163
3164                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3165                         : this (type, l)
3166                 {
3167                         Methods = new MethodBase [mi.Length];
3168                         mi.CopyTo (Methods, 0);
3169                 }
3170
3171                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3172                         : this (type, l)
3173                 {
3174                         try {
3175                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3176                         } catch {
3177                                 foreach (MemberInfo m in list){
3178                                         if (!(m is MethodBase)){
3179                                                 Console.WriteLine ("Name " + m.Name);
3180                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3181                                         }
3182                                 }
3183                                 throw;
3184                         }
3185
3186
3187                 }
3188
3189                 protected MethodGroupExpr (Type type, Location loc)
3190                 {
3191                         this.loc = loc;
3192                         eclass = ExprClass.MethodGroup;
3193                         this.type = type;
3194                 }
3195
3196                 public override Type DeclaringType {
3197                         get {
3198                                 //
3199                                 // We assume that the top-level type is in the end
3200                                 //
3201                                 return Methods [Methods.Length - 1].DeclaringType;
3202                                 //return Methods [0].DeclaringType;
3203                         }
3204                 }
3205
3206                 public Type DelegateType {
3207                         set {
3208                                 delegate_type = value;
3209                         }
3210                 }
3211
3212                 public bool IdenticalTypeName {
3213                         get {
3214                                 return identical_type_name;
3215                         }
3216
3217                         set {
3218                                 identical_type_name = value;
3219                         }
3220                 }
3221
3222                 public override string GetSignatureForError ()
3223                 {
3224                         if (best_candidate != null)
3225                                 return TypeManager.CSharpSignature (best_candidate);
3226
3227                         return TypeManager.CSharpSignature (Methods [0]);
3228                 }
3229
3230                 public override string Name {
3231                         get {
3232                                 return Methods [0].Name;
3233                         }
3234                 }
3235
3236                 public override bool IsInstance {
3237                         get {
3238                                 if (best_candidate != null)
3239                                         return !best_candidate.IsStatic;
3240
3241                                 foreach (MethodBase mb in Methods)
3242                                         if (!mb.IsStatic)
3243                                                 return true;
3244
3245                                 return false;
3246                         }
3247                 }
3248
3249                 public override bool IsStatic {
3250                         get {
3251                                 if (best_candidate != null)
3252                                         return best_candidate.IsStatic;
3253
3254                                 foreach (MethodBase mb in Methods)
3255                                         if (mb.IsStatic)
3256                                                 return true;
3257
3258                                 return false;
3259                         }
3260                 }
3261
3262                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3263                 {
3264                         return (ConstructorInfo)mg.best_candidate;
3265                 }
3266
3267                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3268                 {
3269                         return (MethodInfo)mg.best_candidate;
3270                 }
3271
3272                 //
3273                 //  7.4.3.3  Better conversion from expression
3274                 //  Returns :   1    if a->p is better,
3275                 //              2    if a->q is better,
3276                 //              0 if neither is better
3277                 //
3278                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3279                 {
3280                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3281                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3282                                 //
3283                                 // Uwrap delegate from Expression<T>
3284                                 //
3285                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3286                                         p = TypeManager.GetTypeArguments (p) [0];
3287                                         q = TypeManager.GetTypeArguments (q) [0];
3288                                 }
3289                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3290                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3291                         } else {
3292                                 if (argument_type == p)
3293                                         return 1;
3294
3295                                 if (argument_type == q)
3296                                         return 2;
3297                         }
3298
3299                         return BetterTypeConversion (ec, p, q);
3300                 }
3301
3302                 //
3303                 // 7.4.3.4  Better conversion from type
3304                 //
3305                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3306                 {
3307                         if (p == null || q == null)
3308                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3309
3310                         if (p == TypeManager.int32_type) {
3311                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3312                                         return 1;
3313                         } else if (p == TypeManager.int64_type) {
3314                                 if (q == TypeManager.uint64_type)
3315                                         return 1;
3316                         } else if (p == TypeManager.sbyte_type) {
3317                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3318                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3319                                         return 1;
3320                         } else if (p == TypeManager.short_type) {
3321                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3322                                         q == TypeManager.uint64_type)
3323                                         return 1;
3324                         }
3325
3326                         if (q == TypeManager.int32_type) {
3327                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3328                                         return 2;
3329                         } if (q == TypeManager.int64_type) {
3330                                 if (p == TypeManager.uint64_type)
3331                                         return 2;
3332                         } else if (q == TypeManager.sbyte_type) {
3333                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3334                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3335                                         return 2;
3336                         } if (q == TypeManager.short_type) {
3337                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3338                                         p == TypeManager.uint64_type)
3339                                         return 2;
3340                         }
3341
3342                         // TODO: this is expensive
3343                         Expression p_tmp = new EmptyExpression (p);
3344                         Expression q_tmp = new EmptyExpression (q);
3345
3346                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3347                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3348
3349                         if (p_to_q && !q_to_p)
3350                                 return 1;
3351
3352                         if (q_to_p && !p_to_q)
3353                                 return 2;
3354
3355                         return 0;
3356                 }
3357
3358                 /// <summary>
3359                 ///   Determines "Better function" between candidate
3360                 ///   and the current best match
3361                 /// </summary>
3362                 /// <remarks>
3363                 ///    Returns a boolean indicating :
3364                 ///     false if candidate ain't better
3365                 ///     true  if candidate is better than the current best match
3366                 /// </remarks>
3367                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3368                         MethodBase candidate, bool candidate_params,
3369                         MethodBase best, bool best_params)
3370                 {
3371                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3372                         ParameterData best_pd = TypeManager.GetParameterData (best);
3373
3374                         bool better_at_least_one = false;
3375                         bool same = true;
3376                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3377                         {
3378                                 Argument a = (Argument) args [j];
3379
3380                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3381                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3382
3383                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3384                                 {
3385                                         ct = TypeManager.GetElementType (ct);
3386                                         --c_idx;
3387                                 }
3388
3389                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3390                                 {
3391                                         bt = TypeManager.GetElementType (bt);
3392                                         --b_idx;
3393                                 }
3394
3395                                 if (ct.Equals (bt))
3396                                         continue;
3397
3398                                 same = false;
3399                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3400
3401                                 // for each argument, the conversion to 'ct' should be no worse than
3402                                 // the conversion to 'bt'.
3403                                 if (result == 2)
3404                                         return false;
3405
3406                                 // for at least one argument, the conversion to 'ct' should be better than
3407                                 // the conversion to 'bt'.
3408                                 if (result != 0)
3409                                         better_at_least_one = true;
3410                         }
3411
3412                         if (better_at_least_one)
3413                                 return true;
3414
3415                         //
3416                         // This handles the case
3417                         //
3418                         //   Add (float f1, float f2, float f3);
3419                         //   Add (params decimal [] foo);
3420                         //
3421                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3422                         // first candidate would've chosen as better.
3423                         //
3424                         if (!same)
3425                                 return false;
3426
3427                         //
3428                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3429                         //
3430                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3431                                 return true;
3432                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3433                                 return false;
3434
3435                         //
3436                         // This handles the following cases:
3437                         //
3438                         //   Trim () is better than Trim (params char[] chars)
3439                         //   Concat (string s1, string s2, string s3) is better than
3440                         //     Concat (string s1, params string [] srest)
3441                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3442                         //
3443                         if (!candidate_params && best_params)
3444                                 return true;
3445                         if (candidate_params && !best_params)
3446                                 return false;
3447
3448                         int candidate_param_count = candidate_pd.Count;
3449                         int best_param_count = best_pd.Count;
3450
3451                         if (candidate_param_count != best_param_count)
3452                                 // can only happen if (candidate_params && best_params)
3453                                 return candidate_param_count > best_param_count;
3454
3455                         //
3456                         // now, both methods have the same number of parameters, and the parameters have the same types
3457                         // Pick the "more specific" signature
3458                         //
3459
3460                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3461                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3462
3463                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3464                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3465
3466                         bool specific_at_least_once = false;
3467                         for (int j = 0; j < candidate_param_count; ++j)
3468                         {
3469                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3470                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3471                                 if (ct.Equals (bt))
3472                                         continue;
3473                                 Type specific = MoreSpecific (ct, bt);
3474                                 if (specific == bt)
3475                                         return false;
3476                                 if (specific == ct)
3477                                         specific_at_least_once = true;
3478                         }
3479
3480                         if (specific_at_least_once)
3481                                 return true;
3482
3483                         // FIXME: handle lifted operators
3484                         // ...
3485
3486                         return false;
3487                 }
3488
3489                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3490                 {
3491                         if (!IsStatic)
3492                                 return base.ResolveExtensionMemberAccess (left);
3493
3494                         //
3495                         // When left side is an expression and at least one candidate method is
3496                         // static, it can be extension method
3497                         //
3498                         InstanceExpression = left;
3499                         return this;
3500                 }
3501
3502                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3503                                                                 SimpleName original)
3504                 {
3505                         if (!(left is TypeExpr) &&
3506                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3507                                 IdenticalTypeName = true;
3508
3509                         return base.ResolveMemberAccess (ec, left, loc, original);
3510                 }
3511
3512                 public override Expression CreateExpressionTree (EmitContext ec)
3513                 {
3514                         return new Cast (new TypeExpression (typeof (MethodInfo), loc),
3515                                 new TypeOfMethod ((MethodInfo)best_candidate, loc));
3516                 }
3517
3518                 override public Expression DoResolve (EmitContext ec)
3519                 {
3520                         if (InstanceExpression != null) {
3521                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3522                                 if (InstanceExpression == null)
3523                                         return null;
3524                         }
3525
3526                         return this;
3527                 }
3528
3529                 public void ReportUsageError ()
3530                 {
3531                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3532                                       Name + "()' is referenced without parentheses");
3533                 }
3534
3535                 override public void Emit (EmitContext ec)
3536                 {
3537                         ReportUsageError ();
3538                 }
3539
3540                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3541                 {
3542                         Invocation.EmitArguments (ec, arguments, false, null);
3543                 }
3544
3545                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3546                 {
3547                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3548                 }
3549
3550                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3551                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3552                 {
3553                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3554                                 Report.SymbolRelatedToPreviousError (method);
3555                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3556                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3557                                                 TypeManager.CSharpSignature (method));
3558                                         return;
3559                                 }
3560                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3561                                           TypeManager.CSharpSignature (method));
3562                         } else if (delegate_type == null) {
3563                                 Report.SymbolRelatedToPreviousError (method);
3564                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3565                                                   TypeManager.CSharpSignature (method));
3566                         } else
3567                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3568                                         TypeManager.CSharpName (delegate_type));
3569
3570                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3571
3572                         string index = (idx + 1).ToString ();
3573                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3574                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3575                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3576                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3577                                                 index, Parameter.GetModifierSignature (a.Modifier));
3578                                 else
3579                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3580                                                 index, Parameter.GetModifierSignature (mod));
3581                         } else {
3582                                 string p1 = a.GetSignatureForError ();
3583                                 string p2 = TypeManager.CSharpName (paramType);
3584
3585                                 if (p1 == p2) {
3586                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3587                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3588                                         Report.SymbolRelatedToPreviousError (paramType);
3589                                 }
3590                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3591                         }
3592                 }
3593
3594                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3595                 {
3596                         return parameters.Count;
3597                 }
3598
3599                 public static bool IsAncestralType (Type first_type, Type second_type)
3600                 {
3601                         return first_type != second_type &&
3602                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3603                                 TypeManager.ImplementsInterface (second_type, first_type));
3604                 }
3605
3606                 ///
3607                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3608                 /// to the given set of arguments
3609                 /// A return value rates candidate method compatibility,
3610                 /// 0 = the best, int.MaxValue = the worst
3611                 ///
3612                 public int IsApplicable (EmitContext ec,
3613                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3614                 {
3615                         MethodBase candidate = method;
3616
3617                         ParameterData pd = TypeManager.GetParameterData (candidate);
3618                         int param_count = GetApplicableParametersCount (candidate, pd);
3619
3620                         if (arg_count != param_count) {
3621                                 if (!pd.HasParams)
3622                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3623                                 if (arg_count < param_count - 1)
3624                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3625                         }
3626
3627 #if GMCS_SOURCE
3628                         //
3629                         // 1. Handle generic method using type arguments when specified or type inference
3630                         //
3631                         if (TypeManager.IsGenericMethod (candidate)) {
3632                                 if (type_arguments != null) {
3633                                         Type [] g_args = candidate.GetGenericArguments ();
3634                                         if (g_args.Length != type_arguments.Count)
3635                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3636
3637                                         // TODO: Don't create new method, create Parameters only
3638                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3639                                         candidate = method;
3640                                         pd = TypeManager.GetParameterData (candidate);
3641                                 } else {
3642                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3643                                         if (score != 0)
3644                                                 return score - 20000;
3645
3646                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3647                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3648                                                         TypeManager.CSharpSignature (candidate));
3649
3650                                         pd = TypeManager.GetParameterData (candidate);
3651                                 }
3652                         } else {
3653                                 if (type_arguments != null)
3654                                         return int.MaxValue - 15000;
3655                         }
3656 #endif
3657
3658                         //
3659                         // 2. Each argument has to be implicitly convertible to method parameter
3660                         //
3661                         method = candidate;
3662                         Parameter.Modifier p_mod = 0;
3663                         Type pt = null;
3664                         for (int i = 0; i < arg_count; i++) {
3665                                 Argument a = (Argument) arguments [i];
3666                                 Parameter.Modifier a_mod = a.Modifier &
3667                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3668
3669                                 if (p_mod != Parameter.Modifier.PARAMS) {
3670                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3671
3672                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3673                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3674                                                         continue;
3675
3676                                                 p_mod = 0;
3677                                         }
3678
3679                                         pt = pd.ParameterType (i);
3680                                 } else {
3681                                         params_expanded_form = true;
3682                                 }
3683
3684                                 int score = 1;
3685                                 if (!params_expanded_form)
3686                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3687
3688                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3689                                         // It can be applicable in expanded form
3690                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3691                                         if (score == 0)
3692                                                 params_expanded_form = true;
3693                                 }
3694
3695                                 if (score != 0) {
3696                                         if (params_expanded_form)
3697                                                 ++score;
3698                                         return (arg_count - i) * 2 + score;
3699                                 }
3700                         }
3701
3702                         if (arg_count != param_count)
3703                                 params_expanded_form = true;
3704
3705                         return 0;
3706                 }
3707
3708                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3709                 {
3710                         //
3711                         // Types have to be identical when ref or out modifer is used
3712                         //
3713                         if (arg_mod != 0 || param_mod != 0) {
3714                                 if (TypeManager.HasElementType (parameter))
3715                                         parameter = parameter.GetElementType ();
3716
3717                                 Type a_type = argument.Type;
3718                                 if (TypeManager.HasElementType (a_type))
3719                                         a_type = a_type.GetElementType ();
3720
3721                                 if (a_type != parameter)
3722                                         return 2;
3723
3724                                 return 0;
3725                         }
3726
3727                         // FIXME: Kill this abomination (EmitContext.TempEc)
3728                         EmitContext prevec = EmitContext.TempEc;
3729                         EmitContext.TempEc = ec;
3730                         try {
3731                                 if (delegate_type != null ?
3732                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3733                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3734                                         return 2;
3735
3736                                 if (arg_mod != param_mod)
3737                                         return 1;
3738
3739                         } finally {
3740                                 EmitContext.TempEc = prevec;
3741                         }
3742
3743                         return 0;
3744                 }
3745
3746                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3747                 {
3748                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3749                                 return false;
3750
3751                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3752                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3753
3754                         if (cand_pd.Count != base_pd.Count)
3755                                 return false;
3756
3757                         for (int j = 0; j < cand_pd.Count; ++j)
3758                         {
3759                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3760                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3761                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3762                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3763
3764                                 if (cm != bm || ct != bt)
3765                                         return false;
3766                         }
3767
3768                         return true;
3769                 }
3770
3771                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3772                 {
3773                         MemberInfo [] miset;
3774                         MethodGroupExpr union;
3775
3776                         if (mg1 == null) {
3777                                 if (mg2 == null)
3778                                         return null;
3779                                 return (MethodGroupExpr) mg2;
3780                         } else {
3781                                 if (mg2 == null)
3782                                         return (MethodGroupExpr) mg1;
3783                         }
3784
3785                         MethodGroupExpr left_set = null, right_set = null;
3786                         int length1 = 0, length2 = 0;
3787
3788                         left_set = (MethodGroupExpr) mg1;
3789                         length1 = left_set.Methods.Length;
3790
3791                         right_set = (MethodGroupExpr) mg2;
3792                         length2 = right_set.Methods.Length;
3793
3794                         ArrayList common = new ArrayList ();
3795
3796                         foreach (MethodBase r in right_set.Methods){
3797                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3798                                         common.Add (r);
3799                         }
3800
3801                         miset = new MemberInfo [length1 + length2 - common.Count];
3802                         left_set.Methods.CopyTo (miset, 0);
3803
3804                         int k = length1;
3805
3806                         foreach (MethodBase r in right_set.Methods) {
3807                                 if (!common.Contains (r))
3808                                         miset [k++] = r;
3809                         }
3810
3811                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3812
3813                         return union;
3814                 }
3815
3816                 static Type MoreSpecific (Type p, Type q)
3817                 {
3818                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3819                                 return q;
3820                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3821                                 return p;
3822
3823                         if (TypeManager.HasElementType (p))
3824                         {
3825                                 Type pe = TypeManager.GetElementType (p);
3826                                 Type qe = TypeManager.GetElementType (q);
3827                                 Type specific = MoreSpecific (pe, qe);
3828                                 if (specific == pe)
3829                                         return p;
3830                                 if (specific == qe)
3831                                         return q;
3832                         }
3833                         else if (TypeManager.IsGenericType (p))
3834                         {
3835                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3836                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3837
3838                                 bool p_specific_at_least_once = false;
3839                                 bool q_specific_at_least_once = false;
3840
3841                                 for (int i = 0; i < pargs.Length; i++)
3842                                 {
3843                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3844                                         if (specific == pargs [i])
3845                                                 p_specific_at_least_once = true;
3846                                         if (specific == qargs [i])
3847                                                 q_specific_at_least_once = true;
3848                                 }
3849
3850                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3851                                         return p;
3852                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3853                                         return q;
3854                         }
3855
3856                         return null;
3857                 }
3858
3859                 /// <summary>
3860                 ///   Find the Applicable Function Members (7.4.2.1)
3861                 ///
3862                 ///   me: Method Group expression with the members to select.
3863                 ///       it might contain constructors or methods (or anything
3864                 ///       that maps to a method).
3865                 ///
3866                 ///   Arguments: ArrayList containing resolved Argument objects.
3867                 ///
3868                 ///   loc: The location if we want an error to be reported, or a Null
3869                 ///        location for "probing" purposes.
3870                 ///
3871                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3872                 ///            that is the best match of me on Arguments.
3873                 ///
3874                 /// </summary>
3875                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
3876                         bool may_fail, Location loc)
3877                 {
3878                         bool method_params = false;
3879                         Type applicable_type = null;
3880                         int arg_count = 0;
3881                         ArrayList candidates = new ArrayList (2);
3882                         ArrayList candidate_overrides = null;
3883
3884                         //
3885                         // Used to keep a map between the candidate
3886                         // and whether it is being considered in its
3887                         // normal or expanded form
3888                         //
3889                         // false is normal form, true is expanded form
3890                         //
3891                         Hashtable candidate_to_form = null;
3892
3893                         if (Arguments != null)
3894                                 arg_count = Arguments.Count;
3895
3896                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3897                                 if (!may_fail)
3898                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3899                                 return null;
3900                         }
3901
3902                         int nmethods = Methods.Length;
3903
3904                         if (!IsBase) {
3905                                 //
3906                                 // Methods marked 'override' don't take part in 'applicable_type'
3907                                 // computation, nor in the actual overload resolution.
3908                                 // However, they still need to be emitted instead of a base virtual method.
3909                                 // So, we salt them away into the 'candidate_overrides' array.
3910                                 //
3911                                 // In case of reflected methods, we replace each overriding method with
3912                                 // its corresponding base virtual method.  This is to improve compatibility
3913                                 // with non-C# libraries which change the visibility of overrides (#75636)
3914                                 //
3915                                 int j = 0;
3916                                 for (int i = 0; i < Methods.Length; ++i) {
3917                                         MethodBase m = Methods [i];
3918                                         if (TypeManager.IsOverride (m)) {
3919                                                 if (candidate_overrides == null)
3920                                                         candidate_overrides = new ArrayList ();
3921                                                 candidate_overrides.Add (m);
3922                                                 m = TypeManager.TryGetBaseDefinition (m);
3923                                         }
3924                                         if (m != null)
3925                                                 Methods [j++] = m;
3926                                 }
3927                                 nmethods = j;
3928                         }
3929
3930                         //
3931                         // Enable message recording, it's used mainly by lambda expressions
3932                         //
3933                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
3934                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
3935
3936                         //
3937                         // First we construct the set of applicable methods
3938                         //
3939                         bool is_sorted = true;
3940                         int best_candidate_rate = int.MaxValue;
3941                         for (int i = 0; i < nmethods; i++) {
3942                                 Type decl_type = Methods [i].DeclaringType;
3943
3944                                 //
3945                                 // If we have already found an applicable method
3946                                 // we eliminate all base types (Section 14.5.5.1)
3947                                 //
3948                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
3949                                         continue;
3950
3951                                 //
3952                                 // Check if candidate is applicable (section 14.4.2.1)
3953                                 //
3954                                 bool params_expanded_form = false;
3955                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
3956
3957                                 if (candidate_rate < best_candidate_rate) {
3958                                         best_candidate_rate = candidate_rate;
3959                                         best_candidate = Methods [i];
3960                                 }
3961
3962                                 if (params_expanded_form) {
3963                                         if (candidate_to_form == null)
3964                                                 candidate_to_form = new PtrHashtable ();
3965                                         MethodBase candidate = Methods [i];
3966                                         candidate_to_form [candidate] = candidate;
3967                                 }
3968
3969                                 if (candidate_rate != 0) {
3970                                         if (msg_recorder != null)
3971                                                 msg_recorder.EndSession ();
3972                                         continue;
3973                                 }
3974
3975                                 msg_recorder = null;
3976                                 candidates.Add (Methods [i]);
3977
3978                                 if (applicable_type == null)
3979                                         applicable_type = decl_type;
3980                                 else if (applicable_type != decl_type) {
3981                                         is_sorted = false;
3982                                         if (IsAncestralType (applicable_type, decl_type))
3983                                                 applicable_type = decl_type;
3984                                 }
3985                         }
3986
3987                         Report.SetMessageRecorder (prev_recorder);
3988                         if (msg_recorder != null && msg_recorder.PrintMessages ())
3989                                 return null;
3990
3991                         int candidate_top = candidates.Count;
3992
3993                         if (applicable_type == null) {
3994                                 //
3995                                 // When we found a top level method which does not match and it's
3996                                 // not an extension method. We start extension methods lookup from here
3997                                 //
3998                                 if (InstanceExpression != null) {
3999                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name);
4000                                         if (ex_method_lookup != null) {
4001                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4002                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4003                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4004                                         }
4005                                 }
4006
4007                                 if (may_fail)
4008                                         return null;
4009
4010                                 //
4011                                 // Okay so we have failed to find exact match so we
4012                                 // return error info about the closest match
4013                                 //
4014                                 if (best_candidate != null) {
4015                                         if (CustomErrorHandler != null) {
4016                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4017                                                         return null;
4018                                         }
4019
4020                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4021                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4022                                         if (arg_count == pd.Count || pd.HasParams) {
4023                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4024                                                         if (type_arguments == null) {
4025                                                                 Report.Error (411, loc,
4026                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4027                                                                         "the usage. Try specifying the type arguments explicitly",
4028                                                                         TypeManager.CSharpSignature (best_candidate));
4029                                                                 return null;
4030                                                         }
4031
4032                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4033                                                         if (type_arguments.Count != g_args.Length) {
4034                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4035                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4036                                                                         TypeManager.CSharpSignature (best_candidate),
4037                                                                         g_args.Length.ToString ());
4038                                                                 return null;
4039                                                         }
4040                                                 } else {
4041                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4042                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4043                                                                 return null;
4044                                                         }
4045                                                 }
4046
4047                                                 if (VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4048                                                         throw new InternalErrorException ("Overload verification expected failure");
4049                                                 return null;
4050                                         }
4051                                 }
4052
4053                                 if (almost_matched_members.Count != 0) {
4054                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4055                                         null, MemberTypes.Constructor, AllBindingFlags);
4056                                         return null;
4057                                 }
4058
4059                                 //
4060                                 // We failed to find any method with correct argument count
4061                                 //
4062                                 if (Name == ConstructorInfo.ConstructorName) {
4063                                         Report.SymbolRelatedToPreviousError (type);
4064                                         Report.Error (1729, loc,
4065                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4066                                                 TypeManager.CSharpName (type), arg_count);
4067                                 } else {
4068                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4069                                                 Name, arg_count.ToString ());
4070                                 }
4071
4072                                 return null;
4073                         }
4074
4075                         if (!is_sorted) {
4076                                 //
4077                                 // At this point, applicable_type is _one_ of the most derived types
4078                                 // in the set of types containing the methods in this MethodGroup.
4079                                 // Filter the candidates so that they only contain methods from the
4080                                 // most derived types.
4081                                 //
4082
4083                                 int finalized = 0; // Number of finalized candidates
4084
4085                                 do {
4086                                         // Invariant: applicable_type is a most derived type
4087
4088                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4089                                         // eliminating all it's base types.  At the same time, we'll also move
4090                                         // every unrelated type to the end of the array, and pick the next
4091                                         // 'applicable_type'.
4092
4093                                         Type next_applicable_type = null;
4094                                         int j = finalized; // where to put the next finalized candidate
4095                                         int k = finalized; // where to put the next undiscarded candidate
4096                                         for (int i = finalized; i < candidate_top; ++i) {
4097                                                 MethodBase candidate = (MethodBase) candidates [i];
4098                                                 Type decl_type = candidate.DeclaringType;
4099
4100                                                 if (decl_type == applicable_type) {
4101                                                         candidates [k++] = candidates [j];
4102                                                         candidates [j++] = candidates [i];
4103                                                         continue;
4104                                                 }
4105
4106                                                 if (IsAncestralType (decl_type, applicable_type))
4107                                                         continue;
4108
4109                                                 if (next_applicable_type != null &&
4110                                                         IsAncestralType (decl_type, next_applicable_type))
4111                                                         continue;
4112
4113                                                 candidates [k++] = candidates [i];
4114
4115                                                 if (next_applicable_type == null ||
4116                                                         IsAncestralType (next_applicable_type, decl_type))
4117                                                         next_applicable_type = decl_type;
4118                                         }
4119
4120                                         applicable_type = next_applicable_type;
4121                                         finalized = j;
4122                                         candidate_top = k;
4123                                 } while (applicable_type != null);
4124                         }
4125
4126                         //
4127                         // Now we actually find the best method
4128                         //
4129
4130                         best_candidate = (MethodBase) candidates [0];
4131                         if (delegate_type == null)
4132                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4133
4134                         for (int ix = 1; ix < candidate_top; ix++) {
4135                                 MethodBase candidate = (MethodBase) candidates [ix];
4136
4137                                 if (candidate == best_candidate)
4138                                         continue;
4139
4140                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4141
4142                                 if (BetterFunction (ec, Arguments, arg_count,
4143                                         candidate, cand_params,
4144                                         best_candidate, method_params)) {
4145                                         best_candidate = candidate;
4146                                         method_params = cand_params;
4147                                 }
4148                         }
4149                         //
4150                         // Now check that there are no ambiguities i.e the selected method
4151                         // should be better than all the others
4152                         //
4153                         MethodBase ambiguous = null;
4154                         for (int ix = 0; ix < candidate_top; ix++) {
4155                                 MethodBase candidate = (MethodBase) candidates [ix];
4156
4157                                 if (candidate == best_candidate)
4158                                         continue;
4159
4160                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4161                                 if (!BetterFunction (ec, Arguments, arg_count,
4162                                         best_candidate, method_params,
4163                                         candidate, cand_params))
4164                                 {
4165                                         if (!may_fail)
4166                                                 Report.SymbolRelatedToPreviousError (candidate);
4167                                         ambiguous = candidate;
4168                                 }
4169                         }
4170
4171                         if (ambiguous != null) {
4172                                 Report.SymbolRelatedToPreviousError (best_candidate);
4173                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4174                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4175                                 return this;
4176                         }
4177
4178                         //
4179                         // If the method is a virtual function, pick an override closer to the LHS type.
4180                         //
4181                         if (!IsBase && best_candidate.IsVirtual) {
4182                                 if (TypeManager.IsOverride (best_candidate))
4183                                         throw new InternalErrorException (
4184                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4185
4186                                 if (candidate_overrides != null) {
4187                                         Type[] gen_args = null;
4188                                         bool gen_override = false;
4189                                         if (TypeManager.IsGenericMethod (best_candidate))
4190                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4191
4192                                         foreach (MethodBase candidate in candidate_overrides) {
4193                                                 if (TypeManager.IsGenericMethod (candidate)) {
4194                                                         if (gen_args == null)
4195                                                                 continue;
4196
4197                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4198                                                                 continue;
4199                                                 } else {
4200                                                         if (gen_args != null)
4201                                                                 continue;
4202                                                 }
4203
4204                                                 if (IsOverride (candidate, best_candidate)) {
4205                                                         gen_override = true;
4206                                                         best_candidate = candidate;
4207                                                 }
4208                                         }
4209
4210                                         if (gen_override && gen_args != null) {
4211 #if GMCS_SOURCE
4212                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4213 #endif
4214                                         }
4215                                 }
4216                         }
4217
4218                         //
4219                         // And now check if the arguments are all
4220                         // compatible, perform conversions if
4221                         // necessary etc. and return if everything is
4222                         // all right
4223                         //
4224                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4225                                 method_params, may_fail, loc))
4226                                 return null;
4227
4228                         if (best_candidate == null)
4229                                 return null;
4230
4231                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4232 #if GMCS_SOURCE
4233                         if (the_method.IsGenericMethodDefinition &&
4234                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4235                                 return null;
4236 #endif
4237
4238                         IMethodData data = TypeManager.GetMethod (the_method);
4239                         if (data != null)
4240                                 data.SetMemberIsUsed ();
4241
4242                         return this;
4243                 }
4244
4245                 public override void SetTypeArguments (TypeArguments ta)
4246                 {
4247                         type_arguments = ta;
4248                 }
4249
4250                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4251                                                           int arg_count, MethodBase method,
4252                                                           bool chose_params_expanded,
4253                                                           bool may_fail, Location loc)
4254                 {
4255                         ParameterData pd = TypeManager.GetParameterData (method);
4256
4257                         int errors = Report.Errors;
4258                         Parameter.Modifier p_mod = 0;
4259                         Type pt = null;
4260                         int a_idx = 0, a_pos = 0;
4261                         Argument a = null;
4262                         ArrayList params_initializers = null;
4263
4264                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4265                                 a = (Argument) arguments [a_idx];
4266                                 if (p_mod != Parameter.Modifier.PARAMS) {
4267                                         p_mod = pd.ParameterModifier (a_idx);
4268                                         pt = pd.ParameterType (a_idx);
4269
4270                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4271                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4272                                                         break;
4273                                                 continue;
4274                                         }
4275
4276                                         if (pt.IsPointer && !ec.InUnsafe) {
4277                                                 if (may_fail)
4278                                                         return false;
4279
4280                                                 UnsafeError (loc);
4281                                         }
4282
4283                                         if (p_mod == Parameter.Modifier.PARAMS) {
4284                                                 if (chose_params_expanded) {
4285                                                         params_initializers = new ArrayList (arg_count - a_idx);
4286                                                         pt = TypeManager.GetElementType (pt);
4287                                                 }
4288                                         } else if (p_mod != 0) {
4289                                                 pt = TypeManager.GetElementType (pt);
4290                                         }
4291                                 }
4292
4293                                 //
4294                                 // Types have to be identical when ref or out modifer is used
4295                                 //
4296                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4297                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4298                                                 break;
4299
4300                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4301                                                 break;
4302
4303                                         continue;
4304                                 }
4305
4306                                 Expression conv;
4307                                 if (TypeManager.IsEqual (a.Type, pt)) {
4308                                         conv = a.Expr;
4309                                 } else {
4310                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4311                                         if (conv == null)
4312                                                 break;
4313                                 }
4314
4315                                 //
4316                                 // Convert params arguments to an array initializer
4317                                 //
4318                                 if (params_initializers != null) {
4319                                         params_initializers.Add (conv);
4320                                         arguments.RemoveAt (a_idx--);
4321                                         --arg_count;
4322                                         continue;
4323                                 }
4324
4325                                 // Update the argument with the implicit conversion
4326                                 a.Expr = conv;
4327                         }
4328
4329                         //
4330                         // Fill not provided arguments required by params modifier
4331                         //
4332                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count) {
4333                                 if (arguments == null)
4334                                         arguments = new ArrayList (1);
4335
4336                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4337                                 pt = TypeManager.GetElementType (pt);
4338                                 params_initializers = new ArrayList (0);
4339                         }
4340
4341                         if (a_idx == arg_count) {
4342                                 //
4343                                 // Append an array argument with all params arguments
4344                                 //
4345                                 if (params_initializers != null) {
4346                                         arguments.Add (new Argument (
4347                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4348                                                 params_initializers, loc).Resolve (ec)));
4349                                 }
4350                                 return true;
4351                         }
4352
4353                         if (!may_fail && Report.Errors == errors) {
4354                                 if (CustomErrorHandler != null)
4355                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4356                                 else
4357                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4358                         }
4359                         return false;
4360                 }
4361         }
4362
4363         public class ConstantExpr : MemberExpr
4364         {
4365                 FieldInfo constant;
4366
4367                 public ConstantExpr (FieldInfo constant, Location loc)
4368                 {
4369                         this.constant = constant;
4370                         this.loc = loc;
4371                 }
4372
4373                 public override string Name {
4374                         get { throw new NotImplementedException (); }
4375                 }
4376
4377                 public override bool IsInstance {
4378                         get { return !IsStatic; }
4379                 }
4380
4381                 public override bool IsStatic {
4382                         get { return constant.IsStatic; }
4383                 }
4384
4385                 public override Type DeclaringType {
4386                         get { return constant.DeclaringType; }
4387                 }
4388
4389                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4390                 {
4391                         constant = TypeManager.GetGenericFieldDefinition (constant);
4392
4393                         IConstant ic = TypeManager.GetConstant (constant);
4394                         if (ic == null) {
4395                                 if (constant.IsLiteral) {
4396                                         ic = new ExternalConstant (constant);
4397                                 } else {
4398                                         ic = ExternalConstant.CreateDecimal (constant);
4399                                         // HACK: decimal field was not resolved as constant
4400                                         if (ic == null)
4401                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4402                                 }
4403                                 TypeManager.RegisterConstant (constant, ic);
4404                         }
4405
4406                         return base.ResolveMemberAccess (ec, left, loc, original);
4407                 }
4408
4409                 public override Expression DoResolve (EmitContext ec)
4410                 {
4411                         IConstant ic = TypeManager.GetConstant (constant);
4412                         if (ic.ResolveValue ()) {
4413                                 if (!ec.IsInObsoleteScope)
4414                                         ic.CheckObsoleteness (loc);
4415                         }
4416
4417                         return ic.CreateConstantReference (loc);
4418                 }
4419
4420                 public override void Emit (EmitContext ec)
4421                 {
4422                         throw new NotSupportedException ();
4423                 }
4424
4425                 public override string GetSignatureForError ()
4426                 {
4427                         return TypeManager.GetFullNameSignature (constant);
4428                 }
4429         }
4430
4431         /// <summary>
4432         ///   Fully resolved expression that evaluates to a Field
4433         /// </summary>
4434         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4435                 public readonly FieldInfo FieldInfo;
4436                 VariableInfo variable_info;
4437
4438                 LocalTemporary temp;
4439                 bool prepared;
4440                 bool in_initializer;
4441
4442                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4443                         this (fi, l)
4444                 {
4445                         this.in_initializer = in_initializer;
4446                 }
4447
4448                 public FieldExpr (FieldInfo fi, Location l)
4449                 {
4450                         FieldInfo = fi;
4451                         eclass = ExprClass.Variable;
4452                         type = TypeManager.TypeToCoreType (fi.FieldType);
4453                         loc = l;
4454                 }
4455
4456                 public override string Name {
4457                         get {
4458                                 return FieldInfo.Name;
4459                         }
4460                 }
4461
4462                 public override bool IsInstance {
4463                         get {
4464                                 return !FieldInfo.IsStatic;
4465                         }
4466                 }
4467
4468                 public override bool IsStatic {
4469                         get {
4470                                 return FieldInfo.IsStatic;
4471                         }
4472                 }
4473
4474                 public override Type DeclaringType {
4475                         get {
4476                                 return FieldInfo.DeclaringType;
4477                         }
4478                 }
4479
4480                 public override string GetSignatureForError ()
4481                 {
4482                         return TypeManager.GetFullNameSignature (FieldInfo);
4483                 }
4484
4485                 public VariableInfo VariableInfo {
4486                         get {
4487                                 return variable_info;
4488                         }
4489                 }
4490
4491                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4492                                                                 SimpleName original)
4493                 {
4494                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4495                         Type t = fi.FieldType;
4496
4497                         if (t.IsPointer && !ec.InUnsafe) {
4498                                 UnsafeError (loc);
4499                         }
4500
4501                         return base.ResolveMemberAccess (ec, left, loc, original);
4502                 }
4503
4504                 override public Expression DoResolve (EmitContext ec)
4505                 {
4506                         return DoResolve (ec, false, false);
4507                 }
4508
4509                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4510                 {
4511                         if (!FieldInfo.IsStatic){
4512                                 if (InstanceExpression == null){
4513                                         //
4514                                         // This can happen when referencing an instance field using
4515                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4516                                         //
4517                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4518                                         return null;
4519                                 }
4520
4521                                 // Resolve the field's instance expression while flow analysis is turned
4522                                 // off: when accessing a field "a.b", we must check whether the field
4523                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4524
4525                                 if (lvalue_instance) {
4526                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4527                                                 Expression right_side =
4528                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4529                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4530                                         }
4531                                 } else {
4532                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4533                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4534                                 }
4535
4536                                 if (InstanceExpression == null)
4537                                         return null;
4538
4539                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4540                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4541                                 }
4542                         }
4543
4544                         if (!in_initializer && !ec.IsInFieldInitializer) {
4545                                 ObsoleteAttribute oa;
4546                                 FieldBase f = TypeManager.GetField (FieldInfo);
4547                                 if (f != null) {
4548                                         if (!ec.IsInObsoleteScope)
4549                                                 f.CheckObsoleteness (loc);
4550
4551                                         // To be sure that type is external because we do not register generated fields
4552                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4553                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4554                                         if (oa != null)
4555                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4556                                 }
4557                         }
4558
4559                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4560                         if (am != null){
4561                                 if (!FieldInfo.IsStatic){
4562                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4563                                                 Report.Error (1673, loc,
4564                                                 "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",
4565                                                         "this");
4566                                                 return null;
4567                                         }
4568                                 }
4569                         }
4570
4571                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4572                         if (fb != null) {
4573                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4574                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4575                                 }
4576
4577                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4578                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4579                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4580                                                 TypeManager.GetFullNameSignature (FieldInfo));
4581                                 }
4582
4583                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4584                         }
4585
4586                         // If the instance expression is a local variable or parameter.
4587                         IVariable var = InstanceExpression as IVariable;
4588                         if ((var == null) || (var.VariableInfo == null))
4589                                 return this;
4590
4591                         VariableInfo vi = var.VariableInfo;
4592                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4593                                 return null;
4594
4595                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4596                         return this;
4597                 }
4598
4599                 static readonly int [] codes = {
4600                         191,    // instance, write access
4601                         192,    // instance, out access
4602                         198,    // static, write access
4603                         199,    // static, out access
4604                         1648,   // member of value instance, write access
4605                         1649,   // member of value instance, out access
4606                         1650,   // member of value static, write access
4607                         1651    // member of value static, out access
4608                 };
4609
4610                 static readonly string [] msgs = {
4611                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4612                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4613                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4614                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4615                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4616                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4617                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4618                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4619                 };
4620
4621                 // The return value is always null.  Returning a value simplifies calling code.
4622                 Expression Report_AssignToReadonly (Expression right_side)
4623                 {
4624                         int i = 0;
4625                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4626                                 i += 1;
4627                         if (IsStatic)
4628                                 i += 2;
4629                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4630                                 i += 4;
4631                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4632
4633                         return null;
4634                 }
4635
4636                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4637                 {
4638                         IVariable var = InstanceExpression as IVariable;
4639                         if ((var != null) && (var.VariableInfo != null))
4640                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4641
4642                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4643                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4644
4645                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4646
4647                         if (e == null)
4648                                 return null;
4649
4650                         FieldBase fb = TypeManager.GetField (FieldInfo);
4651                         if (fb != null)
4652                                 fb.SetAssigned ();
4653
4654                         if (FieldInfo.IsInitOnly) {
4655                                 // InitOnly fields can only be assigned in constructors or initializers
4656                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4657                                         return Report_AssignToReadonly (right_side);
4658
4659                                 if (ec.IsConstructor) {
4660                                         Type ctype = ec.TypeContainer.CurrentType;
4661                                         if (ctype == null)
4662                                                 ctype = ec.ContainerType;
4663
4664                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4665                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4666                                                 return Report_AssignToReadonly (right_side);
4667                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4668                                         if (IsStatic && !ec.IsStatic)
4669                                                 return Report_AssignToReadonly (right_side);
4670                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4671                                         if (!IsStatic && !(InstanceExpression is This))
4672                                                 return Report_AssignToReadonly (right_side);
4673                                 }
4674                         }
4675
4676                         if (right_side == EmptyExpression.OutAccess &&
4677                             !IsStatic && !(InstanceExpression is This) && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4678                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4679                                 Report.Warning (197, 1, loc,
4680                                                 "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",
4681                                                 GetSignatureForError ());
4682                         }
4683
4684                         return this;
4685                 }
4686
4687                 public override void CheckMarshalByRefAccess (EmitContext ec)
4688                 {
4689                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4690                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4691                                 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",
4692                                                 GetSignatureForError ());
4693                         }
4694                 }
4695
4696                 public bool VerifyFixed ()
4697                 {
4698                         IVariable variable = InstanceExpression as IVariable;
4699                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4700                         // We defer the InstanceExpression check after the variable check to avoid a
4701                         // separate null check on InstanceExpression.
4702                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4703                 }
4704
4705                 public override int GetHashCode ()
4706                 {
4707                         return FieldInfo.GetHashCode ();
4708                 }
4709
4710                 public override bool Equals (object obj)
4711                 {
4712                         FieldExpr fe = obj as FieldExpr;
4713                         if (fe == null)
4714                                 return false;
4715
4716                         if (FieldInfo != fe.FieldInfo)
4717                                 return false;
4718
4719                         if (InstanceExpression == null || fe.InstanceExpression == null)
4720                                 return true;
4721
4722                         return InstanceExpression.Equals (fe.InstanceExpression);
4723                 }
4724
4725                 public void Emit (EmitContext ec, bool leave_copy)
4726                 {
4727                         ILGenerator ig = ec.ig;
4728                         bool is_volatile = false;
4729
4730                         FieldBase f = TypeManager.GetField (FieldInfo);
4731                         if (f != null){
4732                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4733                                         is_volatile = true;
4734
4735                                 f.SetMemberIsUsed ();
4736                         }
4737
4738                         if (FieldInfo.IsStatic){
4739                                 if (is_volatile)
4740                                         ig.Emit (OpCodes.Volatile);
4741
4742                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4743                         } else {
4744                                 if (!prepared)
4745                                         EmitInstance (ec, false);
4746
4747                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4748                                 if (ff != null) {
4749                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4750                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4751                                 } else {
4752                                         if (is_volatile)
4753                                                 ig.Emit (OpCodes.Volatile);
4754
4755                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4756                                 }
4757                         }
4758
4759                         if (leave_copy) {
4760                                 ec.ig.Emit (OpCodes.Dup);
4761                                 if (!FieldInfo.IsStatic) {
4762                                         temp = new LocalTemporary (this.Type);
4763                                         temp.Store (ec);
4764                                 }
4765                         }
4766                 }
4767
4768                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4769                 {
4770                         FieldAttributes fa = FieldInfo.Attributes;
4771                         bool is_static = (fa & FieldAttributes.Static) != 0;
4772                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4773                         ILGenerator ig = ec.ig;
4774
4775                         if (is_readonly && !ec.IsConstructor){
4776                                 Report_AssignToReadonly (source);
4777                                 return;
4778                         }
4779
4780                         //
4781                         // String concatenation creates a new string instance
4782                         //
4783                         prepared = prepare_for_load && !(source is StringConcat);
4784                         EmitInstance (ec, prepared);
4785
4786                         source.Emit (ec);
4787                         if (leave_copy) {
4788                                 ec.ig.Emit (OpCodes.Dup);
4789                                 if (!FieldInfo.IsStatic) {
4790                                         temp = new LocalTemporary (this.Type);
4791                                         temp.Store (ec);
4792                                 }
4793                         }
4794
4795                         FieldBase f = TypeManager.GetField (FieldInfo);
4796                         if (f != null){
4797                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4798                                         ig.Emit (OpCodes.Volatile);
4799
4800                                 f.SetAssigned ();
4801                         }
4802
4803                         if (is_static)
4804                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4805                         else
4806                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4807
4808                         if (temp != null) {
4809                                 temp.Emit (ec);
4810                                 temp.Release (ec);
4811                         }
4812                 }
4813
4814                 public override void Emit (EmitContext ec)
4815                 {
4816                         Emit (ec, false);
4817                 }
4818
4819                 public void AddressOf (EmitContext ec, AddressOp mode)
4820                 {
4821                         ILGenerator ig = ec.ig;
4822
4823                         FieldBase f = TypeManager.GetField (FieldInfo);
4824                         if (f != null){
4825                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4826                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4827                                                         f.GetSignatureForError ());
4828                                 }
4829
4830                                 if ((mode & AddressOp.Store) != 0)
4831                                         f.SetAssigned ();
4832                                 if ((mode & AddressOp.Load) != 0)
4833                                         f.SetMemberIsUsed ();
4834                         }
4835
4836                         //
4837                         // Handle initonly fields specially: make a copy and then
4838                         // get the address of the copy.
4839                         //
4840                         bool need_copy;
4841                         if (FieldInfo.IsInitOnly){
4842                                 need_copy = true;
4843                                 if (ec.IsConstructor){
4844                                         if (FieldInfo.IsStatic){
4845                                                 if (ec.IsStatic)
4846                                                         need_copy = false;
4847                                         } else
4848                                                 need_copy = false;
4849                                 }
4850                         } else
4851                                 need_copy = false;
4852
4853                         if (need_copy){
4854                                 LocalBuilder local;
4855                                 Emit (ec);
4856                                 local = ig.DeclareLocal (type);
4857                                 ig.Emit (OpCodes.Stloc, local);
4858                                 ig.Emit (OpCodes.Ldloca, local);
4859                                 return;
4860                         }
4861
4862
4863                         if (FieldInfo.IsStatic){
4864                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
4865                         } else {
4866                                 if (!prepared)
4867                                         EmitInstance (ec, false);
4868                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
4869                         }
4870                 }
4871         }
4872
4873
4874         /// <summary>
4875         ///   Expression that evaluates to a Property.  The Assign class
4876         ///   might set the `Value' expression if we are in an assignment.
4877         ///
4878         ///   This is not an LValue because we need to re-write the expression, we
4879         ///   can not take data from the stack and store it.
4880         /// </summary>
4881         public class PropertyExpr : MemberExpr, IAssignMethod {
4882                 public readonly PropertyInfo PropertyInfo;
4883                 MethodInfo getter, setter;
4884                 bool is_static;
4885
4886                 bool resolved;
4887
4888                 LocalTemporary temp;
4889                 bool prepared;
4890
4891                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
4892                 {
4893                         PropertyInfo = pi;
4894                         eclass = ExprClass.PropertyAccess;
4895                         is_static = false;
4896                         loc = l;
4897
4898                         type = TypeManager.TypeToCoreType (pi.PropertyType);
4899
4900                         ResolveAccessors (container_type);
4901                 }
4902
4903                 public override string Name {
4904                         get {
4905                                 return PropertyInfo.Name;
4906                         }
4907                 }
4908
4909                 public override bool IsInstance {
4910                         get {
4911                                 return !is_static;
4912                         }
4913                 }
4914
4915                 public override bool IsStatic {
4916                         get {
4917                                 return is_static;
4918                         }
4919                 }
4920
4921                 public override Expression CreateExpressionTree (EmitContext ec)
4922                 {
4923                         if (IsSingleDimensionalArrayLength ()) {
4924                                 ArrayList args = new ArrayList (1);
4925                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
4926                                 return CreateExpressionFactoryCall ("ArrayLength", args);
4927                         }
4928
4929                         // TODO: it's waiting for PropertyExpr refactoring
4930                         //ArrayList args = new ArrayList (2);
4931                         //args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
4932                         //args.Add (getter expression);
4933                         //return CreateExpressionFactoryCall ("Property", args);
4934                         return base.CreateExpressionTree (ec);
4935                 }
4936
4937                 public override Type DeclaringType {
4938                         get {
4939                                 return PropertyInfo.DeclaringType;
4940                         }
4941                 }
4942
4943                 public override string GetSignatureForError ()
4944                 {
4945                         return TypeManager.GetFullNameSignature (PropertyInfo);
4946                 }
4947
4948                 void FindAccessors (Type invocation_type)
4949                 {
4950                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
4951                                 BindingFlags.Static | BindingFlags.Instance |
4952                                 BindingFlags.DeclaredOnly;
4953
4954                         Type current = PropertyInfo.DeclaringType;
4955                         for (; current != null; current = current.BaseType) {
4956                                 MemberInfo[] group = TypeManager.MemberLookup (
4957                                         invocation_type, invocation_type, current,
4958                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
4959
4960                                 if (group == null)
4961                                         continue;
4962
4963                                 if (group.Length != 1)
4964                                         // Oooops, can this ever happen ?
4965                                         return;
4966
4967                                 PropertyInfo pi = (PropertyInfo) group [0];
4968
4969                                 if (getter == null)
4970                                         getter = pi.GetGetMethod (true);
4971
4972                                 if (setter == null)
4973                                         setter = pi.GetSetMethod (true);
4974
4975                                 MethodInfo accessor = getter != null ? getter : setter;
4976
4977                                 if (!accessor.IsVirtual)
4978                                         return;
4979                         }
4980                 }
4981
4982                 //
4983                 // We also perform the permission checking here, as the PropertyInfo does not
4984                 // hold the information for the accessibility of its setter/getter
4985                 //
4986                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
4987                 void ResolveAccessors (Type container_type)
4988                 {
4989                         FindAccessors (container_type);
4990
4991                         if (getter != null) {
4992                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
4993                                 IMethodData md = TypeManager.GetMethod (the_getter);
4994                                 if (md != null)
4995                                         md.SetMemberIsUsed ();
4996
4997                                 is_static = getter.IsStatic;
4998                         }
4999
5000                         if (setter != null) {
5001                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5002                                 IMethodData md = TypeManager.GetMethod (the_setter);
5003                                 if (md != null)
5004                                         md.SetMemberIsUsed ();
5005
5006                                 is_static = setter.IsStatic;
5007                         }
5008                 }
5009
5010                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5011                 {
5012                         if (is_static) {
5013                                 InstanceExpression = null;
5014                                 return true;
5015                         }
5016
5017                         if (InstanceExpression == null) {
5018                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5019                                 return false;
5020                         }
5021
5022                         InstanceExpression = InstanceExpression.DoResolve (ec);
5023                         if (lvalue_instance && InstanceExpression != null)
5024                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5025
5026                         if (InstanceExpression == null)
5027                                 return false;
5028
5029                         InstanceExpression.CheckMarshalByRefAccess (ec);
5030
5031                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5032                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5033                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5034                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5035                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5036                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5037                                 return false;
5038                         }
5039
5040                         return true;
5041                 }
5042
5043                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5044                 {
5045                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5046                         if (mi is MethodBuilder) {
5047                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5048                                 return;
5049                         }
5050
5051                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5052                         sig.Append ('.');
5053                         ParameterData iparams = TypeManager.GetParameterData (mi);
5054                         sig.Append (getter ? "get_" : "set_");
5055                         sig.Append (Name);
5056                         sig.Append (iparams.GetSignatureForError ());
5057
5058                         Report.SymbolRelatedToPreviousError (mi);
5059                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5060                                 Name, sig.ToString ());
5061                 }
5062
5063                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5064                 {
5065                         bool dummy;
5066                         MethodInfo accessor = lvalue ? setter : getter;
5067                         if (accessor == null && lvalue)
5068                                 accessor = getter;
5069                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5070                 }
5071
5072                 bool IsSingleDimensionalArrayLength ()
5073                 {
5074                         if (getter == TypeManager.system_int_array_get_length ||
5075                                 getter == TypeManager.int_array_get_length) {
5076                                 Type iet = InstanceExpression.Type;
5077
5078                                 //
5079                                 // System.Array.Length can be called, but the Type does not
5080                                 // support invoking GetArrayRank, so test for that case first
5081                                 //
5082                                 return iet != TypeManager.array_type && (iet.GetArrayRank () == 1);
5083                         }
5084
5085                         return false;
5086                 }
5087
5088                 override public Expression DoResolve (EmitContext ec)
5089                 {
5090                         if (resolved)
5091                                 return this;
5092
5093                         if (getter != null){
5094                                 if (TypeManager.GetParameterData (getter).Count != 0){
5095                                         Error_PropertyNotFound (getter, true);
5096                                         return null;
5097                                 }
5098                         }
5099
5100                         if (getter == null){
5101                                 //
5102                                 // The following condition happens if the PropertyExpr was
5103                                 // created, but is invalid (ie, the property is inaccessible),
5104                                 // and we did not want to embed the knowledge about this in
5105                                 // the caller routine.  This only avoids double error reporting.
5106                                 //
5107                                 if (setter == null)
5108                                         return null;
5109
5110                                 if (InstanceExpression != EmptyExpression.Null) {
5111                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5112                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5113                                         return null;
5114                                 }
5115                         }
5116
5117                         bool must_do_cs1540_check = false;
5118                         if (getter != null &&
5119                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5120                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5121                                 if (pm != null && pm.HasCustomAccessModifier) {
5122                                         Report.SymbolRelatedToPreviousError (pm);
5123                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5124                                                 TypeManager.CSharpSignature (getter));
5125                                 }
5126                                 else {
5127                                         Report.SymbolRelatedToPreviousError (getter);
5128                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5129                                 }
5130                                 return null;
5131                         }
5132
5133                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5134                                 return null;
5135
5136                         //
5137                         // Only base will allow this invocation to happen.
5138                         //
5139                         if (IsBase && getter.IsAbstract) {
5140                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5141                                 return null;
5142                         }
5143
5144                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5145                                 UnsafeError (loc);
5146                                 return null;
5147                         }
5148
5149                         resolved = true;
5150
5151                         return this;
5152                 }
5153
5154                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5155                 {
5156                         if (right_side == EmptyExpression.OutAccess) {
5157                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5158                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5159                                             PropertyInfo.Name);
5160                                 } else {
5161                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5162                                               GetSignatureForError ());
5163                                 }
5164                                 return null;
5165                         }
5166
5167                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5168                                 Error_CannotModifyIntermediateExpressionValue (ec);
5169                         }
5170
5171                         if (setter == null){
5172                                 //
5173                                 // The following condition happens if the PropertyExpr was
5174                                 // created, but is invalid (ie, the property is inaccessible),
5175                                 // and we did not want to embed the knowledge about this in
5176                                 // the caller routine.  This only avoids double error reporting.
5177                                 //
5178                                 if (getter == null)
5179                                         return null;
5180                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5181                                               GetSignatureForError ());
5182                                 return null;
5183                         }
5184
5185                         if (TypeManager.GetParameterData (setter).Count != 1){
5186                                 Error_PropertyNotFound (setter, false);
5187                                 return null;
5188                         }
5189
5190                         bool must_do_cs1540_check;
5191                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5192                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5193                                 if (pm != null && pm.HasCustomAccessModifier) {
5194                                         Report.SymbolRelatedToPreviousError (pm);
5195                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5196                                                 TypeManager.CSharpSignature (setter));
5197                                 }
5198                                 else {
5199                                         Report.SymbolRelatedToPreviousError (setter);
5200                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5201                                 }
5202                                 return null;
5203                         }
5204
5205                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5206                                 return null;
5207
5208                         //
5209                         // Only base will allow this invocation to happen.
5210                         //
5211                         if (IsBase && setter.IsAbstract){
5212                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5213                                 return null;
5214                         }
5215
5216                         return this;
5217                 }
5218
5219                 public override void Emit (EmitContext ec)
5220                 {
5221                         Emit (ec, false);
5222                 }
5223
5224                 public void Emit (EmitContext ec, bool leave_copy)
5225                 {
5226                         //
5227                         // Special case: length of single dimension array property is turned into ldlen
5228                         //
5229                         if (IsSingleDimensionalArrayLength ()) {
5230                                 if (!prepared)
5231                                         EmitInstance (ec, false);
5232                                 ec.ig.Emit (OpCodes.Ldlen);
5233                                 ec.ig.Emit (OpCodes.Conv_I4);
5234                                 return;
5235                         }
5236
5237                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5238
5239                         if (leave_copy) {
5240                                 ec.ig.Emit (OpCodes.Dup);
5241                                 if (!is_static) {
5242                                         temp = new LocalTemporary (this.Type);
5243                                         temp.Store (ec);
5244                                 }
5245                         }
5246                 }
5247
5248                 //
5249                 // Implements the IAssignMethod interface for assignments
5250                 //
5251                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5252                 {
5253                         Expression my_source = source;
5254
5255                         if (prepare_for_load) {
5256                                 if (source is StringConcat)
5257                                         EmitInstance (ec, false);
5258                                 else
5259                                         prepared = true;
5260
5261                                 source.Emit (ec);
5262
5263                                 prepared = true;
5264                                 if (leave_copy) {
5265                                         ec.ig.Emit (OpCodes.Dup);
5266                                         if (!is_static) {
5267                                                 temp = new LocalTemporary (this.Type);
5268                                                 temp.Store (ec);
5269                                         }
5270                                 }
5271                         } else if (leave_copy) {
5272                                 source.Emit (ec);
5273                                 temp = new LocalTemporary (this.Type);
5274                                 temp.Store (ec);
5275                                 my_source = temp;
5276                         }
5277
5278                         ArrayList args = new ArrayList (1);
5279                         args.Add (new Argument (my_source, Argument.AType.Expression));
5280
5281                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5282
5283                         if (temp != null) {
5284                                 temp.Emit (ec);
5285                                 temp.Release (ec);
5286                         }
5287                 }
5288         }
5289
5290         /// <summary>
5291         ///   Fully resolved expression that evaluates to an Event
5292         /// </summary>
5293         public class EventExpr : MemberExpr {
5294                 public readonly EventInfo EventInfo;
5295
5296                 bool is_static;
5297                 MethodInfo add_accessor, remove_accessor;
5298
5299                 public EventExpr (EventInfo ei, Location loc)
5300                 {
5301                         EventInfo = ei;
5302                         this.loc = loc;
5303                         eclass = ExprClass.EventAccess;
5304
5305                         add_accessor = TypeManager.GetAddMethod (ei);
5306                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5307                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5308                                 is_static = true;
5309
5310                         if (EventInfo is MyEventBuilder){
5311                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5312                                 type = eb.EventType;
5313                                 eb.SetUsed ();
5314                         } else
5315                                 type = EventInfo.EventHandlerType;
5316                 }
5317
5318                 public override string Name {
5319                         get {
5320                                 return EventInfo.Name;
5321                         }
5322                 }
5323
5324                 public override bool IsInstance {
5325                         get {
5326                                 return !is_static;
5327                         }
5328                 }
5329
5330                 public override bool IsStatic {
5331                         get {
5332                                 return is_static;
5333                         }
5334                 }
5335
5336                 public override Type DeclaringType {
5337                         get {
5338                                 return EventInfo.DeclaringType;
5339                         }
5340                 }
5341
5342                 void Error_AssignmentEventOnly ()
5343                 {
5344                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5345                                 GetSignatureForError ());
5346                 }
5347
5348                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5349                                                                 SimpleName original)
5350                 {
5351                         //
5352                         // If the event is local to this class, we transform ourselves into a FieldExpr
5353                         //
5354
5355                         if (EventInfo.DeclaringType == ec.ContainerType ||
5356                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5357                                 EventField mi = TypeManager.GetEventField (EventInfo);
5358
5359                                 if (mi != null) {
5360                                         if (!ec.IsInObsoleteScope)
5361                                                 mi.CheckObsoleteness (loc);
5362
5363                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5364                                                 Error_AssignmentEventOnly ();
5365
5366                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5367
5368                                         InstanceExpression = null;
5369
5370                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5371                                 }
5372                         }
5373
5374                         if (left is This && !ec.IsInCompoundAssignment)
5375                                 Error_AssignmentEventOnly ();
5376
5377                         return base.ResolveMemberAccess (ec, left, loc, original);
5378                 }
5379
5380
5381                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5382                 {
5383                         if (is_static) {
5384                                 InstanceExpression = null;
5385                                 return true;
5386                         }
5387
5388                         if (InstanceExpression == null) {
5389                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5390                                 return false;
5391                         }
5392
5393                         InstanceExpression = InstanceExpression.DoResolve (ec);
5394                         if (InstanceExpression == null)
5395                                 return false;
5396
5397                         if (IsBase && add_accessor.IsAbstract) {
5398                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5399                                 return false;
5400                         }
5401
5402                         //
5403                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5404                         // However, in the Event case, we reported a CS0122 instead.
5405                         //
5406                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5407                             InstanceExpression.Type != ec.ContainerType &&
5408                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5409                                 Report.SymbolRelatedToPreviousError (EventInfo);
5410                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5411                                 return false;
5412                         }
5413
5414                         return true;
5415                 }
5416
5417                 public bool IsAccessibleFrom (Type invocation_type)
5418                 {
5419                         bool dummy;
5420                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5421                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5422                 }
5423
5424                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5425                 {
5426                         return DoResolve (ec);
5427                 }
5428
5429                 public override Expression DoResolve (EmitContext ec)
5430                 {
5431                         bool must_do_cs1540_check;
5432                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5433                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5434                                 Report.SymbolRelatedToPreviousError (EventInfo);
5435                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5436                                 return null;
5437                         }
5438
5439                         if (!InstanceResolve (ec, must_do_cs1540_check))
5440                                 return null;
5441
5442                         return this;
5443                 }
5444
5445                 public override void Emit (EmitContext ec)
5446                 {
5447                         Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5448                                       "(except on the defining type)", GetSignatureForError ());
5449                 }
5450
5451                 public override string GetSignatureForError ()
5452                 {
5453                         return TypeManager.CSharpSignature (EventInfo);
5454                 }
5455
5456                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5457                 {
5458                         BinaryDelegate source_del = source as BinaryDelegate;
5459                         if (source_del == null) {
5460                                 Emit (ec);
5461                                 return;
5462                         }
5463                         Expression handler = source_del.Right;
5464
5465                         Argument arg = new Argument (handler, Argument.AType.Expression);
5466                         ArrayList args = new ArrayList ();
5467
5468                         args.Add (arg);
5469
5470                         if (source_del.IsAddition)
5471                                 Invocation.EmitCall (
5472                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5473                         else
5474                                 Invocation.EmitCall (
5475                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5476                 }
5477         }
5478
5479         public class TemporaryVariable : Expression, IMemoryLocation
5480         {
5481                 LocalInfo li;
5482                 Variable var;
5483
5484                 public TemporaryVariable (Type type, Location loc)
5485                 {
5486                         this.type = type;
5487                         this.loc = loc;
5488                         eclass = ExprClass.Value;
5489                 }
5490
5491                 public override Expression DoResolve (EmitContext ec)
5492                 {
5493                         if (li != null)
5494                                 return this;
5495
5496                         TypeExpr te = new TypeExpression (type, loc);
5497                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5498                         if (!li.Resolve (ec))
5499                                 return null;
5500
5501                         if (ec.MustCaptureVariable (li)) {
5502                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5503                                 var = scope.AddLocal (li);
5504                                 type = var.Type;
5505                         }
5506
5507                         return this;
5508                 }
5509
5510                 public Variable Variable {
5511                         get { return var != null ? var : li.Variable; }
5512                 }
5513
5514                 public override void Emit (EmitContext ec)
5515                 {
5516                         Variable.EmitInstance (ec);
5517                         Variable.Emit (ec);
5518                 }
5519
5520                 public void EmitLoadAddress (EmitContext ec)
5521                 {
5522                         Variable.EmitInstance (ec);
5523                         Variable.EmitAddressOf (ec);
5524                 }
5525
5526                 public void Store (EmitContext ec, Expression right_side)
5527                 {
5528                         Variable.EmitInstance (ec);
5529                         right_side.Emit (ec);
5530                         Variable.EmitAssign (ec);
5531                 }
5532
5533                 public void EmitThis (EmitContext ec)
5534                 {
5535                         Variable.EmitInstance (ec);
5536                 }
5537
5538                 public void EmitStore (EmitContext ec)
5539                 {
5540                         Variable.EmitAssign (ec);
5541                 }
5542
5543                 public void AddressOf (EmitContext ec, AddressOp mode)
5544                 {
5545                         EmitLoadAddress (ec);
5546                 }
5547         }
5548
5549         ///
5550         /// Handles `var' contextual keyword; var becomes a keyword only
5551         /// if no type called var exists in a variable scope
5552         ///
5553         public class VarExpr : SimpleName
5554         {
5555                 // Used for error reporting only
5556                 ArrayList initializer;
5557
5558                 public VarExpr (Location loc)
5559                         : base ("var", loc)
5560                 {
5561                 }
5562
5563                 public ArrayList VariableInitializer {
5564                         set {
5565                                 this.initializer = value;
5566                         }
5567                 }
5568
5569                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5570                 {
5571                         if (type != null)
5572                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5573
5574                         type = right_side.Type;
5575                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5576                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5577                                               right_side.GetSignatureForError ());
5578                                 return null;
5579                         }
5580
5581                         eclass = ExprClass.Variable;
5582                         return this;
5583                 }
5584
5585                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5586                 {
5587                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5588                 }
5589
5590                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5591                 {
5592                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5593                         if (te != null)
5594                                 return te;
5595
5596                         if (initializer == null)
5597                                 return null;
5598
5599                         if (initializer.Count > 1) {
5600                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5601                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5602                                 initializer = null;
5603                                 return null;
5604                         }
5605
5606                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5607                         if (variable_initializer == null) {
5608                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5609                                 return null;
5610                         }
5611
5612                         return null;
5613                 }
5614         }
5615 }