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 (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 169                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 170                                         return true;
 171                         } else {
 172                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 173                                         return false;
 174                         }
 175
 176                         // Family and FamANDAssem require that we derive.
 177                         // FamORAssem requires that we derive if in different assemblies.
 178                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 179                                 return false;
 180
 181                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 182                                 must_do_cs1540_check = true;
 183
 184                         return true;
 185                 }
 186
 187                 public virtual bool IsNull {
 188                         get {
 189                                 return false;
 190                         }
 191                 }
 192
 193                 /// <summary>
 194                 ///   Performs semantic analysis on the Expression
 195                 /// </summary>
 196                 ///
 197                 /// <remarks>
 198                 ///   The Resolve method is invoked to perform the semantic analysis
 199                 ///   on the node.
 200                 ///
 201                 ///   The return value is an expression (it can be the
 202                 ///   same expression in some cases) or a new
 203                 ///   expression that better represents this node.
 204                 ///
 205                 ///   For example, optimizations of Unary (LiteralInt)
 206                 ///   would return a new LiteralInt with a negated
 207                 ///   value.
 208                 ///
 209                 ///   If there is an error during semantic analysis,
 210                 ///   then an error should be reported (using Report)
 211                 ///   and a null value should be returned.
 212                 ///
 213                 ///   There are two side effects expected from calling
 214                 ///   Resolve(): the the field variable "eclass" should
 215                 ///   be set to any value of the enumeration
 216                 ///   `ExprClass' and the type variable should be set
 217                 ///   to a valid type (this is the type of the
 218                 ///   expression).
 219                 /// </remarks>
 220                 public abstract Expression DoResolve (EmitContext ec);
 221
 222                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 223                 {
 224                         return null;
 225                 }
 226
 227                 //
 228                 // This is used if the expression should be resolved as a type or namespace name.
 229                 // the default implementation fails.
 230                 //
 231                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 232                 {
 233                         if (!silent) {
 234                                 Expression e = this;
 235                                 EmitContext ec = rc as EmitContext;
 236                                 if (ec != null)
 237                                         e = e.Resolve (ec);
 238                                 if (e != null)
 239                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 240                         }
 241                         return null;
 242                 }
 243
 244                 //
 245                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 246                 // same name exists or as a keyword when no type was found
 247                 //
 248                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 249                 {
 250                         return ResolveAsTypeTerminal (rc, silent);
 251                 }
 252
 253                 //
 254                 // This is used to resolve the expression as a type, a null
 255                 // value will be returned if the expression is not a type
 256                 // reference
 257                 //
 258                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 259                 {
 260                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 261                         if (te == null)
 262                                 return null;
 263
 264                         if (!silent) { // && !(te is TypeParameterExpr)) {
 265                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 266                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 267                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 268                                 }
 269                         }
 270
 271                         // Constrains don't need to be checked for overrides
 272                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 273                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 274                                 te.loc = loc;
 275                                 return te;
 276                         }
 277
 278                         ConstructedType ct = te as ConstructedType;
 279                         if ((ct != null) && !ct.CheckConstraints (ec))
 280                                 return null;
 281
 282                         return te;
 283                 }
 284
 285                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 286                 {
 287                         int errors = Report.Errors;
 288
 289                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 290
 291                         if (fne == null)
 292                                 return null;
 293
 294                         if (fne.eclass != ExprClass.Type) {
 295                                 if (!silent && errors == Report.Errors)
 296                                         fne.Error_UnexpectedKind (null, "type", loc);
 297                                 return null;
 298                         }
 299
 300                         TypeExpr te = fne as TypeExpr;
 301
 302                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 303                                 Report.SymbolRelatedToPreviousError (te.Type);
 304                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 305                                 return null;
 306                         }
 307
 308                         te.loc = loc;
 309                         return te;
 310                 }
 311
 312                 public static void ErrorIsInaccesible (Location loc, string name)
 313                 {
 314                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 315                 }
 316
 317                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 318                 {
 319                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 320                                 + " The qualifier must be of type `{2}' or derived from it",
 321                                 TypeManager.GetFullNameSignature (m),
 322                                 TypeManager.CSharpName (qualifier),
 323                                 TypeManager.CSharpName (container));
 324
 325                 }
 326
 327                 public static void Error_InvalidExpressionStatement (Location loc)
 328                 {
 329                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 330                                        "expressions can be used as a statement");
 331                 }
 332
 333                 public void Error_InvalidExpressionStatement ()
 334                 {
 335                         Error_InvalidExpressionStatement (loc);
 336                 }
 337
 338                 protected void Error_CannotAssign (string to, string roContext)
 339                 {
 340                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 341                                 to, roContext);
 342                 }
 343
 344                 public static void Error_VoidInvalidInTheContext (Location loc)
 345                 {
 346                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 347                 }
 348
 349                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 350                 {
 351                         // The error was already reported as CS1660
 352                         if (type == TypeManager.anonymous_method_type)
 353                                 return;
 354
 355                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 356 #if GMCS_SOURCE
 357                                 string sig1 = type.DeclaringMethod == null ?
 358                                         TypeManager.CSharpName (type.DeclaringType) :
 359                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 360                                 string sig2 = target.DeclaringMethod == null ?
 361                                         TypeManager.CSharpName (target.DeclaringType) :
 362                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 363                                 Report.ExtraInformation (loc,
 364                                         String.Format (
 365                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 366                                                 Type.Name, sig1, sig2));
 367 #endif
 368                         } else if (Type.FullName == target.FullName){
 369                                 Report.ExtraInformation (loc,
 370                                         String.Format (
 371                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 372                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 373                         }
 374
 375                         if (expl) {
 376                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 377                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 378                                 return;
 379                         }
 380
 381                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 382                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 383
 384                         if (b ||
 385                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 386                             Convert.ExplicitUnsafe (e, target) != null ||
 387                             (ec != null && Convert.ExplicitUserConversion (ec, this, target, Location.Null) != null))
 388                         {
 389                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 390                                               "An explicit conversion exists (are you missing a cast?)",
 391                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 392                                 return;
 393                         }
 394
 395                         if (Type != TypeManager.string_type && this is Constant && !(this is EmptyConstantCast)) {
 396                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 397                                         ((Constant)(this)).GetValue ().ToString (), TypeManager.CSharpName (target));
 398                                 return;
 399                         }
 400
 401                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 402                                 TypeManager.CSharpName (type),
 403                                 TypeManager.CSharpName (target));
 404                 }
 405
 406                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 407                 {
 408                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 409                                 name);
 410                 }
 411
 412                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 413                 {
 414                         Error_TypeDoesNotContainDefinition (loc, type, name);
 415                 }
 416
 417                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 418                 {
 419                         Report.SymbolRelatedToPreviousError (type);
 420                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 421                                 TypeManager.CSharpName (type), name);
 422                 }
 423
 424                 protected static void Error_ValueAssignment (Location loc)
 425                 {
 426                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 427                 }
 428
 429                 ResolveFlags ExprClassToResolveFlags
 430                 {
 431                         get {
 432                                 switch (eclass) {
 433                                         case ExprClass.Type:
 434                                         case ExprClass.Namespace:
 435                                                 return ResolveFlags.Type;
 436
 437                                         case ExprClass.MethodGroup:
 438                                                 return ResolveFlags.MethodGroup;
 439
 440                                         case ExprClass.Value:
 441                                         case ExprClass.Variable:
 442                                         case ExprClass.PropertyAccess:
 443                                         case ExprClass.EventAccess:
 444                                         case ExprClass.IndexerAccess:
 445                                                 return ResolveFlags.VariableOrValue;
 446
 447                                         default:
 448                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 449                                 }
 450                         }
 451                 }
 452
 453                 /// <summary>
 454                 ///   Resolves an expression and performs semantic analysis on it.
 455                 /// </summary>
 456                 ///
 457                 /// <remarks>
 458                 ///   Currently Resolve wraps DoResolve to perform sanity
 459                 ///   checking and assertion checking on what we expect from Resolve.
 460                 /// </remarks>
 461                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 462                 {
 463                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 464                                 return ResolveAsTypeStep (ec, false);
 465
 466                         bool do_flow_analysis = ec.DoFlowAnalysis;
 467                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 468                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 469                                 do_flow_analysis = false;
 470                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 471                                 omit_struct_analysis = true;
 472
 473                         Expression e;
 474                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 475                                 if (this is SimpleName) {
 476                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 477                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 478                                 } else {
 479                                         e = DoResolve (ec);
 480                                 }
 481                         }
 482
 483                         if (e == null)
 484                                 return null;
 485
 486                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 487                                 e.Error_UnexpectedKind (flags, loc);
 488                                 return null;
 489                         }
 490
 491                         if (e.type == null && !(e is Namespace)) {
 492                                 throw new Exception (
 493                                         "Expression " + e.GetType () +
 494                                         " did not set its type after Resolve\n" +
 495                                         "called from: " + this.GetType ());
 496                         }
 497
 498                         return e;
 499                 }
 500
 501                 /// <summary>
 502                 ///   Resolves an expression and performs semantic analysis on it.
 503                 /// </summary>
 504                 public Expression Resolve (EmitContext ec)
 505                 {
 506                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 507
 508                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 509                                 ((MethodGroupExpr) e).ReportUsageError ();
 510                                 return null;
 511                         }
 512                         return e;
 513                 }
 514
 515                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 516                 {
 517                         Expression e = Resolve (ec);
 518                         if (e == null)
 519                                 return null;
 520
 521                         Constant c = e as Constant;
 522                         if (c != null)
 523                                 return c;
 524
 525                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 526                         return null;
 527                 }
 528
 529                 /// <summary>
 530                 ///   Resolves an expression for LValue assignment
 531                 /// </summary>
 532                 ///
 533                 /// <remarks>
 534                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 535                 ///   checking and assertion checking on what we expect from Resolve
 536                 /// </remarks>
 537                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 538                 {
 539                         int errors = Report.Errors;
 540                         bool out_access = right_side == EmptyExpression.OutAccess;
 541
 542                         Expression e = DoResolveLValue (ec, right_side);
 543
 544                         if (e != null && out_access && !(e is IMemoryLocation)) {
 545                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 546                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 547
 548                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 549                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 550                                 e = null;
 551                         }
 552
 553                         if (e == null) {
 554                                 if (errors == Report.Errors) {
 555                                         if (out_access)
 556                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 557                                         else
 558                                                 Error_ValueAssignment (loc);
 559                                 }
 560                                 return null;
 561                         }
 562
 563                         if (e.eclass == ExprClass.Invalid)
 564                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 565
 566                         if (e.eclass == ExprClass.MethodGroup) {
 567                                 ((MethodGroupExpr) e).ReportUsageError ();
 568                                 return null;
 569                         }
 570
 571                         if ((e.type == null) && !(e is ConstructedType))
 572                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 573
 574                         return e;
 575                 }
 576
 577                 /// <summary>
 578                 ///   Emits the code for the expression
 579                 /// </summary>
 580                 ///
 581                 /// <remarks>
 582                 ///   The Emit method is invoked to generate the code
 583                 ///   for the expression.
 584                 /// </remarks>
 585                 public abstract void Emit (EmitContext ec);
 586
 587                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 588                 {
 589                         Emit (ec);
 590                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 591                 }
 592
 593                 /// <summary>
 594                 ///   Protected constructor.  Only derivate types should
 595                 ///   be able to be created
 596                 /// </summary>
 597
 598                 protected Expression ()
 599                 {
 600                         eclass = ExprClass.Invalid;
 601                         type = null;
 602                 }
 603
 604                 /// <summary>
 605                 ///   Returns a fully formed expression after a MemberLookup
 606                 /// </summary>
 607                 ///
 608                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 609                 {
 610                         if (mi is EventInfo)
 611                                 return new EventExpr ((EventInfo) mi, loc);
 612                         else if (mi is FieldInfo) {
 613                                 FieldInfo fi = (FieldInfo) mi;
 614                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 615                                         return new ConstantExpr (fi, loc);
 616                                 return new FieldExpr (fi, loc);
 617                         } else if (mi is PropertyInfo)
 618                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 619                         else if (mi is Type) {
 620                                 return new TypeExpression ((System.Type) mi, loc);
 621                         }
 622
 623                         return null;
 624                 }
 625
 626                 protected static ArrayList almost_matched_members = new ArrayList (4);
 627
 628                 //
 629                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 630                 //
 631                 // This code could use some optimizations, but we need to do some
 632                 // measurements.  For example, we could use a delegate to `flag' when
 633                 // something can not any longer be a method-group (because it is something
 634                 // else).
 635                 //
 636                 // Return values:
 637                 //     If the return value is an Array, then it is an array of
 638                 //     MethodBases
 639                 //
 640                 //     If the return value is an MemberInfo, it is anything, but a Method
 641                 //
 642                 //     null on error.
 643                 //
 644                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 645                 // the arguments here and have MemberLookup return only the methods that
 646                 // match the argument count/type, unlike we are doing now (we delay this
 647                 // decision).
 648                 //
 649                 // This is so we can catch correctly attempts to invoke instance methods
 650                 // from a static body (scan for error 120 in ResolveSimpleName).
 651                 //
 652                 //
 653                 // FIXME: Potential optimization, have a static ArrayList
 654                 //
 655
 656                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 657                                                        MemberTypes mt, BindingFlags bf, Location loc)
 658                 {
 659                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 660                 }
 661
 662                 //
 663                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 664                 // `qualifier_type' or null to lookup members in the current class.
 665                 //
 666
 667                 public static Expression MemberLookup (Type container_type,
 668                                                        Type qualifier_type, Type queried_type,
 669                                                        string name, MemberTypes mt,
 670                                                        BindingFlags bf, Location loc)
 671                 {
 672                         almost_matched_members.Clear ();
 673
 674                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 675                                                                      queried_type, mt, bf, name, almost_matched_members);
 676
 677                         if (mi == null)
 678                                 return null;
 679
 680                         if (mi.Length > 1) {
 681                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 682                                 ArrayList methods = new ArrayList (2);
 683                                 ArrayList non_methods = null;
 684
 685                                 foreach (MemberInfo m in mi) {
 686                                         if (m is MethodBase) {
 687                                                 methods.Add (m);
 688                                                 continue;
 689                                         }
 690
 691                                         if (non_methods == null) {
 692                                                 non_methods = new ArrayList (2);
 693                                                 non_methods.Add (m);
 694                                                 continue;
 695                                         }
 696
 697                                         foreach (MemberInfo n_m in non_methods) {
 698                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 699                                                         continue;
 700
 701                                                 Report.SymbolRelatedToPreviousError (m);
 702                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 703                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 704                                                 return null;
 705                                         }
 706                                 }
 707
 708                                 if (methods.Count == 0)
 709                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 710
 711                                 if (non_methods != null) {
 712                                         MethodBase method = (MethodBase) methods [0];
 713                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 714                                         if (method.DeclaringType == non_method.DeclaringType) {
 715                                                 // Cannot happen with C# code, but is valid in IL
 716                                                 Report.SymbolRelatedToPreviousError (method);
 717                                                 Report.SymbolRelatedToPreviousError (non_method);
 718                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 719                                                               TypeManager.GetFullNameSignature (non_method),
 720                                                               TypeManager.CSharpSignature (method));
 721                                                 return null;
 722                                         }
 723
 724                                         if (is_interface) {
 725                                                 Report.SymbolRelatedToPreviousError (method);
 726                                                 Report.SymbolRelatedToPreviousError (non_method);
 727                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 728                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 729                                         }
 730                                 }
 731
 732                                 return new MethodGroupExpr (methods, queried_type, loc);
 733                         }
 734
 735                         if (mi [0] is MethodBase)
 736                                 return new MethodGroupExpr (mi, queried_type, loc);
 737
 738                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 739                 }
 740
 741                 public const MemberTypes AllMemberTypes =
 742                         MemberTypes.Constructor |
 743                         MemberTypes.Event       |
 744                         MemberTypes.Field       |
 745                         MemberTypes.Method      |
 746                         MemberTypes.NestedType  |
 747                         MemberTypes.Property;
 748
 749                 public const BindingFlags AllBindingFlags =
 750                         BindingFlags.Public |
 751                         BindingFlags.Static |
 752                         BindingFlags.Instance;
 753
 754                 public static Expression MemberLookup (Type container_type, Type queried_type,
 755                                                        string name, Location loc)
 756                 {
 757                         return MemberLookup (container_type, null, queried_type, name,
 758                                              AllMemberTypes, AllBindingFlags, loc);
 759                 }
 760
 761                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 762                                                        Type queried_type, string name, Location loc)
 763                 {
 764                         return MemberLookup (container_type, qualifier_type, queried_type,
 765                                              name, AllMemberTypes, AllBindingFlags, loc);
 766                 }
 767
 768                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 769                                                        string name, Location loc)
 770                 {
 771                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 772                                              MemberTypes.Method, AllBindingFlags, loc);
 773                 }
 774
 775                 /// <summary>
 776                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 777                 ///   to find a final definition.  If the final definition is not found, we
 778                 ///   look for private members and display a useful debugging message if we
 779                 ///   find it.
 780                 /// </summary>
 781                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 782                                                             Type queried_type, string name,
 783                                                             MemberTypes mt, BindingFlags bf,
 784                                                             Location loc)
 785                 {
 786                         Expression e;
 787
 788                         int errors = Report.Errors;
 789
 790                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 791
 792                         if (e != null || errors != Report.Errors)
 793                                 return e;
 794
 795                         // No errors were reported by MemberLookup, but there was an error.
 796                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 797                                         name, null, mt, bf);
 798                 }
 799
 800                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 801                                                        Type queried_type, string name, string class_name,
 802                                                            MemberTypes mt, BindingFlags bf)
 803                 {
 804                         if (almost_matched_members.Count != 0) {
 805                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 806                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 807                                         for (int j = 0; j < i; ++j) {
 808                                                 if (m == almost_matched_members [j]) {
 809                                                         m = null;
 810                                                         break;
 811                                                 }
 812                                         }
 813                                         if (m == null)
 814                                                 continue;
 815
 816                                         Type declaring_type = m.DeclaringType;
 817
 818                                         Report.SymbolRelatedToPreviousError (m);
 819                                         if (qualifier_type == null) {
 820                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 821                                                               TypeManager.CSharpName (m.DeclaringType),
 822                                                               TypeManager.CSharpName (container_type));
 823
 824                                         } else if (qualifier_type != container_type &&
 825                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 826                                                 // Although a derived class can access protected members of
 827                                                 // its base class it cannot do so through an instance of the
 828                                                 // base class (CS1540).  If the qualifier_type is a base of the
 829                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 830                                                 // then we are in this situation.
 831                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 832                                         } else {
 833                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 834                                         }
 835                                 }
 836                                 almost_matched_members.Clear ();
 837                                 return null;
 838                         }
 839
 840                         MemberInfo[] lookup = null;
 841                         if (queried_type == null) {
 842                                 class_name = "global::";
 843                         } else {
 844                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 845                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 846                                         name, null);
 847
 848                                 if (lookup != null) {
 849                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 850                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 851                                         return Error_MemberLookupFailed (lookup);
 852                                 }
 853
 854                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 855                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 856                                         name, null);
 857                         }
 858
 859                         if (lookup == null) {
 860                                 if (class_name != null) {
 861                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 862                                                 name);
 863                                 } else {
 864                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 865                                 }
 866                                 return null;
 867                         }
 868
 869                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 870                                                       AllMemberTypes, AllBindingFlags |
 871                                                       BindingFlags.NonPublic, name, null) == null) {
 872                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 873                                         Type t = (Type) lookup [0];
 874
 875                                         Report.Error (305, loc,
 876                                                       "Using the generic type `{0}' " +
 877                                                       "requires {1} type arguments",
 878                                                       TypeManager.CSharpName (t),
 879                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 880                                         return null;
 881                                 }
 882                         }
 883
 884                         return Error_MemberLookupFailed (lookup);
 885                 }
 886
 887                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 888                 {
 889                         for (int i = 0; i < members.Length; ++i) {
 890                                 if (!(members [i] is MethodBase))
 891                                         return null;
 892                         }
 893
 894                         // By default propagate the closest candidates upwards
 895                         return new MethodGroupExpr (members, type, loc);
 896                 }
 897
 898                 protected virtual void Error_NegativeArrayIndex (Location loc)
 899                 {
 900                         throw new NotImplementedException ();
 901                 }
 902
 903                 /// <summary>
 904                 ///   Returns an expression that can be used to invoke operator true
 905                 ///   on the expression if it exists.
 906                 /// </summary>
 907                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 908                 {
 909                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 910                 }
 911
 912                 /// <summary>
 913                 ///   Returns an expression that can be used to invoke operator false
 914                 ///   on the expression if it exists.
 915                 /// </summary>
 916                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 917                 {
 918                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 919                 }
 920
 921                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 922                 {
 923                         MethodGroupExpr operator_group;
 924                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 925                         if (operator_group == null)
 926                                 return null;
 927
 928                         ArrayList arguments = new ArrayList (1);
 929                         arguments.Add (new Argument (e, Argument.AType.Expression));
 930                         operator_group = operator_group.OverloadResolve (
 931                                 ec, ref arguments, false, loc);
 932
 933                         if (operator_group == null)
 934                                 return null;
 935
 936                         return new UserOperatorCall (operator_group, arguments, null, loc);
 937                 }
 938
 939                 /// <summary>
 940                 ///   Resolves the expression `e' into a boolean expression: either through
 941                 ///   an implicit conversion, or through an `operator true' invocation
 942                 /// </summary>
 943                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 944                 {
 945                         e = e.Resolve (ec);
 946                         if (e == null)
 947                                 return null;
 948
 949                         if (e.Type == TypeManager.bool_type)
 950                                 return e;
 951
 952                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 953
 954                         if (converted != null)
 955                                 return converted;
 956
 957                         //
 958                         // If no implicit conversion to bool exists, try using `operator true'
 959                         //
 960                         converted = Expression.GetOperatorTrue (ec, e, loc);
 961                         if (converted == null){
 962                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 963                                 return null;
 964                         }
 965                         return converted;
 966                 }
 967
 968                 public virtual string ExprClassName
 969                 {
 970                         get {
 971                                 switch (eclass){
 972                                         case ExprClass.Invalid:
 973                                                 return "Invalid";
 974                                         case ExprClass.Value:
 975                                                 return "value";
 976                                         case ExprClass.Variable:
 977                                                 return "variable";
 978                                         case ExprClass.Namespace:
 979                                                 return "namespace";
 980                                         case ExprClass.Type:
 981                                                 return "type";
 982                                         case ExprClass.MethodGroup:
 983                                                 return "method group";
 984                                         case ExprClass.PropertyAccess:
 985                                                 return "property access";
 986                                         case ExprClass.EventAccess:
 987                                                 return "event access";
 988                                         case ExprClass.IndexerAccess:
 989                                                 return "indexer access";
 990                                         case ExprClass.Nothing:
 991                                                 return "null";
 992                                 }
 993                                 throw new Exception ("Should not happen");
 994                         }
 995                 }
 996
 997                 /// <summary>
 998                 ///   Reports that we were expecting `expr' to be of class `expected'
 999                 /// </summary>
1000                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1001                 {
1002                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1003                 }
1004
1005                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1006                 {
1007                         string name = GetSignatureForError ();
1008                         if (ds != null)
1009                                 name = ds.GetSignatureForError () + '.' + name;
1010
1011                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1012                               name, was, expected);
1013                 }
1014
1015                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1016                 {
1017                         string [] valid = new string [4];
1018                         int count = 0;
1019
1020                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1021                                 valid [count++] = "variable";
1022                                 valid [count++] = "value";
1023                         }
1024
1025                         if ((flags & ResolveFlags.Type) != 0)
1026                                 valid [count++] = "type";
1027
1028                         if ((flags & ResolveFlags.MethodGroup) != 0)
1029                                 valid [count++] = "method group";
1030
1031                         if (count == 0)
1032                                 valid [count++] = "unknown";
1033
1034                         StringBuilder sb = new StringBuilder (valid [0]);
1035                         for (int i = 1; i < count - 1; i++) {
1036                                 sb.Append ("', `");
1037                                 sb.Append (valid [i]);
1038                         }
1039                         if (count > 1) {
1040                                 sb.Append ("' or `");
1041                                 sb.Append (valid [count - 1]);
1042                         }
1043
1044                         Report.Error (119, loc,
1045                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1046                 }
1047
1048                 public static void UnsafeError (Location loc)
1049                 {
1050                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1051                 }
1052
1053                 //
1054                 // Load the object from the pointer.
1055                 //
1056                 public static void LoadFromPtr (ILGenerator ig, Type t)
1057                 {
1058                         if (t == TypeManager.int32_type)
1059                                 ig.Emit (OpCodes.Ldind_I4);
1060                         else if (t == TypeManager.uint32_type)
1061                                 ig.Emit (OpCodes.Ldind_U4);
1062                         else if (t == TypeManager.short_type)
1063                                 ig.Emit (OpCodes.Ldind_I2);
1064                         else if (t == TypeManager.ushort_type)
1065                                 ig.Emit (OpCodes.Ldind_U2);
1066                         else if (t == TypeManager.char_type)
1067                                 ig.Emit (OpCodes.Ldind_U2);
1068                         else if (t == TypeManager.byte_type)
1069                                 ig.Emit (OpCodes.Ldind_U1);
1070                         else if (t == TypeManager.sbyte_type)
1071                                 ig.Emit (OpCodes.Ldind_I1);
1072                         else if (t == TypeManager.uint64_type)
1073                                 ig.Emit (OpCodes.Ldind_I8);
1074                         else if (t == TypeManager.int64_type)
1075                                 ig.Emit (OpCodes.Ldind_I8);
1076                         else if (t == TypeManager.float_type)
1077                                 ig.Emit (OpCodes.Ldind_R4);
1078                         else if (t == TypeManager.double_type)
1079                                 ig.Emit (OpCodes.Ldind_R8);
1080                         else if (t == TypeManager.bool_type)
1081                                 ig.Emit (OpCodes.Ldind_I1);
1082                         else if (t == TypeManager.intptr_type)
1083                                 ig.Emit (OpCodes.Ldind_I);
1084                         else if (TypeManager.IsEnumType (t)) {
1085                                 if (t == TypeManager.enum_type)
1086                                         ig.Emit (OpCodes.Ldind_Ref);
1087                                 else
1088                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1089                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1090                                 ig.Emit (OpCodes.Ldobj, t);
1091                         else if (t.IsPointer)
1092                                 ig.Emit (OpCodes.Ldind_I);
1093                         else
1094                                 ig.Emit (OpCodes.Ldind_Ref);
1095                 }
1096
1097                 //
1098                 // The stack contains the pointer and the value of type `type'
1099                 //
1100                 public static void StoreFromPtr (ILGenerator ig, Type type)
1101                 {
1102                         if (TypeManager.IsEnumType (type))
1103                                 type = TypeManager.GetEnumUnderlyingType (type);
1104                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1105                                 ig.Emit (OpCodes.Stind_I4);
1106                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1107                                 ig.Emit (OpCodes.Stind_I8);
1108                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1109                                  type == TypeManager.ushort_type)
1110                                 ig.Emit (OpCodes.Stind_I2);
1111                         else if (type == TypeManager.float_type)
1112                                 ig.Emit (OpCodes.Stind_R4);
1113                         else if (type == TypeManager.double_type)
1114                                 ig.Emit (OpCodes.Stind_R8);
1115                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1116                                  type == TypeManager.bool_type)
1117                                 ig.Emit (OpCodes.Stind_I1);
1118                         else if (type == TypeManager.intptr_type)
1119                                 ig.Emit (OpCodes.Stind_I);
1120                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1121                                 ig.Emit (OpCodes.Stobj, type);
1122                         else
1123                                 ig.Emit (OpCodes.Stind_Ref);
1124                 }
1125
1126                 //
1127                 // Returns the size of type `t' if known, otherwise, 0
1128                 //
1129                 public static int GetTypeSize (Type t)
1130                 {
1131                         t = TypeManager.TypeToCoreType (t);
1132                         if (t == TypeManager.int32_type ||
1133                             t == TypeManager.uint32_type ||
1134                             t == TypeManager.float_type)
1135                                 return 4;
1136                         else if (t == TypeManager.int64_type ||
1137                                  t == TypeManager.uint64_type ||
1138                                  t == TypeManager.double_type)
1139                                 return 8;
1140                         else if (t == TypeManager.byte_type ||
1141                                  t == TypeManager.sbyte_type ||
1142                                  t == TypeManager.bool_type)
1143                                 return 1;
1144                         else if (t == TypeManager.short_type ||
1145                                  t == TypeManager.char_type ||
1146                                  t == TypeManager.ushort_type)
1147                                 return 2;
1148                         else if (t == TypeManager.decimal_type)
1149                                 return 16;
1150                         else
1151                                 return 0;
1152                 }
1153
1154                 protected void Error_CannotCallAbstractBase (string name)
1155                 {
1156                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1157                 }
1158
1159                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1160                 {
1161                         Report.SymbolRelatedToPreviousError (type);
1162                         if (ec.CurrentInitializerVariable != null) {
1163                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1164                                         GetSignatureForError ());
1165                         } else {
1166                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1167                                         GetSignatureForError ());
1168                         }
1169                 }
1170
1171                 //
1172                 // Converts `source' to an int, uint, long or ulong.
1173                 //
1174                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1175                 {
1176                         Expression converted;
1177
1178                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1179                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1180                                 if (converted == null)
1181                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1182                                 if (converted == null)
1183                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1184                                 if (converted == null)
1185                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1186
1187                                 if (converted == null) {
1188                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1189                                         return null;
1190                                 }
1191                         }
1192
1193                         //
1194                         // Only positive constants are allowed at compile time
1195                         //
1196                         Constant c = converted as Constant;
1197                         if (c != null) {
1198                                 if (c.IsNegative) {
1199                                         Error_NegativeArrayIndex (source.loc);
1200                                 }
1201                                 return c;
1202                         }
1203
1204                         return new ArrayIndexCast (converted).Resolve (ec);
1205                 }
1206
1207                 //
1208                 // Derived classes implement this method by cloning the fields that
1209                 // could become altered during the Resolve stage
1210                 //
1211                 // Only expressions that are created for the parser need to implement
1212                 // this.
1213                 //
1214                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1215                 {
1216                         throw new NotImplementedException (
1217                                 String.Format (
1218                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1219                 }
1220
1221                 //
1222                 // Clones an expression created by the parser.
1223                 //
1224                 // We only support expressions created by the parser so far, not
1225                 // expressions that have been resolved (many more classes would need
1226                 // to implement CloneTo).
1227                 //
1228                 // This infrastructure is here merely for Lambda expressions which
1229                 // compile the same code using different type values for the same
1230                 // arguments to find the correct overload
1231                 //
1232                 public Expression Clone (CloneContext clonectx)
1233                 {
1234                         Expression cloned = (Expression) MemberwiseClone ();
1235                         CloneTo (clonectx, cloned);
1236
1237                         return cloned;
1238                 }
1239
1240                 public virtual Expression CreateExpressionTree (EmitContext ec)
1241                 {
1242                         throw new NotImplementedException (
1243                                 "Expression tree conversion not implemented for " + GetType ());
1244                 }
1245
1246                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1247                 {
1248                         return CreateExpressionFactoryCall (name, null, args, loc);
1249                 }
1250
1251                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1252                 {
1253                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1254                 }
1255
1256                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1257                 {
1258                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1259                 }
1260
1261                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1262                 {
1263                         TypeExpr texpr = TypeManager.expression_type_expr;
1264                         if (texpr == null) {
1265                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1266                                 if (t == null)
1267                                         return null;
1268
1269                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1270                         }
1271
1272                         return texpr;
1273                 }
1274         }
1275
1276         /// <summary>
1277         ///   This is just a base class for expressions that can
1278         ///   appear on statements (invocations, object creation,
1279         ///   assignments, post/pre increment and decrement).  The idea
1280         ///   being that they would support an extra Emition interface that
1281         ///   does not leave a result on the stack.
1282         /// </summary>
1283         public abstract class ExpressionStatement : Expression {
1284
1285                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1286                 {
1287                         Expression e = Resolve (ec);
1288                         if (e == null)
1289                                 return null;
1290
1291                         ExpressionStatement es = e as ExpressionStatement;
1292                         if (es == null)
1293                                 Error_InvalidExpressionStatement ();
1294
1295                         return es;
1296                 }
1297
1298                 /// <summary>
1299                 ///   Requests the expression to be emitted in a `statement'
1300                 ///   context.  This means that no new value is left on the
1301                 ///   stack after invoking this method (constrasted with
1302                 ///   Emit that will always leave a value on the stack).
1303                 /// </summary>
1304                 public abstract void EmitStatement (EmitContext ec);
1305         }
1306
1307         /// <summary>
1308         ///   This kind of cast is used to encapsulate the child
1309         ///   whose type is child.Type into an expression that is
1310         ///   reported to return "return_type".  This is used to encapsulate
1311         ///   expressions which have compatible types, but need to be dealt
1312         ///   at higher levels with.
1313         ///
1314         ///   For example, a "byte" expression could be encapsulated in one
1315         ///   of these as an "unsigned int".  The type for the expression
1316         ///   would be "unsigned int".
1317         ///
1318         /// </summary>
1319         public class EmptyCast : Expression
1320         {
1321                 protected Expression child;
1322
1323                 protected EmptyCast (Expression child, Type return_type)
1324                 {
1325                         eclass = child.eclass;
1326                         loc = child.Location;
1327                         type = return_type;
1328                         this.child = child;
1329                 }
1330
1331                 public static Expression Create (Expression child, Type type)
1332                 {
1333                         Constant c = child as Constant;
1334                         if (c != null)
1335                                 return new EmptyConstantCast (c, type);
1336
1337                         return new EmptyCast (child, type);
1338                 }
1339
1340                 public override Expression CreateExpressionTree (EmitContext ec)
1341                 {
1342                         ArrayList args = new ArrayList (2);
1343                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1344                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1345                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1346                 }
1347
1348                 public override Expression DoResolve (EmitContext ec)
1349                 {
1350                         // This should never be invoked, we are born in fully
1351                         // initialized state.
1352
1353                         return this;
1354                 }
1355
1356                 public override void Emit (EmitContext ec)
1357                 {
1358                         child.Emit (ec);
1359                 }
1360
1361                 public override bool GetAttributableValue (Type value_type, out object value)
1362                 {
1363                         return child.GetAttributableValue (value_type, out value);
1364                 }
1365
1366                 protected override void CloneTo (CloneContext clonectx, Expression t)
1367                 {
1368                         EmptyCast target = (EmptyCast) t;
1369
1370                         target.child = child.Clone (clonectx);
1371                 }
1372         }
1373
1374         /// <summary>
1375         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1376         /// </summary>
1377         public class OperatorCast : EmptyCast {
1378                 MethodInfo conversion_operator;
1379                 bool find_explicit;
1380
1381                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1382
1383                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1384                         : base (child, target_type)
1385                 {
1386                         this.find_explicit = find_explicit;
1387                 }
1388
1389                 // Returns the implicit operator that converts from
1390                 // 'child.Type' to our target type (type)
1391                 MethodInfo GetConversionOperator (bool find_explicit)
1392                 {
1393                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1394
1395                         MemberInfo [] mi;
1396
1397                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1398                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1399
1400                         if (mi == null){
1401                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1402                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1403                         }
1404
1405                         foreach (MethodInfo oper in mi) {
1406                                 ParameterData pd = TypeManager.GetParameterData (oper);
1407
1408                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1409                                         return oper;
1410                         }
1411
1412                         return null;
1413
1414
1415                 }
1416                 public override void Emit (EmitContext ec)
1417                 {
1418                         ILGenerator ig = ec.ig;
1419
1420                         child.Emit (ec);
1421                         conversion_operator = GetConversionOperator (find_explicit);
1422
1423                         if (conversion_operator == null)
1424                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1425
1426                         ig.Emit (OpCodes.Call, conversion_operator);
1427                 }
1428
1429         }
1430
1431         /// <summary>
1432         ///     This is a numeric cast to a Decimal
1433         /// </summary>
1434         public class CastToDecimal : EmptyCast {
1435                 MethodInfo conversion_operator;
1436
1437                 public CastToDecimal (Expression child)
1438                         : this (child, false)
1439                 {
1440                 }
1441
1442                 public CastToDecimal (Expression child, bool find_explicit)
1443                         : base (child, TypeManager.decimal_type)
1444                 {
1445                         conversion_operator = GetConversionOperator (find_explicit);
1446
1447                         if (conversion_operator == null)
1448                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1449                 }
1450
1451                 // Returns the implicit operator that converts from
1452                 // 'child.Type' to System.Decimal.
1453                 MethodInfo GetConversionOperator (bool find_explicit)
1454                 {
1455                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1456
1457                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1458                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1459
1460                         foreach (MethodInfo oper in mi) {
1461                                 ParameterData pd = TypeManager.GetParameterData (oper);
1462
1463                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1464                                         return oper;
1465                         }
1466
1467                         return null;
1468                 }
1469                 public override void Emit (EmitContext ec)
1470                 {
1471                         ILGenerator ig = ec.ig;
1472                         child.Emit (ec);
1473
1474                         ig.Emit (OpCodes.Call, conversion_operator);
1475                 }
1476         }
1477
1478         /// <summary>
1479         ///     This is an explicit numeric cast from a Decimal
1480         /// </summary>
1481         public class CastFromDecimal : EmptyCast
1482         {
1483                 static IDictionary operators;
1484
1485                 public CastFromDecimal (Expression child, Type return_type)
1486                         : base (child, return_type)
1487                 {
1488                         if (child.Type != TypeManager.decimal_type)
1489                                 throw new InternalErrorException (
1490                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1491                 }
1492
1493                 // Returns the explicit operator that converts from an
1494                 // express of type System.Decimal to 'type'.
1495                 public Expression Resolve ()
1496                 {
1497                         if (operators == null) {
1498                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1499                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1500                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1501
1502                                 operators = new System.Collections.Specialized.HybridDictionary ();
1503                                 foreach (MethodInfo oper in all_oper) {
1504                                         ParameterData pd = TypeManager.GetParameterData (oper);
1505                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1506                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1507                                 }
1508                         }
1509
1510                         return operators.Contains (type) ? this : null;
1511                 }
1512
1513                 public override void Emit (EmitContext ec)
1514                 {
1515                         ILGenerator ig = ec.ig;
1516                         child.Emit (ec);
1517
1518                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1519                 }
1520         }
1521
1522
1523         //
1524         // Constant specialization of EmptyCast.
1525         // We need to special case this since an empty cast of
1526         // a constant is still a constant.
1527         //
1528         public class EmptyConstantCast : Constant
1529         {
1530                 public readonly Constant child;
1531
1532                 public EmptyConstantCast(Constant child, Type type)
1533                         : base (child.Location)
1534                 {
1535                         eclass = child.eclass;
1536                         this.child = child;
1537                         this.type = type;
1538                 }
1539
1540                 public override string AsString ()
1541                 {
1542                         return child.AsString ();
1543                 }
1544
1545                 public override object GetValue ()
1546                 {
1547                         return child.GetValue ();
1548                 }
1549
1550                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1551                 {
1552                         // FIXME: check that 'type' can be converted to 'target_type' first
1553                         return child.ConvertExplicitly (in_checked_context, target_type);
1554                 }
1555
1556                 public override Expression CreateExpressionTree (EmitContext ec)
1557                 {
1558                         ArrayList args = new ArrayList (2);
1559                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1560                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1561                         return CreateExpressionFactoryCall ("Convert", args);
1562                 }
1563
1564                 public override Constant Increment ()
1565                 {
1566                         return child.Increment ();
1567                 }
1568
1569                 public override bool IsDefaultValue {
1570                         get { return child.IsDefaultValue; }
1571                 }
1572
1573                 public override bool IsNegative {
1574                         get { return child.IsNegative; }
1575                 }
1576
1577                 public override bool IsNull {
1578                         get { return child.IsNull; }
1579                 }
1580
1581                 public override bool IsZeroInteger {
1582                         get { return child.IsZeroInteger; }
1583                 }
1584
1585                 public override void Emit (EmitContext ec)
1586                 {
1587                         child.Emit (ec);
1588                 }
1589
1590                 public override Constant ConvertImplicitly (Type target_type)
1591                 {
1592                         // FIXME: Do we need to check user conversions?
1593                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1594                                 return null;
1595                         return child.ConvertImplicitly (target_type);
1596                 }
1597         }
1598
1599
1600         /// <summary>
1601         ///  This class is used to wrap literals which belong inside Enums
1602         /// </summary>
1603         public class EnumConstant : Constant {
1604                 public Constant Child;
1605
1606                 public EnumConstant (Constant child, Type enum_type):
1607                         base (child.Location)
1608                 {
1609                         eclass = child.eclass;
1610                         this.Child = child;
1611                         type = enum_type;
1612                 }
1613
1614                 public override Expression DoResolve (EmitContext ec)
1615                 {
1616                         // This should never be invoked, we are born in fully
1617                         // initialized state.
1618
1619                         return this;
1620                 }
1621
1622                 public override void Emit (EmitContext ec)
1623                 {
1624                         Child.Emit (ec);
1625                 }
1626
1627                 public override bool GetAttributableValue (Type value_type, out object value)
1628                 {
1629                         value = GetTypedValue ();
1630                         return true;
1631                 }
1632
1633                 public override string GetSignatureForError()
1634                 {
1635                         return TypeManager.CSharpName (Type);
1636                 }
1637
1638                 public override object GetValue ()
1639                 {
1640                         return Child.GetValue ();
1641                 }
1642
1643                 public override object GetTypedValue ()
1644                 {
1645                         // FIXME: runtime is not ready to work with just emited enums
1646                         if (!RootContext.StdLib) {
1647                                 return Child.GetValue ();
1648                         }
1649
1650                         return System.Enum.ToObject (type, Child.GetValue ());
1651                 }
1652
1653                 public override string AsString ()
1654                 {
1655                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1656                 }
1657
1658                 public override Constant Increment()
1659                 {
1660                         return new EnumConstant (Child.Increment (), type);
1661                 }
1662
1663                 public override bool IsDefaultValue {
1664                         get {
1665                                 return Child.IsDefaultValue;
1666                         }
1667                 }
1668
1669                 public override bool IsZeroInteger {
1670                         get { return Child.IsZeroInteger; }
1671                 }
1672
1673                 public override bool IsNegative {
1674                         get {
1675                                 return Child.IsNegative;
1676                         }
1677                 }
1678
1679                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1680                 {
1681                         if (Child.Type == target_type)
1682                                 return Child;
1683
1684                         return Child.ConvertExplicitly (in_checked_context, target_type);
1685                 }
1686
1687                 public override Constant ConvertImplicitly (Type type)
1688                 {
1689                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1690                         type = TypeManager.DropGenericTypeArguments (type);
1691
1692                         if (this_type == type) {
1693                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1694                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1695                                         return this;
1696
1697                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1698                                 if (type.UnderlyingSystemType != child_type)
1699                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1700                                 return this;
1701                         }
1702
1703                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1704                                 return null;
1705                         }
1706
1707                         return Child.ConvertImplicitly(type);
1708                 }
1709
1710         }
1711
1712         /// <summary>
1713         ///   This kind of cast is used to encapsulate Value Types in objects.
1714         ///
1715         ///   The effect of it is to box the value type emitted by the previous
1716         ///   operation.
1717         /// </summary>
1718         public class BoxedCast : EmptyCast {
1719
1720                 public BoxedCast (Expression expr, Type target_type)
1721                         : base (expr, target_type)
1722                 {
1723                         eclass = ExprClass.Value;
1724                 }
1725
1726                 public override Expression DoResolve (EmitContext ec)
1727                 {
1728                         // This should never be invoked, we are born in fully
1729                         // initialized state.
1730
1731                         return this;
1732                 }
1733
1734                 public override void Emit (EmitContext ec)
1735                 {
1736                         base.Emit (ec);
1737
1738                         ec.ig.Emit (OpCodes.Box, child.Type);
1739                 }
1740         }
1741
1742         public class UnboxCast : EmptyCast {
1743                 public UnboxCast (Expression expr, Type return_type)
1744                         : base (expr, return_type)
1745                 {
1746                 }
1747
1748                 public override Expression DoResolve (EmitContext ec)
1749                 {
1750                         // This should never be invoked, we are born in fully
1751                         // initialized state.
1752
1753                         return this;
1754                 }
1755
1756                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1757                 {
1758                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1759                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1760                         return base.DoResolveLValue (ec, right_side);
1761                 }
1762
1763                 public override void Emit (EmitContext ec)
1764                 {
1765                         Type t = type;
1766                         ILGenerator ig = ec.ig;
1767
1768                         base.Emit (ec);
1769 #if GMCS_SOURCE
1770                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1771                                 ig.Emit (OpCodes.Unbox_Any, t);
1772                         else
1773 #endif
1774                         {
1775                                 ig.Emit (OpCodes.Unbox, t);
1776
1777                                 LoadFromPtr (ig, t);
1778                         }
1779                 }
1780         }
1781
1782         /// <summary>
1783         ///   This is used to perform explicit numeric conversions.
1784         ///
1785         ///   Explicit numeric conversions might trigger exceptions in a checked
1786         ///   context, so they should generate the conv.ovf opcodes instead of
1787         ///   conv opcodes.
1788         /// </summary>
1789         public class ConvCast : EmptyCast {
1790                 public enum Mode : byte {
1791                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1792                         U1_I1, U1_CH,
1793                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1794                         U2_I1, U2_U1, U2_I2, U2_CH,
1795                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1796                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1797                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1798                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1799                         CH_I1, CH_U1, CH_I2,
1800                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1801                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1802                 }
1803
1804                 Mode mode;
1805
1806                 public ConvCast (Expression child, Type return_type, Mode m)
1807                         : base (child, return_type)
1808                 {
1809                         mode = m;
1810                 }
1811
1812                 public override Expression DoResolve (EmitContext ec)
1813                 {
1814                         // This should never be invoked, we are born in fully
1815                         // initialized state.
1816
1817                         return this;
1818                 }
1819
1820                 public override string ToString ()
1821                 {
1822                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1823                 }
1824
1825                 public override void Emit (EmitContext ec)
1826                 {
1827                         ILGenerator ig = ec.ig;
1828
1829                         base.Emit (ec);
1830
1831                         if (ec.CheckState){
1832                                 switch (mode){
1833                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1834                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1835                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1836                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1837                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1838
1839                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1840                                 case Mode.U1_CH: /* nothing */ break;
1841
1842                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1843                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1844                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1845                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1846                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1847                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1848
1849                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1850                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1851                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1852                                 case Mode.U2_CH: /* nothing */ break;
1853
1854                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1855                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1856                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1857                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1858                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1859                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1860                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1861
1862                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1863                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1864                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1865                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1866                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1867                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1868
1869                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1870                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1871                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1872                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1873                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1874                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1875                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1876                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1877
1878                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1879                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1880                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1881                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1882                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1883                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1884                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1885                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1886
1887                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1888                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1889                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1890
1891                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1892                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1893                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1894                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1895                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1896                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1897                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1898                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1899                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1900
1901                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1902                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1903                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1904                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1905                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1906                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1907                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1908                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1909                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1910                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1911                                 }
1912                         } else {
1913                                 switch (mode){
1914                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1915                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1916                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1917                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1918                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1919
1920                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1921                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1922
1923                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1924                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1925                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1926                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1927                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1928                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1929
1930                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1931                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1932                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1933                                 case Mode.U2_CH: /* nothing */ break;
1934
1935                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1936                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1937                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1938                                 case Mode.I4_U4: /* nothing */ break;
1939                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1940                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1941                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1942
1943                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1944                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1945                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1946                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1947                                 case Mode.U4_I4: /* nothing */ break;
1948                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1949
1950                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1951                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1952                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1953                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1954                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1955                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1956                                 case Mode.I8_U8: /* nothing */ break;
1957                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1958
1959                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1960                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1961                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1962                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1963                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1964                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1965                                 case Mode.U8_I8: /* nothing */ break;
1966                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1967
1968                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1969                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1970                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1971
1972                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1973                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1974                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1975                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1976                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1977                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1978                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1979                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1980                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1981
1982                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1983                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1984                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1985                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1986                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1987                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1988                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1989                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1990                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1991                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1992                                 }
1993                         }
1994                 }
1995         }
1996
1997         public class OpcodeCast : EmptyCast {
1998                 OpCode op, op2;
1999                 bool second_valid;
2000
2001                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2002                         : base (child, return_type)
2003
2004                 {
2005                         this.op = op;
2006                         second_valid = false;
2007                 }
2008
2009                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
2010                         : base (child, return_type)
2011
2012                 {
2013                         this.op = op;
2014                         this.op2 = op2;
2015                         second_valid = true;
2016                 }
2017
2018                 public override Expression DoResolve (EmitContext ec)
2019                 {
2020                         // This should never be invoked, we are born in fully
2021                         // initialized state.
2022
2023                         return this;
2024                 }
2025
2026                 public override void Emit (EmitContext ec)
2027                 {
2028                         base.Emit (ec);
2029                         ec.ig.Emit (op);
2030
2031                         if (second_valid)
2032                                 ec.ig.Emit (op2);
2033                 }
2034
2035                 public Type UnderlyingType {
2036                         get { return child.Type; }
2037                 }
2038         }
2039
2040         /// <summary>
2041         ///   This kind of cast is used to encapsulate a child and cast it
2042         ///   to the class requested
2043         /// </summary>
2044         public class ClassCast : EmptyCast {
2045                 public ClassCast (Expression child, Type return_type)
2046                         : base (child, return_type)
2047
2048                 {
2049                 }
2050
2051                 public override Expression DoResolve (EmitContext ec)
2052                 {
2053                         // This should never be invoked, we are born in fully
2054                         // initialized state.
2055
2056                         return this;
2057                 }
2058
2059                 public override void Emit (EmitContext ec)
2060                 {
2061                         base.Emit (ec);
2062
2063                         if (TypeManager.IsGenericParameter (child.Type))
2064                                 ec.ig.Emit (OpCodes.Box, child.Type);
2065
2066 #if GMCS_SOURCE
2067                         if (type.IsGenericParameter)
2068                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2069                         else
2070 #endif
2071                                 ec.ig.Emit (OpCodes.Castclass, type);
2072                 }
2073         }
2074
2075         //
2076         // Used when resolved expression has different representations for
2077         // expression trees and emit phase
2078         //
2079         public class ReducedExpression : Expression
2080         {
2081                 class ReducedConstantExpression : Constant
2082                 {
2083                         readonly Constant expr;
2084                         readonly Expression orig_expr;
2085
2086                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2087                                 : base (expr.Location)
2088                         {
2089                                 this.expr = expr;
2090                                 this.orig_expr = orig_expr;
2091                                 eclass = expr.eclass;
2092                                 type = expr.Type;
2093                         }
2094
2095                         public override string AsString ()
2096                         {
2097                                 return expr.AsString ();
2098                         }
2099
2100                         public override Expression CreateExpressionTree (EmitContext ec)
2101                         {
2102                                 return orig_expr.CreateExpressionTree (ec);
2103                         }
2104
2105                         public override object GetValue ()
2106                         {
2107                                 return expr.GetValue ();
2108                         }
2109
2110                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2111                         {
2112                                 throw new NotImplementedException ();
2113                         }
2114
2115                         public override Expression DoResolve (EmitContext ec)
2116                         {
2117                                 return this;
2118                         }
2119
2120                         public override Constant Increment ()
2121                         {
2122                                 throw new NotImplementedException ();
2123                         }
2124
2125                         public override bool IsDefaultValue {
2126                                 get {
2127                                         return expr.IsDefaultValue;
2128                                 }
2129                         }
2130
2131                         public override bool IsNegative {
2132                                 get {
2133                                         return expr.IsNegative;
2134                                 }
2135                         }
2136
2137                         public override void Emit (EmitContext ec)
2138                         {
2139                                 expr.Emit (ec);
2140                         }
2141                 }
2142
2143                 readonly Expression expr, orig_expr;
2144
2145                 private ReducedExpression (Expression expr, Expression orig_expr)
2146                 {
2147                         this.expr = expr;
2148                         this.orig_expr = orig_expr;
2149                         this.loc = orig_expr.Location;
2150                 }
2151
2152                 public static Expression Create (Constant expr, Expression original_expr)
2153                 {
2154                         return new ReducedConstantExpression (expr, original_expr);
2155                 }
2156
2157                 public static Expression Create (Expression expr, Expression original_expr)
2158                 {
2159                         Constant c = expr as Constant;
2160                         if (c != null)
2161                                 return Create (c, original_expr);
2162
2163                         return new ReducedExpression (expr, original_expr);
2164                 }
2165
2166                 public override Expression CreateExpressionTree (EmitContext ec)
2167                 {
2168                         return orig_expr.CreateExpressionTree (ec);
2169                 }
2170
2171                 public override Expression DoResolve (EmitContext ec)
2172                 {
2173                         eclass = expr.eclass;
2174                         type = expr.Type;
2175                         return this;
2176                 }
2177
2178                 public override void Emit (EmitContext ec)
2179                 {
2180                         expr.Emit (ec);
2181                 }
2182
2183                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2184                 {
2185                         expr.EmitBranchable (ec, target, on_true);
2186                 }
2187         }
2188
2189         /// <summary>
2190         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2191         ///   of a dotted-name.
2192         /// </summary>
2193         public class SimpleName : Expression {
2194                 public readonly string Name;
2195                 public readonly TypeArguments Arguments;
2196                 bool in_transit;
2197
2198                 public SimpleName (string name, Location l)
2199                 {
2200                         Name = name;
2201                         loc = l;
2202                 }
2203
2204                 public SimpleName (string name, TypeArguments args, Location l)
2205                 {
2206                         Name = name;
2207                         Arguments = args;
2208                         loc = l;
2209                 }
2210
2211                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2212                 {
2213                         Name = name;
2214                         loc = l;
2215
2216                         Arguments = new TypeArguments (l);
2217                         foreach (TypeParameter type_param in type_params)
2218                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2219                 }
2220
2221                 public static string RemoveGenericArity (string name)
2222                 {
2223                         int start = 0;
2224                         StringBuilder sb = null;
2225                         do {
2226                                 int pos = name.IndexOf ('`', start);
2227                                 if (pos < 0) {
2228                                         if (start == 0)
2229                                                 return name;
2230
2231                                         sb.Append (name.Substring (start));
2232                                         break;
2233                                 }
2234
2235                                 if (sb == null)
2236                                         sb = new StringBuilder ();
2237                                 sb.Append (name.Substring (start, pos-start));
2238
2239                                 pos++;
2240                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2241                                         pos++;
2242
2243                                 start = pos;
2244                         } while (start < name.Length);
2245
2246                         return sb.ToString ();
2247                 }
2248
2249                 public SimpleName GetMethodGroup ()
2250                 {
2251                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2252                 }
2253
2254                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2255                 {
2256                         if (ec.IsInFieldInitializer)
2257                                 Report.Error (236, l,
2258                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2259                                         name);
2260                         else
2261                                 Report.Error (
2262                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2263                                         name);
2264                 }
2265
2266                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2267                 {
2268                         return resolved_to != null && resolved_to.Type != null &&
2269                                 resolved_to.Type.Name == Name &&
2270                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2271                 }
2272
2273                 public override Expression DoResolve (EmitContext ec)
2274                 {
2275                         return SimpleNameResolve (ec, null, false);
2276                 }
2277
2278                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2279                 {
2280                         return SimpleNameResolve (ec, right_side, false);
2281                 }
2282
2283
2284                 public Expression DoResolve (EmitContext ec, bool intermediate)
2285                 {
2286                         return SimpleNameResolve (ec, null, intermediate);
2287                 }
2288
2289                 static bool IsNestedChild (Type t, Type parent)
2290                 {
2291                         while (parent != null) {
2292                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2293                                         return true;
2294
2295                                 parent = parent.BaseType;
2296                         }
2297
2298                         return false;
2299                 }
2300
2301                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2302                 {
2303                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2304                                 return null;
2305
2306                         DeclSpace ds = ec.DeclContainer;
2307                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2308                                 ds = ds.Parent;
2309
2310                         if (ds == null)
2311                                 return null;
2312
2313                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2314
2315                         int arg_count = Arguments != null ? Arguments.Count : 0;
2316
2317                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2318                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2319                                         TypeArguments new_args = new TypeArguments (loc);
2320                                         foreach (TypeParameter param in ds.TypeParameters)
2321                                                 new_args.Add (new TypeParameterExpr (param, loc));
2322
2323                                         if (Arguments != null)
2324                                                 new_args.Add (Arguments);
2325
2326                                         return new ConstructedType (t, new_args, loc);
2327                                 }
2328                         }
2329
2330                         return null;
2331                 }
2332
2333                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2334                 {
2335                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2336                         if (fne != null)
2337                                 return fne.ResolveAsTypeStep (ec, silent);
2338
2339                         int errors = Report.Errors;
2340                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2341
2342                         if (fne != null) {
2343                                 if (fne.Type == null)
2344                                         return fne;
2345
2346                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2347                                 if (nested != null)
2348                                         return nested.ResolveAsTypeStep (ec, false);
2349
2350                                 if (Arguments != null) {
2351                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2352                                         return ct.ResolveAsTypeStep (ec, false);
2353                                 }
2354
2355                                 return fne;
2356                         }
2357
2358                         if (silent || errors != Report.Errors)
2359                                 return null;
2360
2361                         Error_TypeOrNamespaceNotFound (ec);
2362                         return null;
2363                 }
2364
2365                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2366                 {
2367                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2368                         if (mc != null) {
2369                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2370                                 return;
2371                         }
2372
2373                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2374                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2375                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2376                                 Type type = a.GetType (fullname);
2377                                 if (type != null) {
2378                                         Report.SymbolRelatedToPreviousError (type);
2379                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2380                                         return;
2381                                 }
2382                         }
2383
2384                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2385                         if (t != null) {
2386                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2387                                 return;
2388                         }
2389
2390                         if (Arguments != null) {
2391                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2392                                 if (retval != null) {
2393                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2394                                         return;
2395                                 }
2396                         }
2397
2398                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2399                 }
2400
2401                 // TODO: I am still not convinced about this. If someone else will need it
2402                 // implement this as virtual property in MemberCore hierarchy
2403                 public static string GetMemberType (MemberCore mc)
2404                 {
2405                         if (mc is Property)
2406                                 return "property";
2407                         if (mc is Indexer)
2408                                 return "indexer";
2409                         if (mc is FieldBase)
2410                                 return "field";
2411                         if (mc is MethodCore)
2412                                 return "method";
2413                         if (mc is EnumMember)
2414                                 return "enum";
2415                         if (mc is Event)
2416                                 return "event";
2417
2418                         return "type";
2419                 }
2420
2421                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2422                 {
2423                         if (in_transit)
2424                                 return null;
2425
2426                         in_transit = true;
2427                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2428                         in_transit = false;
2429
2430                         if (e == null)
2431                                 return null;
2432
2433                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2434                                 return e;
2435
2436                         return null;
2437                 }
2438
2439                 /// <remarks>
2440                 ///   7.5.2: Simple Names.
2441                 ///
2442                 ///   Local Variables and Parameters are handled at
2443                 ///   parse time, so they never occur as SimpleNames.
2444                 ///
2445                 ///   The `intermediate' flag is used by MemberAccess only
2446                 ///   and it is used to inform us that it is ok for us to
2447                 ///   avoid the static check, because MemberAccess might end
2448                 ///   up resolving the Name as a Type name and the access as
2449                 ///   a static type access.
2450                 ///
2451                 ///   ie: Type Type; .... { Type.GetType (""); }
2452                 ///
2453                 ///   Type is both an instance variable and a Type;  Type.GetType
2454                 ///   is the static method not an instance method of type.
2455                 /// </remarks>
2456                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2457                 {
2458                         Expression e = null;
2459
2460                         //
2461                         // Stage 1: Performed by the parser (binding to locals or parameters).
2462                         //
2463                         Block current_block = ec.CurrentBlock;
2464                         if (current_block != null){
2465                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2466                                 if (vi != null){
2467                                         if (Arguments != null) {
2468                                                 Report.Error (307, loc,
2469                                                               "The variable `{0}' cannot be used with type arguments",
2470                                                               Name);
2471                                                 return null;
2472                                         }
2473
2474                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2475                                         if (right_side != null) {
2476                                                 return var.ResolveLValue (ec, right_side, loc);
2477                                         } else {
2478                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2479                                                 if (intermediate)
2480                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2481                                                 return var.Resolve (ec, rf);
2482                                         }
2483                                 }
2484
2485                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2486                                 if (pref != null) {
2487                                         if (Arguments != null) {
2488                                                 Report.Error (307, loc,
2489                                                               "The variable `{0}' cannot be used with type arguments",
2490                                                               Name);
2491                                                 return null;
2492                                         }
2493
2494                                         if (right_side != null)
2495                                                 return pref.ResolveLValue (ec, right_side, loc);
2496                                         else
2497                                                 return pref.Resolve (ec);
2498                                 }
2499
2500                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2501                                 if (expr != null) {
2502                                         if (right_side != null)
2503                                                 return expr.ResolveLValue (ec, right_side, loc);
2504                                         return expr.Resolve (ec);
2505                                 }
2506                         }
2507
2508                         //
2509                         // Stage 2: Lookup members
2510                         //
2511
2512                         Type almost_matched_type = null;
2513                         ArrayList almost_matched = null;
2514                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2515                                 // either RootDeclSpace or GenericMethod
2516                                 if (lookup_ds.TypeBuilder == null)
2517                                         continue;
2518
2519                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2520                                 if (e != null) {
2521                                         if (e is PropertyExpr) {
2522                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2523                                                 // it doesn't know which accessor to check permissions against
2524                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2525                                                         break;
2526                                         } else if (e is EventExpr) {
2527                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2528                                                         break;
2529                                         } else {
2530                                                 break;
2531                                         }
2532                                         e = null;
2533                                 }
2534
2535                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2536                                         almost_matched_type = lookup_ds.TypeBuilder;
2537                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2538                                 }
2539                         }
2540
2541                         if (e == null) {
2542                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2543                                         almost_matched_type = ec.ContainerType;
2544                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2545                                 }
2546                                 e = ResolveAsTypeStep (ec, true);
2547                         }
2548
2549                         if (e == null) {
2550                                 if (current_block != null) {
2551                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2552                                         if (ikv != null) {
2553                                                 LocalInfo li = ikv as LocalInfo;
2554                                                 // Supress CS0219 warning
2555                                                 if (li != null)
2556                                                         li.Used = true;
2557
2558                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2559                                                 return null;
2560                                         }
2561                                 }
2562
2563                                 if (almost_matched != null)
2564                                         almost_matched_members = almost_matched;
2565                                 if (almost_matched_type == null)
2566                                         almost_matched_type = ec.ContainerType;
2567                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2568                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2569                                 return null;
2570                         }
2571
2572                         if (e is TypeExpr) {
2573                                 if (Arguments == null)
2574                                         return e;
2575
2576                                 ConstructedType ct = new ConstructedType (
2577                                         (FullNamedExpression) e, Arguments, loc);
2578                                 return ct.ResolveAsTypeStep (ec, false);
2579                         }
2580
2581                         if (e is MemberExpr) {
2582                                 MemberExpr me = (MemberExpr) e;
2583
2584                                 Expression left;
2585                                 if (me.IsInstance) {
2586                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2587                                                 //
2588                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2589                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2590                                                 // and each predicate is true if the MethodGroupExpr contains
2591                                                 // at least one of that kind of method.
2592                                                 //
2593
2594                                                 if (!me.IsStatic &&
2595                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2596                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2597                                                         return null;
2598                                                 }
2599
2600                                                 //
2601                                                 // Pass the buck to MemberAccess and Invocation.
2602                                                 //
2603                                                 left = EmptyExpression.Null;
2604                                         } else {
2605                                                 left = ec.GetThis (loc);
2606                                         }
2607                                 } else {
2608                                         left = new TypeExpression (ec.ContainerType, loc);
2609                                 }
2610
2611                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2612                                 if (me == null)
2613                                         return null;
2614
2615                                 if (Arguments != null) {
2616                                         Arguments.Resolve (ec);
2617                                         me.SetTypeArguments (Arguments);
2618                                 }
2619
2620                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2621                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2622                                     me.InstanceExpression.Type != me.DeclaringType &&
2623                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2624                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2625                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2626                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2627                                         return null;
2628                                 }
2629
2630                                 return (right_side != null)
2631                                         ? me.DoResolveLValue (ec, right_side)
2632                                         : me.DoResolve (ec);
2633                         }
2634
2635                         return e;
2636                 }
2637
2638                 public override void Emit (EmitContext ec)
2639                 {
2640                         throw new InternalErrorException ("The resolve phase was not executed");
2641                 }
2642
2643                 public override string ToString ()
2644                 {
2645                         return Name;
2646                 }
2647
2648                 public override string GetSignatureForError ()
2649                 {
2650                         if (Arguments != null) {
2651                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2652                                         Arguments.GetSignatureForError () + ">";
2653                         }
2654
2655                         return Name;
2656                 }
2657
2658                 protected override void CloneTo (CloneContext clonectx, Expression target)
2659                 {
2660                         // CloneTo: Nothing, we do not keep any state on this expression
2661                 }
2662         }
2663
2664         /// <summary>
2665         ///   Represents a namespace or a type.  The name of the class was inspired by
2666         ///   section 10.8.1 (Fully Qualified Names).
2667         /// </summary>
2668         public abstract class FullNamedExpression : Expression {
2669                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2670                 {
2671                         return this;
2672                 }
2673
2674                 public abstract string FullName {
2675                         get;
2676                 }
2677         }
2678
2679         /// <summary>
2680         ///   Expression that evaluates to a type
2681         /// </summary>
2682         public abstract class TypeExpr : FullNamedExpression {
2683                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2684                 {
2685                         TypeExpr t = DoResolveAsTypeStep (ec);
2686                         if (t == null)
2687                                 return null;
2688
2689                         eclass = ExprClass.Type;
2690                         return t;
2691                 }
2692
2693                 override public Expression DoResolve (EmitContext ec)
2694                 {
2695                         return ResolveAsTypeTerminal (ec, false);
2696                 }
2697
2698                 override public void Emit (EmitContext ec)
2699                 {
2700                         throw new Exception ("Should never be called");
2701                 }
2702
2703                 public virtual bool CheckAccessLevel (DeclSpace ds)
2704                 {
2705                         return ds.CheckAccessLevel (Type);
2706                 }
2707
2708                 public virtual bool AsAccessible (DeclSpace ds)
2709                 {
2710                         return ds.IsAccessibleAs (Type);
2711                 }
2712
2713                 public virtual bool IsClass {
2714                         get { return Type.IsClass; }
2715                 }
2716
2717                 public virtual bool IsValueType {
2718                         get { return Type.IsValueType; }
2719                 }
2720
2721                 public virtual bool IsInterface {
2722                         get { return Type.IsInterface; }
2723                 }
2724
2725                 public virtual bool IsSealed {
2726                         get { return Type.IsSealed; }
2727                 }
2728
2729                 public virtual bool CanInheritFrom ()
2730                 {
2731                         if (Type == TypeManager.enum_type ||
2732                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2733                             Type == TypeManager.multicast_delegate_type ||
2734                             Type == TypeManager.delegate_type ||
2735                             Type == TypeManager.array_type)
2736                                 return false;
2737
2738                         return true;
2739                 }
2740
2741                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2742
2743                 public abstract string Name {
2744                         get;
2745                 }
2746
2747                 public override bool Equals (object obj)
2748                 {
2749                         TypeExpr tobj = obj as TypeExpr;
2750                         if (tobj == null)
2751                                 return false;
2752
2753                         return Type == tobj.Type;
2754                 }
2755
2756                 public override int GetHashCode ()
2757                 {
2758                         return Type.GetHashCode ();
2759                 }
2760
2761                 public override string ToString ()
2762                 {
2763                         return Name;
2764                 }
2765         }
2766
2767         /// <summary>
2768         ///   Fully resolved Expression that already evaluated to a type
2769         /// </summary>
2770         public class TypeExpression : TypeExpr {
2771                 public TypeExpression (Type t, Location l)
2772                 {
2773                         Type = t;
2774                         eclass = ExprClass.Type;
2775                         loc = l;
2776                 }
2777
2778                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2779                 {
2780                         return this;
2781                 }
2782
2783                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2784                 {
2785                         return this;
2786                 }
2787
2788                 public override string Name {
2789                         get { return Type.ToString (); }
2790                 }
2791
2792                 public override string FullName {
2793                         get { return Type.FullName; }
2794                 }
2795         }
2796
2797         /// <summary>
2798         ///   Used to create types from a fully qualified name.  These are just used
2799         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2800         ///   classified as a type.
2801         /// </summary>
2802         public sealed class TypeLookupExpression : TypeExpr {
2803                 readonly string name;
2804
2805                 public TypeLookupExpression (string name)
2806                 {
2807                         this.name = name;
2808                         eclass = ExprClass.Type;
2809                 }
2810
2811                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2812                 {
2813                         // It's null for corlib compilation only
2814                         if (type == null)
2815                                 return DoResolveAsTypeStep (ec);
2816
2817                         return this;
2818                 }
2819
2820                 private class UnexpectedType
2821                 {
2822                 }
2823
2824                 // This performes recursive type lookup, providing support for generic types.
2825                 // For example, given the type:
2826                 //
2827                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2828                 //
2829                 // The types will be checked in the following order:
2830                 //                                                                             _
2831                 // System                                                                       |
2832                 // System.Collections                                                           |
2833                 // System.Collections.Generic                                                   |
2834                 //                        _                                                     |
2835                 //     System              | recursive call 1                                   |
2836                 //     System.Int32       _|                                                    | main method call
2837                 //                        _                                                     |
2838                 //     System              | recursive call 2                                   |
2839                 //     System.String      _|                                                    |
2840                 //                                                                              |
2841                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2842                 //
2843                 private Type TypeLookup (IResolveContext ec, string name)
2844                 {
2845                         int index = 0;
2846                         int dot = 0;
2847                         bool done = false;
2848                         FullNamedExpression resolved = null;
2849                         Type type = null;
2850                         Type recursive_type = null;
2851                         while (index < name.Length) {
2852                                 if (name[index] == '[') {
2853                                         int open = index;
2854                                         int braces = 1;
2855                                         do {
2856                                                 index++;
2857                                                 if (name[index] == '[')
2858                                                         braces++;
2859                                                 else if (name[index] == ']')
2860                                                         braces--;
2861                                         } while (braces > 0);
2862                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2863                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2864                                                 return recursive_type;
2865                                 }
2866                                 else {
2867                                         if (name[index] == ',')
2868                                                 done = true;
2869                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2870                                                 string substring = name.Substring(dot, index - dot);
2871
2872                                                 if (resolved == null)
2873                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2874                                                 else if (resolved is Namespace)
2875                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2876                                                 else if (type != null)
2877                                                         type = TypeManager.GetNestedType (type, substring);
2878                                                 else
2879                                                         return null;
2880
2881                                                 if (resolved == null)
2882                                                         return null;
2883                                                 else if (type == null && resolved is TypeExpr)
2884                                                         type = resolved.Type;
2885
2886                                                 dot = index + 1;
2887                                         }
2888                                 }
2889                                 index++;
2890                         }
2891                         if (name[0] != '[') {
2892                                 string substring = name.Substring(dot, index - dot);
2893
2894                                 if (type != null)
2895                                         return TypeManager.GetNestedType (type, substring);
2896
2897                                 if (resolved != null) {
2898                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2899                                         if (resolved is TypeExpr)
2900                                                 return resolved.Type;
2901
2902                                         if (resolved == null)
2903                                                 return null;
2904
2905                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2906                                         return typeof (UnexpectedType);
2907                                 }
2908                                 else
2909                                         return null;
2910                         }
2911                         else
2912                                 return recursive_type;
2913                         }
2914
2915                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2916                 {
2917                         Type t = TypeLookup (ec, name);
2918                         if (t == null) {
2919                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2920                                 return null;
2921                         }
2922                         if (t == typeof(UnexpectedType))
2923                                 return null;
2924                         type = t;
2925                         return this;
2926                 }
2927
2928                 public override string Name {
2929                         get { return name; }
2930                 }
2931
2932                 public override string FullName {
2933                         get { return name; }
2934                 }
2935
2936                 protected override void CloneTo (CloneContext clonectx, Expression target)
2937                 {
2938                         // CloneTo: Nothing, we do not keep any state on this expression
2939                 }
2940
2941                 public override string GetSignatureForError ()
2942                 {
2943                         if (type == null)
2944                                 return TypeManager.CSharpName (name);
2945
2946                         return base.GetSignatureForError ();
2947                 }
2948         }
2949
2950         /// <summary>
2951         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2952         ///   See 14.5.11.
2953         /// </summary>
2954         public class UnboundTypeExpression : TypeExpr
2955         {
2956                 MemberName name;
2957
2958                 public UnboundTypeExpression (MemberName name, Location l)
2959                 {
2960                         this.name = name;
2961                         loc = l;
2962                 }
2963
2964                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2965                 {
2966                         Expression expr;
2967                         if (name.Left != null) {
2968                                 Expression lexpr = name.Left.GetTypeExpression ();
2969                                 expr = new MemberAccess (lexpr, name.Basename);
2970                         } else {
2971                                 expr = new SimpleName (name.Basename, loc);
2972                         }
2973
2974                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2975                         if (fne == null)
2976                                 return null;
2977
2978                         type = fne.Type;
2979                         return new TypeExpression (type, loc);
2980                 }
2981
2982                 public override string Name {
2983                         get { return name.FullName; }
2984                 }
2985
2986                 public override string FullName {
2987                         get { return name.FullName; }
2988                 }
2989         }
2990
2991         public class TypeAliasExpression : TypeExpr {
2992                 FullNamedExpression alias;
2993                 TypeExpr texpr;
2994                 TypeArguments args;
2995                 string name;
2996
2997                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2998                 {
2999                         this.alias = alias;
3000                         this.args = args;
3001                         loc = l;
3002
3003                         eclass = ExprClass.Type;
3004                         if (args != null)
3005                                 name = alias.FullName + "<" + args.ToString () + ">";
3006                         else
3007                                 name = alias.FullName;
3008                 }
3009
3010                 public override string Name {
3011                         get { return alias.FullName; }
3012                 }
3013
3014                 public override string FullName {
3015                         get { return name; }
3016                 }
3017
3018                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3019                 {
3020                         texpr = alias.ResolveAsTypeTerminal (ec, false);
3021                         if (texpr == null)
3022                                 return null;
3023
3024                         Type type = texpr.Type;
3025                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
3026
3027                         if (args != null) {
3028                                 if (num_args == 0) {
3029                                         Report.Error (308, loc,
3030                                                       "The non-generic type `{0}' cannot " +
3031                                                       "be used with type arguments.",
3032                                                       TypeManager.CSharpName (type));
3033                                         return null;
3034                                 }
3035
3036                                 ConstructedType ctype = new ConstructedType (type, args, loc);
3037                                 return ctype.ResolveAsTypeTerminal (ec, false);
3038                         } else if (num_args > 0) {
3039                                 Report.Error (305, loc,
3040                                               "Using the generic type `{0}' " +
3041                                               "requires {1} type arguments",
3042                                               TypeManager.CSharpName (type), num_args.ToString ());
3043                                 return null;
3044                         }
3045
3046                         return texpr;
3047                 }
3048
3049                 public override bool CheckAccessLevel (DeclSpace ds)
3050                 {
3051                         return texpr.CheckAccessLevel (ds);
3052                 }
3053
3054                 public override bool AsAccessible (DeclSpace ds)
3055                 {
3056                         return texpr.AsAccessible (ds);
3057                 }
3058
3059                 public override bool IsClass {
3060                         get { return texpr.IsClass; }
3061                 }
3062
3063                 public override bool IsValueType {
3064                         get { return texpr.IsValueType; }
3065                 }
3066
3067                 public override bool IsInterface {
3068                         get { return texpr.IsInterface; }
3069                 }
3070
3071                 public override bool IsSealed {
3072                         get { return texpr.IsSealed; }
3073                 }
3074         }
3075
3076         /// <summary>
3077         ///   This class denotes an expression which evaluates to a member
3078         ///   of a struct or a class.
3079         /// </summary>
3080         public abstract class MemberExpr : Expression
3081         {
3082                 protected bool is_base;
3083
3084                 /// <summary>
3085                 ///   The name of this member.
3086                 /// </summary>
3087                 public abstract string Name {
3088                         get;
3089                 }
3090
3091                 //
3092                 // When base.member is used
3093                 //
3094                 public bool IsBase {
3095                         get { return is_base; }
3096                         set { is_base = value; }
3097                 }
3098
3099                 /// <summary>
3100                 ///   Whether this is an instance member.
3101                 /// </summary>
3102                 public abstract bool IsInstance {
3103                         get;
3104                 }
3105
3106                 /// <summary>
3107                 ///   Whether this is a static member.
3108                 /// </summary>
3109                 public abstract bool IsStatic {
3110                         get;
3111                 }
3112
3113                 /// <summary>
3114                 ///   The type which declares this member.
3115                 /// </summary>
3116                 public abstract Type DeclaringType {
3117                         get;
3118                 }
3119
3120                 /// <summary>
3121                 ///   The instance expression associated with this member, if it's a
3122                 ///   non-static member.
3123                 /// </summary>
3124                 public Expression InstanceExpression;
3125
3126                 public static void error176 (Location loc, string name)
3127                 {
3128                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3129                                       "with an instance reference, qualify it with a type name instead", name);
3130                 }
3131
3132                 // TODO: possible optimalization
3133                 // Cache resolved constant result in FieldBuilder <-> expression map
3134                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3135                                                                SimpleName original)
3136                 {
3137                         //
3138                         // Precondition:
3139                         //   original == null || original.Resolve (...) ==> left
3140                         //
3141
3142                         if (left is TypeExpr) {
3143                                 left = left.ResolveAsTypeTerminal (ec, true);
3144                                 if (left == null)
3145                                         return null;
3146
3147                                 if (!IsStatic) {
3148                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3149                                         return null;
3150                                 }
3151
3152                                 return this;
3153                         }
3154
3155                         if (!IsInstance) {
3156                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3157                                         return this;
3158
3159                                 return ResolveExtensionMemberAccess (left);
3160                         }
3161
3162                         InstanceExpression = left;
3163                         return this;
3164                 }
3165
3166                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3167                 {
3168                         error176 (loc, GetSignatureForError ());
3169                         return this;
3170                 }
3171
3172                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3173                 {
3174                         if (IsStatic)
3175                                 return;
3176
3177                         if (InstanceExpression == EmptyExpression.Null) {
3178                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3179                                 return;
3180                         }
3181
3182                         if (InstanceExpression.Type.IsValueType) {
3183                                 if (InstanceExpression is IMemoryLocation) {
3184                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3185                                 } else {
3186                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3187                                         InstanceExpression.Emit (ec);
3188                                         t.Store (ec);
3189                                         t.AddressOf (ec, AddressOp.Store);
3190                                 }
3191                         } else
3192                                 InstanceExpression.Emit (ec);
3193
3194                         if (prepare_for_load)
3195                                 ec.ig.Emit (OpCodes.Dup);
3196                 }
3197
3198                 public virtual void SetTypeArguments (TypeArguments ta)
3199                 {
3200                         // TODO: need to get correct member type
3201                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3202                                 GetSignatureForError ());
3203                 }
3204         }
3205
3206         ///
3207         /// Represents group of extension methods
3208         ///
3209         public class ExtensionMethodGroupExpr : MethodGroupExpr
3210         {
3211                 readonly NamespaceEntry namespace_entry;
3212                 public Expression ExtensionExpression;
3213                 Argument extension_argument;
3214
3215                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3216                         : base (list, extensionType, l)
3217                 {
3218                         this.namespace_entry = n;
3219                 }
3220
3221                 public override bool IsStatic {
3222                         get { return true; }
3223                 }
3224
3225                 public bool IsTopLevel {
3226                         get { return namespace_entry == null; }
3227                 }
3228
3229                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3230                 {
3231                         if (arguments == null)
3232                                 arguments = new ArrayList (1);
3233                         arguments.Insert (0, extension_argument);
3234                         base.EmitArguments (ec, arguments);
3235                 }
3236
3237                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3238                 {
3239                         if (arguments == null)
3240                                 arguments = new ArrayList (1);
3241                         arguments.Insert (0, extension_argument);
3242                         base.EmitCall (ec, arguments);
3243                 }
3244
3245                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3246                 {
3247                         if (arguments == null)
3248                                 arguments = new ArrayList (1);
3249
3250                         arguments.Insert (0, new Argument (ExtensionExpression));
3251                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3252
3253                         // Store resolved argument and restore original arguments
3254                         if (mg != null)
3255                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3256                         arguments.RemoveAt (0);
3257
3258                         return mg;
3259                 }
3260
3261                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3262                 {
3263                         // Use normal resolve rules
3264                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3265                         if (mg != null)
3266                                 return mg;
3267
3268                         if (ns == null)
3269                                 return null;
3270
3271                         // Search continues
3272                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3273                         if (e == null)
3274                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3275
3276                         e.ExtensionExpression = ExtensionExpression;
3277                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3278                 }
3279         }
3280
3281         /// <summary>
3282         ///   MethodGroupExpr represents a group of method candidates which
3283         ///   can be resolved to the best method overload
3284         /// </summary>
3285         public class MethodGroupExpr : MemberExpr
3286         {
3287                 public interface IErrorHandler
3288                 {
3289                         bool NoExactMatch (EmitContext ec, MethodBase method);
3290                 }
3291
3292                 public IErrorHandler CustomErrorHandler;
3293                 public MethodBase [] Methods;
3294                 MethodBase best_candidate;
3295                 // TODO: make private
3296                 public TypeArguments type_arguments;
3297                 bool identical_type_name;
3298                 Type delegate_type;
3299
3300                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3301                         : this (type, l)
3302                 {
3303                         Methods = new MethodBase [mi.Length];
3304                         mi.CopyTo (Methods, 0);
3305                 }
3306
3307                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3308                         : this (type, l)
3309                 {
3310                         try {
3311                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3312                         } catch {
3313                                 foreach (MemberInfo m in list){
3314                                         if (!(m is MethodBase)){
3315                                                 Console.WriteLine ("Name " + m.Name);
3316                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3317                                         }
3318                                 }
3319                                 throw;
3320                         }
3321
3322
3323                 }
3324
3325                 protected MethodGroupExpr (Type type, Location loc)
3326                 {
3327                         this.loc = loc;
3328                         eclass = ExprClass.MethodGroup;
3329                         this.type = type;
3330                 }
3331
3332                 public override Type DeclaringType {
3333                         get {
3334                                 //
3335                                 // We assume that the top-level type is in the end
3336                                 //
3337                                 return Methods [Methods.Length - 1].DeclaringType;
3338                                 //return Methods [0].DeclaringType;
3339                         }
3340                 }
3341
3342                 public Type DelegateType {
3343                         set {
3344                                 delegate_type = value;
3345                         }
3346                 }
3347
3348                 public bool IdenticalTypeName {
3349                         get {
3350                                 return identical_type_name;
3351                         }
3352
3353                         set {
3354                                 identical_type_name = value;
3355                         }
3356                 }
3357
3358                 public override string GetSignatureForError ()
3359                 {
3360                         if (best_candidate != null)
3361                                 return TypeManager.CSharpSignature (best_candidate);
3362
3363                         return TypeManager.CSharpSignature (Methods [0]);
3364                 }
3365
3366                 public override string Name {
3367                         get {
3368                                 return Methods [0].Name;
3369                         }
3370                 }
3371
3372                 public override bool IsInstance {
3373                         get {
3374                                 if (best_candidate != null)
3375                                         return !best_candidate.IsStatic;
3376
3377                                 foreach (MethodBase mb in Methods)
3378                                         if (!mb.IsStatic)
3379                                                 return true;
3380
3381                                 return false;
3382                         }
3383                 }
3384
3385                 public override bool IsStatic {
3386                         get {
3387                                 if (best_candidate != null)
3388                                         return best_candidate.IsStatic;
3389
3390                                 foreach (MethodBase mb in Methods)
3391                                         if (mb.IsStatic)
3392                                                 return true;
3393
3394                                 return false;
3395                         }
3396                 }
3397
3398                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3399                 {
3400                         return (ConstructorInfo)mg.best_candidate;
3401                 }
3402
3403                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3404                 {
3405                         return (MethodInfo)mg.best_candidate;
3406                 }
3407
3408                 //
3409                 //  7.4.3.3  Better conversion from expression
3410                 //  Returns :   1    if a->p is better,
3411                 //              2    if a->q is better,
3412                 //              0 if neither is better
3413                 //
3414                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3415                 {
3416                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3417                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3418                                 //
3419                                 // Uwrap delegate from Expression<T>
3420                                 //
3421                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3422                                         p = TypeManager.GetTypeArguments (p) [0];
3423                                         q = TypeManager.GetTypeArguments (q) [0];
3424                                 }
3425                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3426                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3427                         } else {
3428                                 if (argument_type == p)
3429                                         return 1;
3430
3431                                 if (argument_type == q)
3432                                         return 2;
3433                         }
3434
3435                         return BetterTypeConversion (ec, p, q);
3436                 }
3437
3438                 //
3439                 // 7.4.3.4  Better conversion from type
3440                 //
3441                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3442                 {
3443                         if (p == null || q == null)
3444                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3445
3446                         if (p == TypeManager.int32_type) {
3447                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3448                                         return 1;
3449                         } else if (p == TypeManager.int64_type) {
3450                                 if (q == TypeManager.uint64_type)
3451                                         return 1;
3452                         } else if (p == TypeManager.sbyte_type) {
3453                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3454                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3455                                         return 1;
3456                         } else if (p == TypeManager.short_type) {
3457                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3458                                         q == TypeManager.uint64_type)
3459                                         return 1;
3460                         }
3461
3462                         if (q == TypeManager.int32_type) {
3463                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3464                                         return 2;
3465                         } if (q == TypeManager.int64_type) {
3466                                 if (p == TypeManager.uint64_type)
3467                                         return 2;
3468                         } else if (q == TypeManager.sbyte_type) {
3469                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3470                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3471                                         return 2;
3472                         } if (q == TypeManager.short_type) {
3473                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3474                                         p == TypeManager.uint64_type)
3475                                         return 2;
3476                         }
3477
3478                         // TODO: this is expensive
3479                         Expression p_tmp = new EmptyExpression (p);
3480                         Expression q_tmp = new EmptyExpression (q);
3481
3482                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3483                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3484
3485                         if (p_to_q && !q_to_p)
3486                                 return 1;
3487
3488                         if (q_to_p && !p_to_q)
3489                                 return 2;
3490
3491                         return 0;
3492                 }
3493
3494                 /// <summary>
3495                 ///   Determines "Better function" between candidate
3496                 ///   and the current best match
3497                 /// </summary>
3498                 /// <remarks>
3499                 ///    Returns a boolean indicating :
3500                 ///     false if candidate ain't better
3501                 ///     true  if candidate is better than the current best match
3502                 /// </remarks>
3503                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3504                         MethodBase candidate, bool candidate_params,
3505                         MethodBase best, bool best_params)
3506                 {
3507                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3508                         ParameterData best_pd = TypeManager.GetParameterData (best);
3509
3510                         bool better_at_least_one = false;
3511                         bool same = true;
3512                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3513                         {
3514                                 Argument a = (Argument) args [j];
3515
3516                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3517                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3518
3519                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3520                                 {
3521                                         ct = TypeManager.GetElementType (ct);
3522                                         --c_idx;
3523                                 }
3524
3525                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3526                                 {
3527                                         bt = TypeManager.GetElementType (bt);
3528                                         --b_idx;
3529                                 }
3530
3531                                 if (ct.Equals (bt))
3532                                         continue;
3533
3534                                 same = false;
3535                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3536
3537                                 // for each argument, the conversion to 'ct' should be no worse than
3538                                 // the conversion to 'bt'.
3539                                 if (result == 2)
3540                                         return false;
3541
3542                                 // for at least one argument, the conversion to 'ct' should be better than
3543                                 // the conversion to 'bt'.
3544                                 if (result != 0)
3545                                         better_at_least_one = true;
3546                         }
3547
3548                         if (better_at_least_one)
3549                                 return true;
3550
3551                         //
3552                         // This handles the case
3553                         //
3554                         //   Add (float f1, float f2, float f3);
3555                         //   Add (params decimal [] foo);
3556                         //
3557                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3558                         // first candidate would've chosen as better.
3559                         //
3560                         if (!same)
3561                                 return false;
3562
3563                         //
3564                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3565                         //
3566                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3567                                 return true;
3568                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3569                                 return false;
3570
3571                         //
3572                         // This handles the following cases:
3573                         //
3574                         //   Trim () is better than Trim (params char[] chars)
3575                         //   Concat (string s1, string s2, string s3) is better than
3576                         //     Concat (string s1, params string [] srest)
3577                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3578                         //
3579                         if (!candidate_params && best_params)
3580                                 return true;
3581                         if (candidate_params && !best_params)
3582                                 return false;
3583
3584                         int candidate_param_count = candidate_pd.Count;
3585                         int best_param_count = best_pd.Count;
3586
3587                         if (candidate_param_count != best_param_count)
3588                                 // can only happen if (candidate_params && best_params)
3589                                 return candidate_param_count > best_param_count;
3590
3591                         //
3592                         // now, both methods have the same number of parameters, and the parameters have the same types
3593                         // Pick the "more specific" signature
3594                         //
3595
3596                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3597                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3598
3599                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3600                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3601
3602                         bool specific_at_least_once = false;
3603                         for (int j = 0; j < candidate_param_count; ++j)
3604                         {
3605                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3606                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3607                                 if (ct.Equals (bt))
3608                                         continue;
3609                                 Type specific = MoreSpecific (ct, bt);
3610                                 if (specific == bt)
3611                                         return false;
3612                                 if (specific == ct)
3613                                         specific_at_least_once = true;
3614                         }
3615
3616                         if (specific_at_least_once)
3617                                 return true;
3618
3619                         // FIXME: handle lifted operators
3620                         // ...
3621
3622                         return false;
3623                 }
3624
3625                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3626                 {
3627                         if (!IsStatic)
3628                                 return base.ResolveExtensionMemberAccess (left);
3629
3630                         //
3631                         // When left side is an expression and at least one candidate method is
3632                         // static, it can be extension method
3633                         //
3634                         InstanceExpression = left;
3635                         return this;
3636                 }
3637
3638                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3639                                                                 SimpleName original)
3640                 {
3641                         if (!(left is TypeExpr) &&
3642                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3643                                 IdenticalTypeName = true;
3644
3645                         return base.ResolveMemberAccess (ec, left, loc, original);
3646                 }
3647
3648                 public override Expression CreateExpressionTree (EmitContext ec)
3649                 {
3650                         Type t = best_candidate.IsConstructor ?
3651                                 typeof (ConstructorInfo) : typeof (MethodInfo);
3652
3653                         return new Cast (new TypeExpression (t, loc), new TypeOfMethod (best_candidate, loc));
3654                 }
3655
3656                 override public Expression DoResolve (EmitContext ec)
3657                 {
3658                         if (InstanceExpression != null) {
3659                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3660                                 if (InstanceExpression == null)
3661                                         return null;
3662                         }
3663
3664                         return this;
3665                 }
3666
3667                 public void ReportUsageError ()
3668                 {
3669                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3670                                       Name + "()' is referenced without parentheses");
3671                 }
3672
3673                 override public void Emit (EmitContext ec)
3674                 {
3675                         ReportUsageError ();
3676                 }
3677
3678                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3679                 {
3680                         Invocation.EmitArguments (ec, arguments, false, null);
3681                 }
3682
3683                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3684                 {
3685                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3686                 }
3687
3688                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3689                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3690                 {
3691                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3692                                 Report.SymbolRelatedToPreviousError (method);
3693                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3694                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3695                                                 TypeManager.CSharpSignature (method));
3696                                         return;
3697                                 }
3698                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3699                                           TypeManager.CSharpSignature (method));
3700                         } else if (delegate_type == null) {
3701                                 Report.SymbolRelatedToPreviousError (method);
3702                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3703                                                   TypeManager.CSharpSignature (method));
3704                         } else
3705                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3706                                         TypeManager.CSharpName (delegate_type));
3707
3708                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3709
3710                         string index = (idx + 1).ToString ();
3711                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3712                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3713                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3714                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3715                                                 index, Parameter.GetModifierSignature (a.Modifier));
3716                                 else
3717                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3718                                                 index, Parameter.GetModifierSignature (mod));
3719                         } else {
3720                                 string p1 = a.GetSignatureForError ();
3721                                 string p2 = TypeManager.CSharpName (paramType);
3722
3723                                 if (p1 == p2) {
3724                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3725                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3726                                         Report.SymbolRelatedToPreviousError (paramType);
3727                                 }
3728                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3729                         }
3730                 }
3731
3732                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3733                 {
3734                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3735                                 Name, TypeManager.CSharpName (target));
3736                 }
3737
3738                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3739                 {
3740                         return parameters.Count;
3741                 }
3742
3743                 public static bool IsAncestralType (Type first_type, Type second_type)
3744                 {
3745                         return first_type != second_type &&
3746                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3747                                 TypeManager.ImplementsInterface (second_type, first_type));
3748                 }
3749
3750                 ///
3751                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3752                 /// to the given set of arguments
3753                 /// A return value rates candidate method compatibility,
3754                 /// 0 = the best, int.MaxValue = the worst
3755                 ///
3756                 public int IsApplicable (EmitContext ec,
3757                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3758                 {
3759                         MethodBase candidate = method;
3760
3761                         ParameterData pd = TypeManager.GetParameterData (candidate);
3762                         int param_count = GetApplicableParametersCount (candidate, pd);
3763
3764                         if (arg_count != param_count) {
3765                                 if (!pd.HasParams)
3766                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3767                                 if (arg_count < param_count - 1)
3768                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3769                         }
3770
3771 #if GMCS_SOURCE
3772                         //
3773                         // 1. Handle generic method using type arguments when specified or type inference
3774                         //
3775                         if (TypeManager.IsGenericMethod (candidate)) {
3776                                 if (type_arguments != null) {
3777                                         Type [] g_args = candidate.GetGenericArguments ();
3778                                         if (g_args.Length != type_arguments.Count)
3779                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3780
3781                                         // TODO: Don't create new method, create Parameters only
3782                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3783                                         candidate = method;
3784                                         pd = TypeManager.GetParameterData (candidate);
3785                                 } else {
3786                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3787                                         if (score != 0)
3788                                                 return score - 20000;
3789
3790                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3791                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3792                                                         TypeManager.CSharpSignature (candidate));
3793
3794                                         pd = TypeManager.GetParameterData (candidate);
3795                                 }
3796                         } else {
3797                                 if (type_arguments != null)
3798                                         return int.MaxValue - 15000;
3799                         }
3800 #endif
3801
3802                         //
3803                         // 2. Each argument has to be implicitly convertible to method parameter
3804                         //
3805                         method = candidate;
3806                         Parameter.Modifier p_mod = 0;
3807                         Type pt = null;
3808                         for (int i = 0; i < arg_count; i++) {
3809                                 Argument a = (Argument) arguments [i];
3810                                 Parameter.Modifier a_mod = a.Modifier &
3811                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3812
3813                                 if (p_mod != Parameter.Modifier.PARAMS) {
3814                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3815
3816                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3817                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3818                                                         continue;
3819
3820                                                 p_mod = 0;
3821                                         }
3822
3823                                         pt = pd.ParameterType (i);
3824                                 } else {
3825                                         params_expanded_form = true;
3826                                 }
3827
3828                                 int score = 1;
3829                                 if (!params_expanded_form)
3830                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3831
3832                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3833                                         // It can be applicable in expanded form
3834                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3835                                         if (score == 0)
3836                                                 params_expanded_form = true;
3837                                 }
3838
3839                                 if (score != 0) {
3840                                         if (params_expanded_form)
3841                                                 ++score;
3842                                         return (arg_count - i) * 2 + score;
3843                                 }
3844                         }
3845
3846                         if (arg_count != param_count)
3847                                 params_expanded_form = true;
3848
3849                         return 0;
3850                 }
3851
3852                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3853                 {
3854                         //
3855                         // Types have to be identical when ref or out modifer is used
3856                         //
3857                         if (arg_mod != 0 || param_mod != 0) {
3858                                 if (TypeManager.HasElementType (parameter))
3859                                         parameter = parameter.GetElementType ();
3860
3861                                 Type a_type = argument.Type;
3862                                 if (TypeManager.HasElementType (a_type))
3863                                         a_type = a_type.GetElementType ();
3864
3865                                 if (a_type != parameter)
3866                                         return 2;
3867
3868                                 return 0;
3869                         }
3870
3871                         // FIXME: Kill this abomination (EmitContext.TempEc)
3872                         EmitContext prevec = EmitContext.TempEc;
3873                         EmitContext.TempEc = ec;
3874                         try {
3875                                 if (delegate_type != null ?
3876                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3877                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3878                                         return 2;
3879
3880                                 if (arg_mod != param_mod)
3881                                         return 1;
3882
3883                         } finally {
3884                                 EmitContext.TempEc = prevec;
3885                         }
3886
3887                         return 0;
3888                 }
3889
3890                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3891                 {
3892                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3893                                 return false;
3894
3895                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3896                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3897
3898                         if (cand_pd.Count != base_pd.Count)
3899                                 return false;
3900
3901                         for (int j = 0; j < cand_pd.Count; ++j)
3902                         {
3903                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3904                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3905                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3906                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3907
3908                                 if (cm != bm || ct != bt)
3909                                         return false;
3910                         }
3911
3912                         return true;
3913                 }
3914
3915                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3916                 {
3917                         MemberInfo [] miset;
3918                         MethodGroupExpr union;
3919
3920                         if (mg1 == null) {
3921                                 if (mg2 == null)
3922                                         return null;
3923                                 return (MethodGroupExpr) mg2;
3924                         } else {
3925                                 if (mg2 == null)
3926                                         return (MethodGroupExpr) mg1;
3927                         }
3928
3929                         MethodGroupExpr left_set = null, right_set = null;
3930                         int length1 = 0, length2 = 0;
3931
3932                         left_set = (MethodGroupExpr) mg1;
3933                         length1 = left_set.Methods.Length;
3934
3935                         right_set = (MethodGroupExpr) mg2;
3936                         length2 = right_set.Methods.Length;
3937
3938                         ArrayList common = new ArrayList ();
3939
3940                         foreach (MethodBase r in right_set.Methods){
3941                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3942                                         common.Add (r);
3943                         }
3944
3945                         miset = new MemberInfo [length1 + length2 - common.Count];
3946                         left_set.Methods.CopyTo (miset, 0);
3947
3948                         int k = length1;
3949
3950                         foreach (MethodBase r in right_set.Methods) {
3951                                 if (!common.Contains (r))
3952                                         miset [k++] = r;
3953                         }
3954
3955                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3956
3957                         return union;
3958                 }
3959
3960                 static Type MoreSpecific (Type p, Type q)
3961                 {
3962                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3963                                 return q;
3964                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3965                                 return p;
3966
3967                         if (TypeManager.HasElementType (p))
3968                         {
3969                                 Type pe = TypeManager.GetElementType (p);
3970                                 Type qe = TypeManager.GetElementType (q);
3971                                 Type specific = MoreSpecific (pe, qe);
3972                                 if (specific == pe)
3973                                         return p;
3974                                 if (specific == qe)
3975                                         return q;
3976                         }
3977                         else if (TypeManager.IsGenericType (p))
3978                         {
3979                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3980                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3981
3982                                 bool p_specific_at_least_once = false;
3983                                 bool q_specific_at_least_once = false;
3984
3985                                 for (int i = 0; i < pargs.Length; i++)
3986                                 {
3987                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3988                                         if (specific == pargs [i])
3989                                                 p_specific_at_least_once = true;
3990                                         if (specific == qargs [i])
3991                                                 q_specific_at_least_once = true;
3992                                 }
3993
3994                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3995                                         return p;
3996                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3997                                         return q;
3998                         }
3999
4000                         return null;
4001                 }
4002
4003                 /// <summary>
4004                 ///   Find the Applicable Function Members (7.4.2.1)
4005                 ///
4006                 ///   me: Method Group expression with the members to select.
4007                 ///       it might contain constructors or methods (or anything
4008                 ///       that maps to a method).
4009                 ///
4010                 ///   Arguments: ArrayList containing resolved Argument objects.
4011                 ///
4012                 ///   loc: The location if we want an error to be reported, or a Null
4013                 ///        location for "probing" purposes.
4014                 ///
4015                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4016                 ///            that is the best match of me on Arguments.
4017                 ///
4018                 /// </summary>
4019                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4020                         bool may_fail, Location loc)
4021                 {
4022                         bool method_params = false;
4023                         Type applicable_type = null;
4024                         int arg_count = 0;
4025                         ArrayList candidates = new ArrayList (2);
4026                         ArrayList candidate_overrides = null;
4027
4028                         //
4029                         // Used to keep a map between the candidate
4030                         // and whether it is being considered in its
4031                         // normal or expanded form
4032                         //
4033                         // false is normal form, true is expanded form
4034                         //
4035                         Hashtable candidate_to_form = null;
4036
4037                         if (Arguments != null)
4038                                 arg_count = Arguments.Count;
4039
4040                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4041                                 if (!may_fail)
4042                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4043                                 return null;
4044                         }
4045
4046                         int nmethods = Methods.Length;
4047
4048                         if (!IsBase) {
4049                                 //
4050                                 // Methods marked 'override' don't take part in 'applicable_type'
4051                                 // computation, nor in the actual overload resolution.
4052                                 // However, they still need to be emitted instead of a base virtual method.
4053                                 // So, we salt them away into the 'candidate_overrides' array.
4054                                 //
4055                                 // In case of reflected methods, we replace each overriding method with
4056                                 // its corresponding base virtual method.  This is to improve compatibility
4057                                 // with non-C# libraries which change the visibility of overrides (#75636)
4058                                 //
4059                                 int j = 0;
4060                                 for (int i = 0; i < Methods.Length; ++i) {
4061                                         MethodBase m = Methods [i];
4062                                         if (TypeManager.IsOverride (m)) {
4063                                                 if (candidate_overrides == null)
4064                                                         candidate_overrides = new ArrayList ();
4065                                                 candidate_overrides.Add (m);
4066                                                 m = TypeManager.TryGetBaseDefinition (m);
4067                                         }
4068                                         if (m != null)
4069                                                 Methods [j++] = m;
4070                                 }
4071                                 nmethods = j;
4072                         }
4073
4074                         //
4075                         // Enable message recording, it's used mainly by lambda expressions
4076                         //
4077                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4078                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4079
4080                         //
4081                         // First we construct the set of applicable methods
4082                         //
4083                         bool is_sorted = true;
4084                         int best_candidate_rate = int.MaxValue;
4085                         for (int i = 0; i < nmethods; i++) {
4086                                 Type decl_type = Methods [i].DeclaringType;
4087
4088                                 //
4089                                 // If we have already found an applicable method
4090                                 // we eliminate all base types (Section 14.5.5.1)
4091                                 //
4092                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4093                                         continue;
4094
4095                                 //
4096                                 // Check if candidate is applicable (section 14.4.2.1)
4097                                 //
4098                                 bool params_expanded_form = false;
4099                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4100
4101                                 if (candidate_rate < best_candidate_rate) {
4102                                         best_candidate_rate = candidate_rate;
4103                                         best_candidate = Methods [i];
4104                                 }
4105
4106                                 if (params_expanded_form) {
4107                                         if (candidate_to_form == null)
4108                                                 candidate_to_form = new PtrHashtable ();
4109                                         MethodBase candidate = Methods [i];
4110                                         candidate_to_form [candidate] = candidate;
4111                                 }
4112
4113                                 if (candidate_rate != 0) {
4114                                         if (msg_recorder != null)
4115                                                 msg_recorder.EndSession ();
4116                                         continue;
4117                                 }
4118
4119                                 msg_recorder = null;
4120                                 candidates.Add (Methods [i]);
4121
4122                                 if (applicable_type == null)
4123                                         applicable_type = decl_type;
4124                                 else if (applicable_type != decl_type) {
4125                                         is_sorted = false;
4126                                         if (IsAncestralType (applicable_type, decl_type))
4127                                                 applicable_type = decl_type;
4128                                 }
4129                         }
4130
4131                         Report.SetMessageRecorder (prev_recorder);
4132                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4133                                 return null;
4134
4135                         int candidate_top = candidates.Count;
4136
4137                         if (applicable_type == null) {
4138                                 //
4139                                 // When we found a top level method which does not match and it's
4140                                 // not an extension method. We start extension methods lookup from here
4141                                 //
4142                                 if (InstanceExpression != null) {
4143                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4144                                         if (ex_method_lookup != null) {
4145                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4146                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4147                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4148                                         }
4149                                 }
4150
4151                                 if (may_fail)
4152                                         return null;
4153
4154                                 //
4155                                 // Okay so we have failed to find exact match so we
4156                                 // return error info about the closest match
4157                                 //
4158                                 if (best_candidate != null) {
4159                                         if (CustomErrorHandler != null) {
4160                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4161                                                         return null;
4162                                         }
4163
4164                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4165                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4166                                         if (arg_count == pd.Count || pd.HasParams) {
4167                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4168                                                         if (type_arguments == null) {
4169                                                                 Report.Error (411, loc,
4170                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4171                                                                         "the usage. Try specifying the type arguments explicitly",
4172                                                                         TypeManager.CSharpSignature (best_candidate));
4173                                                                 return null;
4174                                                         }
4175
4176                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4177                                                         if (type_arguments.Count != g_args.Length) {
4178                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4179                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4180                                                                         TypeManager.CSharpSignature (best_candidate),
4181                                                                         g_args.Length.ToString ());
4182                                                                 return null;
4183                                                         }
4184                                                 } else {
4185                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4186                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4187                                                                 return null;
4188                                                         }
4189                                                 }
4190
4191                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4192                                                         return null;
4193                                         }
4194                                 }
4195
4196                                 if (almost_matched_members.Count != 0) {
4197                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4198                                         null, MemberTypes.Constructor, AllBindingFlags);
4199                                         return null;
4200                                 }
4201
4202                                 //
4203                                 // We failed to find any method with correct argument count
4204                                 //
4205                                 if (Name == ConstructorInfo.ConstructorName) {
4206                                         Report.SymbolRelatedToPreviousError (type);
4207                                         Report.Error (1729, loc,
4208                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4209                                                 TypeManager.CSharpName (type), arg_count);
4210                                 } else {
4211                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4212                                                 Name, arg_count.ToString ());
4213                                 }
4214
4215                                 return null;
4216                         }
4217
4218                         if (!is_sorted) {
4219                                 //
4220                                 // At this point, applicable_type is _one_ of the most derived types
4221                                 // in the set of types containing the methods in this MethodGroup.
4222                                 // Filter the candidates so that they only contain methods from the
4223                                 // most derived types.
4224                                 //
4225
4226                                 int finalized = 0; // Number of finalized candidates
4227
4228                                 do {
4229                                         // Invariant: applicable_type is a most derived type
4230
4231                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4232                                         // eliminating all it's base types.  At the same time, we'll also move
4233                                         // every unrelated type to the end of the array, and pick the next
4234                                         // 'applicable_type'.
4235
4236                                         Type next_applicable_type = null;
4237                                         int j = finalized; // where to put the next finalized candidate
4238                                         int k = finalized; // where to put the next undiscarded candidate
4239                                         for (int i = finalized; i < candidate_top; ++i) {
4240                                                 MethodBase candidate = (MethodBase) candidates [i];
4241                                                 Type decl_type = candidate.DeclaringType;
4242
4243                                                 if (decl_type == applicable_type) {
4244                                                         candidates [k++] = candidates [j];
4245                                                         candidates [j++] = candidates [i];
4246                                                         continue;
4247                                                 }
4248
4249                                                 if (IsAncestralType (decl_type, applicable_type))
4250                                                         continue;
4251
4252                                                 if (next_applicable_type != null &&
4253                                                         IsAncestralType (decl_type, next_applicable_type))
4254                                                         continue;
4255
4256                                                 candidates [k++] = candidates [i];
4257
4258                                                 if (next_applicable_type == null ||
4259                                                         IsAncestralType (next_applicable_type, decl_type))
4260                                                         next_applicable_type = decl_type;
4261                                         }
4262
4263                                         applicable_type = next_applicable_type;
4264                                         finalized = j;
4265                                         candidate_top = k;
4266                                 } while (applicable_type != null);
4267                         }
4268
4269                         //
4270                         // Now we actually find the best method
4271                         //
4272
4273                         best_candidate = (MethodBase) candidates [0];
4274                         if (delegate_type == null)
4275                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4276
4277                         for (int ix = 1; ix < candidate_top; ix++) {
4278                                 MethodBase candidate = (MethodBase) candidates [ix];
4279
4280                                 if (candidate == best_candidate)
4281                                         continue;
4282
4283                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4284
4285                                 if (BetterFunction (ec, Arguments, arg_count,
4286                                         candidate, cand_params,
4287                                         best_candidate, method_params)) {
4288                                         best_candidate = candidate;
4289                                         method_params = cand_params;
4290                                 }
4291                         }
4292                         //
4293                         // Now check that there are no ambiguities i.e the selected method
4294                         // should be better than all the others
4295                         //
4296                         MethodBase ambiguous = null;
4297                         for (int ix = 1; ix < candidate_top; ix++) {
4298                                 MethodBase candidate = (MethodBase) candidates [ix];
4299
4300                                 if (candidate == best_candidate)
4301                                         continue;
4302
4303                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4304                                 if (!BetterFunction (ec, Arguments, arg_count,
4305                                         best_candidate, method_params,
4306                                         candidate, cand_params))
4307                                 {
4308                                         if (!may_fail)
4309                                                 Report.SymbolRelatedToPreviousError (candidate);
4310                                         ambiguous = candidate;
4311                                 }
4312                         }
4313
4314                         if (ambiguous != null) {
4315                                 Report.SymbolRelatedToPreviousError (best_candidate);
4316                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4317                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4318                                 return this;
4319                         }
4320
4321                         //
4322                         // If the method is a virtual function, pick an override closer to the LHS type.
4323                         //
4324                         if (!IsBase && best_candidate.IsVirtual) {
4325                                 if (TypeManager.IsOverride (best_candidate))
4326                                         throw new InternalErrorException (
4327                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4328
4329                                 if (candidate_overrides != null) {
4330                                         Type[] gen_args = null;
4331                                         bool gen_override = false;
4332                                         if (TypeManager.IsGenericMethod (best_candidate))
4333                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4334
4335                                         foreach (MethodBase candidate in candidate_overrides) {
4336                                                 if (TypeManager.IsGenericMethod (candidate)) {
4337                                                         if (gen_args == null)
4338                                                                 continue;
4339
4340                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4341                                                                 continue;
4342                                                 } else {
4343                                                         if (gen_args != null)
4344                                                                 continue;
4345                                                 }
4346
4347                                                 if (IsOverride (candidate, best_candidate)) {
4348                                                         gen_override = true;
4349                                                         best_candidate = candidate;
4350                                                 }
4351                                         }
4352
4353                                         if (gen_override && gen_args != null) {
4354 #if GMCS_SOURCE
4355                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4356 #endif
4357                                         }
4358                                 }
4359                         }
4360
4361                         //
4362                         // And now check if the arguments are all
4363                         // compatible, perform conversions if
4364                         // necessary etc. and return if everything is
4365                         // all right
4366                         //
4367                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4368                                 method_params, may_fail, loc))
4369                                 return null;
4370
4371                         if (best_candidate == null)
4372                                 return null;
4373
4374                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4375 #if GMCS_SOURCE
4376                         if (the_method.IsGenericMethodDefinition &&
4377                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4378                                 return null;
4379 #endif
4380
4381                         IMethodData data = TypeManager.GetMethod (the_method);
4382                         if (data != null)
4383                                 data.SetMemberIsUsed ();
4384
4385                         return this;
4386                 }
4387
4388                 public override void SetTypeArguments (TypeArguments ta)
4389                 {
4390                         type_arguments = ta;
4391                 }
4392
4393                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4394                                                           int arg_count, MethodBase method,
4395                                                           bool chose_params_expanded,
4396                                                           bool may_fail, Location loc)
4397                 {
4398                         ParameterData pd = TypeManager.GetParameterData (method);
4399
4400                         int errors = Report.Errors;
4401                         Parameter.Modifier p_mod = 0;
4402                         Type pt = null;
4403                         int a_idx = 0, a_pos = 0;
4404                         Argument a = null;
4405                         ArrayList params_initializers = null;
4406
4407                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4408                                 a = (Argument) arguments [a_idx];
4409                                 if (p_mod != Parameter.Modifier.PARAMS) {
4410                                         p_mod = pd.ParameterModifier (a_idx);
4411                                         pt = pd.ParameterType (a_idx);
4412
4413                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4414                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4415                                                         break;
4416                                                 continue;
4417                                         }
4418
4419                                         if (pt.IsPointer && !ec.InUnsafe) {
4420                                                 if (may_fail)
4421                                                         return false;
4422
4423                                                 UnsafeError (loc);
4424                                         }
4425
4426                                         if (p_mod == Parameter.Modifier.PARAMS) {
4427                                                 if (chose_params_expanded) {
4428                                                         params_initializers = new ArrayList (arg_count - a_idx);
4429                                                         pt = TypeManager.GetElementType (pt);
4430                                                 }
4431                                         } else if (p_mod != 0) {
4432                                                 pt = TypeManager.GetElementType (pt);
4433                                         }
4434                                 }
4435
4436                                 //
4437                                 // Types have to be identical when ref or out modifer is used
4438                                 //
4439                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4440                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4441                                                 break;
4442
4443                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4444                                                 break;
4445
4446                                         continue;
4447                                 }
4448
4449                                 Expression conv;
4450                                 if (TypeManager.IsEqual (a.Type, pt)) {
4451                                         conv = a.Expr;
4452                                 } else {
4453                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4454                                         if (conv == null)
4455                                                 break;
4456                                 }
4457
4458                                 //
4459                                 // Convert params arguments to an array initializer
4460                                 //
4461                                 if (params_initializers != null) {
4462                                         params_initializers.Add (conv);
4463                                         arguments.RemoveAt (a_idx--);
4464                                         --arg_count;
4465                                         continue;
4466                                 }
4467
4468                                 // Update the argument with the implicit conversion
4469                                 a.Expr = conv;
4470                         }
4471
4472                         //
4473                         // Fill not provided arguments required by params modifier
4474                         //
4475                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4476                                 if (arguments == null)
4477                                         arguments = new ArrayList (1);
4478
4479                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4480                                 pt = TypeManager.GetElementType (pt);
4481                                 params_initializers = new ArrayList (0);
4482                         }
4483
4484                         if (a_idx == arg_count) {
4485                                 //
4486                                 // Append an array argument with all params arguments
4487                                 //
4488                                 if (params_initializers != null) {
4489                                         arguments.Add (new Argument (
4490                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4491                                                 params_initializers, loc).Resolve (ec)));
4492                                 }
4493                                 return true;
4494                         }
4495
4496                         if (!may_fail && Report.Errors == errors) {
4497                                 if (CustomErrorHandler != null)
4498                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4499                                 else
4500                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4501                         }
4502                         return false;
4503                 }
4504         }
4505
4506         public class ConstantExpr : MemberExpr
4507         {
4508                 FieldInfo constant;
4509
4510                 public ConstantExpr (FieldInfo constant, Location loc)
4511                 {
4512                         this.constant = constant;
4513                         this.loc = loc;
4514                 }
4515
4516                 public override string Name {
4517                         get { throw new NotImplementedException (); }
4518                 }
4519
4520                 public override bool IsInstance {
4521                         get { return !IsStatic; }
4522                 }
4523
4524                 public override bool IsStatic {
4525                         get { return constant.IsStatic; }
4526                 }
4527
4528                 public override Type DeclaringType {
4529                         get { return constant.DeclaringType; }
4530                 }
4531
4532                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4533                 {
4534                         constant = TypeManager.GetGenericFieldDefinition (constant);
4535
4536                         IConstant ic = TypeManager.GetConstant (constant);
4537                         if (ic == null) {
4538                                 if (constant.IsLiteral) {
4539                                         ic = new ExternalConstant (constant);
4540                                 } else {
4541                                         ic = ExternalConstant.CreateDecimal (constant);
4542                                         // HACK: decimal field was not resolved as constant
4543                                         if (ic == null)
4544                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4545                                 }
4546                                 TypeManager.RegisterConstant (constant, ic);
4547                         }
4548
4549                         return base.ResolveMemberAccess (ec, left, loc, original);
4550                 }
4551
4552                 public override Expression CreateExpressionTree (EmitContext ec)
4553                 {
4554                         throw new NotSupportedException ();
4555                 }
4556
4557                 public override Expression DoResolve (EmitContext ec)
4558                 {
4559                         IConstant ic = TypeManager.GetConstant (constant);
4560                         if (ic.ResolveValue ()) {
4561                                 if (!ec.IsInObsoleteScope)
4562                                         ic.CheckObsoleteness (loc);
4563                         }
4564
4565                         return ic.CreateConstantReference (loc);
4566                 }
4567
4568                 public override void Emit (EmitContext ec)
4569                 {
4570                         throw new NotSupportedException ();
4571                 }
4572
4573                 public override string GetSignatureForError ()
4574                 {
4575                         return TypeManager.GetFullNameSignature (constant);
4576                 }
4577         }
4578
4579         /// <summary>
4580         ///   Fully resolved expression that evaluates to a Field
4581         /// </summary>
4582         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4583                 public readonly FieldInfo FieldInfo;
4584                 VariableInfo variable_info;
4585
4586                 LocalTemporary temp;
4587                 bool prepared;
4588                 bool in_initializer;
4589
4590                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4591                         this (fi, l)
4592                 {
4593                         this.in_initializer = in_initializer;
4594                 }
4595
4596                 public FieldExpr (FieldInfo fi, Location l)
4597                 {
4598                         FieldInfo = fi;
4599                         eclass = ExprClass.Variable;
4600                         type = TypeManager.TypeToCoreType (fi.FieldType);
4601                         loc = l;
4602                 }
4603
4604                 public override string Name {
4605                         get {
4606                                 return FieldInfo.Name;
4607                         }
4608                 }
4609
4610                 public override bool IsInstance {
4611                         get {
4612                                 return !FieldInfo.IsStatic;
4613                         }
4614                 }
4615
4616                 public override bool IsStatic {
4617                         get {
4618                                 return FieldInfo.IsStatic;
4619                         }
4620                 }
4621
4622                 public override Type DeclaringType {
4623                         get {
4624                                 return FieldInfo.DeclaringType;
4625                         }
4626                 }
4627
4628                 public override string GetSignatureForError ()
4629                 {
4630                         return TypeManager.GetFullNameSignature (FieldInfo);
4631                 }
4632
4633                 public VariableInfo VariableInfo {
4634                         get {
4635                                 return variable_info;
4636                         }
4637                 }
4638
4639                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4640                                                                 SimpleName original)
4641                 {
4642                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4643                         Type t = fi.FieldType;
4644
4645                         if (t.IsPointer && !ec.InUnsafe) {
4646                                 UnsafeError (loc);
4647                         }
4648
4649                         return base.ResolveMemberAccess (ec, left, loc, original);
4650                 }
4651
4652                 public override Expression CreateExpressionTree (EmitContext ec)
4653                 {
4654                         Expression instance;
4655                         if (InstanceExpression == null) {
4656                                 instance = new NullLiteral (loc);
4657                         } else {
4658                                 instance = InstanceExpression.CreateExpressionTree (ec);
4659                         }
4660
4661                         ArrayList args = new ArrayList (2);
4662                         args.Add (new Argument (instance));
4663                         args.Add (new Argument (CreateTypeOfExpression ()));
4664                         return CreateExpressionFactoryCall ("Field", args);
4665                 }
4666
4667                 public Expression CreateTypeOfExpression ()
4668                 {
4669                         return new TypeOfField (FieldInfo, loc);
4670                 }
4671
4672                 override public Expression DoResolve (EmitContext ec)
4673                 {
4674                         return DoResolve (ec, false, false);
4675                 }
4676
4677                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4678                 {
4679                         if (!FieldInfo.IsStatic){
4680                                 if (InstanceExpression == null){
4681                                         //
4682                                         // This can happen when referencing an instance field using
4683                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4684                                         //
4685                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4686                                         return null;
4687                                 }
4688
4689                                 // Resolve the field's instance expression while flow analysis is turned
4690                                 // off: when accessing a field "a.b", we must check whether the field
4691                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4692
4693                                 if (lvalue_instance) {
4694                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4695                                                 Expression right_side =
4696                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4697                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4698                                         }
4699                                 } else {
4700                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4701                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4702                                 }
4703
4704                                 if (InstanceExpression == null)
4705                                         return null;
4706
4707                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4708                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4709                                 }
4710                         }
4711
4712                         if (!in_initializer && !ec.IsInFieldInitializer) {
4713                                 ObsoleteAttribute oa;
4714                                 FieldBase f = TypeManager.GetField (FieldInfo);
4715                                 if (f != null) {
4716                                         if (!ec.IsInObsoleteScope)
4717                                                 f.CheckObsoleteness (loc);
4718
4719                                         // To be sure that type is external because we do not register generated fields
4720                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4721                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4722                                         if (oa != null)
4723                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4724                                 }
4725                         }
4726
4727                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4728                         if (am != null){
4729                                 if (!FieldInfo.IsStatic){
4730                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4731                                                 Report.Error (1673, loc,
4732                                                 "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",
4733                                                         "this");
4734                                                 return null;
4735                                         }
4736                                 }
4737                         }
4738
4739                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4740                         if (fb != null) {
4741                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4742                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4743                                 }
4744
4745                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4746                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4747                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4748                                                 TypeManager.GetFullNameSignature (FieldInfo));
4749                                 }
4750
4751                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4752                         }
4753
4754                         // If the instance expression is a local variable or parameter.
4755                         IVariable var = InstanceExpression as IVariable;
4756                         if ((var == null) || (var.VariableInfo == null))
4757                                 return this;
4758
4759                         VariableInfo vi = var.VariableInfo;
4760                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4761                                 return null;
4762
4763                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4764                         return this;
4765                 }
4766
4767                 static readonly int [] codes = {
4768                         191,    // instance, write access
4769                         192,    // instance, out access
4770                         198,    // static, write access
4771                         199,    // static, out access
4772                         1648,   // member of value instance, write access
4773                         1649,   // member of value instance, out access
4774                         1650,   // member of value static, write access
4775                         1651    // member of value static, out access
4776                 };
4777
4778                 static readonly string [] msgs = {
4779                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4780                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4781                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4782                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4783                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4784                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4785                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4786                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4787                 };
4788
4789                 // The return value is always null.  Returning a value simplifies calling code.
4790                 Expression Report_AssignToReadonly (Expression right_side)
4791                 {
4792                         int i = 0;
4793                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4794                                 i += 1;
4795                         if (IsStatic)
4796                                 i += 2;
4797                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4798                                 i += 4;
4799                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4800
4801                         return null;
4802                 }
4803
4804                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4805                 {
4806                         IVariable var = InstanceExpression as IVariable;
4807                         if ((var != null) && (var.VariableInfo != null))
4808                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4809
4810                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4811                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4812
4813                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4814
4815                         if (e == null)
4816                                 return null;
4817
4818                         FieldBase fb = TypeManager.GetField (FieldInfo);
4819                         if (fb != null)
4820                                 fb.SetAssigned ();
4821
4822                         if (FieldInfo.IsInitOnly) {
4823                                 // InitOnly fields can only be assigned in constructors or initializers
4824                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4825                                         return Report_AssignToReadonly (right_side);
4826
4827                                 if (ec.IsConstructor) {
4828                                         Type ctype = ec.TypeContainer.CurrentType;
4829                                         if (ctype == null)
4830                                                 ctype = ec.ContainerType;
4831
4832                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4833                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4834                                                 return Report_AssignToReadonly (right_side);
4835                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4836                                         if (IsStatic && !ec.IsStatic)
4837                                                 return Report_AssignToReadonly (right_side);
4838                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4839                                         if (!IsStatic && !(InstanceExpression is This))
4840                                                 return Report_AssignToReadonly (right_side);
4841                                 }
4842                         }
4843
4844                         if (right_side == EmptyExpression.OutAccess &&
4845                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4846                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4847                                 Report.Warning (197, 1, loc,
4848                                                 "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",
4849                                                 GetSignatureForError ());
4850                         }
4851
4852                         return this;
4853                 }
4854
4855                 public override void CheckMarshalByRefAccess (EmitContext ec)
4856                 {
4857                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4858                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4859                                 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",
4860                                                 GetSignatureForError ());
4861                         }
4862                 }
4863
4864                 public bool VerifyFixed ()
4865                 {
4866                         IVariable variable = InstanceExpression as IVariable;
4867                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4868                         // We defer the InstanceExpression check after the variable check to avoid a
4869                         // separate null check on InstanceExpression.
4870                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4871                 }
4872
4873                 public override int GetHashCode ()
4874                 {
4875                         return FieldInfo.GetHashCode ();
4876                 }
4877
4878                 public override bool Equals (object obj)
4879                 {
4880                         FieldExpr fe = obj as FieldExpr;
4881                         if (fe == null)
4882                                 return false;
4883
4884                         if (FieldInfo != fe.FieldInfo)
4885                                 return false;
4886
4887                         if (InstanceExpression == null || fe.InstanceExpression == null)
4888                                 return true;
4889
4890                         return InstanceExpression.Equals (fe.InstanceExpression);
4891                 }
4892
4893                 public void Emit (EmitContext ec, bool leave_copy)
4894                 {
4895                         ILGenerator ig = ec.ig;
4896                         bool is_volatile = false;
4897
4898                         FieldBase f = TypeManager.GetField (FieldInfo);
4899                         if (f != null){
4900                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4901                                         is_volatile = true;
4902
4903                                 f.SetMemberIsUsed ();
4904                         }
4905
4906                         if (FieldInfo.IsStatic){
4907                                 if (is_volatile)
4908                                         ig.Emit (OpCodes.Volatile);
4909
4910                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4911                         } else {
4912                                 if (!prepared)
4913                                         EmitInstance (ec, false);
4914
4915                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4916                                 if (ff != null) {
4917                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4918                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4919                                 } else {
4920                                         if (is_volatile)
4921                                                 ig.Emit (OpCodes.Volatile);
4922
4923                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4924                                 }
4925                         }
4926
4927                         if (leave_copy) {
4928                                 ec.ig.Emit (OpCodes.Dup);
4929                                 if (!FieldInfo.IsStatic) {
4930                                         temp = new LocalTemporary (this.Type);
4931                                         temp.Store (ec);
4932                                 }
4933                         }
4934                 }
4935
4936                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4937                 {
4938                         FieldAttributes fa = FieldInfo.Attributes;
4939                         bool is_static = (fa & FieldAttributes.Static) != 0;
4940                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4941                         ILGenerator ig = ec.ig;
4942
4943                         if (is_readonly && !ec.IsConstructor){
4944                                 Report_AssignToReadonly (source);
4945                                 return;
4946                         }
4947
4948                         //
4949                         // String concatenation creates a new string instance
4950                         //
4951                         prepared = prepare_for_load && !(source is StringConcat);
4952                         EmitInstance (ec, prepared);
4953
4954                         source.Emit (ec);
4955                         if (leave_copy) {
4956                                 ec.ig.Emit (OpCodes.Dup);
4957                                 if (!FieldInfo.IsStatic) {
4958                                         temp = new LocalTemporary (this.Type);
4959                                         temp.Store (ec);
4960                                 }
4961                         }
4962
4963                         FieldBase f = TypeManager.GetField (FieldInfo);
4964                         if (f != null){
4965                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4966                                         ig.Emit (OpCodes.Volatile);
4967
4968                                 f.SetAssigned ();
4969                         }
4970
4971                         if (is_static)
4972                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4973                         else
4974                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4975
4976                         if (temp != null) {
4977                                 temp.Emit (ec);
4978                                 temp.Release (ec);
4979                         }
4980                 }
4981
4982                 public override void Emit (EmitContext ec)
4983                 {
4984                         Emit (ec, false);
4985                 }
4986
4987                 public void AddressOf (EmitContext ec, AddressOp mode)
4988                 {
4989                         ILGenerator ig = ec.ig;
4990
4991                         FieldBase f = TypeManager.GetField (FieldInfo);
4992                         if (f != null){
4993                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4994                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4995                                                         f.GetSignatureForError ());
4996                                 }
4997
4998                                 if ((mode & AddressOp.Store) != 0)
4999                                         f.SetAssigned ();
5000                                 if ((mode & AddressOp.Load) != 0)
5001                                         f.SetMemberIsUsed ();
5002                         }
5003
5004                         //
5005                         // Handle initonly fields specially: make a copy and then
5006                         // get the address of the copy.
5007                         //
5008                         bool need_copy;
5009                         if (FieldInfo.IsInitOnly){
5010                                 need_copy = true;
5011                                 if (ec.IsConstructor){
5012                                         if (FieldInfo.IsStatic){
5013                                                 if (ec.IsStatic)
5014                                                         need_copy = false;
5015                                         } else
5016                                                 need_copy = false;
5017                                 }
5018                         } else
5019                                 need_copy = false;
5020
5021                         if (need_copy){
5022                                 LocalBuilder local;
5023                                 Emit (ec);
5024                                 local = ig.DeclareLocal (type);
5025                                 ig.Emit (OpCodes.Stloc, local);
5026                                 ig.Emit (OpCodes.Ldloca, local);
5027                                 return;
5028                         }
5029
5030
5031                         if (FieldInfo.IsStatic){
5032                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
5033                         } else {
5034                                 if (!prepared)
5035                                         EmitInstance (ec, false);
5036                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
5037                         }
5038                 }
5039         }
5040
5041
5042         /// <summary>
5043         ///   Expression that evaluates to a Property.  The Assign class
5044         ///   might set the `Value' expression if we are in an assignment.
5045         ///
5046         ///   This is not an LValue because we need to re-write the expression, we
5047         ///   can not take data from the stack and store it.
5048         /// </summary>
5049         public class PropertyExpr : MemberExpr, IAssignMethod {
5050                 public readonly PropertyInfo PropertyInfo;
5051                 MethodInfo getter, setter;
5052                 bool is_static;
5053
5054                 bool resolved;
5055
5056                 LocalTemporary temp;
5057                 bool prepared;
5058
5059                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5060                 {
5061                         PropertyInfo = pi;
5062                         eclass = ExprClass.PropertyAccess;
5063                         is_static = false;
5064                         loc = l;
5065
5066                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5067
5068                         ResolveAccessors (container_type);
5069                 }
5070
5071                 public override string Name {
5072                         get {
5073                                 return PropertyInfo.Name;
5074                         }
5075                 }
5076
5077                 public override bool IsInstance {
5078                         get {
5079                                 return !is_static;
5080                         }
5081                 }
5082
5083                 public override bool IsStatic {
5084                         get {
5085                                 return is_static;
5086                         }
5087                 }
5088
5089                 public override Expression CreateExpressionTree (EmitContext ec)
5090                 {
5091                         if (IsSingleDimensionalArrayLength ()) {
5092                                 ArrayList args = new ArrayList (1);
5093                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5094                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5095                         }
5096
5097                         // TODO: it's waiting for PropertyExpr refactoring
5098                         //ArrayList args = new ArrayList (2);
5099                         //args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5100                         //args.Add (getter expression);
5101                         //return CreateExpressionFactoryCall ("Property", args);
5102                         return base.CreateExpressionTree (ec);
5103                 }
5104
5105                 public Expression CreateSetterTypeOfExpression ()
5106                 {
5107                         return new Cast (new TypeExpression (typeof (MethodInfo), loc), new TypeOfMethod (setter, loc));
5108                 }
5109
5110                 public override Type DeclaringType {
5111                         get {
5112                                 return PropertyInfo.DeclaringType;
5113                         }
5114                 }
5115
5116                 public override string GetSignatureForError ()
5117                 {
5118                         return TypeManager.GetFullNameSignature (PropertyInfo);
5119                 }
5120
5121                 void FindAccessors (Type invocation_type)
5122                 {
5123                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5124                                 BindingFlags.Static | BindingFlags.Instance |
5125                                 BindingFlags.DeclaredOnly;
5126
5127                         Type current = PropertyInfo.DeclaringType;
5128                         for (; current != null; current = current.BaseType) {
5129                                 MemberInfo[] group = TypeManager.MemberLookup (
5130                                         invocation_type, invocation_type, current,
5131                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5132
5133                                 if (group == null)
5134                                         continue;
5135
5136                                 if (group.Length != 1)
5137                                         // Oooops, can this ever happen ?
5138                                         return;
5139
5140                                 PropertyInfo pi = (PropertyInfo) group [0];
5141
5142                                 if (getter == null)
5143                                         getter = pi.GetGetMethod (true);
5144
5145                                 if (setter == null)
5146                                         setter = pi.GetSetMethod (true);
5147
5148                                 MethodInfo accessor = getter != null ? getter : setter;
5149
5150                                 if (!accessor.IsVirtual)
5151                                         return;
5152                         }
5153                 }
5154
5155                 //
5156                 // We also perform the permission checking here, as the PropertyInfo does not
5157                 // hold the information for the accessibility of its setter/getter
5158                 //
5159                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5160                 void ResolveAccessors (Type container_type)
5161                 {
5162                         FindAccessors (container_type);
5163
5164                         if (getter != null) {
5165                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5166                                 IMethodData md = TypeManager.GetMethod (the_getter);
5167                                 if (md != null)
5168                                         md.SetMemberIsUsed ();
5169
5170                                 is_static = getter.IsStatic;
5171                         }
5172
5173                         if (setter != null) {
5174                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5175                                 IMethodData md = TypeManager.GetMethod (the_setter);
5176                                 if (md != null)
5177                                         md.SetMemberIsUsed ();
5178
5179                                 is_static = setter.IsStatic;
5180                         }
5181                 }
5182
5183                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5184                 {
5185                         if (is_static) {
5186                                 InstanceExpression = null;
5187                                 return true;
5188                         }
5189
5190                         if (InstanceExpression == null) {
5191                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5192                                 return false;
5193                         }
5194
5195                         InstanceExpression = InstanceExpression.DoResolve (ec);
5196                         if (lvalue_instance && InstanceExpression != null)
5197                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5198
5199                         if (InstanceExpression == null)
5200                                 return false;
5201
5202                         InstanceExpression.CheckMarshalByRefAccess (ec);
5203
5204                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5205                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5206                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5207                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5208                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5209                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5210                                 return false;
5211                         }
5212
5213                         return true;
5214                 }
5215
5216                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5217                 {
5218                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5219                         if (mi is MethodBuilder) {
5220                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5221                                 return;
5222                         }
5223
5224                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5225                         sig.Append ('.');
5226                         ParameterData iparams = TypeManager.GetParameterData (mi);
5227                         sig.Append (getter ? "get_" : "set_");
5228                         sig.Append (Name);
5229                         sig.Append (iparams.GetSignatureForError ());
5230
5231                         Report.SymbolRelatedToPreviousError (mi);
5232                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5233                                 Name, sig.ToString ());
5234                 }
5235
5236                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5237                 {
5238                         bool dummy;
5239                         MethodInfo accessor = lvalue ? setter : getter;
5240                         if (accessor == null && lvalue)
5241                                 accessor = getter;
5242                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5243                 }
5244
5245                 bool IsSingleDimensionalArrayLength ()
5246                 {
5247                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5248                                 return false;
5249
5250                         string t_name = InstanceExpression.Type.Name;
5251                         int t_name_len = t_name.Length;
5252                         return t_name_len > 2 && t_name [t_name_len - 2] == '[' && t_name [t_name_len - 3] != ']';
5253                 }
5254
5255                 override public Expression DoResolve (EmitContext ec)
5256                 {
5257                         if (resolved)
5258                                 return this;
5259
5260                         if (getter != null){
5261                                 if (TypeManager.GetParameterData (getter).Count != 0){
5262                                         Error_PropertyNotFound (getter, true);
5263                                         return null;
5264                                 }
5265                         }
5266
5267                         if (getter == null){
5268                                 //
5269                                 // The following condition happens if the PropertyExpr was
5270                                 // created, but is invalid (ie, the property is inaccessible),
5271                                 // and we did not want to embed the knowledge about this in
5272                                 // the caller routine.  This only avoids double error reporting.
5273                                 //
5274                                 if (setter == null)
5275                                         return null;
5276
5277                                 if (InstanceExpression != EmptyExpression.Null) {
5278                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5279                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5280                                         return null;
5281                                 }
5282                         }
5283
5284                         bool must_do_cs1540_check = false;
5285                         if (getter != null &&
5286                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5287                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5288                                 if (pm != null && pm.HasCustomAccessModifier) {
5289                                         Report.SymbolRelatedToPreviousError (pm);
5290                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5291                                                 TypeManager.CSharpSignature (getter));
5292                                 }
5293                                 else {
5294                                         Report.SymbolRelatedToPreviousError (getter);
5295                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5296                                 }
5297                                 return null;
5298                         }
5299
5300                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5301                                 return null;
5302
5303                         //
5304                         // Only base will allow this invocation to happen.
5305                         //
5306                         if (IsBase && getter.IsAbstract) {
5307                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5308                                 return null;
5309                         }
5310
5311                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5312                                 UnsafeError (loc);
5313                                 return null;
5314                         }
5315
5316                         resolved = true;
5317
5318                         return this;
5319                 }
5320
5321                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5322                 {
5323                         if (right_side == EmptyExpression.OutAccess) {
5324                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5325                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5326                                             PropertyInfo.Name);
5327                                 } else {
5328                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5329                                               GetSignatureForError ());
5330                                 }
5331                                 return null;
5332                         }
5333
5334                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5335                                 Error_CannotModifyIntermediateExpressionValue (ec);
5336                         }
5337
5338                         if (setter == null){
5339                                 //
5340                                 // The following condition happens if the PropertyExpr was
5341                                 // created, but is invalid (ie, the property is inaccessible),
5342                                 // and we did not want to embed the knowledge about this in
5343                                 // the caller routine.  This only avoids double error reporting.
5344                                 //
5345                                 if (getter == null)
5346                                         return null;
5347                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5348                                               GetSignatureForError ());
5349                                 return null;
5350                         }
5351
5352                         if (TypeManager.GetParameterData (setter).Count != 1){
5353                                 Error_PropertyNotFound (setter, false);
5354                                 return null;
5355                         }
5356
5357                         bool must_do_cs1540_check;
5358                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5359                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5360                                 if (pm != null && pm.HasCustomAccessModifier) {
5361                                         Report.SymbolRelatedToPreviousError (pm);
5362                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5363                                                 TypeManager.CSharpSignature (setter));
5364                                 }
5365                                 else {
5366                                         Report.SymbolRelatedToPreviousError (setter);
5367                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5368                                 }
5369                                 return null;
5370                         }
5371
5372                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5373                                 return null;
5374
5375                         //
5376                         // Only base will allow this invocation to happen.
5377                         //
5378                         if (IsBase && setter.IsAbstract){
5379                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5380                                 return null;
5381                         }
5382
5383                         return this;
5384                 }
5385
5386                 public override void Emit (EmitContext ec)
5387                 {
5388                         Emit (ec, false);
5389                 }
5390
5391                 public void Emit (EmitContext ec, bool leave_copy)
5392                 {
5393                         //
5394                         // Special case: length of single dimension array property is turned into ldlen
5395                         //
5396                         if (IsSingleDimensionalArrayLength ()) {
5397                                 if (!prepared)
5398                                         EmitInstance (ec, false);
5399                                 ec.ig.Emit (OpCodes.Ldlen);
5400                                 ec.ig.Emit (OpCodes.Conv_I4);
5401                                 return;
5402                         }
5403
5404                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5405
5406                         if (leave_copy) {
5407                                 ec.ig.Emit (OpCodes.Dup);
5408                                 if (!is_static) {
5409                                         temp = new LocalTemporary (this.Type);
5410                                         temp.Store (ec);
5411                                 }
5412                         }
5413                 }
5414
5415                 //
5416                 // Implements the IAssignMethod interface for assignments
5417                 //
5418                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5419                 {
5420                         Expression my_source = source;
5421
5422                         if (prepare_for_load) {
5423                                 if (source is StringConcat)
5424                                         EmitInstance (ec, false);
5425                                 else
5426                                         prepared = true;
5427
5428                                 source.Emit (ec);
5429
5430                                 prepared = true;
5431                                 if (leave_copy) {
5432                                         ec.ig.Emit (OpCodes.Dup);
5433                                         if (!is_static) {
5434                                                 temp = new LocalTemporary (this.Type);
5435                                                 temp.Store (ec);
5436                                         }
5437                                 }
5438                         } else if (leave_copy) {
5439                                 source.Emit (ec);
5440                                 temp = new LocalTemporary (this.Type);
5441                                 temp.Store (ec);
5442                                 my_source = temp;
5443                         }
5444
5445                         ArrayList args = new ArrayList (1);
5446                         args.Add (new Argument (my_source, Argument.AType.Expression));
5447
5448                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5449
5450                         if (temp != null) {
5451                                 temp.Emit (ec);
5452                                 temp.Release (ec);
5453                         }
5454                 }
5455         }
5456
5457         /// <summary>
5458         ///   Fully resolved expression that evaluates to an Event
5459         /// </summary>
5460         public class EventExpr : MemberExpr {
5461                 public readonly EventInfo EventInfo;
5462
5463                 bool is_static;
5464                 MethodInfo add_accessor, remove_accessor;
5465
5466                 public EventExpr (EventInfo ei, Location loc)
5467                 {
5468                         EventInfo = ei;
5469                         this.loc = loc;
5470                         eclass = ExprClass.EventAccess;
5471
5472                         add_accessor = TypeManager.GetAddMethod (ei);
5473                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5474                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5475                                 is_static = true;
5476
5477                         if (EventInfo is MyEventBuilder){
5478                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5479                                 type = eb.EventType;
5480                                 eb.SetUsed ();
5481                         } else
5482                                 type = EventInfo.EventHandlerType;
5483                 }
5484
5485                 public override string Name {
5486                         get {
5487                                 return EventInfo.Name;
5488                         }
5489                 }
5490
5491                 public override bool IsInstance {
5492                         get {
5493                                 return !is_static;
5494                         }
5495                 }
5496
5497                 public override bool IsStatic {
5498                         get {
5499                                 return is_static;
5500                         }
5501                 }
5502
5503                 public override Type DeclaringType {
5504                         get {
5505                                 return EventInfo.DeclaringType;
5506                         }
5507                 }
5508
5509                 void Error_AssignmentEventOnly ()
5510                 {
5511                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5512                                 GetSignatureForError ());
5513                 }
5514
5515                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5516                                                                 SimpleName original)
5517                 {
5518                         //
5519                         // If the event is local to this class, we transform ourselves into a FieldExpr
5520                         //
5521
5522                         if (EventInfo.DeclaringType == ec.ContainerType ||
5523                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5524                                 EventField mi = TypeManager.GetEventField (EventInfo);
5525
5526                                 if (mi != null) {
5527                                         if (!ec.IsInObsoleteScope)
5528                                                 mi.CheckObsoleteness (loc);
5529
5530                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5531                                                 Error_AssignmentEventOnly ();
5532
5533                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5534
5535                                         InstanceExpression = null;
5536
5537                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5538                                 }
5539                         }
5540
5541                         if (left is This && !ec.IsInCompoundAssignment)
5542                                 Error_AssignmentEventOnly ();
5543
5544                         return base.ResolveMemberAccess (ec, left, loc, original);
5545                 }
5546
5547
5548                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5549                 {
5550                         if (is_static) {
5551                                 InstanceExpression = null;
5552                                 return true;
5553                         }
5554
5555                         if (InstanceExpression == null) {
5556                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5557                                 return false;
5558                         }
5559
5560                         InstanceExpression = InstanceExpression.DoResolve (ec);
5561                         if (InstanceExpression == null)
5562                                 return false;
5563
5564                         if (IsBase && add_accessor.IsAbstract) {
5565                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5566                                 return false;
5567                         }
5568
5569                         //
5570                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5571                         // However, in the Event case, we reported a CS0122 instead.
5572                         //
5573                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5574                             InstanceExpression.Type != ec.ContainerType &&
5575                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5576                                 Report.SymbolRelatedToPreviousError (EventInfo);
5577                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5578                                 return false;
5579                         }
5580
5581                         return true;
5582                 }
5583
5584                 public bool IsAccessibleFrom (Type invocation_type)
5585                 {
5586                         bool dummy;
5587                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5588                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5589                 }
5590
5591                 public override Expression CreateExpressionTree (EmitContext ec)
5592                 {
5593                         throw new NotSupportedException ();
5594                 }
5595
5596                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5597                 {
5598                         return DoResolve (ec);
5599                 }
5600
5601                 public override Expression DoResolve (EmitContext ec)
5602                 {
5603                         bool must_do_cs1540_check;
5604                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5605                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5606                                 Report.SymbolRelatedToPreviousError (EventInfo);
5607                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5608                                 return null;
5609                         }
5610
5611                         if (!InstanceResolve (ec, must_do_cs1540_check))
5612                                 return null;
5613
5614                         return this;
5615                 }
5616
5617                 public override void Emit (EmitContext ec)
5618                 {
5619                         Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5620                                       "(except on the defining type)", GetSignatureForError ());
5621                 }
5622
5623                 public override string GetSignatureForError ()
5624                 {
5625                         return TypeManager.CSharpSignature (EventInfo);
5626                 }
5627
5628                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5629                 {
5630                         BinaryDelegate source_del = source as BinaryDelegate;
5631                         if (source_del == null) {
5632                                 Emit (ec);
5633                                 return;
5634                         }
5635                         Expression handler = source_del.Right;
5636
5637                         Argument arg = new Argument (handler, Argument.AType.Expression);
5638                         ArrayList args = new ArrayList ();
5639
5640                         args.Add (arg);
5641
5642                         if (source_del.IsAddition)
5643                                 Invocation.EmitCall (
5644                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5645                         else
5646                                 Invocation.EmitCall (
5647                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5648                 }
5649         }
5650
5651         public class TemporaryVariable : Expression, IMemoryLocation
5652         {
5653                 LocalInfo li;
5654                 Variable var;
5655
5656                 public TemporaryVariable (Type type, Location loc)
5657                 {
5658                         this.type = type;
5659                         this.loc = loc;
5660                         eclass = ExprClass.Value;
5661                 }
5662
5663                 public override Expression DoResolve (EmitContext ec)
5664                 {
5665                         if (li != null)
5666                                 return this;
5667
5668                         TypeExpr te = new TypeExpression (type, loc);
5669                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5670                         if (!li.Resolve (ec))
5671                                 return null;
5672
5673                         if (ec.MustCaptureVariable (li)) {
5674                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5675                                 var = scope.AddLocal (li);
5676                                 type = var.Type;
5677                         }
5678
5679                         return this;
5680                 }
5681
5682                 public Variable Variable {
5683                         get { return var != null ? var : li.Variable; }
5684                 }
5685
5686                 public override void Emit (EmitContext ec)
5687                 {
5688                         Variable.EmitInstance (ec);
5689                         Variable.Emit (ec);
5690                 }
5691
5692                 public void EmitLoadAddress (EmitContext ec)
5693                 {
5694                         Variable.EmitInstance (ec);
5695                         Variable.EmitAddressOf (ec);
5696                 }
5697
5698                 public void Store (EmitContext ec, Expression right_side)
5699                 {
5700                         Variable.EmitInstance (ec);
5701                         right_side.Emit (ec);
5702                         Variable.EmitAssign (ec);
5703                 }
5704
5705                 public void EmitThis (EmitContext ec)
5706                 {
5707                         Variable.EmitInstance (ec);
5708                 }
5709
5710                 public void EmitStore (EmitContext ec)
5711                 {
5712                         Variable.EmitAssign (ec);
5713                 }
5714
5715                 public void AddressOf (EmitContext ec, AddressOp mode)
5716                 {
5717                         EmitLoadAddress (ec);
5718                 }
5719         }
5720
5721         ///
5722         /// Handles `var' contextual keyword; var becomes a keyword only
5723         /// if no type called var exists in a variable scope
5724         ///
5725         public class VarExpr : SimpleName
5726         {
5727                 // Used for error reporting only
5728                 ArrayList initializer;
5729
5730                 public VarExpr (Location loc)
5731                         : base ("var", loc)
5732                 {
5733                 }
5734
5735                 public ArrayList VariableInitializer {
5736                         set {
5737                                 this.initializer = value;
5738                         }
5739                 }
5740
5741                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5742                 {
5743                         if (type != null)
5744                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5745
5746                         type = right_side.Type;
5747                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5748                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5749                                               right_side.GetSignatureForError ());
5750                                 return null;
5751                         }
5752
5753                         eclass = ExprClass.Variable;
5754                         return this;
5755                 }
5756
5757                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5758                 {
5759                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5760                 }
5761
5762                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5763                 {
5764                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5765                         if (te != null)
5766                                 return te;
5767
5768                         if (initializer == null)
5769                                 return null;
5770
5771                         if (initializer.Count > 1) {
5772                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5773                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5774                                 initializer = null;
5775                                 return null;
5776                         }
5777
5778                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5779                         if (variable_initializer == null) {
5780                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5781                                 return null;
5782                         }
5783
5784                         return null;
5785                 }
5786         }
5787 }