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                 public virtual void EmitSideEffect (EmitContext ec)
 594                 {
 595                         Emit (ec);
 596                         ec.ig.Emit (OpCodes.Pop);
 597                 }
 598
 599                 /// <summary>
 600                 ///   Protected constructor.  Only derivate types should
 601                 ///   be able to be created
 602                 /// </summary>
 603
 604                 protected Expression ()
 605                 {
 606                         eclass = ExprClass.Invalid;
 607                         type = null;
 608                 }
 609
 610                 /// <summary>
 611                 ///   Returns a fully formed expression after a MemberLookup
 612                 /// </summary>
 613                 ///
 614                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 615                 {
 616                         if (mi is EventInfo)
 617                                 return new EventExpr ((EventInfo) mi, loc);
 618                         else if (mi is FieldInfo) {
 619                                 FieldInfo fi = (FieldInfo) mi;
 620                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 621                                         return new ConstantExpr (fi, loc);
 622                                 return new FieldExpr (fi, loc);
 623                         } else if (mi is PropertyInfo)
 624                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 625                         else if (mi is Type) {
 626                                 return new TypeExpression ((System.Type) mi, loc);
 627                         }
 628
 629                         return null;
 630                 }
 631
 632                 protected static ArrayList almost_matched_members = new ArrayList (4);
 633
 634                 //
 635                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 636                 //
 637                 // This code could use some optimizations, but we need to do some
 638                 // measurements.  For example, we could use a delegate to `flag' when
 639                 // something can not any longer be a method-group (because it is something
 640                 // else).
 641                 //
 642                 // Return values:
 643                 //     If the return value is an Array, then it is an array of
 644                 //     MethodBases
 645                 //
 646                 //     If the return value is an MemberInfo, it is anything, but a Method
 647                 //
 648                 //     null on error.
 649                 //
 650                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 651                 // the arguments here and have MemberLookup return only the methods that
 652                 // match the argument count/type, unlike we are doing now (we delay this
 653                 // decision).
 654                 //
 655                 // This is so we can catch correctly attempts to invoke instance methods
 656                 // from a static body (scan for error 120 in ResolveSimpleName).
 657                 //
 658                 //
 659                 // FIXME: Potential optimization, have a static ArrayList
 660                 //
 661
 662                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 663                                                        MemberTypes mt, BindingFlags bf, Location loc)
 664                 {
 665                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 666                 }
 667
 668                 //
 669                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 670                 // `qualifier_type' or null to lookup members in the current class.
 671                 //
 672
 673                 public static Expression MemberLookup (Type container_type,
 674                                                        Type qualifier_type, Type queried_type,
 675                                                        string name, MemberTypes mt,
 676                                                        BindingFlags bf, Location loc)
 677                 {
 678                         almost_matched_members.Clear ();
 679
 680                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 681                                                                      queried_type, mt, bf, name, almost_matched_members);
 682
 683                         if (mi == null)
 684                                 return null;
 685
 686                         if (mi.Length > 1) {
 687                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 688                                 ArrayList methods = new ArrayList (2);
 689                                 ArrayList non_methods = null;
 690
 691                                 foreach (MemberInfo m in mi) {
 692                                         if (m is MethodBase) {
 693                                                 methods.Add (m);
 694                                                 continue;
 695                                         }
 696
 697                                         if (non_methods == null) {
 698                                                 non_methods = new ArrayList (2);
 699                                                 non_methods.Add (m);
 700                                                 continue;
 701                                         }
 702
 703                                         foreach (MemberInfo n_m in non_methods) {
 704                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 705                                                         continue;
 706
 707                                                 Report.SymbolRelatedToPreviousError (m);
 708                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 709                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 710                                                 return null;
 711                                         }
 712                                 }
 713
 714                                 if (methods.Count == 0)
 715                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 716
 717                                 if (non_methods != null) {
 718                                         MethodBase method = (MethodBase) methods [0];
 719                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 720                                         if (method.DeclaringType == non_method.DeclaringType) {
 721                                                 // Cannot happen with C# code, but is valid in IL
 722                                                 Report.SymbolRelatedToPreviousError (method);
 723                                                 Report.SymbolRelatedToPreviousError (non_method);
 724                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 725                                                               TypeManager.GetFullNameSignature (non_method),
 726                                                               TypeManager.CSharpSignature (method));
 727                                                 return null;
 728                                         }
 729
 730                                         if (is_interface) {
 731                                                 Report.SymbolRelatedToPreviousError (method);
 732                                                 Report.SymbolRelatedToPreviousError (non_method);
 733                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 734                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 735                                         }
 736                                 }
 737
 738                                 return new MethodGroupExpr (methods, queried_type, loc);
 739                         }
 740
 741                         if (mi [0] is MethodBase)
 742                                 return new MethodGroupExpr (mi, queried_type, loc);
 743
 744                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 745                 }
 746
 747                 public const MemberTypes AllMemberTypes =
 748                         MemberTypes.Constructor |
 749                         MemberTypes.Event       |
 750                         MemberTypes.Field       |
 751                         MemberTypes.Method      |
 752                         MemberTypes.NestedType  |
 753                         MemberTypes.Property;
 754
 755                 public const BindingFlags AllBindingFlags =
 756                         BindingFlags.Public |
 757                         BindingFlags.Static |
 758                         BindingFlags.Instance;
 759
 760                 public static Expression MemberLookup (Type container_type, Type queried_type,
 761                                                        string name, Location loc)
 762                 {
 763                         return MemberLookup (container_type, null, queried_type, name,
 764                                              AllMemberTypes, AllBindingFlags, loc);
 765                 }
 766
 767                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 768                                                        Type queried_type, string name, Location loc)
 769                 {
 770                         return MemberLookup (container_type, qualifier_type, queried_type,
 771                                              name, AllMemberTypes, AllBindingFlags, loc);
 772                 }
 773
 774                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 775                                                        string name, Location loc)
 776                 {
 777                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 778                                              MemberTypes.Method, AllBindingFlags, loc);
 779                 }
 780
 781                 /// <summary>
 782                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 783                 ///   to find a final definition.  If the final definition is not found, we
 784                 ///   look for private members and display a useful debugging message if we
 785                 ///   find it.
 786                 /// </summary>
 787                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 788                                                             Type queried_type, string name,
 789                                                             MemberTypes mt, BindingFlags bf,
 790                                                             Location loc)
 791                 {
 792                         Expression e;
 793
 794                         int errors = Report.Errors;
 795
 796                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 797
 798                         if (e != null || errors != Report.Errors)
 799                                 return e;
 800
 801                         // No errors were reported by MemberLookup, but there was an error.
 802                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 803                                         name, null, mt, bf);
 804                 }
 805
 806                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 807                                                        Type queried_type, string name, string class_name,
 808                                                            MemberTypes mt, BindingFlags bf)
 809                 {
 810                         if (almost_matched_members.Count != 0) {
 811                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 812                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 813                                         for (int j = 0; j < i; ++j) {
 814                                                 if (m == almost_matched_members [j]) {
 815                                                         m = null;
 816                                                         break;
 817                                                 }
 818                                         }
 819                                         if (m == null)
 820                                                 continue;
 821
 822                                         Type declaring_type = m.DeclaringType;
 823
 824                                         Report.SymbolRelatedToPreviousError (m);
 825                                         if (qualifier_type == null) {
 826                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 827                                                               TypeManager.CSharpName (m.DeclaringType),
 828                                                               TypeManager.CSharpName (container_type));
 829
 830                                         } else if (qualifier_type != container_type &&
 831                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 832                                                 // Although a derived class can access protected members of
 833                                                 // its base class it cannot do so through an instance of the
 834                                                 // base class (CS1540).  If the qualifier_type is a base of the
 835                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 836                                                 // then we are in this situation.
 837                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 838                                         } else {
 839                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 840                                         }
 841                                 }
 842                                 almost_matched_members.Clear ();
 843                                 return null;
 844                         }
 845
 846                         MemberInfo[] lookup = null;
 847                         if (queried_type == null) {
 848                                 class_name = "global::";
 849                         } else {
 850                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 851                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 852                                         name, null);
 853
 854                                 if (lookup != null) {
 855                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 856                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 857                                         return Error_MemberLookupFailed (lookup);
 858                                 }
 859
 860                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 861                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 862                                         name, null);
 863                         }
 864
 865                         if (lookup == null) {
 866                                 if (class_name != null) {
 867                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 868                                                 name);
 869                                 } else {
 870                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 871                                 }
 872                                 return null;
 873                         }
 874
 875                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 876                                                       AllMemberTypes, AllBindingFlags |
 877                                                       BindingFlags.NonPublic, name, null) == null) {
 878                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 879                                         Type t = (Type) lookup [0];
 880
 881                                         Report.Error (305, loc,
 882                                                       "Using the generic type `{0}' " +
 883                                                       "requires {1} type arguments",
 884                                                       TypeManager.CSharpName (t),
 885                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 886                                         return null;
 887                                 }
 888                         }
 889
 890                         return Error_MemberLookupFailed (lookup);
 891                 }
 892
 893                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 894                 {
 895                         for (int i = 0; i < members.Length; ++i) {
 896                                 if (!(members [i] is MethodBase))
 897                                         return null;
 898                         }
 899
 900                         // By default propagate the closest candidates upwards
 901                         return new MethodGroupExpr (members, type, loc);
 902                 }
 903
 904                 protected virtual void Error_NegativeArrayIndex (Location loc)
 905                 {
 906                         throw new NotImplementedException ();
 907                 }
 908
 909                 /// <summary>
 910                 ///   Returns an expression that can be used to invoke operator true
 911                 ///   on the expression if it exists.
 912                 /// </summary>
 913                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 914                 {
 915                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 916                 }
 917
 918                 /// <summary>
 919                 ///   Returns an expression that can be used to invoke operator false
 920                 ///   on the expression if it exists.
 921                 /// </summary>
 922                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 923                 {
 924                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 925                 }
 926
 927                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 928                 {
 929                         MethodGroupExpr operator_group;
 930                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 931                         if (operator_group == null)
 932                                 return null;
 933
 934                         ArrayList arguments = new ArrayList (1);
 935                         arguments.Add (new Argument (e, Argument.AType.Expression));
 936                         operator_group = operator_group.OverloadResolve (
 937                                 ec, ref arguments, false, loc);
 938
 939                         if (operator_group == null)
 940                                 return null;
 941
 942                         return new UserOperatorCall (operator_group, arguments, null, loc);
 943                 }
 944
 945                 /// <summary>
 946                 ///   Resolves the expression `e' into a boolean expression: either through
 947                 ///   an implicit conversion, or through an `operator true' invocation
 948                 /// </summary>
 949                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 950                 {
 951                         e = e.Resolve (ec);
 952                         if (e == null)
 953                                 return null;
 954
 955                         if (e.Type == TypeManager.bool_type)
 956                                 return e;
 957
 958                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 959
 960                         if (converted != null)
 961                                 return converted;
 962
 963                         //
 964                         // If no implicit conversion to bool exists, try using `operator true'
 965                         //
 966                         converted = Expression.GetOperatorTrue (ec, e, loc);
 967                         if (converted == null){
 968                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 969                                 return null;
 970                         }
 971                         return converted;
 972                 }
 973
 974                 public virtual string ExprClassName
 975                 {
 976                         get {
 977                                 switch (eclass){
 978                                         case ExprClass.Invalid:
 979                                                 return "Invalid";
 980                                         case ExprClass.Value:
 981                                                 return "value";
 982                                         case ExprClass.Variable:
 983                                                 return "variable";
 984                                         case ExprClass.Namespace:
 985                                                 return "namespace";
 986                                         case ExprClass.Type:
 987                                                 return "type";
 988                                         case ExprClass.MethodGroup:
 989                                                 return "method group";
 990                                         case ExprClass.PropertyAccess:
 991                                                 return "property access";
 992                                         case ExprClass.EventAccess:
 993                                                 return "event access";
 994                                         case ExprClass.IndexerAccess:
 995                                                 return "indexer access";
 996                                         case ExprClass.Nothing:
 997                                                 return "null";
 998                                 }
 999                                 throw new Exception ("Should not happen");
1000                         }
1001                 }
1002
1003                 /// <summary>
1004                 ///   Reports that we were expecting `expr' to be of class `expected'
1005                 /// </summary>
1006                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1007                 {
1008                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1009                 }
1010
1011                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1012                 {
1013                         string name = GetSignatureForError ();
1014                         if (ds != null)
1015                                 name = ds.GetSignatureForError () + '.' + name;
1016
1017                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1018                               name, was, expected);
1019                 }
1020
1021                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1022                 {
1023                         string [] valid = new string [4];
1024                         int count = 0;
1025
1026                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1027                                 valid [count++] = "variable";
1028                                 valid [count++] = "value";
1029                         }
1030
1031                         if ((flags & ResolveFlags.Type) != 0)
1032                                 valid [count++] = "type";
1033
1034                         if ((flags & ResolveFlags.MethodGroup) != 0)
1035                                 valid [count++] = "method group";
1036
1037                         if (count == 0)
1038                                 valid [count++] = "unknown";
1039
1040                         StringBuilder sb = new StringBuilder (valid [0]);
1041                         for (int i = 1; i < count - 1; i++) {
1042                                 sb.Append ("', `");
1043                                 sb.Append (valid [i]);
1044                         }
1045                         if (count > 1) {
1046                                 sb.Append ("' or `");
1047                                 sb.Append (valid [count - 1]);
1048                         }
1049
1050                         Report.Error (119, loc,
1051                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1052                 }
1053
1054                 public static void UnsafeError (Location loc)
1055                 {
1056                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1057                 }
1058
1059                 //
1060                 // Load the object from the pointer.
1061                 //
1062                 public static void LoadFromPtr (ILGenerator ig, Type t)
1063                 {
1064                         if (t == TypeManager.int32_type)
1065                                 ig.Emit (OpCodes.Ldind_I4);
1066                         else if (t == TypeManager.uint32_type)
1067                                 ig.Emit (OpCodes.Ldind_U4);
1068                         else if (t == TypeManager.short_type)
1069                                 ig.Emit (OpCodes.Ldind_I2);
1070                         else if (t == TypeManager.ushort_type)
1071                                 ig.Emit (OpCodes.Ldind_U2);
1072                         else if (t == TypeManager.char_type)
1073                                 ig.Emit (OpCodes.Ldind_U2);
1074                         else if (t == TypeManager.byte_type)
1075                                 ig.Emit (OpCodes.Ldind_U1);
1076                         else if (t == TypeManager.sbyte_type)
1077                                 ig.Emit (OpCodes.Ldind_I1);
1078                         else if (t == TypeManager.uint64_type)
1079                                 ig.Emit (OpCodes.Ldind_I8);
1080                         else if (t == TypeManager.int64_type)
1081                                 ig.Emit (OpCodes.Ldind_I8);
1082                         else if (t == TypeManager.float_type)
1083                                 ig.Emit (OpCodes.Ldind_R4);
1084                         else if (t == TypeManager.double_type)
1085                                 ig.Emit (OpCodes.Ldind_R8);
1086                         else if (t == TypeManager.bool_type)
1087                                 ig.Emit (OpCodes.Ldind_I1);
1088                         else if (t == TypeManager.intptr_type)
1089                                 ig.Emit (OpCodes.Ldind_I);
1090                         else if (TypeManager.IsEnumType (t)) {
1091                                 if (t == TypeManager.enum_type)
1092                                         ig.Emit (OpCodes.Ldind_Ref);
1093                                 else
1094                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1095                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1096                                 ig.Emit (OpCodes.Ldobj, t);
1097                         else if (t.IsPointer)
1098                                 ig.Emit (OpCodes.Ldind_I);
1099                         else
1100                                 ig.Emit (OpCodes.Ldind_Ref);
1101                 }
1102
1103                 //
1104                 // The stack contains the pointer and the value of type `type'
1105                 //
1106                 public static void StoreFromPtr (ILGenerator ig, Type type)
1107                 {
1108                         if (TypeManager.IsEnumType (type))
1109                                 type = TypeManager.GetEnumUnderlyingType (type);
1110                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1111                                 ig.Emit (OpCodes.Stind_I4);
1112                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1113                                 ig.Emit (OpCodes.Stind_I8);
1114                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1115                                  type == TypeManager.ushort_type)
1116                                 ig.Emit (OpCodes.Stind_I2);
1117                         else if (type == TypeManager.float_type)
1118                                 ig.Emit (OpCodes.Stind_R4);
1119                         else if (type == TypeManager.double_type)
1120                                 ig.Emit (OpCodes.Stind_R8);
1121                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1122                                  type == TypeManager.bool_type)
1123                                 ig.Emit (OpCodes.Stind_I1);
1124                         else if (type == TypeManager.intptr_type)
1125                                 ig.Emit (OpCodes.Stind_I);
1126                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1127                                 ig.Emit (OpCodes.Stobj, type);
1128                         else
1129                                 ig.Emit (OpCodes.Stind_Ref);
1130                 }
1131
1132                 //
1133                 // Returns the size of type `t' if known, otherwise, 0
1134                 //
1135                 public static int GetTypeSize (Type t)
1136                 {
1137                         t = TypeManager.TypeToCoreType (t);
1138                         if (t == TypeManager.int32_type ||
1139                             t == TypeManager.uint32_type ||
1140                             t == TypeManager.float_type)
1141                                 return 4;
1142                         else if (t == TypeManager.int64_type ||
1143                                  t == TypeManager.uint64_type ||
1144                                  t == TypeManager.double_type)
1145                                 return 8;
1146                         else if (t == TypeManager.byte_type ||
1147                                  t == TypeManager.sbyte_type ||
1148                                  t == TypeManager.bool_type)
1149                                 return 1;
1150                         else if (t == TypeManager.short_type ||
1151                                  t == TypeManager.char_type ||
1152                                  t == TypeManager.ushort_type)
1153                                 return 2;
1154                         else if (t == TypeManager.decimal_type)
1155                                 return 16;
1156                         else
1157                                 return 0;
1158                 }
1159
1160                 protected void Error_CannotCallAbstractBase (string name)
1161                 {
1162                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1163                 }
1164
1165                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1166                 {
1167                         Report.SymbolRelatedToPreviousError (type);
1168                         if (ec.CurrentInitializerVariable != null) {
1169                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1170                                         GetSignatureForError ());
1171                         } else {
1172                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1173                                         GetSignatureForError ());
1174                         }
1175                 }
1176
1177                 //
1178                 // Converts `source' to an int, uint, long or ulong.
1179                 //
1180                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1181                 {
1182                         Expression converted;
1183
1184                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1185                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1186                                 if (converted == null)
1187                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1188                                 if (converted == null)
1189                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1190                                 if (converted == null)
1191                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1192
1193                                 if (converted == null) {
1194                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1195                                         return null;
1196                                 }
1197                         }
1198
1199                         //
1200                         // Only positive constants are allowed at compile time
1201                         //
1202                         Constant c = converted as Constant;
1203                         if (c != null) {
1204                                 if (c.IsNegative) {
1205                                         Error_NegativeArrayIndex (source.loc);
1206                                 }
1207                                 return c;
1208                         }
1209
1210                         return new ArrayIndexCast (converted).Resolve (ec);
1211                 }
1212
1213                 //
1214                 // Derived classes implement this method by cloning the fields that
1215                 // could become altered during the Resolve stage
1216                 //
1217                 // Only expressions that are created for the parser need to implement
1218                 // this.
1219                 //
1220                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1221                 {
1222                         throw new NotImplementedException (
1223                                 String.Format (
1224                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1225                 }
1226
1227                 //
1228                 // Clones an expression created by the parser.
1229                 //
1230                 // We only support expressions created by the parser so far, not
1231                 // expressions that have been resolved (many more classes would need
1232                 // to implement CloneTo).
1233                 //
1234                 // This infrastructure is here merely for Lambda expressions which
1235                 // compile the same code using different type values for the same
1236                 // arguments to find the correct overload
1237                 //
1238                 public Expression Clone (CloneContext clonectx)
1239                 {
1240                         Expression cloned = (Expression) MemberwiseClone ();
1241                         CloneTo (clonectx, cloned);
1242
1243                         return cloned;
1244                 }
1245
1246                 public virtual Expression CreateExpressionTree (EmitContext ec)
1247                 {
1248                         throw new NotImplementedException (
1249                                 "Expression tree conversion not implemented for " + GetType ());
1250                 }
1251
1252                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1253                 {
1254                         return CreateExpressionFactoryCall (name, null, args, loc);
1255                 }
1256
1257                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1258                 {
1259                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1260                 }
1261
1262                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1263                 {
1264                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1265                 }
1266
1267                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1268                 {
1269                         TypeExpr texpr = TypeManager.expression_type_expr;
1270                         if (texpr == null) {
1271                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1272                                 if (t == null)
1273                                         return null;
1274
1275                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1276                         }
1277
1278                         return texpr;
1279                 }
1280         }
1281
1282         /// <summary>
1283         ///   This is just a base class for expressions that can
1284         ///   appear on statements (invocations, object creation,
1285         ///   assignments, post/pre increment and decrement).  The idea
1286         ///   being that they would support an extra Emition interface that
1287         ///   does not leave a result on the stack.
1288         /// </summary>
1289         public abstract class ExpressionStatement : Expression {
1290
1291                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1292                 {
1293                         Expression e = Resolve (ec);
1294                         if (e == null)
1295                                 return null;
1296
1297                         ExpressionStatement es = e as ExpressionStatement;
1298                         if (es == null)
1299                                 Error_InvalidExpressionStatement ();
1300
1301                         return es;
1302                 }
1303
1304                 /// <summary>
1305                 ///   Requests the expression to be emitted in a `statement'
1306                 ///   context.  This means that no new value is left on the
1307                 ///   stack after invoking this method (constrasted with
1308                 ///   Emit that will always leave a value on the stack).
1309                 /// </summary>
1310                 public abstract void EmitStatement (EmitContext ec);
1311
1312                 public override void EmitSideEffect (EmitContext ec)
1313                 {
1314                         EmitStatement (ec);
1315                 }
1316         }
1317
1318         /// <summary>
1319         ///   This kind of cast is used to encapsulate the child
1320         ///   whose type is child.Type into an expression that is
1321         ///   reported to return "return_type".  This is used to encapsulate
1322         ///   expressions which have compatible types, but need to be dealt
1323         ///   at higher levels with.
1324         ///
1325         ///   For example, a "byte" expression could be encapsulated in one
1326         ///   of these as an "unsigned int".  The type for the expression
1327         ///   would be "unsigned int".
1328         ///
1329         /// </summary>
1330         public abstract class TypeCast : Expression
1331         {
1332                 protected Expression child;
1333
1334                 protected TypeCast (Expression child, Type return_type)
1335                 {
1336                         eclass = child.eclass;
1337                         loc = child.Location;
1338                         type = return_type;
1339                         this.child = child;
1340                 }
1341
1342                 public override Expression CreateExpressionTree (EmitContext ec)
1343                 {
1344                         ArrayList args = new ArrayList (2);
1345                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1346                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1347                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1348                 }
1349
1350                 public override Expression DoResolve (EmitContext ec)
1351                 {
1352                         // This should never be invoked, we are born in fully
1353                         // initialized state.
1354
1355                         return this;
1356                 }
1357
1358                 public override void Emit (EmitContext ec)
1359                 {
1360                         child.Emit (ec);
1361                 }
1362
1363                 public override bool GetAttributableValue (Type value_type, out object value)
1364                 {
1365                         return child.GetAttributableValue (value_type, out value);
1366                 }
1367
1368                 protected override void CloneTo (CloneContext clonectx, Expression t)
1369                 {
1370                         TypeCast target = (TypeCast) t;
1371
1372                         target.child = child.Clone (clonectx);
1373                 }
1374         }
1375
1376         public class EmptyCast : TypeCast {
1377                 EmptyCast (Expression child, Type target_type)
1378                         : base (child, target_type)
1379                 {
1380                 }
1381
1382                 public static Expression Create (Expression child, Type type)
1383                 {
1384                         Constant c = child as Constant;
1385                         if (c != null)
1386                                 return new EmptyConstantCast (c, type);
1387
1388                         return new EmptyCast (child, type);
1389                 }
1390
1391                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1392                 {
1393                         child.EmitBranchable (ec, label, on_true);
1394                 }
1395
1396                 public override void EmitSideEffect (EmitContext ec)
1397                 {
1398                         child.EmitSideEffect (ec);
1399                 }
1400
1401         }
1402
1403         /// <summary>
1404         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1405         /// </summary>
1406         public class OperatorCast : TypeCast {
1407                 MethodInfo conversion_operator;
1408                 bool find_explicit;
1409
1410                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1411
1412                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1413                         : base (child, target_type)
1414                 {
1415                         this.find_explicit = find_explicit;
1416                 }
1417
1418                 // Returns the implicit operator that converts from
1419                 // 'child.Type' to our target type (type)
1420                 MethodInfo GetConversionOperator (bool find_explicit)
1421                 {
1422                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1423
1424                         MemberInfo [] mi;
1425
1426                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1427                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1428
1429                         if (mi == null){
1430                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1431                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1432                         }
1433
1434                         foreach (MethodInfo oper in mi) {
1435                                 ParameterData pd = TypeManager.GetParameterData (oper);
1436
1437                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1438                                         return oper;
1439                         }
1440
1441                         return null;
1442
1443
1444                 }
1445                 public override void Emit (EmitContext ec)
1446                 {
1447                         ILGenerator ig = ec.ig;
1448
1449                         child.Emit (ec);
1450                         conversion_operator = GetConversionOperator (find_explicit);
1451
1452                         if (conversion_operator == null)
1453                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1454
1455                         ig.Emit (OpCodes.Call, conversion_operator);
1456                 }
1457
1458         }
1459
1460         /// <summary>
1461         ///     This is a numeric cast to a Decimal
1462         /// </summary>
1463         public class CastToDecimal : TypeCast {
1464                 MethodInfo conversion_operator;
1465
1466                 public CastToDecimal (Expression child)
1467                         : this (child, false)
1468                 {
1469                 }
1470
1471                 public CastToDecimal (Expression child, bool find_explicit)
1472                         : base (child, TypeManager.decimal_type)
1473                 {
1474                         conversion_operator = GetConversionOperator (find_explicit);
1475
1476                         if (conversion_operator == null)
1477                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1478                 }
1479
1480                 // Returns the implicit operator that converts from
1481                 // 'child.Type' to System.Decimal.
1482                 MethodInfo GetConversionOperator (bool find_explicit)
1483                 {
1484                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1485
1486                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1487                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1488
1489                         foreach (MethodInfo oper in mi) {
1490                                 ParameterData pd = TypeManager.GetParameterData (oper);
1491
1492                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1493                                         return oper;
1494                         }
1495
1496                         return null;
1497                 }
1498                 public override void Emit (EmitContext ec)
1499                 {
1500                         ILGenerator ig = ec.ig;
1501                         child.Emit (ec);
1502
1503                         ig.Emit (OpCodes.Call, conversion_operator);
1504                 }
1505         }
1506
1507         /// <summary>
1508         ///     This is an explicit numeric cast from a Decimal
1509         /// </summary>
1510         public class CastFromDecimal : TypeCast
1511         {
1512                 static IDictionary operators;
1513
1514                 public CastFromDecimal (Expression child, Type return_type)
1515                         : base (child, return_type)
1516                 {
1517                         if (child.Type != TypeManager.decimal_type)
1518                                 throw new InternalErrorException (
1519                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1520                 }
1521
1522                 // Returns the explicit operator that converts from an
1523                 // express of type System.Decimal to 'type'.
1524                 public Expression Resolve ()
1525                 {
1526                         if (operators == null) {
1527                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1528                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1529                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1530
1531                                 operators = new System.Collections.Specialized.HybridDictionary ();
1532                                 foreach (MethodInfo oper in all_oper) {
1533                                         ParameterData pd = TypeManager.GetParameterData (oper);
1534                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1535                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1536                                 }
1537                         }
1538
1539                         return operators.Contains (type) ? this : null;
1540                 }
1541
1542                 public override void Emit (EmitContext ec)
1543                 {
1544                         ILGenerator ig = ec.ig;
1545                         child.Emit (ec);
1546
1547                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1548                 }
1549         }
1550
1551
1552         //
1553         // Constant specialization of EmptyCast.
1554         // We need to special case this since an empty cast of
1555         // a constant is still a constant.
1556         //
1557         public class EmptyConstantCast : Constant
1558         {
1559                 public readonly Constant child;
1560
1561                 public EmptyConstantCast(Constant child, Type type)
1562                         : base (child.Location)
1563                 {
1564                         eclass = child.eclass;
1565                         this.child = child;
1566                         this.type = type;
1567                 }
1568
1569                 public override string AsString ()
1570                 {
1571                         return child.AsString ();
1572                 }
1573
1574                 public override object GetValue ()
1575                 {
1576                         return child.GetValue ();
1577                 }
1578
1579                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1580                 {
1581                         // FIXME: check that 'type' can be converted to 'target_type' first
1582                         return child.ConvertExplicitly (in_checked_context, target_type);
1583                 }
1584
1585                 public override Expression CreateExpressionTree (EmitContext ec)
1586                 {
1587                         ArrayList args = new ArrayList (2);
1588                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1589                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1590                         return CreateExpressionFactoryCall ("Convert", args);
1591                 }
1592
1593                 public override Constant Increment ()
1594                 {
1595                         return child.Increment ();
1596                 }
1597
1598                 public override bool IsDefaultValue {
1599                         get { return child.IsDefaultValue; }
1600                 }
1601
1602                 public override bool IsNegative {
1603                         get { return child.IsNegative; }
1604                 }
1605
1606                 public override bool IsNull {
1607                         get { return child.IsNull; }
1608                 }
1609
1610                 public override bool IsZeroInteger {
1611                         get { return child.IsZeroInteger; }
1612                 }
1613
1614                 public override void Emit (EmitContext ec)
1615                 {
1616                         child.Emit (ec);
1617                 }
1618
1619                 public override Constant ConvertImplicitly (Type target_type)
1620                 {
1621                         // FIXME: Do we need to check user conversions?
1622                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1623                                 return null;
1624                         return child.ConvertImplicitly (target_type);
1625                 }
1626         }
1627
1628
1629         /// <summary>
1630         ///  This class is used to wrap literals which belong inside Enums
1631         /// </summary>
1632         public class EnumConstant : Constant {
1633                 public Constant Child;
1634
1635                 public EnumConstant (Constant child, Type enum_type):
1636                         base (child.Location)
1637                 {
1638                         eclass = child.eclass;
1639                         this.Child = child;
1640                         type = enum_type;
1641                 }
1642
1643                 public override Expression DoResolve (EmitContext ec)
1644                 {
1645                         // This should never be invoked, we are born in fully
1646                         // initialized state.
1647
1648                         return this;
1649                 }
1650
1651                 public override void Emit (EmitContext ec)
1652                 {
1653                         Child.Emit (ec);
1654                 }
1655
1656                 public override bool GetAttributableValue (Type value_type, out object value)
1657                 {
1658                         value = GetTypedValue ();
1659                         return true;
1660                 }
1661
1662                 public override string GetSignatureForError()
1663                 {
1664                         return TypeManager.CSharpName (Type);
1665                 }
1666
1667                 public override object GetValue ()
1668                 {
1669                         return Child.GetValue ();
1670                 }
1671
1672                 public override object GetTypedValue ()
1673                 {
1674                         // FIXME: runtime is not ready to work with just emited enums
1675                         if (!RootContext.StdLib) {
1676                                 return Child.GetValue ();
1677                         }
1678
1679                         return System.Enum.ToObject (type, Child.GetValue ());
1680                 }
1681
1682                 public override string AsString ()
1683                 {
1684                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1685                 }
1686
1687                 public override Constant Increment()
1688                 {
1689                         return new EnumConstant (Child.Increment (), type);
1690                 }
1691
1692                 public override bool IsDefaultValue {
1693                         get {
1694                                 return Child.IsDefaultValue;
1695                         }
1696                 }
1697
1698                 public override bool IsZeroInteger {
1699                         get { return Child.IsZeroInteger; }
1700                 }
1701
1702                 public override bool IsNegative {
1703                         get {
1704                                 return Child.IsNegative;
1705                         }
1706                 }
1707
1708                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1709                 {
1710                         if (Child.Type == target_type)
1711                                 return Child;
1712
1713                         return Child.ConvertExplicitly (in_checked_context, target_type);
1714                 }
1715
1716                 public override Constant ConvertImplicitly (Type type)
1717                 {
1718                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1719                         type = TypeManager.DropGenericTypeArguments (type);
1720
1721                         if (this_type == type) {
1722                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1723                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1724                                         return this;
1725
1726                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1727                                 if (type.UnderlyingSystemType != child_type)
1728                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1729                                 return this;
1730                         }
1731
1732                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1733                                 return null;
1734                         }
1735
1736                         return Child.ConvertImplicitly(type);
1737                 }
1738
1739         }
1740
1741         /// <summary>
1742         ///   This kind of cast is used to encapsulate Value Types in objects.
1743         ///
1744         ///   The effect of it is to box the value type emitted by the previous
1745         ///   operation.
1746         /// </summary>
1747         public class BoxedCast : TypeCast {
1748
1749                 public BoxedCast (Expression expr, Type target_type)
1750                         : base (expr, target_type)
1751                 {
1752                         eclass = ExprClass.Value;
1753                 }
1754
1755                 public override Expression DoResolve (EmitContext ec)
1756                 {
1757                         // This should never be invoked, we are born in fully
1758                         // initialized state.
1759
1760                         return this;
1761                 }
1762
1763                 public override void Emit (EmitContext ec)
1764                 {
1765                         base.Emit (ec);
1766
1767                         ec.ig.Emit (OpCodes.Box, child.Type);
1768                 }
1769
1770                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1771                 {
1772                         if (child.Type.IsValueType &&
1773                             (type == TypeManager.object_type || type == TypeManager.value_type)) {
1774                                 // 'Box' involves runtime checks for interface types, so we can't unconditionally assume we'll get a non-null here
1775                                 child.EmitSideEffect (ec);
1776                                 if (on_true)
1777                                         ec.ig.Emit (OpCodes.Br, label);
1778                                 return;
1779                         }
1780                         base.EmitBranchable (ec, label, on_true);
1781                 }
1782
1783                 public override void EmitSideEffect (EmitContext ec)
1784                 {
1785                         if (child.Type.IsValueType &&
1786                             (type == TypeManager.object_type || type == TypeManager.value_type)) {
1787                                 child.EmitSideEffect (ec);
1788                                 return;
1789                         }
1790                         // boxing is side-effectful, since it involves runtime checks
1791                         base.EmitSideEffect (ec);
1792                 }
1793         }
1794
1795         public class UnboxCast : TypeCast {
1796                 public UnboxCast (Expression expr, Type return_type)
1797                         : base (expr, return_type)
1798                 {
1799                 }
1800
1801                 public override Expression DoResolve (EmitContext ec)
1802                 {
1803                         // This should never be invoked, we are born in fully
1804                         // initialized state.
1805
1806                         return this;
1807                 }
1808
1809                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1810                 {
1811                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1812                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1813                         return base.DoResolveLValue (ec, right_side);
1814                 }
1815
1816                 public override void Emit (EmitContext ec)
1817                 {
1818                         Type t = type;
1819                         ILGenerator ig = ec.ig;
1820
1821                         base.Emit (ec);
1822 #if GMCS_SOURCE
1823                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1824                                 ig.Emit (OpCodes.Unbox_Any, t);
1825                         else
1826 #endif
1827                         {
1828                                 ig.Emit (OpCodes.Unbox, t);
1829
1830                                 LoadFromPtr (ig, t);
1831                         }
1832                 }
1833         }
1834
1835         /// <summary>
1836         ///   This is used to perform explicit numeric conversions.
1837         ///
1838         ///   Explicit numeric conversions might trigger exceptions in a checked
1839         ///   context, so they should generate the conv.ovf opcodes instead of
1840         ///   conv opcodes.
1841         /// </summary>
1842         public class ConvCast : TypeCast {
1843                 public enum Mode : byte {
1844                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1845                         U1_I1, U1_CH,
1846                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1847                         U2_I1, U2_U1, U2_I2, U2_CH,
1848                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1849                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1850                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1851                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1852                         CH_I1, CH_U1, CH_I2,
1853                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1854                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1855                 }
1856
1857                 Mode mode;
1858
1859                 public ConvCast (Expression child, Type return_type, Mode m)
1860                         : base (child, return_type)
1861                 {
1862                         mode = m;
1863                 }
1864
1865                 public override Expression DoResolve (EmitContext ec)
1866                 {
1867                         // This should never be invoked, we are born in fully
1868                         // initialized state.
1869
1870                         return this;
1871                 }
1872
1873                 public override string ToString ()
1874                 {
1875                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1876                 }
1877
1878                 public override void Emit (EmitContext ec)
1879                 {
1880                         ILGenerator ig = ec.ig;
1881
1882                         base.Emit (ec);
1883
1884                         if (ec.CheckState){
1885                                 switch (mode){
1886                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1887                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1888                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1889                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1890                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1891
1892                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1893                                 case Mode.U1_CH: /* nothing */ break;
1894
1895                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1896                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1897                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1898                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1899                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1900                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1901
1902                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1903                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1904                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1905                                 case Mode.U2_CH: /* nothing */ break;
1906
1907                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1908                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1909                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1910                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1911                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1912                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1913                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1914
1915                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1916                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1917                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1918                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1919                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1920                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1921
1922                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1923                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1924                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1925                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1926                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1927                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1928                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1929                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1930
1931                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1932                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1933                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1934                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1935                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1936                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1937                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1938                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1939
1940                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1941                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1942                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1943
1944                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1945                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1946                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1947                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1948                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1949                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1950                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1951                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1952                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1953
1954                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1955                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1956                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1957                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1958                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1959                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1960                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1961                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1962                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1963                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1964                                 }
1965                         } else {
1966                                 switch (mode){
1967                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1968                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1969                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1970                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1971                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1972
1973                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1974                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1975
1976                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1977                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1978                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1979                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1980                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1981                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1982
1983                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1984                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1985                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1986                                 case Mode.U2_CH: /* nothing */ break;
1987
1988                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1989                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1990                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1991                                 case Mode.I4_U4: /* nothing */ break;
1992                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1993                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1994                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1995
1996                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1997                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1998                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1999                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2000                                 case Mode.U4_I4: /* nothing */ break;
2001                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2002
2003                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2004                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2005                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2006                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2007                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2008                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2009                                 case Mode.I8_U8: /* nothing */ break;
2010                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2011
2012                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2013                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2014                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2015                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2016                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2017                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2018                                 case Mode.U8_I8: /* nothing */ break;
2019                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2020
2021                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2022                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2023                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2024
2025                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2026                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2027                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2028                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2029                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2030                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2031                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2032                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2033                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2034
2035                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2036                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2037                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2038                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2039                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2040                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2041                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2042                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2043                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2044                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2045                                 }
2046                         }
2047                 }
2048         }
2049
2050         public class OpcodeCast : TypeCast {
2051                 OpCode op, op2;
2052                 bool second_valid;
2053
2054                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2055                         : base (child, return_type)
2056
2057                 {
2058                         this.op = op;
2059                         second_valid = false;
2060                 }
2061
2062                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
2063                         : base (child, return_type)
2064
2065                 {
2066                         this.op = op;
2067                         this.op2 = op2;
2068                         second_valid = true;
2069                 }
2070
2071                 public override Expression DoResolve (EmitContext ec)
2072                 {
2073                         // This should never be invoked, we are born in fully
2074                         // initialized state.
2075
2076                         return this;
2077                 }
2078
2079                 public override void Emit (EmitContext ec)
2080                 {
2081                         base.Emit (ec);
2082                         ec.ig.Emit (op);
2083
2084                         if (second_valid)
2085                                 ec.ig.Emit (op2);
2086                 }
2087
2088                 public Type UnderlyingType {
2089                         get { return child.Type; }
2090                 }
2091         }
2092
2093         /// <summary>
2094         ///   This kind of cast is used to encapsulate a child and cast it
2095         ///   to the class requested
2096         /// </summary>
2097         public class ClassCast : TypeCast {
2098                 public ClassCast (Expression child, Type return_type)
2099                         : base (child, return_type)
2100
2101                 {
2102                 }
2103
2104                 public override Expression DoResolve (EmitContext ec)
2105                 {
2106                         // This should never be invoked, we are born in fully
2107                         // initialized state.
2108
2109                         return this;
2110                 }
2111
2112                 public override void Emit (EmitContext ec)
2113                 {
2114                         base.Emit (ec);
2115
2116                         if (TypeManager.IsGenericParameter (child.Type))
2117                                 ec.ig.Emit (OpCodes.Box, child.Type);
2118
2119 #if GMCS_SOURCE
2120                         if (type.IsGenericParameter)
2121                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2122                         else
2123 #endif
2124                                 ec.ig.Emit (OpCodes.Castclass, type);
2125                 }
2126         }
2127
2128         //
2129         // Used when resolved expression has different representations for
2130         // expression trees and emit phase
2131         //
2132         public class ReducedExpression : Expression
2133         {
2134                 class ReducedConstantExpression : Constant
2135                 {
2136                         readonly Constant expr;
2137                         readonly Expression orig_expr;
2138
2139                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2140                                 : base (expr.Location)
2141                         {
2142                                 this.expr = expr;
2143                                 this.orig_expr = orig_expr;
2144                                 eclass = expr.eclass;
2145                                 type = expr.Type;
2146                         }
2147
2148                         public override string AsString ()
2149                         {
2150                                 return expr.AsString ();
2151                         }
2152
2153                         public override Expression CreateExpressionTree (EmitContext ec)
2154                         {
2155                                 return orig_expr.CreateExpressionTree (ec);
2156                         }
2157
2158                         public override object GetValue ()
2159                         {
2160                                 return expr.GetValue ();
2161                         }
2162
2163                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2164                         {
2165                                 throw new NotImplementedException ();
2166                         }
2167
2168                         public override Expression DoResolve (EmitContext ec)
2169                         {
2170                                 return this;
2171                         }
2172
2173                         public override Constant Increment ()
2174                         {
2175                                 throw new NotImplementedException ();
2176                         }
2177
2178                         public override bool IsDefaultValue {
2179                                 get {
2180                                         return expr.IsDefaultValue;
2181                                 }
2182                         }
2183
2184                         public override bool IsNegative {
2185                                 get {
2186                                         return expr.IsNegative;
2187                                 }
2188                         }
2189
2190                         public override void Emit (EmitContext ec)
2191                         {
2192                                 expr.Emit (ec);
2193                         }
2194                 }
2195
2196                 readonly Expression expr, orig_expr;
2197
2198                 private ReducedExpression (Expression expr, Expression orig_expr)
2199                 {
2200                         this.expr = expr;
2201                         this.orig_expr = orig_expr;
2202                         this.loc = orig_expr.Location;
2203                 }
2204
2205                 public static Expression Create (Constant expr, Expression original_expr)
2206                 {
2207                         return new ReducedConstantExpression (expr, original_expr);
2208                 }
2209
2210                 public static Expression Create (Expression expr, Expression original_expr)
2211                 {
2212                         Constant c = expr as Constant;
2213                         if (c != null)
2214                                 return Create (c, original_expr);
2215
2216                         return new ReducedExpression (expr, original_expr);
2217                 }
2218
2219                 public override Expression CreateExpressionTree (EmitContext ec)
2220                 {
2221                         return orig_expr.CreateExpressionTree (ec);
2222                 }
2223
2224                 public override Expression DoResolve (EmitContext ec)
2225                 {
2226                         eclass = expr.eclass;
2227                         type = expr.Type;
2228                         return this;
2229                 }
2230
2231                 public override void Emit (EmitContext ec)
2232                 {
2233                         expr.Emit (ec);
2234                 }
2235
2236                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2237                 {
2238                         expr.EmitBranchable (ec, target, on_true);
2239                 }
2240         }
2241
2242         /// <summary>
2243         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2244         ///   of a dotted-name.
2245         /// </summary>
2246         public class SimpleName : Expression {
2247                 public readonly string Name;
2248                 public readonly TypeArguments Arguments;
2249                 bool in_transit;
2250
2251                 public SimpleName (string name, Location l)
2252                 {
2253                         Name = name;
2254                         loc = l;
2255                 }
2256
2257                 public SimpleName (string name, TypeArguments args, Location l)
2258                 {
2259                         Name = name;
2260                         Arguments = args;
2261                         loc = l;
2262                 }
2263
2264                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2265                 {
2266                         Name = name;
2267                         loc = l;
2268
2269                         Arguments = new TypeArguments (l);
2270                         foreach (TypeParameter type_param in type_params)
2271                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2272                 }
2273
2274                 public static string RemoveGenericArity (string name)
2275                 {
2276                         int start = 0;
2277                         StringBuilder sb = null;
2278                         do {
2279                                 int pos = name.IndexOf ('`', start);
2280                                 if (pos < 0) {
2281                                         if (start == 0)
2282                                                 return name;
2283
2284                                         sb.Append (name.Substring (start));
2285                                         break;
2286                                 }
2287
2288                                 if (sb == null)
2289                                         sb = new StringBuilder ();
2290                                 sb.Append (name.Substring (start, pos-start));
2291
2292                                 pos++;
2293                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2294                                         pos++;
2295
2296                                 start = pos;
2297                         } while (start < name.Length);
2298
2299                         return sb.ToString ();
2300                 }
2301
2302                 public SimpleName GetMethodGroup ()
2303                 {
2304                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2305                 }
2306
2307                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2308                 {
2309                         if (ec.IsInFieldInitializer)
2310                                 Report.Error (236, l,
2311                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2312                                         name);
2313                         else
2314                                 Report.Error (
2315                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2316                                         name);
2317                 }
2318
2319                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2320                 {
2321                         return resolved_to != null && resolved_to.Type != null &&
2322                                 resolved_to.Type.Name == Name &&
2323                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2324                 }
2325
2326                 public override Expression DoResolve (EmitContext ec)
2327                 {
2328                         return SimpleNameResolve (ec, null, false);
2329                 }
2330
2331                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2332                 {
2333                         return SimpleNameResolve (ec, right_side, false);
2334                 }
2335
2336
2337                 public Expression DoResolve (EmitContext ec, bool intermediate)
2338                 {
2339                         return SimpleNameResolve (ec, null, intermediate);
2340                 }
2341
2342                 static bool IsNestedChild (Type t, Type parent)
2343                 {
2344                         while (parent != null) {
2345                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2346                                         return true;
2347
2348                                 parent = parent.BaseType;
2349                         }
2350
2351                         return false;
2352                 }
2353
2354                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2355                 {
2356                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2357                                 return null;
2358
2359                         DeclSpace ds = ec.DeclContainer;
2360                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2361                                 ds = ds.Parent;
2362
2363                         if (ds == null)
2364                                 return null;
2365
2366                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2367
2368                         int arg_count = Arguments != null ? Arguments.Count : 0;
2369
2370                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2371                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2372                                         TypeArguments new_args = new TypeArguments (loc);
2373                                         foreach (TypeParameter param in ds.TypeParameters)
2374                                                 new_args.Add (new TypeParameterExpr (param, loc));
2375
2376                                         if (Arguments != null)
2377                                                 new_args.Add (Arguments);
2378
2379                                         return new ConstructedType (t, new_args, loc);
2380                                 }
2381                         }
2382
2383                         return null;
2384                 }
2385
2386                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2387                 {
2388                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2389                         if (fne != null)
2390                                 return fne.ResolveAsTypeStep (ec, silent);
2391
2392                         int errors = Report.Errors;
2393                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2394
2395                         if (fne != null) {
2396                                 if (fne.Type == null)
2397                                         return fne;
2398
2399                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2400                                 if (nested != null)
2401                                         return nested.ResolveAsTypeStep (ec, false);
2402
2403                                 if (Arguments != null) {
2404                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2405                                         return ct.ResolveAsTypeStep (ec, false);
2406                                 }
2407
2408                                 return fne;
2409                         }
2410
2411                         if (silent || errors != Report.Errors)
2412                                 return null;
2413
2414                         Error_TypeOrNamespaceNotFound (ec);
2415                         return null;
2416                 }
2417
2418                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2419                 {
2420                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2421                         if (mc != null) {
2422                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2423                                 return;
2424                         }
2425
2426                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2427                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2428                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2429                                 Type type = a.GetType (fullname);
2430                                 if (type != null) {
2431                                         Report.SymbolRelatedToPreviousError (type);
2432                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2433                                         return;
2434                                 }
2435                         }
2436
2437                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2438                         if (t != null) {
2439                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2440                                 return;
2441                         }
2442
2443                         if (Arguments != null) {
2444                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2445                                 if (retval != null) {
2446                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2447                                         return;
2448                                 }
2449                         }
2450
2451                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2452                 }
2453
2454                 // TODO: I am still not convinced about this. If someone else will need it
2455                 // implement this as virtual property in MemberCore hierarchy
2456                 public static string GetMemberType (MemberCore mc)
2457                 {
2458                         if (mc is Property)
2459                                 return "property";
2460                         if (mc is Indexer)
2461                                 return "indexer";
2462                         if (mc is FieldBase)
2463                                 return "field";
2464                         if (mc is MethodCore)
2465                                 return "method";
2466                         if (mc is EnumMember)
2467                                 return "enum";
2468                         if (mc is Event)
2469                                 return "event";
2470
2471                         return "type";
2472                 }
2473
2474                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2475                 {
2476                         if (in_transit)
2477                                 return null;
2478
2479                         in_transit = true;
2480                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2481                         in_transit = false;
2482
2483                         if (e == null)
2484                                 return null;
2485
2486                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2487                                 return e;
2488
2489                         return null;
2490                 }
2491
2492                 /// <remarks>
2493                 ///   7.5.2: Simple Names.
2494                 ///
2495                 ///   Local Variables and Parameters are handled at
2496                 ///   parse time, so they never occur as SimpleNames.
2497                 ///
2498                 ///   The `intermediate' flag is used by MemberAccess only
2499                 ///   and it is used to inform us that it is ok for us to
2500                 ///   avoid the static check, because MemberAccess might end
2501                 ///   up resolving the Name as a Type name and the access as
2502                 ///   a static type access.
2503                 ///
2504                 ///   ie: Type Type; .... { Type.GetType (""); }
2505                 ///
2506                 ///   Type is both an instance variable and a Type;  Type.GetType
2507                 ///   is the static method not an instance method of type.
2508                 /// </remarks>
2509                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2510                 {
2511                         Expression e = null;
2512
2513                         //
2514                         // Stage 1: Performed by the parser (binding to locals or parameters).
2515                         //
2516                         Block current_block = ec.CurrentBlock;
2517                         if (current_block != null){
2518                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2519                                 if (vi != null){
2520                                         if (Arguments != null) {
2521                                                 Report.Error (307, loc,
2522                                                               "The variable `{0}' cannot be used with type arguments",
2523                                                               Name);
2524                                                 return null;
2525                                         }
2526
2527                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2528                                         if (right_side != null) {
2529                                                 return var.ResolveLValue (ec, right_side, loc);
2530                                         } else {
2531                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2532                                                 if (intermediate)
2533                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2534                                                 return var.Resolve (ec, rf);
2535                                         }
2536                                 }
2537
2538                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2539                                 if (pref != null) {
2540                                         if (Arguments != null) {
2541                                                 Report.Error (307, loc,
2542                                                               "The variable `{0}' cannot be used with type arguments",
2543                                                               Name);
2544                                                 return null;
2545                                         }
2546
2547                                         if (right_side != null)
2548                                                 return pref.ResolveLValue (ec, right_side, loc);
2549                                         else
2550                                                 return pref.Resolve (ec);
2551                                 }
2552
2553                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2554                                 if (expr != null) {
2555                                         if (right_side != null)
2556                                                 return expr.ResolveLValue (ec, right_side, loc);
2557                                         return expr.Resolve (ec);
2558                                 }
2559                         }
2560
2561                         //
2562                         // Stage 2: Lookup members
2563                         //
2564
2565                         Type almost_matched_type = null;
2566                         ArrayList almost_matched = null;
2567                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2568                                 // either RootDeclSpace or GenericMethod
2569                                 if (lookup_ds.TypeBuilder == null)
2570                                         continue;
2571
2572                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2573                                 if (e != null) {
2574                                         if (e is PropertyExpr) {
2575                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2576                                                 // it doesn't know which accessor to check permissions against
2577                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2578                                                         break;
2579                                         } else if (e is EventExpr) {
2580                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2581                                                         break;
2582                                         } else {
2583                                                 break;
2584                                         }
2585                                         e = null;
2586                                 }
2587
2588                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2589                                         almost_matched_type = lookup_ds.TypeBuilder;
2590                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2591                                 }
2592                         }
2593
2594                         if (e == null) {
2595                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2596                                         almost_matched_type = ec.ContainerType;
2597                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2598                                 }
2599                                 e = ResolveAsTypeStep (ec, true);
2600                         }
2601
2602                         if (e == null) {
2603                                 if (current_block != null) {
2604                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2605                                         if (ikv != null) {
2606                                                 LocalInfo li = ikv as LocalInfo;
2607                                                 // Supress CS0219 warning
2608                                                 if (li != null)
2609                                                         li.Used = true;
2610
2611                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2612                                                 return null;
2613                                         }
2614                                 }
2615
2616                                 if (almost_matched != null)
2617                                         almost_matched_members = almost_matched;
2618                                 if (almost_matched_type == null)
2619                                         almost_matched_type = ec.ContainerType;
2620                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2621                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2622                                 return null;
2623                         }
2624
2625                         if (e is TypeExpr) {
2626                                 if (Arguments == null)
2627                                         return e;
2628
2629                                 ConstructedType ct = new ConstructedType (
2630                                         (FullNamedExpression) e, Arguments, loc);
2631                                 return ct.ResolveAsTypeStep (ec, false);
2632                         }
2633
2634                         if (e is MemberExpr) {
2635                                 MemberExpr me = (MemberExpr) e;
2636
2637                                 Expression left;
2638                                 if (me.IsInstance) {
2639                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2640                                                 //
2641                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2642                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2643                                                 // and each predicate is true if the MethodGroupExpr contains
2644                                                 // at least one of that kind of method.
2645                                                 //
2646
2647                                                 if (!me.IsStatic &&
2648                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2649                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2650                                                         return null;
2651                                                 }
2652
2653                                                 //
2654                                                 // Pass the buck to MemberAccess and Invocation.
2655                                                 //
2656                                                 left = EmptyExpression.Null;
2657                                         } else {
2658                                                 left = ec.GetThis (loc);
2659                                         }
2660                                 } else {
2661                                         left = new TypeExpression (ec.ContainerType, loc);
2662                                 }
2663
2664                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2665                                 if (me == null)
2666                                         return null;
2667
2668                                 if (Arguments != null) {
2669                                         Arguments.Resolve (ec);
2670                                         me.SetTypeArguments (Arguments);
2671                                 }
2672
2673                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2674                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2675                                     me.InstanceExpression.Type != me.DeclaringType &&
2676                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2677                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2678                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2679                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2680                                         return null;
2681                                 }
2682
2683                                 return (right_side != null)
2684                                         ? me.DoResolveLValue (ec, right_side)
2685                                         : me.DoResolve (ec);
2686                         }
2687
2688                         return e;
2689                 }
2690
2691                 public override void Emit (EmitContext ec)
2692                 {
2693                         throw new InternalErrorException ("The resolve phase was not executed");
2694                 }
2695
2696                 public override string ToString ()
2697                 {
2698                         return Name;
2699                 }
2700
2701                 public override string GetSignatureForError ()
2702                 {
2703                         if (Arguments != null) {
2704                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2705                                         Arguments.GetSignatureForError () + ">";
2706                         }
2707
2708                         return Name;
2709                 }
2710
2711                 protected override void CloneTo (CloneContext clonectx, Expression target)
2712                 {
2713                         // CloneTo: Nothing, we do not keep any state on this expression
2714                 }
2715         }
2716
2717         /// <summary>
2718         ///   Represents a namespace or a type.  The name of the class was inspired by
2719         ///   section 10.8.1 (Fully Qualified Names).
2720         /// </summary>
2721         public abstract class FullNamedExpression : Expression {
2722                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2723                 {
2724                         return this;
2725                 }
2726
2727                 public abstract string FullName {
2728                         get;
2729                 }
2730         }
2731
2732         /// <summary>
2733         ///   Expression that evaluates to a type
2734         /// </summary>
2735         public abstract class TypeExpr : FullNamedExpression {
2736                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2737                 {
2738                         TypeExpr t = DoResolveAsTypeStep (ec);
2739                         if (t == null)
2740                                 return null;
2741
2742                         eclass = ExprClass.Type;
2743                         return t;
2744                 }
2745
2746                 override public Expression DoResolve (EmitContext ec)
2747                 {
2748                         return ResolveAsTypeTerminal (ec, false);
2749                 }
2750
2751                 override public void Emit (EmitContext ec)
2752                 {
2753                         throw new Exception ("Should never be called");
2754                 }
2755
2756                 public virtual bool CheckAccessLevel (DeclSpace ds)
2757                 {
2758                         return ds.CheckAccessLevel (Type);
2759                 }
2760
2761                 public virtual bool AsAccessible (DeclSpace ds)
2762                 {
2763                         return ds.IsAccessibleAs (Type);
2764                 }
2765
2766                 public virtual bool IsClass {
2767                         get { return Type.IsClass; }
2768                 }
2769
2770                 public virtual bool IsValueType {
2771                         get { return Type.IsValueType; }
2772                 }
2773
2774                 public virtual bool IsInterface {
2775                         get { return Type.IsInterface; }
2776                 }
2777
2778                 public virtual bool IsSealed {
2779                         get { return Type.IsSealed; }
2780                 }
2781
2782                 public virtual bool CanInheritFrom ()
2783                 {
2784                         if (Type == TypeManager.enum_type ||
2785                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2786                             Type == TypeManager.multicast_delegate_type ||
2787                             Type == TypeManager.delegate_type ||
2788                             Type == TypeManager.array_type)
2789                                 return false;
2790
2791                         return true;
2792                 }
2793
2794                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2795
2796                 public abstract string Name {
2797                         get;
2798                 }
2799
2800                 public override bool Equals (object obj)
2801                 {
2802                         TypeExpr tobj = obj as TypeExpr;
2803                         if (tobj == null)
2804                                 return false;
2805
2806                         return Type == tobj.Type;
2807                 }
2808
2809                 public override int GetHashCode ()
2810                 {
2811                         return Type.GetHashCode ();
2812                 }
2813
2814                 public override string ToString ()
2815                 {
2816                         return Name;
2817                 }
2818         }
2819
2820         /// <summary>
2821         ///   Fully resolved Expression that already evaluated to a type
2822         /// </summary>
2823         public class TypeExpression : TypeExpr {
2824                 public TypeExpression (Type t, Location l)
2825                 {
2826                         Type = t;
2827                         eclass = ExprClass.Type;
2828                         loc = l;
2829                 }
2830
2831                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2832                 {
2833                         return this;
2834                 }
2835
2836                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2837                 {
2838                         return this;
2839                 }
2840
2841                 public override string Name {
2842                         get { return Type.ToString (); }
2843                 }
2844
2845                 public override string FullName {
2846                         get { return Type.FullName; }
2847                 }
2848         }
2849
2850         /// <summary>
2851         ///   Used to create types from a fully qualified name.  These are just used
2852         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2853         ///   classified as a type.
2854         /// </summary>
2855         public sealed class TypeLookupExpression : TypeExpr {
2856                 readonly string name;
2857
2858                 public TypeLookupExpression (string name)
2859                 {
2860                         this.name = name;
2861                         eclass = ExprClass.Type;
2862                 }
2863
2864                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2865                 {
2866                         // It's null for corlib compilation only
2867                         if (type == null)
2868                                 return DoResolveAsTypeStep (ec);
2869
2870                         return this;
2871                 }
2872
2873                 private class UnexpectedType
2874                 {
2875                 }
2876
2877                 // This performes recursive type lookup, providing support for generic types.
2878                 // For example, given the type:
2879                 //
2880                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2881                 //
2882                 // The types will be checked in the following order:
2883                 //                                                                             _
2884                 // System                                                                       |
2885                 // System.Collections                                                           |
2886                 // System.Collections.Generic                                                   |
2887                 //                        _                                                     |
2888                 //     System              | recursive call 1                                   |
2889                 //     System.Int32       _|                                                    | main method call
2890                 //                        _                                                     |
2891                 //     System              | recursive call 2                                   |
2892                 //     System.String      _|                                                    |
2893                 //                                                                              |
2894                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2895                 //
2896                 private Type TypeLookup (IResolveContext ec, string name)
2897                 {
2898                         int index = 0;
2899                         int dot = 0;
2900                         bool done = false;
2901                         FullNamedExpression resolved = null;
2902                         Type type = null;
2903                         Type recursive_type = null;
2904                         while (index < name.Length) {
2905                                 if (name[index] == '[') {
2906                                         int open = index;
2907                                         int braces = 1;
2908                                         do {
2909                                                 index++;
2910                                                 if (name[index] == '[')
2911                                                         braces++;
2912                                                 else if (name[index] == ']')
2913                                                         braces--;
2914                                         } while (braces > 0);
2915                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2916                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2917                                                 return recursive_type;
2918                                 }
2919                                 else {
2920                                         if (name[index] == ',')
2921                                                 done = true;
2922                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2923                                                 string substring = name.Substring(dot, index - dot);
2924
2925                                                 if (resolved == null)
2926                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2927                                                 else if (resolved is Namespace)
2928                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2929                                                 else if (type != null)
2930                                                         type = TypeManager.GetNestedType (type, substring);
2931                                                 else
2932                                                         return null;
2933
2934                                                 if (resolved == null)
2935                                                         return null;
2936                                                 else if (type == null && resolved is TypeExpr)
2937                                                         type = resolved.Type;
2938
2939                                                 dot = index + 1;
2940                                         }
2941                                 }
2942                                 index++;
2943                         }
2944                         if (name[0] != '[') {
2945                                 string substring = name.Substring(dot, index - dot);
2946
2947                                 if (type != null)
2948                                         return TypeManager.GetNestedType (type, substring);
2949
2950                                 if (resolved != null) {
2951                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2952                                         if (resolved is TypeExpr)
2953                                                 return resolved.Type;
2954
2955                                         if (resolved == null)
2956                                                 return null;
2957
2958                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2959                                         return typeof (UnexpectedType);
2960                                 }
2961                                 else
2962                                         return null;
2963                         }
2964                         else
2965                                 return recursive_type;
2966                         }
2967
2968                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2969                 {
2970                         Type t = TypeLookup (ec, name);
2971                         if (t == null) {
2972                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2973                                 return null;
2974                         }
2975                         if (t == typeof(UnexpectedType))
2976                                 return null;
2977                         type = t;
2978                         return this;
2979                 }
2980
2981                 public override string Name {
2982                         get { return name; }
2983                 }
2984
2985                 public override string FullName {
2986                         get { return name; }
2987                 }
2988
2989                 protected override void CloneTo (CloneContext clonectx, Expression target)
2990                 {
2991                         // CloneTo: Nothing, we do not keep any state on this expression
2992                 }
2993
2994                 public override string GetSignatureForError ()
2995                 {
2996                         if (type == null)
2997                                 return TypeManager.CSharpName (name);
2998
2999                         return base.GetSignatureForError ();
3000                 }
3001         }
3002
3003         /// <summary>
3004         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
3005         ///   See 14.5.11.
3006         /// </summary>
3007         public class UnboundTypeExpression : TypeExpr
3008         {
3009                 MemberName name;
3010
3011                 public UnboundTypeExpression (MemberName name, Location l)
3012                 {
3013                         this.name = name;
3014                         loc = l;
3015                 }
3016
3017                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3018                 {
3019                         Expression expr;
3020                         if (name.Left != null) {
3021                                 Expression lexpr = name.Left.GetTypeExpression ();
3022                                 expr = new MemberAccess (lexpr, name.Basename);
3023                         } else {
3024                                 expr = new SimpleName (name.Basename, loc);
3025                         }
3026
3027                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
3028                         if (fne == null)
3029                                 return null;
3030
3031                         type = fne.Type;
3032                         return new TypeExpression (type, loc);
3033                 }
3034
3035                 public override string Name {
3036                         get { return name.PrettyName; }
3037                 }
3038
3039                 public override string FullName {
3040                         get { return name.FullyQualifiedName; }
3041                 }
3042         }
3043
3044         public class TypeAliasExpression : TypeExpr {
3045                 FullNamedExpression alias;
3046                 TypeExpr texpr;
3047                 TypeArguments args;
3048                 string name;
3049
3050                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
3051                 {
3052                         this.alias = alias;
3053                         this.args = args;
3054                         loc = l;
3055
3056                         eclass = ExprClass.Type;
3057                         if (args != null)
3058                                 name = alias.FullName + "<" + args.ToString () + ">";
3059                         else
3060                                 name = alias.FullName;
3061                 }
3062
3063                 public override string Name {
3064                         get { return alias.FullName; }
3065                 }
3066
3067                 public override string FullName {
3068                         get { return name; }
3069                 }
3070
3071                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3072                 {
3073                         texpr = alias.ResolveAsTypeTerminal (ec, false);
3074                         if (texpr == null)
3075                                 return null;
3076
3077                         Type type = texpr.Type;
3078                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
3079
3080                         if (args != null) {
3081                                 if (num_args == 0) {
3082                                         Report.Error (308, loc,
3083                                                       "The non-generic type `{0}' cannot " +
3084                                                       "be used with type arguments.",
3085                                                       TypeManager.CSharpName (type));
3086                                         return null;
3087                                 }
3088
3089                                 ConstructedType ctype = new ConstructedType (type, args, loc);
3090                                 return ctype.ResolveAsTypeTerminal (ec, false);
3091                         } else if (num_args > 0) {
3092                                 Report.Error (305, loc,
3093                                               "Using the generic type `{0}' " +
3094                                               "requires {1} type arguments",
3095                                               TypeManager.CSharpName (type), num_args.ToString ());
3096                                 return null;
3097                         }
3098
3099                         return texpr;
3100                 }
3101
3102                 public override bool CheckAccessLevel (DeclSpace ds)
3103                 {
3104                         return texpr.CheckAccessLevel (ds);
3105                 }
3106
3107                 public override bool AsAccessible (DeclSpace ds)
3108                 {
3109                         return texpr.AsAccessible (ds);
3110                 }
3111
3112                 public override bool IsClass {
3113                         get { return texpr.IsClass; }
3114                 }
3115
3116                 public override bool IsValueType {
3117                         get { return texpr.IsValueType; }
3118                 }
3119
3120                 public override bool IsInterface {
3121                         get { return texpr.IsInterface; }
3122                 }
3123
3124                 public override bool IsSealed {
3125                         get { return texpr.IsSealed; }
3126                 }
3127         }
3128
3129         /// <summary>
3130         ///   This class denotes an expression which evaluates to a member
3131         ///   of a struct or a class.
3132         /// </summary>
3133         public abstract class MemberExpr : Expression
3134         {
3135                 protected bool is_base;
3136
3137                 /// <summary>
3138                 ///   The name of this member.
3139                 /// </summary>
3140                 public abstract string Name {
3141                         get;
3142                 }
3143
3144                 //
3145                 // When base.member is used
3146                 //
3147                 public bool IsBase {
3148                         get { return is_base; }
3149                         set { is_base = value; }
3150                 }
3151
3152                 /// <summary>
3153                 ///   Whether this is an instance member.
3154                 /// </summary>
3155                 public abstract bool IsInstance {
3156                         get;
3157                 }
3158
3159                 /// <summary>
3160                 ///   Whether this is a static member.
3161                 /// </summary>
3162                 public abstract bool IsStatic {
3163                         get;
3164                 }
3165
3166                 /// <summary>
3167                 ///   The type which declares this member.
3168                 /// </summary>
3169                 public abstract Type DeclaringType {
3170                         get;
3171                 }
3172
3173                 /// <summary>
3174                 ///   The instance expression associated with this member, if it's a
3175                 ///   non-static member.
3176                 /// </summary>
3177                 public Expression InstanceExpression;
3178
3179                 public static void error176 (Location loc, string name)
3180                 {
3181                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3182                                       "with an instance reference, qualify it with a type name instead", name);
3183                 }
3184
3185                 // TODO: possible optimalization
3186                 // Cache resolved constant result in FieldBuilder <-> expression map
3187                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3188                                                                SimpleName original)
3189                 {
3190                         //
3191                         // Precondition:
3192                         //   original == null || original.Resolve (...) ==> left
3193                         //
3194
3195                         if (left is TypeExpr) {
3196                                 left = left.ResolveAsTypeTerminal (ec, true);
3197                                 if (left == null)
3198                                         return null;
3199
3200                                 if (!IsStatic) {
3201                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3202                                         return null;
3203                                 }
3204
3205                                 return this;
3206                         }
3207
3208                         if (!IsInstance) {
3209                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3210                                         return this;
3211
3212                                 return ResolveExtensionMemberAccess (left);
3213                         }
3214
3215                         InstanceExpression = left;
3216                         return this;
3217                 }
3218
3219                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3220                 {
3221                         error176 (loc, GetSignatureForError ());
3222                         return this;
3223                 }
3224
3225                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3226                 {
3227                         if (IsStatic)
3228                                 return;
3229
3230                         if (InstanceExpression == EmptyExpression.Null) {
3231                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3232                                 return;
3233                         }
3234
3235                         if (InstanceExpression.Type.IsValueType) {
3236                                 if (InstanceExpression is IMemoryLocation) {
3237                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3238                                 } else {
3239                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3240                                         InstanceExpression.Emit (ec);
3241                                         t.Store (ec);
3242                                         t.AddressOf (ec, AddressOp.Store);
3243                                 }
3244                         } else
3245                                 InstanceExpression.Emit (ec);
3246
3247                         if (prepare_for_load)
3248                                 ec.ig.Emit (OpCodes.Dup);
3249                 }
3250
3251                 public virtual void SetTypeArguments (TypeArguments ta)
3252                 {
3253                         // TODO: need to get correct member type
3254                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3255                                 GetSignatureForError ());
3256                 }
3257         }
3258
3259         ///
3260         /// Represents group of extension methods
3261         ///
3262         public class ExtensionMethodGroupExpr : MethodGroupExpr
3263         {
3264                 readonly NamespaceEntry namespace_entry;
3265                 public Expression ExtensionExpression;
3266                 Argument extension_argument;
3267
3268                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3269                         : base (list, extensionType, l)
3270                 {
3271                         this.namespace_entry = n;
3272                 }
3273
3274                 public override bool IsStatic {
3275                         get { return true; }
3276                 }
3277
3278                 public bool IsTopLevel {
3279                         get { return namespace_entry == null; }
3280                 }
3281
3282                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3283                 {
3284                         if (arguments == null)
3285                                 arguments = new ArrayList (1);
3286                         arguments.Insert (0, extension_argument);
3287                         base.EmitArguments (ec, arguments);
3288                 }
3289
3290                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3291                 {
3292                         if (arguments == null)
3293                                 arguments = new ArrayList (1);
3294                         arguments.Insert (0, extension_argument);
3295                         base.EmitCall (ec, arguments);
3296                 }
3297
3298                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3299                 {
3300                         if (arguments == null)
3301                                 arguments = new ArrayList (1);
3302
3303                         arguments.Insert (0, new Argument (ExtensionExpression));
3304                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3305
3306                         // Store resolved argument and restore original arguments
3307                         if (mg != null)
3308                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3309                         arguments.RemoveAt (0);
3310
3311                         return mg;
3312                 }
3313
3314                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3315                 {
3316                         // Use normal resolve rules
3317                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3318                         if (mg != null)
3319                                 return mg;
3320
3321                         if (ns == null)
3322                                 return null;
3323
3324                         // Search continues
3325                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3326                         if (e == null)
3327                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3328
3329                         e.ExtensionExpression = ExtensionExpression;
3330                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3331                 }
3332         }
3333
3334         /// <summary>
3335         ///   MethodGroupExpr represents a group of method candidates which
3336         ///   can be resolved to the best method overload
3337         /// </summary>
3338         public class MethodGroupExpr : MemberExpr
3339         {
3340                 public interface IErrorHandler
3341                 {
3342                         bool NoExactMatch (EmitContext ec, MethodBase method);
3343                 }
3344
3345                 public IErrorHandler CustomErrorHandler;
3346                 public MethodBase [] Methods;
3347                 MethodBase best_candidate;
3348                 // TODO: make private
3349                 public TypeArguments type_arguments;
3350                 bool identical_type_name;
3351                 Type delegate_type;
3352
3353                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3354                         : this (type, l)
3355                 {
3356                         Methods = new MethodBase [mi.Length];
3357                         mi.CopyTo (Methods, 0);
3358                 }
3359
3360                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3361                         : this (type, l)
3362                 {
3363                         try {
3364                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3365                         } catch {
3366                                 foreach (MemberInfo m in list){
3367                                         if (!(m is MethodBase)){
3368                                                 Console.WriteLine ("Name " + m.Name);
3369                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3370                                         }
3371                                 }
3372                                 throw;
3373                         }
3374
3375
3376                 }
3377
3378                 protected MethodGroupExpr (Type type, Location loc)
3379                 {
3380                         this.loc = loc;
3381                         eclass = ExprClass.MethodGroup;
3382                         this.type = type;
3383                 }
3384
3385                 public override Type DeclaringType {
3386                         get {
3387                                 //
3388                                 // We assume that the top-level type is in the end
3389                                 //
3390                                 return Methods [Methods.Length - 1].DeclaringType;
3391                                 //return Methods [0].DeclaringType;
3392                         }
3393                 }
3394
3395                 public Type DelegateType {
3396                         set {
3397                                 delegate_type = value;
3398                         }
3399                 }
3400
3401                 public bool IdenticalTypeName {
3402                         get {
3403                                 return identical_type_name;
3404                         }
3405
3406                         set {
3407                                 identical_type_name = value;
3408                         }
3409                 }
3410
3411                 public override string GetSignatureForError ()
3412                 {
3413                         if (best_candidate != null)
3414                                 return TypeManager.CSharpSignature (best_candidate);
3415
3416                         return TypeManager.CSharpSignature (Methods [0]);
3417                 }
3418
3419                 public override string Name {
3420                         get {
3421                                 return Methods [0].Name;
3422                         }
3423                 }
3424
3425                 public override bool IsInstance {
3426                         get {
3427                                 if (best_candidate != null)
3428                                         return !best_candidate.IsStatic;
3429
3430                                 foreach (MethodBase mb in Methods)
3431                                         if (!mb.IsStatic)
3432                                                 return true;
3433
3434                                 return false;
3435                         }
3436                 }
3437
3438                 public override bool IsStatic {
3439                         get {
3440                                 if (best_candidate != null)
3441                                         return best_candidate.IsStatic;
3442
3443                                 foreach (MethodBase mb in Methods)
3444                                         if (mb.IsStatic)
3445                                                 return true;
3446
3447                                 return false;
3448                         }
3449                 }
3450
3451                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3452                 {
3453                         return (ConstructorInfo)mg.best_candidate;
3454                 }
3455
3456                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3457                 {
3458                         return (MethodInfo)mg.best_candidate;
3459                 }
3460
3461                 //
3462                 //  7.4.3.3  Better conversion from expression
3463                 //  Returns :   1    if a->p is better,
3464                 //              2    if a->q is better,
3465                 //              0 if neither is better
3466                 //
3467                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3468                 {
3469                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3470                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3471                                 //
3472                                 // Uwrap delegate from Expression<T>
3473                                 //
3474                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3475                                         p = TypeManager.GetTypeArguments (p) [0];
3476                                         q = TypeManager.GetTypeArguments (q) [0];
3477                                 }
3478                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3479                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3480                         } else {
3481                                 if (argument_type == p)
3482                                         return 1;
3483
3484                                 if (argument_type == q)
3485                                         return 2;
3486                         }
3487
3488                         return BetterTypeConversion (ec, p, q);
3489                 }
3490
3491                 //
3492                 // 7.4.3.4  Better conversion from type
3493                 //
3494                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3495                 {
3496                         if (p == null || q == null)
3497                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3498
3499                         if (p == TypeManager.int32_type) {
3500                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3501                                         return 1;
3502                         } else if (p == TypeManager.int64_type) {
3503                                 if (q == TypeManager.uint64_type)
3504                                         return 1;
3505                         } else if (p == TypeManager.sbyte_type) {
3506                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3507                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3508                                         return 1;
3509                         } else if (p == TypeManager.short_type) {
3510                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3511                                         q == TypeManager.uint64_type)
3512                                         return 1;
3513                         }
3514
3515                         if (q == TypeManager.int32_type) {
3516                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3517                                         return 2;
3518                         } if (q == TypeManager.int64_type) {
3519                                 if (p == TypeManager.uint64_type)
3520                                         return 2;
3521                         } else if (q == TypeManager.sbyte_type) {
3522                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3523                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3524                                         return 2;
3525                         } if (q == TypeManager.short_type) {
3526                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3527                                         p == TypeManager.uint64_type)
3528                                         return 2;
3529                         }
3530
3531                         // TODO: this is expensive
3532                         Expression p_tmp = new EmptyExpression (p);
3533                         Expression q_tmp = new EmptyExpression (q);
3534
3535                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3536                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3537
3538                         if (p_to_q && !q_to_p)
3539                                 return 1;
3540
3541                         if (q_to_p && !p_to_q)
3542                                 return 2;
3543
3544                         return 0;
3545                 }
3546
3547                 /// <summary>
3548                 ///   Determines "Better function" between candidate
3549                 ///   and the current best match
3550                 /// </summary>
3551                 /// <remarks>
3552                 ///    Returns a boolean indicating :
3553                 ///     false if candidate ain't better
3554                 ///     true  if candidate is better than the current best match
3555                 /// </remarks>
3556                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3557                         MethodBase candidate, bool candidate_params,
3558                         MethodBase best, bool best_params)
3559                 {
3560                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3561                         ParameterData best_pd = TypeManager.GetParameterData (best);
3562
3563                         bool better_at_least_one = false;
3564                         bool same = true;
3565                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3566                         {
3567                                 Argument a = (Argument) args [j];
3568
3569                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3570                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3571
3572                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3573                                 {
3574                                         ct = TypeManager.GetElementType (ct);
3575                                         --c_idx;
3576                                 }
3577
3578                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3579                                 {
3580                                         bt = TypeManager.GetElementType (bt);
3581                                         --b_idx;
3582                                 }
3583
3584                                 if (ct.Equals (bt))
3585                                         continue;
3586
3587                                 same = false;
3588                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3589
3590                                 // for each argument, the conversion to 'ct' should be no worse than
3591                                 // the conversion to 'bt'.
3592                                 if (result == 2)
3593                                         return false;
3594
3595                                 // for at least one argument, the conversion to 'ct' should be better than
3596                                 // the conversion to 'bt'.
3597                                 if (result != 0)
3598                                         better_at_least_one = true;
3599                         }
3600
3601                         if (better_at_least_one)
3602                                 return true;
3603
3604                         //
3605                         // This handles the case
3606                         //
3607                         //   Add (float f1, float f2, float f3);
3608                         //   Add (params decimal [] foo);
3609                         //
3610                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3611                         // first candidate would've chosen as better.
3612                         //
3613                         if (!same)
3614                                 return false;
3615
3616                         //
3617                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3618                         //
3619                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3620                                 return true;
3621                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3622                                 return false;
3623
3624                         //
3625                         // This handles the following cases:
3626                         //
3627                         //   Trim () is better than Trim (params char[] chars)
3628                         //   Concat (string s1, string s2, string s3) is better than
3629                         //     Concat (string s1, params string [] srest)
3630                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3631                         //
3632                         if (!candidate_params && best_params)
3633                                 return true;
3634                         if (candidate_params && !best_params)
3635                                 return false;
3636
3637                         int candidate_param_count = candidate_pd.Count;
3638                         int best_param_count = best_pd.Count;
3639
3640                         if (candidate_param_count != best_param_count)
3641                                 // can only happen if (candidate_params && best_params)
3642                                 return candidate_param_count > best_param_count;
3643
3644                         //
3645                         // now, both methods have the same number of parameters, and the parameters have the same types
3646                         // Pick the "more specific" signature
3647                         //
3648
3649                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3650                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3651
3652                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3653                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3654
3655                         bool specific_at_least_once = false;
3656                         for (int j = 0; j < candidate_param_count; ++j)
3657                         {
3658                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3659                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3660                                 if (ct.Equals (bt))
3661                                         continue;
3662                                 Type specific = MoreSpecific (ct, bt);
3663                                 if (specific == bt)
3664                                         return false;
3665                                 if (specific == ct)
3666                                         specific_at_least_once = true;
3667                         }
3668
3669                         if (specific_at_least_once)
3670                                 return true;
3671
3672                         // FIXME: handle lifted operators
3673                         // ...
3674
3675                         return false;
3676                 }
3677
3678                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3679                 {
3680                         if (!IsStatic)
3681                                 return base.ResolveExtensionMemberAccess (left);
3682
3683                         //
3684                         // When left side is an expression and at least one candidate method is
3685                         // static, it can be extension method
3686                         //
3687                         InstanceExpression = left;
3688                         return this;
3689                 }
3690
3691                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3692                                                                 SimpleName original)
3693                 {
3694                         if (!(left is TypeExpr) &&
3695                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3696                                 IdenticalTypeName = true;
3697
3698                         return base.ResolveMemberAccess (ec, left, loc, original);
3699                 }
3700
3701                 public override Expression CreateExpressionTree (EmitContext ec)
3702                 {
3703                         Type t = best_candidate.IsConstructor ?
3704                                 typeof (ConstructorInfo) : typeof (MethodInfo);
3705
3706                         return new Cast (new TypeExpression (t, loc), new TypeOfMethod (best_candidate, loc));
3707                 }
3708
3709                 override public Expression DoResolve (EmitContext ec)
3710                 {
3711                         if (InstanceExpression != null) {
3712                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3713                                 if (InstanceExpression == null)
3714                                         return null;
3715                         }
3716
3717                         return this;
3718                 }
3719
3720                 public void ReportUsageError ()
3721                 {
3722                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3723                                       Name + "()' is referenced without parentheses");
3724                 }
3725
3726                 override public void Emit (EmitContext ec)
3727                 {
3728                         ReportUsageError ();
3729                 }
3730
3731                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3732                 {
3733                         Invocation.EmitArguments (ec, arguments, false, null);
3734                 }
3735
3736                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3737                 {
3738                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3739                 }
3740
3741                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3742                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3743                 {
3744                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3745                                 Report.SymbolRelatedToPreviousError (method);
3746                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3747                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3748                                                 TypeManager.CSharpSignature (method));
3749                                         return;
3750                                 }
3751                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3752                                           TypeManager.CSharpSignature (method));
3753                         } else if (delegate_type == null) {
3754                                 Report.SymbolRelatedToPreviousError (method);
3755                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3756                                                   TypeManager.CSharpSignature (method));
3757                         } else
3758                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3759                                         TypeManager.CSharpName (delegate_type));
3760
3761                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3762
3763                         string index = (idx + 1).ToString ();
3764                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3765                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3766                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3767                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3768                                                 index, Parameter.GetModifierSignature (a.Modifier));
3769                                 else
3770                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3771                                                 index, Parameter.GetModifierSignature (mod));
3772                         } else {
3773                                 string p1 = a.GetSignatureForError ();
3774                                 string p2 = TypeManager.CSharpName (paramType);
3775
3776                                 if (p1 == p2) {
3777                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3778                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3779                                         Report.SymbolRelatedToPreviousError (paramType);
3780                                 }
3781                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3782                         }
3783                 }
3784
3785                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3786                 {
3787                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3788                                 Name, TypeManager.CSharpName (target));
3789                 }
3790
3791                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3792                 {
3793                         return parameters.Count;
3794                 }
3795
3796                 public static bool IsAncestralType (Type first_type, Type second_type)
3797                 {
3798                         return first_type != second_type &&
3799                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3800                                 TypeManager.ImplementsInterface (second_type, first_type));
3801                 }
3802
3803                 ///
3804                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3805                 /// to the given set of arguments
3806                 /// A return value rates candidate method compatibility,
3807                 /// 0 = the best, int.MaxValue = the worst
3808                 ///
3809                 public int IsApplicable (EmitContext ec,
3810                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3811                 {
3812                         MethodBase candidate = method;
3813
3814                         ParameterData pd = TypeManager.GetParameterData (candidate);
3815                         int param_count = GetApplicableParametersCount (candidate, pd);
3816
3817                         if (arg_count != param_count) {
3818                                 if (!pd.HasParams)
3819                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3820                                 if (arg_count < param_count - 1)
3821                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3822                         }
3823
3824 #if GMCS_SOURCE
3825                         //
3826                         // 1. Handle generic method using type arguments when specified or type inference
3827                         //
3828                         if (TypeManager.IsGenericMethod (candidate)) {
3829                                 if (type_arguments != null) {
3830                                         Type [] g_args = candidate.GetGenericArguments ();
3831                                         if (g_args.Length != type_arguments.Count)
3832                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3833
3834                                         // TODO: Don't create new method, create Parameters only
3835                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3836                                         candidate = method;
3837                                         pd = TypeManager.GetParameterData (candidate);
3838                                 } else {
3839                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3840                                         if (score != 0)
3841                                                 return score - 20000;
3842
3843                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3844                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3845                                                         TypeManager.CSharpSignature (candidate));
3846
3847                                         pd = TypeManager.GetParameterData (candidate);
3848                                 }
3849                         } else {
3850                                 if (type_arguments != null)
3851                                         return int.MaxValue - 15000;
3852                         }
3853 #endif
3854
3855                         //
3856                         // 2. Each argument has to be implicitly convertible to method parameter
3857                         //
3858                         method = candidate;
3859                         Parameter.Modifier p_mod = 0;
3860                         Type pt = null;
3861                         for (int i = 0; i < arg_count; i++) {
3862                                 Argument a = (Argument) arguments [i];
3863                                 Parameter.Modifier a_mod = a.Modifier &
3864                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3865
3866                                 if (p_mod != Parameter.Modifier.PARAMS) {
3867                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3868
3869                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3870                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3871                                                         continue;
3872
3873                                                 p_mod = 0;
3874                                         }
3875
3876                                         pt = pd.ParameterType (i);
3877                                 } else {
3878                                         params_expanded_form = true;
3879                                 }
3880
3881                                 int score = 1;
3882                                 if (!params_expanded_form)
3883                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3884
3885                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3886                                         // It can be applicable in expanded form
3887                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3888                                         if (score == 0)
3889                                                 params_expanded_form = true;
3890                                 }
3891
3892                                 if (score != 0) {
3893                                         if (params_expanded_form)
3894                                                 ++score;
3895                                         return (arg_count - i) * 2 + score;
3896                                 }
3897                         }
3898
3899                         if (arg_count != param_count)
3900                                 params_expanded_form = true;
3901
3902                         return 0;
3903                 }
3904
3905                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3906                 {
3907                         //
3908                         // Types have to be identical when ref or out modifer is used
3909                         //
3910                         if (arg_mod != 0 || param_mod != 0) {
3911                                 if (TypeManager.HasElementType (parameter))
3912                                         parameter = parameter.GetElementType ();
3913
3914                                 Type a_type = argument.Type;
3915                                 if (TypeManager.HasElementType (a_type))
3916                                         a_type = a_type.GetElementType ();
3917
3918                                 if (a_type != parameter)
3919                                         return 2;
3920
3921                                 return 0;
3922                         }
3923
3924                         // FIXME: Kill this abomination (EmitContext.TempEc)
3925                         EmitContext prevec = EmitContext.TempEc;
3926                         EmitContext.TempEc = ec;
3927                         try {
3928                                 if (delegate_type != null ?
3929                                         !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3930                                         !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3931                                         return 2;
3932
3933                                 if (arg_mod != param_mod)
3934                                         return 1;
3935
3936                         } finally {
3937                                 EmitContext.TempEc = prevec;
3938                         }
3939
3940                         return 0;
3941                 }
3942
3943                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3944                 {
3945                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3946                                 return false;
3947
3948                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3949                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3950
3951                         if (cand_pd.Count != base_pd.Count)
3952                                 return false;
3953
3954                         for (int j = 0; j < cand_pd.Count; ++j)
3955                         {
3956                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3957                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3958                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3959                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3960
3961                                 if (cm != bm || ct != bt)
3962                                         return false;
3963                         }
3964
3965                         return true;
3966                 }
3967
3968                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3969                 {
3970                         MemberInfo [] miset;
3971                         MethodGroupExpr union;
3972
3973                         if (mg1 == null) {
3974                                 if (mg2 == null)
3975                                         return null;
3976                                 return (MethodGroupExpr) mg2;
3977                         } else {
3978                                 if (mg2 == null)
3979                                         return (MethodGroupExpr) mg1;
3980                         }
3981
3982                         MethodGroupExpr left_set = null, right_set = null;
3983                         int length1 = 0, length2 = 0;
3984
3985                         left_set = (MethodGroupExpr) mg1;
3986                         length1 = left_set.Methods.Length;
3987
3988                         right_set = (MethodGroupExpr) mg2;
3989                         length2 = right_set.Methods.Length;
3990
3991                         ArrayList common = new ArrayList ();
3992
3993                         foreach (MethodBase r in right_set.Methods){
3994                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3995                                         common.Add (r);
3996                         }
3997
3998                         miset = new MemberInfo [length1 + length2 - common.Count];
3999                         left_set.Methods.CopyTo (miset, 0);
4000
4001                         int k = length1;
4002
4003                         foreach (MethodBase r in right_set.Methods) {
4004                                 if (!common.Contains (r))
4005                                         miset [k++] = r;
4006                         }
4007
4008                         union = new MethodGroupExpr (miset, mg1.Type, loc);
4009
4010                         return union;
4011                 }
4012
4013                 static Type MoreSpecific (Type p, Type q)
4014                 {
4015                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
4016                                 return q;
4017                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
4018                                 return p;
4019
4020                         if (TypeManager.HasElementType (p))
4021                         {
4022                                 Type pe = TypeManager.GetElementType (p);
4023                                 Type qe = TypeManager.GetElementType (q);
4024                                 Type specific = MoreSpecific (pe, qe);
4025                                 if (specific == pe)
4026                                         return p;
4027                                 if (specific == qe)
4028                                         return q;
4029                         }
4030                         else if (TypeManager.IsGenericType (p))
4031                         {
4032                                 Type[] pargs = TypeManager.GetTypeArguments (p);
4033                                 Type[] qargs = TypeManager.GetTypeArguments (q);
4034
4035                                 bool p_specific_at_least_once = false;
4036                                 bool q_specific_at_least_once = false;
4037
4038                                 for (int i = 0; i < pargs.Length; i++)
4039                                 {
4040                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
4041                                         if (specific == pargs [i])
4042                                                 p_specific_at_least_once = true;
4043                                         if (specific == qargs [i])
4044                                                 q_specific_at_least_once = true;
4045                                 }
4046
4047                                 if (p_specific_at_least_once && !q_specific_at_least_once)
4048                                         return p;
4049                                 if (!p_specific_at_least_once && q_specific_at_least_once)
4050                                         return q;
4051                         }
4052
4053                         return null;
4054                 }
4055
4056                 /// <summary>
4057                 ///   Find the Applicable Function Members (7.4.2.1)
4058                 ///
4059                 ///   me: Method Group expression with the members to select.
4060                 ///       it might contain constructors or methods (or anything
4061                 ///       that maps to a method).
4062                 ///
4063                 ///   Arguments: ArrayList containing resolved Argument objects.
4064                 ///
4065                 ///   loc: The location if we want an error to be reported, or a Null
4066                 ///        location for "probing" purposes.
4067                 ///
4068                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4069                 ///            that is the best match of me on Arguments.
4070                 ///
4071                 /// </summary>
4072                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4073                         bool may_fail, Location loc)
4074                 {
4075                         bool method_params = false;
4076                         Type applicable_type = null;
4077                         int arg_count = 0;
4078                         ArrayList candidates = new ArrayList (2);
4079                         ArrayList candidate_overrides = null;
4080
4081                         //
4082                         // Used to keep a map between the candidate
4083                         // and whether it is being considered in its
4084                         // normal or expanded form
4085                         //
4086                         // false is normal form, true is expanded form
4087                         //
4088                         Hashtable candidate_to_form = null;
4089
4090                         if (Arguments != null)
4091                                 arg_count = Arguments.Count;
4092
4093                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4094                                 if (!may_fail)
4095                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4096                                 return null;
4097                         }
4098
4099                         int nmethods = Methods.Length;
4100
4101                         if (!IsBase) {
4102                                 //
4103                                 // Methods marked 'override' don't take part in 'applicable_type'
4104                                 // computation, nor in the actual overload resolution.
4105                                 // However, they still need to be emitted instead of a base virtual method.
4106                                 // So, we salt them away into the 'candidate_overrides' array.
4107                                 //
4108                                 // In case of reflected methods, we replace each overriding method with
4109                                 // its corresponding base virtual method.  This is to improve compatibility
4110                                 // with non-C# libraries which change the visibility of overrides (#75636)
4111                                 //
4112                                 int j = 0;
4113                                 for (int i = 0; i < Methods.Length; ++i) {
4114                                         MethodBase m = Methods [i];
4115                                         if (TypeManager.IsOverride (m)) {
4116                                                 if (candidate_overrides == null)
4117                                                         candidate_overrides = new ArrayList ();
4118                                                 candidate_overrides.Add (m);
4119                                                 m = TypeManager.TryGetBaseDefinition (m);
4120                                         }
4121                                         if (m != null)
4122                                                 Methods [j++] = m;
4123                                 }
4124                                 nmethods = j;
4125                         }
4126
4127                         //
4128                         // Enable message recording, it's used mainly by lambda expressions
4129                         //
4130                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4131                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4132
4133                         //
4134                         // First we construct the set of applicable methods
4135                         //
4136                         bool is_sorted = true;
4137                         int best_candidate_rate = int.MaxValue;
4138                         for (int i = 0; i < nmethods; i++) {
4139                                 Type decl_type = Methods [i].DeclaringType;
4140
4141                                 //
4142                                 // If we have already found an applicable method
4143                                 // we eliminate all base types (Section 14.5.5.1)
4144                                 //
4145                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4146                                         continue;
4147
4148                                 //
4149                                 // Check if candidate is applicable (section 14.4.2.1)
4150                                 //
4151                                 bool params_expanded_form = false;
4152                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4153
4154                                 if (candidate_rate < best_candidate_rate) {
4155                                         best_candidate_rate = candidate_rate;
4156                                         best_candidate = Methods [i];
4157                                 }
4158
4159                                 if (params_expanded_form) {
4160                                         if (candidate_to_form == null)
4161                                                 candidate_to_form = new PtrHashtable ();
4162                                         MethodBase candidate = Methods [i];
4163                                         candidate_to_form [candidate] = candidate;
4164                                 }
4165
4166                                 if (candidate_rate != 0) {
4167                                         if (msg_recorder != null)
4168                                                 msg_recorder.EndSession ();
4169                                         continue;
4170                                 }
4171
4172                                 msg_recorder = null;
4173                                 candidates.Add (Methods [i]);
4174
4175                                 if (applicable_type == null)
4176                                         applicable_type = decl_type;
4177                                 else if (applicable_type != decl_type) {
4178                                         is_sorted = false;
4179                                         if (IsAncestralType (applicable_type, decl_type))
4180                                                 applicable_type = decl_type;
4181                                 }
4182                         }
4183
4184                         Report.SetMessageRecorder (prev_recorder);
4185                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4186                                 return null;
4187
4188                         int candidate_top = candidates.Count;
4189
4190                         if (applicable_type == null) {
4191                                 //
4192                                 // When we found a top level method which does not match and it's
4193                                 // not an extension method. We start extension methods lookup from here
4194                                 //
4195                                 if (InstanceExpression != null) {
4196                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4197                                         if (ex_method_lookup != null) {
4198                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4199                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4200                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4201                                         }
4202                                 }
4203
4204                                 if (may_fail)
4205                                         return null;
4206
4207                                 //
4208                                 // Okay so we have failed to find exact match so we
4209                                 // return error info about the closest match
4210                                 //
4211                                 if (best_candidate != null) {
4212                                         if (CustomErrorHandler != null) {
4213                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4214                                                         return null;
4215                                         }
4216
4217                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4218                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4219                                         if (arg_count == pd.Count || pd.HasParams) {
4220                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4221                                                         if (type_arguments == null) {
4222                                                                 Report.Error (411, loc,
4223                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4224                                                                         "the usage. Try specifying the type arguments explicitly",
4225                                                                         TypeManager.CSharpSignature (best_candidate));
4226                                                                 return null;
4227                                                         }
4228
4229                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4230                                                         if (type_arguments.Count != g_args.Length) {
4231                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4232                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4233                                                                         TypeManager.CSharpSignature (best_candidate),
4234                                                                         g_args.Length.ToString ());
4235                                                                 return null;
4236                                                         }
4237                                                 } else {
4238                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4239                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4240                                                                 return null;
4241                                                         }
4242                                                 }
4243
4244                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4245                                                         return null;
4246                                         }
4247                                 }
4248
4249                                 if (almost_matched_members.Count != 0) {
4250                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4251                                         null, MemberTypes.Constructor, AllBindingFlags);
4252                                         return null;
4253                                 }
4254
4255                                 //
4256                                 // We failed to find any method with correct argument count
4257                                 //
4258                                 if (Name == ConstructorInfo.ConstructorName) {
4259                                         Report.SymbolRelatedToPreviousError (type);
4260                                         Report.Error (1729, loc,
4261                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4262                                                 TypeManager.CSharpName (type), arg_count);
4263                                 } else {
4264                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4265                                                 Name, arg_count.ToString ());
4266                                 }
4267
4268                                 return null;
4269                         }
4270
4271                         if (!is_sorted) {
4272                                 //
4273                                 // At this point, applicable_type is _one_ of the most derived types
4274                                 // in the set of types containing the methods in this MethodGroup.
4275                                 // Filter the candidates so that they only contain methods from the
4276                                 // most derived types.
4277                                 //
4278
4279                                 int finalized = 0; // Number of finalized candidates
4280
4281                                 do {
4282                                         // Invariant: applicable_type is a most derived type
4283
4284                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4285                                         // eliminating all it's base types.  At the same time, we'll also move
4286                                         // every unrelated type to the end of the array, and pick the next
4287                                         // 'applicable_type'.
4288
4289                                         Type next_applicable_type = null;
4290                                         int j = finalized; // where to put the next finalized candidate
4291                                         int k = finalized; // where to put the next undiscarded candidate
4292                                         for (int i = finalized; i < candidate_top; ++i) {
4293                                                 MethodBase candidate = (MethodBase) candidates [i];
4294                                                 Type decl_type = candidate.DeclaringType;
4295
4296                                                 if (decl_type == applicable_type) {
4297                                                         candidates [k++] = candidates [j];
4298                                                         candidates [j++] = candidates [i];
4299                                                         continue;
4300                                                 }
4301
4302                                                 if (IsAncestralType (decl_type, applicable_type))
4303                                                         continue;
4304
4305                                                 if (next_applicable_type != null &&
4306                                                         IsAncestralType (decl_type, next_applicable_type))
4307                                                         continue;
4308
4309                                                 candidates [k++] = candidates [i];
4310
4311                                                 if (next_applicable_type == null ||
4312                                                         IsAncestralType (next_applicable_type, decl_type))
4313                                                         next_applicable_type = decl_type;
4314                                         }
4315
4316                                         applicable_type = next_applicable_type;
4317                                         finalized = j;
4318                                         candidate_top = k;
4319                                 } while (applicable_type != null);
4320                         }
4321
4322                         //
4323                         // Now we actually find the best method
4324                         //
4325
4326                         best_candidate = (MethodBase) candidates [0];
4327                         if (delegate_type == null)
4328                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4329
4330                         for (int ix = 1; ix < candidate_top; ix++) {
4331                                 MethodBase candidate = (MethodBase) candidates [ix];
4332
4333                                 if (candidate == best_candidate)
4334                                         continue;
4335
4336                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4337
4338                                 if (BetterFunction (ec, Arguments, arg_count,
4339                                         candidate, cand_params,
4340                                         best_candidate, method_params)) {
4341                                         best_candidate = candidate;
4342                                         method_params = cand_params;
4343                                 }
4344                         }
4345                         //
4346                         // Now check that there are no ambiguities i.e the selected method
4347                         // should be better than all the others
4348                         //
4349                         MethodBase ambiguous = null;
4350                         for (int ix = 1; ix < candidate_top; ix++) {
4351                                 MethodBase candidate = (MethodBase) candidates [ix];
4352
4353                                 if (candidate == best_candidate)
4354                                         continue;
4355
4356                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4357                                 if (!BetterFunction (ec, Arguments, arg_count,
4358                                         best_candidate, method_params,
4359                                         candidate, cand_params))
4360                                 {
4361                                         if (!may_fail)
4362                                                 Report.SymbolRelatedToPreviousError (candidate);
4363                                         ambiguous = candidate;
4364                                 }
4365                         }
4366
4367                         if (ambiguous != null) {
4368                                 Report.SymbolRelatedToPreviousError (best_candidate);
4369                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4370                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4371                                 return this;
4372                         }
4373
4374                         //
4375                         // If the method is a virtual function, pick an override closer to the LHS type.
4376                         //
4377                         if (!IsBase && best_candidate.IsVirtual) {
4378                                 if (TypeManager.IsOverride (best_candidate))
4379                                         throw new InternalErrorException (
4380                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4381
4382                                 if (candidate_overrides != null) {
4383                                         Type[] gen_args = null;
4384                                         bool gen_override = false;
4385                                         if (TypeManager.IsGenericMethod (best_candidate))
4386                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4387
4388                                         foreach (MethodBase candidate in candidate_overrides) {
4389                                                 if (TypeManager.IsGenericMethod (candidate)) {
4390                                                         if (gen_args == null)
4391                                                                 continue;
4392
4393                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4394                                                                 continue;
4395                                                 } else {
4396                                                         if (gen_args != null)
4397                                                                 continue;
4398                                                 }
4399
4400                                                 if (IsOverride (candidate, best_candidate)) {
4401                                                         gen_override = true;
4402                                                         best_candidate = candidate;
4403                                                 }
4404                                         }
4405
4406                                         if (gen_override && gen_args != null) {
4407 #if GMCS_SOURCE
4408                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4409 #endif
4410                                         }
4411                                 }
4412                         }
4413
4414                         //
4415                         // And now check if the arguments are all
4416                         // compatible, perform conversions if
4417                         // necessary etc. and return if everything is
4418                         // all right
4419                         //
4420                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4421                                 method_params, may_fail, loc))
4422                                 return null;
4423
4424                         if (best_candidate == null)
4425                                 return null;
4426
4427                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4428 #if GMCS_SOURCE
4429                         if (the_method.IsGenericMethodDefinition &&
4430                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4431                                 return null;
4432 #endif
4433
4434                         IMethodData data = TypeManager.GetMethod (the_method);
4435                         if (data != null)
4436                                 data.SetMemberIsUsed ();
4437
4438                         return this;
4439                 }
4440
4441                 public override void SetTypeArguments (TypeArguments ta)
4442                 {
4443                         type_arguments = ta;
4444                 }
4445
4446                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4447                                                           int arg_count, MethodBase method,
4448                                                           bool chose_params_expanded,
4449                                                           bool may_fail, Location loc)
4450                 {
4451                         ParameterData pd = TypeManager.GetParameterData (method);
4452
4453                         int errors = Report.Errors;
4454                         Parameter.Modifier p_mod = 0;
4455                         Type pt = null;
4456                         int a_idx = 0, a_pos = 0;
4457                         Argument a = null;
4458                         ArrayList params_initializers = null;
4459
4460                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4461                                 a = (Argument) arguments [a_idx];
4462                                 if (p_mod != Parameter.Modifier.PARAMS) {
4463                                         p_mod = pd.ParameterModifier (a_idx);
4464                                         pt = pd.ParameterType (a_idx);
4465
4466                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4467                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4468                                                         break;
4469                                                 continue;
4470                                         }
4471
4472                                         if (pt.IsPointer && !ec.InUnsafe) {
4473                                                 if (may_fail)
4474                                                         return false;
4475
4476                                                 UnsafeError (loc);
4477                                         }
4478
4479                                         if (p_mod == Parameter.Modifier.PARAMS) {
4480                                                 if (chose_params_expanded) {
4481                                                         params_initializers = new ArrayList (arg_count - a_idx);
4482                                                         pt = TypeManager.GetElementType (pt);
4483                                                 }
4484                                         } else if (p_mod != 0) {
4485                                                 pt = TypeManager.GetElementType (pt);
4486                                         }
4487                                 }
4488
4489                                 //
4490                                 // Types have to be identical when ref or out modifer is used
4491                                 //
4492                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4493                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4494                                                 break;
4495
4496                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4497                                                 break;
4498
4499                                         continue;
4500                                 }
4501
4502                                 Expression conv;
4503                                 if (TypeManager.IsEqual (a.Type, pt)) {
4504                                         conv = a.Expr;
4505                                 } else {
4506                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4507                                         if (conv == null)
4508                                                 break;
4509                                 }
4510
4511                                 //
4512                                 // Convert params arguments to an array initializer
4513                                 //
4514                                 if (params_initializers != null) {
4515                                         params_initializers.Add (conv);
4516                                         arguments.RemoveAt (a_idx--);
4517                                         --arg_count;
4518                                         continue;
4519                                 }
4520
4521                                 // Update the argument with the implicit conversion
4522                                 a.Expr = conv;
4523                         }
4524
4525                         //
4526                         // Fill not provided arguments required by params modifier
4527                         //
4528                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4529                                 if (arguments == null)
4530                                         arguments = new ArrayList (1);
4531
4532                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4533                                 pt = TypeManager.GetElementType (pt);
4534                                 params_initializers = new ArrayList (0);
4535                         }
4536
4537                         if (a_idx == arg_count) {
4538                                 //
4539                                 // Append an array argument with all params arguments
4540                                 //
4541                                 if (params_initializers != null) {
4542                                         arguments.Add (new Argument (
4543                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4544                                                 params_initializers, loc).Resolve (ec)));
4545                                 }
4546                                 return true;
4547                         }
4548
4549                         if (!may_fail && Report.Errors == errors) {
4550                                 if (CustomErrorHandler != null)
4551                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4552                                 else
4553                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4554                         }
4555                         return false;
4556                 }
4557         }
4558
4559         public class ConstantExpr : MemberExpr
4560         {
4561                 FieldInfo constant;
4562
4563                 public ConstantExpr (FieldInfo constant, Location loc)
4564                 {
4565                         this.constant = constant;
4566                         this.loc = loc;
4567                 }
4568
4569                 public override string Name {
4570                         get { throw new NotImplementedException (); }
4571                 }
4572
4573                 public override bool IsInstance {
4574                         get { return !IsStatic; }
4575                 }
4576
4577                 public override bool IsStatic {
4578                         get { return constant.IsStatic; }
4579                 }
4580
4581                 public override Type DeclaringType {
4582                         get { return constant.DeclaringType; }
4583                 }
4584
4585                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4586                 {
4587                         constant = TypeManager.GetGenericFieldDefinition (constant);
4588
4589                         IConstant ic = TypeManager.GetConstant (constant);
4590                         if (ic == null) {
4591                                 if (constant.IsLiteral) {
4592                                         ic = new ExternalConstant (constant);
4593                                 } else {
4594                                         ic = ExternalConstant.CreateDecimal (constant);
4595                                         // HACK: decimal field was not resolved as constant
4596                                         if (ic == null)
4597                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4598                                 }
4599                                 TypeManager.RegisterConstant (constant, ic);
4600                         }
4601
4602                         return base.ResolveMemberAccess (ec, left, loc, original);
4603                 }
4604
4605                 public override Expression CreateExpressionTree (EmitContext ec)
4606                 {
4607                         throw new NotSupportedException ();
4608                 }
4609
4610                 public override Expression DoResolve (EmitContext ec)
4611                 {
4612                         IConstant ic = TypeManager.GetConstant (constant);
4613                         if (ic.ResolveValue ()) {
4614                                 if (!ec.IsInObsoleteScope)
4615                                         ic.CheckObsoleteness (loc);
4616                         }
4617
4618                         return ic.CreateConstantReference (loc);
4619                 }
4620
4621                 public override void Emit (EmitContext ec)
4622                 {
4623                         throw new NotSupportedException ();
4624                 }
4625
4626                 public override string GetSignatureForError ()
4627                 {
4628                         return TypeManager.GetFullNameSignature (constant);
4629                 }
4630         }
4631
4632         /// <summary>
4633         ///   Fully resolved expression that evaluates to a Field
4634         /// </summary>
4635         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4636                 public readonly FieldInfo FieldInfo;
4637                 VariableInfo variable_info;
4638
4639                 LocalTemporary temp;
4640                 bool prepared;
4641                 bool in_initializer;
4642
4643                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4644                         this (fi, l)
4645                 {
4646                         this.in_initializer = in_initializer;
4647                 }
4648
4649                 public FieldExpr (FieldInfo fi, Location l)
4650                 {
4651                         FieldInfo = fi;
4652                         eclass = ExprClass.Variable;
4653                         type = TypeManager.TypeToCoreType (fi.FieldType);
4654                         loc = l;
4655                 }
4656
4657                 public override string Name {
4658                         get {
4659                                 return FieldInfo.Name;
4660                         }
4661                 }
4662
4663                 public override bool IsInstance {
4664                         get {
4665                                 return !FieldInfo.IsStatic;
4666                         }
4667                 }
4668
4669                 public override bool IsStatic {
4670                         get {
4671                                 return FieldInfo.IsStatic;
4672                         }
4673                 }
4674
4675                 public override Type DeclaringType {
4676                         get {
4677                                 return FieldInfo.DeclaringType;
4678                         }
4679                 }
4680
4681                 public override string GetSignatureForError ()
4682                 {
4683                         return TypeManager.GetFullNameSignature (FieldInfo);
4684                 }
4685
4686                 public VariableInfo VariableInfo {
4687                         get {
4688                                 return variable_info;
4689                         }
4690                 }
4691
4692                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4693                                                                 SimpleName original)
4694                 {
4695                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4696                         Type t = fi.FieldType;
4697
4698                         if (t.IsPointer && !ec.InUnsafe) {
4699                                 UnsafeError (loc);
4700                         }
4701
4702                         return base.ResolveMemberAccess (ec, left, loc, original);
4703                 }
4704
4705                 public override Expression CreateExpressionTree (EmitContext ec)
4706                 {
4707                         Expression instance;
4708                         if (InstanceExpression == null) {
4709                                 instance = new NullLiteral (loc);
4710                         } else {
4711                                 instance = InstanceExpression.CreateExpressionTree (ec);
4712                         }
4713
4714                         ArrayList args = new ArrayList (2);
4715                         args.Add (new Argument (instance));
4716                         args.Add (new Argument (CreateTypeOfExpression ()));
4717                         return CreateExpressionFactoryCall ("Field", args);
4718                 }
4719
4720                 public Expression CreateTypeOfExpression ()
4721                 {
4722                         return new TypeOfField (FieldInfo, loc);
4723                 }
4724
4725                 override public Expression DoResolve (EmitContext ec)
4726                 {
4727                         return DoResolve (ec, false, false);
4728                 }
4729
4730                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4731                 {
4732                         if (!FieldInfo.IsStatic){
4733                                 if (InstanceExpression == null){
4734                                         //
4735                                         // This can happen when referencing an instance field using
4736                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4737                                         //
4738                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4739                                         return null;
4740                                 }
4741
4742                                 // Resolve the field's instance expression while flow analysis is turned
4743                                 // off: when accessing a field "a.b", we must check whether the field
4744                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4745
4746                                 if (lvalue_instance) {
4747                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4748                                                 Expression right_side =
4749                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4750                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4751                                         }
4752                                 } else {
4753                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4754                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4755                                 }
4756
4757                                 if (InstanceExpression == null)
4758                                         return null;
4759
4760                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4761                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4762                                 }
4763                         }
4764
4765                         if (!in_initializer && !ec.IsInFieldInitializer) {
4766                                 ObsoleteAttribute oa;
4767                                 FieldBase f = TypeManager.GetField (FieldInfo);
4768                                 if (f != null) {
4769                                         if (!ec.IsInObsoleteScope)
4770                                                 f.CheckObsoleteness (loc);
4771
4772                                         // To be sure that type is external because we do not register generated fields
4773                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4774                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4775                                         if (oa != null)
4776                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4777                                 }
4778                         }
4779
4780                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4781                         if (am != null){
4782                                 if (!FieldInfo.IsStatic){
4783                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4784                                                 Report.Error (1673, loc,
4785                                                 "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",
4786                                                         "this");
4787                                                 return null;
4788                                         }
4789                                 }
4790                         }
4791
4792                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4793                         if (fb != null) {
4794                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4795                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4796                                 }
4797
4798                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4799                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4800                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4801                                                 TypeManager.GetFullNameSignature (FieldInfo));
4802                                 }
4803
4804                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4805                         }
4806
4807                         // If the instance expression is a local variable or parameter.
4808                         IVariable var = InstanceExpression as IVariable;
4809                         if ((var == null) || (var.VariableInfo == null))
4810                                 return this;
4811
4812                         VariableInfo vi = var.VariableInfo;
4813                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4814                                 return null;
4815
4816                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4817                         return this;
4818                 }
4819
4820                 static readonly int [] codes = {
4821                         191,    // instance, write access
4822                         192,    // instance, out access
4823                         198,    // static, write access
4824                         199,    // static, out access
4825                         1648,   // member of value instance, write access
4826                         1649,   // member of value instance, out access
4827                         1650,   // member of value static, write access
4828                         1651    // member of value static, out access
4829                 };
4830
4831                 static readonly string [] msgs = {
4832                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4833                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4834                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4835                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4836                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4837                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4838                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4839                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4840                 };
4841
4842                 // The return value is always null.  Returning a value simplifies calling code.
4843                 Expression Report_AssignToReadonly (Expression right_side)
4844                 {
4845                         int i = 0;
4846                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4847                                 i += 1;
4848                         if (IsStatic)
4849                                 i += 2;
4850                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4851                                 i += 4;
4852                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4853
4854                         return null;
4855                 }
4856
4857                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4858                 {
4859                         IVariable var = InstanceExpression as IVariable;
4860                         if ((var != null) && (var.VariableInfo != null))
4861                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4862
4863                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4864                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4865
4866                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4867
4868                         if (e == null)
4869                                 return null;
4870
4871                         FieldBase fb = TypeManager.GetField (FieldInfo);
4872                         if (fb != null)
4873                                 fb.SetAssigned ();
4874
4875                         if (FieldInfo.IsInitOnly) {
4876                                 // InitOnly fields can only be assigned in constructors or initializers
4877                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4878                                         return Report_AssignToReadonly (right_side);
4879
4880                                 if (ec.IsConstructor) {
4881                                         Type ctype = ec.TypeContainer.CurrentType;
4882                                         if (ctype == null)
4883                                                 ctype = ec.ContainerType;
4884
4885                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4886                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4887                                                 return Report_AssignToReadonly (right_side);
4888                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4889                                         if (IsStatic && !ec.IsStatic)
4890                                                 return Report_AssignToReadonly (right_side);
4891                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4892                                         if (!IsStatic && !(InstanceExpression is This))
4893                                                 return Report_AssignToReadonly (right_side);
4894                                 }
4895                         }
4896
4897                         if (right_side == EmptyExpression.OutAccess &&
4898                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4899                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4900                                 Report.Warning (197, 1, loc,
4901                                                 "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",
4902                                                 GetSignatureForError ());
4903                         }
4904
4905                         return this;
4906                 }
4907
4908                 public override void CheckMarshalByRefAccess (EmitContext ec)
4909                 {
4910                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4911                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4912                                 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",
4913                                                 GetSignatureForError ());
4914                         }
4915                 }
4916
4917                 public bool VerifyFixed ()
4918                 {
4919                         IVariable variable = InstanceExpression as IVariable;
4920                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4921                         // We defer the InstanceExpression check after the variable check to avoid a
4922                         // separate null check on InstanceExpression.
4923                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4924                 }
4925
4926                 public override int GetHashCode ()
4927                 {
4928                         return FieldInfo.GetHashCode ();
4929                 }
4930
4931                 public override bool Equals (object obj)
4932                 {
4933                         FieldExpr fe = obj as FieldExpr;
4934                         if (fe == null)
4935                                 return false;
4936
4937                         if (FieldInfo != fe.FieldInfo)
4938                                 return false;
4939
4940                         if (InstanceExpression == null || fe.InstanceExpression == null)
4941                                 return true;
4942
4943                         return InstanceExpression.Equals (fe.InstanceExpression);
4944                 }
4945
4946                 public void Emit (EmitContext ec, bool leave_copy)
4947                 {
4948                         ILGenerator ig = ec.ig;
4949                         bool is_volatile = false;
4950
4951                         FieldBase f = TypeManager.GetField (FieldInfo);
4952                         if (f != null){
4953                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4954                                         is_volatile = true;
4955
4956                                 f.SetMemberIsUsed ();
4957                         }
4958
4959                         if (FieldInfo.IsStatic){
4960                                 if (is_volatile)
4961                                         ig.Emit (OpCodes.Volatile);
4962
4963                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4964                         } else {
4965                                 if (!prepared)
4966                                         EmitInstance (ec, false);
4967
4968                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4969                                 if (ff != null) {
4970                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4971                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4972                                 } else {
4973                                         if (is_volatile)
4974                                                 ig.Emit (OpCodes.Volatile);
4975
4976                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4977                                 }
4978                         }
4979
4980                         if (leave_copy) {
4981                                 ec.ig.Emit (OpCodes.Dup);
4982                                 if (!FieldInfo.IsStatic) {
4983                                         temp = new LocalTemporary (this.Type);
4984                                         temp.Store (ec);
4985                                 }
4986                         }
4987                 }
4988
4989                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4990                 {
4991                         FieldAttributes fa = FieldInfo.Attributes;
4992                         bool is_static = (fa & FieldAttributes.Static) != 0;
4993                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4994                         ILGenerator ig = ec.ig;
4995
4996                         if (is_readonly && !ec.IsConstructor){
4997                                 Report_AssignToReadonly (source);
4998                                 return;
4999                         }
5000
5001                         //
5002                         // String concatenation creates a new string instance
5003                         //
5004                         prepared = prepare_for_load && !(source is StringConcat);
5005                         EmitInstance (ec, prepared);
5006
5007                         source.Emit (ec);
5008                         if (leave_copy) {
5009                                 ec.ig.Emit (OpCodes.Dup);
5010                                 if (!FieldInfo.IsStatic) {
5011                                         temp = new LocalTemporary (this.Type);
5012                                         temp.Store (ec);
5013                                 }
5014                         }
5015
5016                         FieldBase f = TypeManager.GetField (FieldInfo);
5017                         if (f != null){
5018                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
5019                                         ig.Emit (OpCodes.Volatile);
5020
5021                                 f.SetAssigned ();
5022                         }
5023
5024                         if (is_static)
5025                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
5026                         else
5027                                 ig.Emit (OpCodes.Stfld, FieldInfo);
5028
5029                         if (temp != null) {
5030                                 temp.Emit (ec);
5031                                 temp.Release (ec);
5032                         }
5033                 }
5034
5035                 public override void Emit (EmitContext ec)
5036                 {
5037                         Emit (ec, false);
5038                 }
5039
5040                 public void AddressOf (EmitContext ec, AddressOp mode)
5041                 {
5042                         ILGenerator ig = ec.ig;
5043
5044                         FieldBase f = TypeManager.GetField (FieldInfo);
5045                         if (f != null){
5046                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
5047                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
5048                                                         f.GetSignatureForError ());
5049                                 }
5050
5051                                 if ((mode & AddressOp.Store) != 0)
5052                                         f.SetAssigned ();
5053                                 if ((mode & AddressOp.Load) != 0)
5054                                         f.SetMemberIsUsed ();
5055                         }
5056
5057                         //
5058                         // Handle initonly fields specially: make a copy and then
5059                         // get the address of the copy.
5060                         //
5061                         bool need_copy;
5062                         if (FieldInfo.IsInitOnly){
5063                                 need_copy = true;
5064                                 if (ec.IsConstructor){
5065                                         if (FieldInfo.IsStatic){
5066                                                 if (ec.IsStatic)
5067                                                         need_copy = false;
5068                                         } else
5069                                                 need_copy = false;
5070                                 }
5071                         } else
5072                                 need_copy = false;
5073
5074                         if (need_copy){
5075                                 LocalBuilder local;
5076                                 Emit (ec);
5077                                 local = ig.DeclareLocal (type);
5078                                 ig.Emit (OpCodes.Stloc, local);
5079                                 ig.Emit (OpCodes.Ldloca, local);
5080                                 return;
5081                         }
5082
5083
5084                         if (FieldInfo.IsStatic){
5085                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
5086                         } else {
5087                                 if (!prepared)
5088                                         EmitInstance (ec, false);
5089                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
5090                         }
5091                 }
5092         }
5093
5094
5095         /// <summary>
5096         ///   Expression that evaluates to a Property.  The Assign class
5097         ///   might set the `Value' expression if we are in an assignment.
5098         ///
5099         ///   This is not an LValue because we need to re-write the expression, we
5100         ///   can not take data from the stack and store it.
5101         /// </summary>
5102         public class PropertyExpr : MemberExpr, IAssignMethod {
5103                 public readonly PropertyInfo PropertyInfo;
5104                 MethodInfo getter, setter;
5105                 bool is_static;
5106
5107                 bool resolved;
5108
5109                 LocalTemporary temp;
5110                 bool prepared;
5111
5112                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5113                 {
5114                         PropertyInfo = pi;
5115                         eclass = ExprClass.PropertyAccess;
5116                         is_static = false;
5117                         loc = l;
5118
5119                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5120
5121                         ResolveAccessors (container_type);
5122                 }
5123
5124                 public override string Name {
5125                         get {
5126                                 return PropertyInfo.Name;
5127                         }
5128                 }
5129
5130                 public override bool IsInstance {
5131                         get {
5132                                 return !is_static;
5133                         }
5134                 }
5135
5136                 public override bool IsStatic {
5137                         get {
5138                                 return is_static;
5139                         }
5140                 }
5141
5142                 public override Expression CreateExpressionTree (EmitContext ec)
5143                 {
5144                         if (IsSingleDimensionalArrayLength ()) {
5145                                 ArrayList args = new ArrayList (1);
5146                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5147                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5148                         }
5149
5150                         // TODO: it's waiting for PropertyExpr refactoring
5151                         //ArrayList args = new ArrayList (2);
5152                         //args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5153                         //args.Add (getter expression);
5154                         //return CreateExpressionFactoryCall ("Property", args);
5155                         return base.CreateExpressionTree (ec);
5156                 }
5157
5158                 public Expression CreateSetterTypeOfExpression ()
5159                 {
5160                         return new Cast (new TypeExpression (typeof (MethodInfo), loc), new TypeOfMethod (setter, loc));
5161                 }
5162
5163                 public override Type DeclaringType {
5164                         get {
5165                                 return PropertyInfo.DeclaringType;
5166                         }
5167                 }
5168
5169                 public override string GetSignatureForError ()
5170                 {
5171                         return TypeManager.GetFullNameSignature (PropertyInfo);
5172                 }
5173
5174                 void FindAccessors (Type invocation_type)
5175                 {
5176                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5177                                 BindingFlags.Static | BindingFlags.Instance |
5178                                 BindingFlags.DeclaredOnly;
5179
5180                         Type current = PropertyInfo.DeclaringType;
5181                         for (; current != null; current = current.BaseType) {
5182                                 MemberInfo[] group = TypeManager.MemberLookup (
5183                                         invocation_type, invocation_type, current,
5184                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5185
5186                                 if (group == null)
5187                                         continue;
5188
5189                                 if (group.Length != 1)
5190                                         // Oooops, can this ever happen ?
5191                                         return;
5192
5193                                 PropertyInfo pi = (PropertyInfo) group [0];
5194
5195                                 if (getter == null)
5196                                         getter = pi.GetGetMethod (true);
5197
5198                                 if (setter == null)
5199                                         setter = pi.GetSetMethod (true);
5200
5201                                 MethodInfo accessor = getter != null ? getter : setter;
5202
5203                                 if (!accessor.IsVirtual)
5204                                         return;
5205                         }
5206                 }
5207
5208                 //
5209                 // We also perform the permission checking here, as the PropertyInfo does not
5210                 // hold the information for the accessibility of its setter/getter
5211                 //
5212                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5213                 void ResolveAccessors (Type container_type)
5214                 {
5215                         FindAccessors (container_type);
5216
5217                         if (getter != null) {
5218                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5219                                 IMethodData md = TypeManager.GetMethod (the_getter);
5220                                 if (md != null)
5221                                         md.SetMemberIsUsed ();
5222
5223                                 is_static = getter.IsStatic;
5224                         }
5225
5226                         if (setter != null) {
5227                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5228                                 IMethodData md = TypeManager.GetMethod (the_setter);
5229                                 if (md != null)
5230                                         md.SetMemberIsUsed ();
5231
5232                                 is_static = setter.IsStatic;
5233                         }
5234                 }
5235
5236                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5237                 {
5238                         if (is_static) {
5239                                 InstanceExpression = null;
5240                                 return true;
5241                         }
5242
5243                         if (InstanceExpression == null) {
5244                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5245                                 return false;
5246                         }
5247
5248                         InstanceExpression = InstanceExpression.DoResolve (ec);
5249                         if (lvalue_instance && InstanceExpression != null)
5250                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5251
5252                         if (InstanceExpression == null)
5253                                 return false;
5254
5255                         InstanceExpression.CheckMarshalByRefAccess (ec);
5256
5257                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5258                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5259                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5260                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5261                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5262                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5263                                 return false;
5264                         }
5265
5266                         return true;
5267                 }
5268
5269                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5270                 {
5271                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5272                         if (mi is MethodBuilder) {
5273                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5274                                 return;
5275                         }
5276
5277                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5278                         sig.Append ('.');
5279                         ParameterData iparams = TypeManager.GetParameterData (mi);
5280                         sig.Append (getter ? "get_" : "set_");
5281                         sig.Append (Name);
5282                         sig.Append (iparams.GetSignatureForError ());
5283
5284                         Report.SymbolRelatedToPreviousError (mi);
5285                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5286                                 Name, sig.ToString ());
5287                 }
5288
5289                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5290                 {
5291                         bool dummy;
5292                         MethodInfo accessor = lvalue ? setter : getter;
5293                         if (accessor == null && lvalue)
5294                                 accessor = getter;
5295                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5296                 }
5297
5298                 bool IsSingleDimensionalArrayLength ()
5299                 {
5300                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5301                                 return false;
5302
5303                         string t_name = InstanceExpression.Type.Name;
5304                         int t_name_len = t_name.Length;
5305                         return t_name_len > 2 && t_name [t_name_len - 2] == '[' && t_name [t_name_len - 3] != ']';
5306                 }
5307
5308                 override public Expression DoResolve (EmitContext ec)
5309                 {
5310                         if (resolved)
5311                                 return this;
5312
5313                         if (getter != null){
5314                                 if (TypeManager.GetParameterData (getter).Count != 0){
5315                                         Error_PropertyNotFound (getter, true);
5316                                         return null;
5317                                 }
5318                         }
5319
5320                         if (getter == null){
5321                                 //
5322                                 // The following condition happens if the PropertyExpr was
5323                                 // created, but is invalid (ie, the property is inaccessible),
5324                                 // and we did not want to embed the knowledge about this in
5325                                 // the caller routine.  This only avoids double error reporting.
5326                                 //
5327                                 if (setter == null)
5328                                         return null;
5329
5330                                 if (InstanceExpression != EmptyExpression.Null) {
5331                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5332                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5333                                         return null;
5334                                 }
5335                         }
5336
5337                         bool must_do_cs1540_check = false;
5338                         if (getter != null &&
5339                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5340                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5341                                 if (pm != null && pm.HasCustomAccessModifier) {
5342                                         Report.SymbolRelatedToPreviousError (pm);
5343                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5344                                                 TypeManager.CSharpSignature (getter));
5345                                 }
5346                                 else {
5347                                         Report.SymbolRelatedToPreviousError (getter);
5348                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5349                                 }
5350                                 return null;
5351                         }
5352
5353                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5354                                 return null;
5355
5356                         //
5357                         // Only base will allow this invocation to happen.
5358                         //
5359                         if (IsBase && getter.IsAbstract) {
5360                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5361                                 return null;
5362                         }
5363
5364                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5365                                 UnsafeError (loc);
5366                                 return null;
5367                         }
5368
5369                         resolved = true;
5370
5371                         return this;
5372                 }
5373
5374                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5375                 {
5376                         if (right_side == EmptyExpression.OutAccess) {
5377                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5378                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5379                                             PropertyInfo.Name);
5380                                 } else {
5381                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5382                                               GetSignatureForError ());
5383                                 }
5384                                 return null;
5385                         }
5386
5387                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5388                                 Error_CannotModifyIntermediateExpressionValue (ec);
5389                         }
5390
5391                         if (setter == null){
5392                                 //
5393                                 // The following condition happens if the PropertyExpr was
5394                                 // created, but is invalid (ie, the property is inaccessible),
5395                                 // and we did not want to embed the knowledge about this in
5396                                 // the caller routine.  This only avoids double error reporting.
5397                                 //
5398                                 if (getter == null)
5399                                         return null;
5400                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5401                                               GetSignatureForError ());
5402                                 return null;
5403                         }
5404
5405                         if (TypeManager.GetParameterData (setter).Count != 1){
5406                                 Error_PropertyNotFound (setter, false);
5407                                 return null;
5408                         }
5409
5410                         bool must_do_cs1540_check;
5411                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5412                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5413                                 if (pm != null && pm.HasCustomAccessModifier) {
5414                                         Report.SymbolRelatedToPreviousError (pm);
5415                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5416                                                 TypeManager.CSharpSignature (setter));
5417                                 }
5418                                 else {
5419                                         Report.SymbolRelatedToPreviousError (setter);
5420                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5421                                 }
5422                                 return null;
5423                         }
5424
5425                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5426                                 return null;
5427
5428                         //
5429                         // Only base will allow this invocation to happen.
5430                         //
5431                         if (IsBase && setter.IsAbstract){
5432                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5433                                 return null;
5434                         }
5435
5436                         return this;
5437                 }
5438
5439                 public override void Emit (EmitContext ec)
5440                 {
5441                         Emit (ec, false);
5442                 }
5443
5444                 public void Emit (EmitContext ec, bool leave_copy)
5445                 {
5446                         //
5447                         // Special case: length of single dimension array property is turned into ldlen
5448                         //
5449                         if (IsSingleDimensionalArrayLength ()) {
5450                                 if (!prepared)
5451                                         EmitInstance (ec, false);
5452                                 ec.ig.Emit (OpCodes.Ldlen);
5453                                 ec.ig.Emit (OpCodes.Conv_I4);
5454                                 return;
5455                         }
5456
5457                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5458
5459                         if (leave_copy) {
5460                                 ec.ig.Emit (OpCodes.Dup);
5461                                 if (!is_static) {
5462                                         temp = new LocalTemporary (this.Type);
5463                                         temp.Store (ec);
5464                                 }
5465                         }
5466                 }
5467
5468                 //
5469                 // Implements the IAssignMethod interface for assignments
5470                 //
5471                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5472                 {
5473                         Expression my_source = source;
5474
5475                         if (prepare_for_load) {
5476                                 if (source is StringConcat)
5477                                         EmitInstance (ec, false);
5478                                 else
5479                                         prepared = true;
5480
5481                                 source.Emit (ec);
5482
5483                                 prepared = true;
5484                                 if (leave_copy) {
5485                                         ec.ig.Emit (OpCodes.Dup);
5486                                         if (!is_static) {
5487                                                 temp = new LocalTemporary (this.Type);
5488                                                 temp.Store (ec);
5489                                         }
5490                                 }
5491                         } else if (leave_copy) {
5492                                 source.Emit (ec);
5493                                 temp = new LocalTemporary (this.Type);
5494                                 temp.Store (ec);
5495                                 my_source = temp;
5496                         }
5497
5498                         ArrayList args = new ArrayList (1);
5499                         args.Add (new Argument (my_source, Argument.AType.Expression));
5500
5501                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5502
5503                         if (temp != null) {
5504                                 temp.Emit (ec);
5505                                 temp.Release (ec);
5506                         }
5507                 }
5508         }
5509
5510         /// <summary>
5511         ///   Fully resolved expression that evaluates to an Event
5512         /// </summary>
5513         public class EventExpr : MemberExpr {
5514                 public readonly EventInfo EventInfo;
5515
5516                 bool is_static;
5517                 MethodInfo add_accessor, remove_accessor;
5518
5519                 public EventExpr (EventInfo ei, Location loc)
5520                 {
5521                         EventInfo = ei;
5522                         this.loc = loc;
5523                         eclass = ExprClass.EventAccess;
5524
5525                         add_accessor = TypeManager.GetAddMethod (ei);
5526                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5527                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5528                                 is_static = true;
5529
5530                         if (EventInfo is MyEventBuilder){
5531                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5532                                 type = eb.EventType;
5533                                 eb.SetUsed ();
5534                         } else
5535                                 type = EventInfo.EventHandlerType;
5536                 }
5537
5538                 public override string Name {
5539                         get {
5540                                 return EventInfo.Name;
5541                         }
5542                 }
5543
5544                 public override bool IsInstance {
5545                         get {
5546                                 return !is_static;
5547                         }
5548                 }
5549
5550                 public override bool IsStatic {
5551                         get {
5552                                 return is_static;
5553                         }
5554                 }
5555
5556                 public override Type DeclaringType {
5557                         get {
5558                                 return EventInfo.DeclaringType;
5559                         }
5560                 }
5561
5562                 void Error_AssignmentEventOnly ()
5563                 {
5564                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5565                                 GetSignatureForError ());
5566                 }
5567
5568                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5569                                                                 SimpleName original)
5570                 {
5571                         //
5572                         // If the event is local to this class, we transform ourselves into a FieldExpr
5573                         //
5574
5575                         if (EventInfo.DeclaringType == ec.ContainerType ||
5576                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5577                                 EventField mi = TypeManager.GetEventField (EventInfo);
5578
5579                                 if (mi != null) {
5580                                         if (!ec.IsInObsoleteScope)
5581                                                 mi.CheckObsoleteness (loc);
5582
5583                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5584                                                 Error_AssignmentEventOnly ();
5585
5586                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5587
5588                                         InstanceExpression = null;
5589
5590                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5591                                 }
5592                         }
5593
5594                         if (left is This && !ec.IsInCompoundAssignment)
5595                                 Error_AssignmentEventOnly ();
5596
5597                         return base.ResolveMemberAccess (ec, left, loc, original);
5598                 }
5599
5600
5601                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5602                 {
5603                         if (is_static) {
5604                                 InstanceExpression = null;
5605                                 return true;
5606                         }
5607
5608                         if (InstanceExpression == null) {
5609                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5610                                 return false;
5611                         }
5612
5613                         InstanceExpression = InstanceExpression.DoResolve (ec);
5614                         if (InstanceExpression == null)
5615                                 return false;
5616
5617                         if (IsBase && add_accessor.IsAbstract) {
5618                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5619                                 return false;
5620                         }
5621
5622                         //
5623                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5624                         // However, in the Event case, we reported a CS0122 instead.
5625                         //
5626                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5627                             InstanceExpression.Type != ec.ContainerType &&
5628                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5629                                 Report.SymbolRelatedToPreviousError (EventInfo);
5630                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5631                                 return false;
5632                         }
5633
5634                         return true;
5635                 }
5636
5637                 public bool IsAccessibleFrom (Type invocation_type)
5638                 {
5639                         bool dummy;
5640                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5641                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5642                 }
5643
5644                 public override Expression CreateExpressionTree (EmitContext ec)
5645                 {
5646                         throw new NotSupportedException ();
5647                 }
5648
5649                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5650                 {
5651                         return DoResolve (ec);
5652                 }
5653
5654                 public override Expression DoResolve (EmitContext ec)
5655                 {
5656                         bool must_do_cs1540_check;
5657                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5658                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5659                                 Report.SymbolRelatedToPreviousError (EventInfo);
5660                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5661                                 return null;
5662                         }
5663
5664                         if (!InstanceResolve (ec, must_do_cs1540_check))
5665                                 return null;
5666
5667                         return this;
5668                 }
5669
5670                 public override void Emit (EmitContext ec)
5671                 {
5672                         Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5673                                       "(except on the defining type)", GetSignatureForError ());
5674                 }
5675
5676                 public override string GetSignatureForError ()
5677                 {
5678                         return TypeManager.CSharpSignature (EventInfo);
5679                 }
5680
5681                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5682                 {
5683                         BinaryDelegate source_del = source as BinaryDelegate;
5684                         if (source_del == null) {
5685                                 Emit (ec);
5686                                 return;
5687                         }
5688                         Expression handler = source_del.Right;
5689
5690                         Argument arg = new Argument (handler, Argument.AType.Expression);
5691                         ArrayList args = new ArrayList ();
5692
5693                         args.Add (arg);
5694
5695                         if (source_del.IsAddition)
5696                                 Invocation.EmitCall (
5697                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5698                         else
5699                                 Invocation.EmitCall (
5700                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5701                 }
5702         }
5703
5704         public class TemporaryVariable : Expression, IMemoryLocation
5705         {
5706                 LocalInfo li;
5707                 Variable var;
5708
5709                 public TemporaryVariable (Type type, Location loc)
5710                 {
5711                         this.type = type;
5712                         this.loc = loc;
5713                         eclass = ExprClass.Value;
5714                 }
5715
5716                 public override Expression DoResolve (EmitContext ec)
5717                 {
5718                         if (li != null)
5719                                 return this;
5720
5721                         TypeExpr te = new TypeExpression (type, loc);
5722                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5723                         if (!li.Resolve (ec))
5724                                 return null;
5725
5726                         if (ec.MustCaptureVariable (li)) {
5727                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5728                                 var = scope.AddLocal (li);
5729                                 type = var.Type;
5730                         }
5731
5732                         return this;
5733                 }
5734
5735                 public Variable Variable {
5736                         get { return var != null ? var : li.Variable; }
5737                 }
5738
5739                 public override void Emit (EmitContext ec)
5740                 {
5741                         Variable.EmitInstance (ec);
5742                         Variable.Emit (ec);
5743                 }
5744
5745                 public void EmitLoadAddress (EmitContext ec)
5746                 {
5747                         Variable.EmitInstance (ec);
5748                         Variable.EmitAddressOf (ec);
5749                 }
5750
5751                 public void Store (EmitContext ec, Expression right_side)
5752                 {
5753                         Variable.EmitInstance (ec);
5754                         right_side.Emit (ec);
5755                         Variable.EmitAssign (ec);
5756                 }
5757
5758                 public void EmitThis (EmitContext ec)
5759                 {
5760                         Variable.EmitInstance (ec);
5761                 }
5762
5763                 public void EmitStore (EmitContext ec)
5764                 {
5765                         Variable.EmitAssign (ec);
5766                 }
5767
5768                 public void AddressOf (EmitContext ec, AddressOp mode)
5769                 {
5770                         EmitLoadAddress (ec);
5771                 }
5772         }
5773
5774         ///
5775         /// Handles `var' contextual keyword; var becomes a keyword only
5776         /// if no type called var exists in a variable scope
5777         ///
5778         public class VarExpr : SimpleName
5779         {
5780                 // Used for error reporting only
5781                 ArrayList initializer;
5782
5783                 public VarExpr (Location loc)
5784                         : base ("var", loc)
5785                 {
5786                 }
5787
5788                 public ArrayList VariableInitializer {
5789                         set {
5790                                 this.initializer = value;
5791                         }
5792                 }
5793
5794                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5795                 {
5796                         if (type != null)
5797                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5798
5799                         type = right_side.Type;
5800                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5801                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5802                                               right_side.GetSignatureForError ());
5803                                 return null;
5804                         }
5805
5806                         eclass = ExprClass.Variable;
5807                         return this;
5808                 }
5809
5810                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5811                 {
5812                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5813                 }
5814
5815                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5816                 {
5817                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5818                         if (te != null)
5819                                 return te;
5820
5821                         if (initializer == null)
5822                                 return null;
5823
5824                         if (initializer.Count > 1) {
5825                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5826                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5827                                 initializer = null;
5828                                 return null;
5829                         }
5830
5831                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5832                         if (variable_initializer == null) {
5833                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5834                                 return null;
5835                         }
5836
5837                         return null;
5838                 }
5839         }
5840 }